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Agradecimentos: The authors acknowledge the support provided by São Paulo Research Foundation (FAPESP) (Grants 2018/10492-1 and 2018/16360-0) and by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001 Abstract: The Zn0.5Cd0.5S/ZnO/carbon xerogel photocatalyst was synthesized through the thermal treatment of ZnO, CdS, and a low-cost carbon xerogel matrix at high temperature (600 degrees C). ZnO is one of the most widely used photocatalysts, but it has low visible-light absorption, while Zn0.5Cd0.5S is a visible-light active photocatalyst, which can be used as a co-catalyst to enhance photoactivity under natural radiation and promote charge separation through the creation of Z-scheme heteroj unctions. The further addition of the carbon xerogel can be justified by its highly developed porous structure and ability to capture photogenerated electrons, which will also promote charge separation. The creation of the hexagonal Zn0.5Cd0.5S and ZnO phases was confirmed through the X-ray diffractometry technique. The addition of the carbon xerogel led to an increase in the specific surface area of the XC/ZnO (630%) and XC/ZnO-Zn0.5Cd0.5S (320%) and a decrease in particle size when compared to the pure ZnO. Regarding the photocatalytic performance of the materials, the Zn0.5Cd0.5S/ZnO/carbon xerogel displayed an enhanced photocatalytic activity for 4-chlorophenol degradation, with 84% degradation after 300 minutes of artificial solar irradiation. The enhanced photoactivity of the Zn0.5Cd0.5S/ZnO/carbon xerogel composite was further confirmed by chronoamperometry, as the composite presented higher photocurrent generation under light irradiation FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Aberto

Agradecimentos: This work was supported by FAPESP (grant numbers 2007/54829-5, 2007/08244-5), CNPq (grant numbers 482390/2012-3 and 308717/2012-0), and CAPES from Brazil. S.F. gratefully acknowledges FAPESP studentship 2012/16860-8. MJP is thankful for the funding provided by the FAPESP grant 2011/12566-3 Abstract: The coverage-dependent self-assembly of Nickel-tetraphenyl porphyins on Gold vicinal surfaces was studied by scanning tunneling microscopy. On Au(788) the molecular self-assembly is square-shaped, following the molecular symmetry. On Au(332) the molecules nucleate in a parallelogram lattice for monolayer coverage and in a squared lattice for multilayer coverage. Depending on the vicinal surface the molecules adopt either a saddle shaped or a more planar conformation. The experiments demonstrate that crystallographic direction, terrace sizes and coverage are important in establishing different assembly geometries FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors are grateful to Capes and UFTM and Horiba LabRAM HR Evolution Raman microscope at the Institute of Physics/Federal University of Uberlândia/Brazil supported by the grant ‘Pró-Equipamentos’ from the Brazilian Agency CAPES. Rogério V. Gelamo would like to thank the National Council of Technological and Scientific Development (CNPq) (Grant 440726/2020-4 and 302582/2021-5), Fapemig (Grant APQ-01359-21), the Brazilian Institute of Science and Technology (INCT) in Carbon Nanomaterials and Nacional de Grafite Ltda for the financial and material support for the current study. J. A. Moreto would like to thank the National Council of Technological and Scientific Development (CNPq) (Grant 303659/2019-0 and 402988/2021-3), and Francisco Rouxinol and Abner de Siervo are supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) under Grant Nos. 2017/08602-0, 2007/08244-5, and 2021/08409-1 Abstract: Flexible self-standing supercapacitor devices (FSSS) have attracted great attention in several areas due to their potential use in a wide range of applications, such as roll-up displays, wearable electronics, and storage energy devices. However, the success of FSSS devices is highly dependent on their electrochemical properties. Here, we presented an innovative process for the preparation of novel low-cost ionic gel and superficial CO2 plasma treatment to modify electrodes based on multiwall carbon nanotubes (MWCNT) and multilayer graphene (MLG). The hybrid supercapacitors were characterized morphologically and structurally via scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. To assess the electrochemical properties, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy were used. The morphological results showed that the new CO2 plasma treatment promoted a better distribution of the carbon components, improving the contact area between the electrolyte and the electrode surface. Electrochemical tests demonstrated excellent behavior of the electrolyte gel, with specific capacitances of 256 mF cm(-2) and 603 F g(-1), energy and power densities of 24.03 mu Wh cm(-2) and 2.16 mW cm(-2), respectively. Additionally, the CNT incorporation on the MLG electrodes and the plasma treatment were important factors to produce flexible supercapacitors fashion. The MLG + MWCNT pure and plasma treated appeared as remarkable material for flexible high-performance energy storage devices COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors gratefully acknowledge financial support from São Paulo Research Foundation – FAPESP (JCP, awards No. 2014/26378-2, 2014/25770-6 and 2020/11578-7), and the Coordination for the Improvement of Higher Education Personnel – CAPES (PNPD No. 88887.466571/2019-00; R. G.) Abstract: In the present work, a new humins-like resin was prepared using 2,5-bis(hydroxymethyl)furan (DHMF) and maleic anhydride in 2 min at 110 degrees C. Such a new material was used as a solid support for palladium immobilization. For metal anchoring, encapsulation was the method of choice and palladium was encapsulated by in-situ polymerization. This resulting Pd@DHMF-based catalyst was characterized by solid-state C-13 NMR, FT-IR, SEM, TGA, DSC, XRD, and XPS. To demonstrate proof of concept, Heck and Suzuki cross-coupling reactions were selected to evaluate the activity and reusability of the catalyst. Green solvents such as gamma-valerolactone (GVL), Cyrene (TM) and ethylene carbonate proved to be excellent reaction media for Heck coupling, whereas EtOH/H2O was preferred for Suzuki coupling. Yields of up to 99 % were obtained in both cases. The recyclability of the Pd@DHMF-based catalyst was also demonstrated, 7 cycles have been achieved without loss of catalytic activity in both Heck and Suzuki reactions FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The authors thankfully acknowledge the financial support provided by São Paulo Research Foundation (FAPESP) (Grants 2018/10492-1, 2018/16360-0, 2007/08244-5, 2007/54829-5, 2017/18574-4, 2017/10118-0, and 2014/50945-4) and by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Grants 465571/2014-0, 302874/2017-8, and 427452/2018-0) Abstract: Recently, the release of antibiotics, such as sulfonamides, into the environment has raised significant concern due to the potential creation of antibiotic-resistant bacteria. Thus, the development of remediation technologies for effluents containing such compounds is of utmost urgency. In this context, this work evaluated the creation of a resorcinol-based carbon xerogel/zinc oxide photocatalyst (XC/ZnO) to efficiently promote the photodegradation of the antibiotic known as sulfamerazine in aqueous media. The employment of this carbonaceous structure as a co-catalyst is justified by its high surface area and electrical conductivity. The methodology used in the synthesis of the composites was a simple one-pot reaction, combining the simultaneous precipitation of zinc oxide and polycondensation of the resorcinol-based carbon gel. Regarding the composites' characterization, X-ray diffractometry confirms that the composites have the Wurtzite structure of the zinc oxide, whereas the carbon xerogel formation is evidenced by the infrared, diffuse reflectance, and X-ray photoelectron spectroscopies. Morphology-wise, the XC/ZnO is arranged as nodular particle agglomerates, with particles between 500 nm and 50 nm. The photocatalytic tests under simulated solar radiation show that the composites developed are superior to the pure oxide in the photodegradation of sulfamerazine, as all XC/ZnO materials developed achieved higher apparent reaction rate constants (kapp) than pure zinc oxide, with the XC/ZnO 0.5 material obtaining a kapp 75% higher than the one observed for the ZnO sample. Furthermore, the chronoamperometry tests confirmed that the optimized composite (XC/ZnO 0.5) has a greater capacity for photocurrent generation when compared to pure zinc oxide. Therefore, the modification proposed was successful to enhance the photodegradation of sulfamerazine in aqueous media, highlighting the viability of the composites developed for photocatalytic applications FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This work was supported by the Brazilian research agencies Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP (proposals 2017/18574-4 and 2017/25983-8), Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq (Grants 310774/2020-9 (AP), 304119/2019-9 (AS), and 302450/2017-3 (PAPN), and CNPEM/LNLS Abstract: The surface composition of a (root 5 x root 5)-R26.6 degrees (Rt5) reconstruction of a strontium titanate (001) single crystal surface was characterized by X-ray photoelectron spectroscopy (XPS), and its atomic surface structure was determined by a combination of low energy electron diffraction (LEED) and X-ray photoelectron diffraction (XPD). The comparison between experimental and theoretical XPD results involving multiple scattering calculations indicated that the analyzed Rt5 reconstruction of the SrTiO3 (001) surface has two possible terminations: 40% of SrO and 60% of TiO2 FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Orientador: Richard Landers Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica "Gleb Wataghin" Resumo: Neste trabalho propomos estudar os mecanismos de emissão de elétrons usando as técnicas de XPS (X-Ray Photoelectron Spectroscopy) and XAES (X-Ray excited Auger Electron Spectroscopy), cujo estado inicial pertence a níveis de caroço (mais especificamente da camada L) nos metais de 5º período, incluindo Nb, Mo, Ru, Rh, Pd, Ag, In, Sn e Sb. Usamos os espectros de XPS para determinar algumas das características do estado inicial: como energia de ligação, tempo de vida (através da largura de linha), e em alguns casos caracterizar o tipo de relaxação do mesmo. No caso dos espectros Auger, fizemos um estudo sistemático das transições LMM e LMN. Estudamos a formação de satélites; caracterizando a sua natureza e origem, nos limites da aproximação abrupta e adiabática usando como fonte de excitação raios-x convencionais (Ka Ti) e radiação síncroton. No caso das transições envolvendo apenas níveis de caroço, podemos considerá-las como quase atômicas; desta forma, fazemos também um modelamento da parte atômica destas transições usando cálculos com aproximação de camadas fechadas nos esquemas de acoplamento jj-LS e jj-IC, verificando aplicabilidade dos mesmos ao longo da série. No caso das transições LMN, onde uma vacância do estado final pertence à banda de valência, usamos o cálculo para verificar se o limite da aproximação de transição quase atômica ainda era aplicável Abstract: Not informed Mestrado Física Mestre em Física

Orientadores: Richard Landers, George G. Kleiman Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo: As propriedades físico-químicas de um material, como uma liga metálica, podem ser entendidas como uma função da sua estrutura eletrônica e das posições relativas entre os átomos. A superfície representa um caso particular, e a quebra da periodicidade em uma direção pode provocar mudanças estruturais e eletrônicas importantes que afetam as propriedades do material. É particularmente importante conhecer a posição dos átomos na rede cristalina. No volume de um material isto pode ser feito através de técnicas consagradas como difração de raios-x; contudo, para a superfície esta tarefa é muito mais complicada. No caso de ligas de superfície estas apresentam-se como novos materiais e desenvolvem um grande interesse do ponto de vista acadêmico e aplicado. Este trabalho apresenta uma investigação da estrutura eletrônica e cristalográfica de ligas de superfície a partir de filmes finos crescidos por MBE sobre superfícies monocristalinas bem caracterizadas. A caracterização da dinâmica de crescimento dos filmes foi feita por XPS e RHEED; e na determinação estrutural das ligas utilizou-se LEED (qualitativo) e Difração de Fotoelétrons. Para o caso de liga ordenada de superfície também é apresentado a determinação estrutural por cálculos de primeiros princípios usando a Teoria do Funcional-Densidade. Nesta dissertação são apresentados os casos de Pd sobre Cu(111), Cu sobrePd(111) e Sb sobre Pd(111) Abstract: The physico-chemical properties of a material, such as a metallic alloy, can be understood as a function of its electronic structure and the relative positions between its atoms. The surface is a particular case in the material, due to the break of periodicity in the direction perpendicular to the surface this can affect the structural and electronic properties of the material. It is particularly important to know the position of the atoms in the crystalline lattice. In the bulk of a material this can be measured using techniques such as rays-x diffraction. For the surface this task is much more complicated. Surface alloys represent new materials and their development is of great interest both from the academic and technological point of view. The present body of work presents a study of the electronic and geometric structure of surface alloys; grown by MBE on well-characterized monocrystalline surfaces. XPS and RHEED were used to characterize the dynamics of growth, and LEED (qualitative) and Photoelectron Diffraction did the structural determination of surface alloys. For the particular case of ordered surface alloys we also present a theoretical first principles structural determination using Density Functional-Theory. This dissertation shows three systems: Pd on Cu(111), Cu on Pd(111) and Sb on Pd(111) Doutorado Física Doutor em Ciências

Agradecimentos: The authors acknowledge the support provided by São Paulo Research Foundation (FAPESP) (Grants 2018/10492-1, 2019/03641-3, 2018/16360-0, 2007/08244-5, 2007/54829-5, and 2017/18574-4) and by Tanac S.A. Abstract: This work aimed to evidence the potential use of tannin-based carbon xerogel as a co-catalyst in photocatalytic processes based on solar light. Specifically, the tin (IV) oxide/carbon xerogel photocatalyst (SnO2/XC) was developed with the objective of improving the photoactivity of tin (IV) oxide (SnO2) under simulated solar light. The photocatalytic efficiency was determined by the degradation of the 4-chlorophenol molecule. The synthesis proposed in this work is based on a simple one-pot precipitation reaction, using black wattle tannin and tin chloride as precursors. The materials synthesized were characterized by X-ray diffractometry, diffuse reflectance spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, scanning electron microscopy, adsorption isotherms, and chronoamperometry. Results showed the presence of tetragonal SnO2 in the samples synthesized. Carbon xerogel addition led to an increased specific surface area (55% higher) and lower bandgap energy (from 3.64?eV to 3.58?eV). The photocatalytic evaluation shows that the SnO2/XC composite has superior photocatalytic efficiency (44% removal vs 20% for the SnO2), obtaining a reaction rate constant (kapp = 0.00172?min-1) which is nearly double the one obtained by the pure SnO2 (kapp = 0.00096?min-1). The chronoamperometric results indicated that the proposed modification enhanced the photocurrent generation and charge separation in the SnO2/XC, facilitating the formation of active radicals during the process and further degrading the reaction intermediates formed during the photodegradation process FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was supported by the Sao Paulo Research Foundation (FAPESP processes 2007/08244-5, 2007/54829-5, 2017/18574-4, 2018/16896-7, 2017/13137-5, and 2020/00325-0) by the National Council for Scientific and Technological Development (CNPq Processes 307271/2017-0 and 311847/2018-8), INCTBio (CNPq grant no. 465389/2014-7), and INCT/Fapesp (Process 2014/50867-3). We also thank Prof. Koiti Araki (Laboratório de Química Supramolecular e Nanotecnologia, IQ-USP) and SisNANO-USP for the use of XRD facility, and Brazilian Nanotechnology National Laboratory-LNNano@CNPEM that granted access to the TEM facility. The authors are grateful to Professor Joseph Wang for allowing them to print the SPEs electrodes at his semi-automatic MMP-SPM screen printer (Speedline Technologies, Franklin, MA, USA). Abstract: Multifunctional nanomaterials have been attracting increasing attention as solutions to the existing challenges in energy systems and sensing technologies. In this regard, multifunctional NiVCe-layered double hydroxide (NiVCe-LDH) nanoparticles were synthesized by the modified sol-gel method. The analysis of this material demonstrated excellent potential for its utilization as electrode materials for hybrid supercapacitor, oxygen evolution reaction (OER), and sensor applications. The NiVCe-LDH nanoparticles delivered a specific charge of 740 C g(-1) at 10 A g(-1) and decent rate performance (charge retention of 68.7% at 100 A g(-1)), showing excellent prospects as electrode material for hybrid energy storage devices. In addition, NiVCe-LDH nanoparticles have also been successfully applied as a proof-of-concept for OER, as confirmed by their low Tafel slope of 47 mV dec(-1). Finally, trimetallic NiVCe-LDH-based screen-printed electrodes were developed for the sensing of hydrogen peroxide directly in a real complex mouthwash sample, achieving a satisfactory recovery value of around 98% using a fast and simple batch injection analysis procedure. These results allow us to predict the great potential of this trimetallic hydroxide for building electrochemical sensors with good perspectives as electroactive material for OER processes and energy storage technologies FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: This research was supported by Sao Paulo Research Foundation (FAPESP) (Grant numbers: 2007/08244-5, 2007/54829-5, 2014/50867-3, 2017/18574-4, 2018/08782-1, 2018/14462-0 2018/16896-7, and 2020/00325-0), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (Pró-Forenses Edital 25/2014) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Grant Number: 305605/2017-8, 307172-2017-0, 311847/2018-8, 465389/2014-7 – INCTBio and 302839/2020-8). We would like to thank the undergraduate student Rodrigo Ramos for the help with the video recording. The authors are also grateful to Central Analítica (IQ/USP) for the SEM infrastructure. We would also like to thank Dr. Gabriel N. Meloni and Dr. Carla S. Santos for the graphical abstract illustration Abstract: 3D printing is the most popular form of additive manufacturing, and conductive 3D-printed platforms have been recognized as an emerging class of devices with high potential for electrochemistry. Nevertheless, as-printed electrodes provide poor conductivity due to the presence of high amounts of insulating thermoplastic material, requiring surface post-treatments to enhance their electrochemical performance. Such treatments often employ non-eco-friendly, costly, and time-consuming protocols. In this regard, we propose, for the first time, a sub-minute (around 50 s) and reagentless surface treatment of carbon-black/PLA-based 3D-printed electrodes using a Photo-Thermal approach by a CO2 laser. After the proposed treatment (optimized conditions: the power of 6.2%, the scan rate of 20 mm s-1, and height of 10 mm), a marked improvement in the electrochemical electrode response (current increase and peak-to-peak separation) was achieved towards the detection of catechol, ascorbic and uric acids, paracetamol, hexaammineruthenium(III) chloride, and Ferri/ferrocyanide redox couple. The enhanced simultaneous determination of Cd2+, Pb2+, and Cu2+ was also demonstrated. As a proof-of-concept, the quantification of the adulterant paracetamol in a real seized cocaine sample was performed using a fully 3D-printed electrochemical system, and a good recovery value of 97.8% was acquired. To explain all the improved results, the electrode was carefully characterized by imaging, spectroscopic and electrochemical techniques. Additionally, the between-measurement % relative standard deviation (%RSD) was 6.8% (n = 12), while the between-device %RSD was 7.5% (n = 6) at the 1 µmol L-1 paracetamol, indicating adequate manufacturing reproducibility. Thus, the strategies developed here open up new possibilities for applications of carbon-based 3D-printed electrodes in analytical electrochemistry FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This research was supported by Sao Paulo Research Foundation (FAPESP) (Grant numbers: 2007/08244-5, 2007/54829-5, 2014/50867-3, 2017/18574-4, 2018/14462-0, and 2020/00325-0), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (Pró-Forenses Edital 25/2014) and Conselho Nacional de Desenvolvimento Científco e Tecnológico (CNPq) (Grant Number: 305605/2017-8, 307172-2017-0, 311847/2018-8, 465389/2014-7 - INCTBio and 302839/2020-8) Abstract: For the first time the development of an electrochemical method for simultaneous quantification of Zn2+ and uric acid (UA) in sweat is described using an electrochemically treated 3D-printed working electrode. Sweat analysis can provide important information about metabolites that are valuable indicators of biological processes. Improved performance of the 3D-printed electrode was achieved after electrochemical treatment of its surface in an alkaline medium. This treatment promotes the PLA removal (insulating layer) and exposes carbon black (CB) conductive sites. The pH and the square-wave anodic stripping voltammetry technique were carefully adjusted to optimize the method. The peaks for Zn2+ and UA were well-defined at around - 1.1 V and + 0.45 V (vs. CB/PLA pseudo-reference), respectively, using the treated surface under optimized conditions. The calibration curve showed a linear range of 1 to 70 mu g L-1 and 1 to 70 mu mol L-1 for Zn2+ and UA, respectively. Relative standard deviation values were estimated as 4.8% (n = 10, 30 mu g L-1) and 6.1% (n = 10, 30 mu mol L-1) for Zn2+ and UA, respectively. The detection limits for Zn2+ and UA were 0.10 mu g L-1 and 0.28 mu mol L-1, respectively. Both species were determined simultaneously in real sweat samples, and the achieved recovery percentages were between 95 and 106% for Zn2+ and 82 and 108% for UA FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This study was financed in part by Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) (projects 2007/54829-5 and 2007/08244-5), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (Finance Code 001), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). A.C.S. and N.H.R thank CNPq for the scholarships. A.P.P. thanks UAEU for an internal start-up grant (No. 31S410). This work used the Imbabura cluster of Yachay Tech University, which was purchased under contract no. 2017-024 (SIE-UITEY-007-2017) Abstract: On-surface coupling reactions and molecular conformation are essential processes for building tailored functional molecular nanostructures. Here, we study the thermal debromination and reactivity of free-base tetra(4-bromophenyl) porphyrin (H2TBrPP) on Cu(111) as a function of the substrate temperature. It has been previously reported in the literature that C-Br bonds remain intact at room temperature (RT) and that the Br center dot center dot center dot Cu(111) interaction induces a drastic surface reconstruction around the molecule periphery and a distortion in the adsorbate itself. However, based on a combination of STM and XPS experiments, supported by density functional theory (DFT) calculations, we instead demonstrate that debromination readily occurs at RT, leading to a new interpretation of both the adsorption behavior and the molecular coupling of H2TBrPP on Cu(111). For the molecules deposited on the metallic substrate held above RT, our STM measurements show the growth of ordered 2D metal-organic frameworks (MOFs) FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: J. A. Moreto would like to acknowledge financial support received from the National Council of Technological and Scientific Development (CNPq), for grants 402142/2016-0 and 303659/2019-0; Coordination for the Improvement of Higher Education Personnel (CAPES), for grant 88881.336769/2019-01-PVEX and FAPEMIG for grant APQ-02276-18. A. Siervo would like to thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Project 2007/54829-5, 2007/08244-5, and 2017/18574-4. R. V. R. V. Gelamo would like to thank Instituto Nacional de Ciência e Tecnologia em Nanomateriais de Carbono and Companhia Brasileira de Metalurgia e Mineração (CBMM) and CNPq grant 440726/2020-4. All authors would like to thank professor Dr. Carlo José Freire for the laboratory facilities, Horiba LabRAM HR Evolution Raman microscope at the Institute of Physics (INFIS) supported by the grant ‘‘Pró-Equipamentos’’ from the Brazilian Agency CAPES and Chemistry Department (University of Uberlândia) for the SEM analysis Abstract: This paper proposes an applied and innovative research for the development of Nb2O5 thin film on the Ti6Al4V alloy surface with great prospects of being used in the biomedical area. Thin films of Nb2O5 have been deposited on the Ti6Al4V alloy surface by using the reactive sputtering technique. The system was characterized morphologically and structurally via SEM/EDX, AFM, FTIR, Raman spectroscopy and XPS. Interfacial tension theory was used for the determination of the surface free energy and showed that the treated surface became more hydrophilic when compared to the bare material. The high-resolution X-ray photoelectron spectra from Nb 3d and O 1s core-levels demonstrate unequivocally the presence of a single-phase Nb2O5. Cytotoxicity and biocompatibility (VERO-CCL-81 cell line) tests as well as analyzes of inflammatory responses with Human blood leukocyte cells were also performed by showing that Nb2O5 coating reduced both Ti6Al4V alloy toxicity and its inflammation induction besides increasing the anti-inflammatory cytokine levels. Since the surface functionalization resulted in both higher biocompatibility and tolerance by immune cells besides low inflammatory levels concerning the base material, we present a superior material with wide spectra of usage in the biomedical area CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This research was supported by CNPq (307172-2017-0; 427731/2018-6 and 465389/2014-7 – INCTBio), INCT-Nanocarbon, FAPEMIG (PPM-00640-16; PPM-00614-18; APQ-03141-18; RED-00042-16), Sao Paulo Research Foundation (FAPESP process 2020/00325-0; 2007/08244-5; 2007/54829-5 and 2017/18574-4), and CAPES (001) Abstract: Conductive 3D-printed platforms have been recognized an emerging class of materials with great potential to electrochemistry. However, such 3D-printed electrodes require a surface treatment to remove excess of polymer that hinders the electron transfer. We report a fast (2-min) and chemical-free protocol for the surface treatment of 3D-printed conductive electrodes based on reactive cold oxygen plasma. A dramatic improvement of electrochemical activity of 3D-printed carbon black-polylactic acid (CB-PLA) electrodes was verified by the decrease in the peak-to-peak separation of the voltammetric response for the [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) couple and in the resistance of change transfer. The O-2 plasma treatment increased oxide groups and graphitic groups at the CB-PLA surface (verified by XPS) and provided higher rugosity (SEM images) thus higher exposure of conducting carbon sites and increased electroactive area in comparison with CO2-plasma, which explains the improved electrochemical performance using O-2-plasma treated electrodes. This protocol is faster and provided improved electrochemical activity compared with electrochemical, chemical, or biological treatments. As proofs-of concept, the benefits of surface plasma treatment of the 3D-printed electrodes were demonstrated towards the electrochemical sensing of dopamine and nitrite, molecules of biological interest, including the analysis of human saliva. Values of sensitivity and detection limit were greatly improved when using O-2 plasma treatment for both molecules (up to 100-fold increase in sensitivity for the voltammetric detection of dopamine), suggesting great promises for the development of highly-sensitive electrochemical sensors CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The authors gratefully acknowledge funding by the German Research Foundation (DFG) through Research Unit FOR 1878 (funCOS), the Collaborative Research Center SFB 953 (project number 182849149) at the Friedrich-Alexander-Universität Erlangen-Nürnberg and São Paulo Research Foundation (FAPESP) through project numbers 2007/54829-5 and 2007/08244-5. M.L., J.K. and H.M are grateful for travel grants from DAAD. R.C.C.F. and A.S. are grateful for travel grants from CAPES (Brazil) under the Brazilian-German collaborative project PROBRAL (1925/2016). Open access funding enabled and organized by Projekt DEAL Abstract: We study the interaction and metalation reaction of a free base 5,10,15,20-terakis(4-cyanophenyl)porphyrin (2HTCNPP) with post-deposited Zn atoms and the targeted reaction product Zn-5,10,15,20-terakis(4-cyanophenyl)porphyrin (ZnTCNPP) on a Ag(111) surface. The investigations are performed with scanning tunneling microscopy at room temperature after Zn deposition and subsequent heating. The goal is to obtain further insights in the metalation reaction and the influence of the cyanogroups on this reaction. The interaction of 2HTCNPP with post-deposited Zn leads to the formation of three different 2D ordered island types that coexist on the surface. All contain a new species with a bright appearance, which increases with the amount of post-deposited Zn. We attribute this to metastable SAT ("sitting atop") complexes formed by Zn and the macrocycle, that is, an intermediate in the metalation reaction to ZnTCNPP, which occurs upon heating to 500 K. Interestingly, the activation barrier for the successive reaction of the SAT complex to the metalated ZnTCNPP species can also be overcome by a voltage pulse applied to the STM tip FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The author are thankful for the financial support from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) under the project numbers 2007/08244-5, 2007/54829-5, and 2017/18574-4 and from Conselho Nacional Científico e Tecnológico (CNPq) under the project numbers 424633/2018-3 and 304119/2019-9. N.H.R. thanks CNPq for the studentship support. L.H.d.L. thanks FAPESP for the studentship support under project number 2016/21402-8 Abstract: Monolayer hexagonal boron-nitrogen-carbon (h-BNC) is considered a prominent candidate for the next generation of semiconductor electronic devices. Nevertheless, experimental evidence of h-BNC formation is limited, including a detailed study of its morphological and electronic properties. Here, successful growth of h-BNC from an unexplored single molecular precursor (hexamethyl borazine, C6H18B3N3) using a conventional CVD approach on Ir(111) is reported. The conformation structure of the monolayer and its correlation with the local electronic properties are discussed based on scanning tunneling microscopy/spectroscopy (STM/STS) and X-ray photoelectron spectroscopy (XPS) results. The results show an h-BNC structure that can be described as BN-doped graphene since the moire ' lattice parameter is preserved along with the alloy. This BN-doped cluster, renamed as h-BN "nanodonuts" according to the electronic density exhibited in STM images, have a tendency to place specific positions within the moire superstructure, and it is constituted by at least (BN)(8) units arranged in a 6-fold BN rings conformation, as evidenced by simulation of STM images based on density functional theory (DFT). For a BN concentration of about 17%, a band gap between 1.4 and 1.6 eV was determined. The versatility of the novel molecular precursor is proven by the growth of a high-quality h-BN monolayer on Rh(111) FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors are grateful to CAPES, CNPq (Grant 440726/2020-4), FAPEMIG, the Brazilian Institute of Science and Technology (INCT) in Carbon Nanomaterials and Nacional de Grafite Ltda for the financial and material support for the current study. J. A. Moreto would like to thank the National Council of Technological and Scientific Development (CNPq) (Grant 303659/2019-0). A. Siervo would like to thank the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (Projects 2007/54829-5, 2007/08244-5, and 2017/18574-4) Abstract: The reactive plasma technique is often employed to activate the surface of materials both chemically and physically. Considering that several parameters should be handled in a plasma treatment process, a multivariate experimental design of three factors in two levels was employed to define the plasma treatment configurations under which the MLG were submitted. Plasma intensity, partial pressure of oxygen and reaction time were employed in the experimental planning. The surface morphology, the generation of C-C bond defects, surface chemical composition, interfacial free energy, and electrochemical properties were analyzed for the MLG electrodes as a function of the plasma treatment parameters. The treatments effectively promoted the MLG electrode's surface activation, considering the results obtained, which showed a dependence on those plasma treatment variables. The results suggested that plasma treatment variable adjustments can be used to modulate specific surface properties and with potential applicability in electrochemical sensors and supercapacitors COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The author thanks the financial supports from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) under the project numbers 2007/08244-5, 2007/54829-5 and 2017/18574-4 and from Conselho Nacional Científico e Tecnológico (CNPq) under the project numbers 424633/2018-3, 304119/2019-9. RJPR and LHL thanks FAPESP for the studentship supports under project numbers 2018/08543-7 and 2016/21402-8. ICT thanks CNPq and Equinor Energia Ltda for the studentship support under project number 304119/2019-9 Abstract: The plethora of new transition metal dichalcogenides (TMDs) materials have attracted a major attention during the last years due to a diversity of new possibilities of applications in different areas from electronic and photonic devices to new sensors and catalysts, as well as a large playground of 2D materials to explore new physical phenomena. Many efforts have been done to develop new growth techniques that can produce single-layer TMDs in large areas and with high quality (low density of defects). Another important issue for electronic device integration is how to perform electrical contacts that show a metallic behavior instead semiconductor junctions. In this work, we have systematically studied the epitaxial growth of MoS2 on Ag(111) using the physical vapor deposition method (PVD). The results, based on a multiple technique approach, demonstrate that is possible to produce a single-layer 1H -MoS2 film on Ag(111). The material presents a metallic behavior due to an electronic hybridization between the MoS2 states and the Ag(111) states as results of the strong TMD-substrate interaction at the interface. This metallic character is preserved even after exposure to atmosphere and hostile oxidation environment which indicates that silver is probably an excellent candidate to perform metal contacts on sulfur-based TMDs FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This work has been supported by FAPESP (Grant Nos. 2016/21402-8, 2017/18574-4, 2007/54829-5, and 2007/08244-5), and CNPq (Grant No. 401826/2013-9). We thank LNLS for the beamtime and PGM beamline staff for the technical support. The authors are grateful to the Multiuser Central Facilities CEMs-UFABC for the computational support. DCM acknowledges UFABC for the studentship Abstract: CVD graphene grown on metallic substrates presents, in several cases, a long-range periodic structure due to a lattice mismatch between the graphene and the substrate. For instance, graphene grown on Ir(111), displays a corrugated supercell with distinct adsorption sites due to a variation of its local electronic structure. This type of surface reconstruction represents a challenging problem for a detailed atomic surface structure determination for experimental and theoretical techniques. In this work, we revisited the surface structure determination of graphene on Ir(111) by using the unique advantage of surface and chemical selectivity of synchrotron-based photoelectron diffraction. We take advantage of the Ir 4f photoemission surface state and use its diffraction signal as a probe to investigate the atomic arrangement of the graphene topping layer. We determine the average height and the overall corrugation of the graphene layer, which are respectively equal to 3.40 +/- 0.11 angstrom and 0.45 +/- 0.03 angstrom. Furthermore, we explore the graphene topography in the vicinity of its high-symmetry adsorption sites and show that the experimental data can be described by three reduced systems simplifying the moire supercell multiple scattering analysis FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) project nos. 2017/08846-7 and 2007/54829-5, CAPES (PROBRAL) grant number 1925/2016, and CNPq from Brazil are gratefully acknowledged. J.C.M.-L. would like to also gratefully acknowledge Yachay Tech University and its authorities for the support to perform the experiments at Instituto de Fisica Gleb Wataghin in Campinas, Brazil. M.L. and H.M are grateful for travel grants from the DAAD Abstract: Metal adatoms play a key role in surface diffusion, adsorption conformation, and self-assembly of porphyrin molecules on metal surfaces. Herein, we study the specific influence of coadsorption of Fe, Co, and Pd atoms on the behavior of 2H-tetiakis(p-cyano)phenylporphyrin (2H-TCNPP) on Cu(111) using scanning tunneling microscopy. Upon codeposition of Fe and Co, the molecules form one-dimensional (1D) linear chains after mild annealing on Cu(111) driven by the interaction of its cyano groups with metal adatoms. A similar behavior has been observed previously on Cu(111), mediated by Cu adatoms, where the functional CN groups were also found to lower the reaction rate of the so-called porphyrin self-metalation reaction with Cu atoms significantly, in comparison to the non-cyano-functionalized porphyrin. Upon co-deposition of Pd and mild annealing, we find a remarkably different behavior, that is, a massive reorganization from 1D molecular chains to a peculiar rectangular 2D (two-dimensional) network. The molecular appearance changes to a clover shape, which is attributed to a Pd-induced dehydrogenation and subsequent ring closure reaction of the phenyl and pyrrole groups FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The authors are grateful F.L. Bernardes for fabrication of the samples. Experimental support of L.H.M. Antunes at Unicamp, Campinas in addition to Mr. L. Wu, Dr. F.E. Montoro and Dr. A.L. Gobbi (projects ME 22425 and LMF 20869) at Brazilian Nanotechnology National Laboratory-LNNano is acknowledged. The authors acknowledge the LNNano and the Brazilian Synchrotron Light Laboratory-LNLS for the use of the XTMS installation at the XRD-1 beamline. Microstructural characterisation was performed at Analytical Centre - UFC/CT-INFRA/MCTI-SISNANO/Pró-Equipamentos CAPES and LNNano. Financial support was provided by CAPES, Brazil (Project 50/2011), CNPEM, Brazil (Project 20170618) and the São Paulo Research Foundation FAPESP, Brazil (grant numbers 2016/09350-2 and 2007/54829-5) Abstract: CoCrMo alloys have been used for several decades in implantable devices due to their favourable mechanical properties, low wear rate in addition to good biocompatibility and high corrosion resistance. These alloys are conventionally produced via casting and/or forging route, however additive manufacturing techniques being recently employed in their fabrication. In this work, CoCrMo samples were produced by direct metal laser sintering additive manufacturing process. The microstructure and surface composition were examined employing scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The corrosion resistance was measured in 0.14 M sodium chloride solution and in phosphate buffered solution (PBS) both with and without addition of albumin at pH 7.4 and 37 degrees C. For this, potentiodynamic tests in addition to electrochemical impedance spectroscopy were employed. The studied CoCrMo alloy exhibits a good corrosion resistance in solutions tested being the highest in PBS solution without albumin addition. The XPS analysis showed that the passive film composition and its thickness are not modified by the adsorbed layer. Microstructural analysis revealed occurrence of strain-induced martensitic transformation COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful to the Brazilian research funding agencies, including the Brazilian National Council for Scientific and Technological Development - CNPq (grants. #302874/2017-8 and #427452/2018-0), São Paulo Research Foundation (FAPESP – grants #2014/50945-4, #2017/10118-0, #2013/02762-5, #2014/11486-4, #2016/12597-0, #2007/54829-5, #2007/08244-5, and #2017/18574-4), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES – Finance Code 001), for the financial assistance granted in support of this research Abstract: Oxygen reduction reaction (ORR) is an important reaction with applications in advanced oxidative processes through in aim hydrogen peroxide electrogeneration. Oxygen can be reduced either to hydrogen peroxide via two-electron pathway or in a competitive way to water via four-electron pathway. This study shows the application of Printex L6 carbon modified with niobium/molybdenum or niobium/palladium oxides for H2O2 generation in K2SO4 0.1 mol L-1 (pH 2), where the modified carbon contributed to an increase in electroconductivity compared to unmodified carbon. The catalysts were prepared by the polymeric precursor method and were analyzed by x-ray absorption near edge structure (XANES), x-ray diffraction (XRD), and xray photoelectron spectroscopy (XPS) which showed the presence of orthorhombic Nb2O5 and MoO3 and tetragonal PdO independent phases. Also, the data obtained from x-ray fluorescence (FRX) and transmission electron microscopy (TEM) showed particle size of about 5 nm for the modified Printex L6 carbon compared to 25-30 nm for the unmodified Printex L6 carbon in an almost homogeneous distribution on the carbon surface. Based on the electrochemical analyses, the values obtained for H2O2 selectivity were 77, 77 and 88% for 5% Nb50Mo50/C, 5%Nb90Pd10/C, and 5% Nb95Pd05/C, respectively, compared to 89% for unmodified Printex L6 carbon. The materials investigated presented potential shifts of 110, 420 and 340 mV for 5% Nb50Mo50/C, 5% Nb-90 Pd-10/C and 5% Nb95Pd05 /C, respectively, compared to Printex L6 carbon at a determined current density Resumo: CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: We acknowledge financial support from the Brazilian agencies FAPESP (Grant Numbers: 2017/10522-5, 2018/16250-0, 2018/08782-1, 2009/054066-7, and 2007/54829-5), CAPES (Grant Number 3359/2014 Pró-Forenses Edital 25/2014), CNPq (grant numbers: 444498/2014-1, 438828/2018- 6, 306690/2015-2, and 305605/2017-8) and INCTBio (573672/2008-3). Additionally, the authors are grateful to Professor Dr. Susana Torresi and A. C. Silva for contact angle measurements. We thank Central Analítica e Central Multiusuário at IQ-USP and IQ-UNICAMP for providing the infrastructure Abstract: This study fabricated a portable, high-performance, and reagentless electrochemical devices using CO2 laser-scribing process, which allowed localized carbonization of a non-conductive and low-cost polymer platform, i.e., phenolic-paper. The carbonized material was extensively characterized by Raman spectroscopy, XPS, XRD, SEM, and electrochemical impedance spectroscopy. The carbon-based electrodes were obtained from the photothermal process induced by CO2 laser radiation and subsequently subjected to electrochemical treatment to fabricate a functional material with excellent conductivity and low charge-transfer resistance. Additionally, the laser-scribed electrodes presented a porous structure with graphene-like domains, thus indicating both potential for on-site electroanalytical applications and better performance than conventional carbon electrodes FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This study was financed in part by Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) projects 2007/54829-5, 2007/08244-5, and 2017/09529-5, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) - Finance Code 001, and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) projects 309586/2016-0 and 424633/2018-3. R.C.C.F. thanks CNPq for the scholarship. This work used the Imbabura cluster of Yachay Tech University, which was purchased under contract no. 2017-024 (SIE-UITEY-007-2017) Abstract: Surface-assisted Ullmann-type coupling reactions are a potential bottom-up approach for building tailored low-dimensional materials with novel physical and chemical properties. In this investigation combining scanning tunneling microscopy (STM), density functional theory (DFT), and X-ray photoelectron spectroscopy (XPS), we study the adsorption behavior, supramolecular ordering, and chemical and physical changes upon annealing of a 5,10,15,20-tetrakis(4-chlorophenyl) porphyrin (Cl4TPP) on the Ag(111) surface. At room temperature, well-ordered two-dimensional (2D) assemblies grow preferentially along the < 1 (1) over bar0 > directions, revealing the coexistence of two distinguishable porous and zigzag structures and lattice parameters. Our DFT calculations show that Cl4TPP adsorbs in the typical saddle-shape conformation on Ag(111) and that the coexistence of these two overlayers is due to translations between nearly isoenergetic adsorption sites. Furthermore, to self-polymerize the organic mesh via an on-surface Ullmann-type coupling reaction, we performed an STM and XPS study of the system upon annealing, following the chemical and structural modifications above room temperature. Under these conditions, we obtain a highly compact 2D framework composed of dechlorinated molecules FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors gratefully acknowledge the Federal University of São Carlos (UFSCar Sorocaba), Fatec Sorocaba, Federal University of Triângulo Mineiro (UFTM) for providing the laboratories facilities, as well as the National Counsel of Technological and Scientific Development (CNPq) grant 402142/2016-0, Coordination for the Improvement of Higher Education Personnel (CAPES) grant 88881.336769/2019-01-PVEX and FAPEMIG grant APQ-02276-18 for the financial support. The authors would also like to thank Professor Dra. Luciana Sgarbi Rossino and her master student Larissa Almeida for providing Ti6Al4V containing a-C:H samples for this study. The authors would like to thank the MSc. Guilherme de Lima Fernandes by the Raman spectroscopy analyzes. The authors would like to thank the Professor Graciela Ines Bolzon de Muniz by the analyzes Abstract: This work aims to investigate the chemical and biological responses of a-C:H films produced by PECVD technique onto substrate of Ti6Al4V alloy. The films produced were characterized morphologically and structurally by optical microscope (OM), SEM, AFM, EDX, FTIR Raman Spectroscopy (RS) and XPS. Afterwards, biocompatibility and cytotoxicity tests on osteoblastic cells and/or Human Peripheral Blood Mononuclear Cells (PBMCs) were performed on the Ti6Al4V alloy with coated and uncoated a-C:H film. The I-D/I-G ratio about 0.71 suggests a hydrogenated amorphous carbon film (a-C:H). The deconvoluted XPS spectra of C 1s peaks disclose the presence of three main components: Cl associated to C=C bonds in one sp(2) hybridization as well as C2 associated to sp(3) hybridization. The impedance results showed that a-C:H film acts as a protective barrier against the corrosion process. Regardless of the cell population, when the total apoptosis of osteoblastic cells or PBMCs was evaluated, only cells cultured on the alloy without a-C:H had significant induction of the apoptotic process. Moreover, only PBMCs cultured on the alloy without a-C:H had significant induction of inflammatory and anti-inflammatory cytokines that characterize immune activation CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG Fechado

Agradecimentos: The authors are pleased to acknowledge the staff of the Brazilian Synchrotron Light Laboratory - LNLS for helping us in the beamline setup. This project was supported by the Brazilian research agencies Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP (process 2017/25983-8), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES, Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq (process 302450/2017-2), FAPEG 07/2016 (23187) and CNPEM/LNLS (proposal D08A – SGM – 2485) Abstract: The formation of surface alloys obtained by annealing ultra-thin films of Sn deposited on a Pd(111) surface was characterized by X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), and X-ray photoelectron diffraction (XPD). Annealing the surface at 600 K produced a (root 3x root 3)R30 degrees LEED pattern, and the comparison between experimental and theoretical XPD results indicated the formation of a corrugated bi-dimensional Pd2Sn surface alloy, with Sn atoms being present not only on the outmost layer but also at least on the second internal layer FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE GOIÁS - FAPEG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: Funding by Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) projects Nos. 2017/08846-7 and 2007/54829-5, CAPES and CNPq from Brazil are gratefully acknowledged. This work used the Quinde I supercomputer of Public Company Yachay E. P., which was implemented under contract No. 0051-2015, corresponding to Component No. 7 of Group No. 2, Re-YACHAY-018-2015, and the Imbabura cluster of Yachay Tech University, which was purchased under contract No. 2017-024 (SIE-UITEY-007-2017). J.C.M.-L. gratefully acknowledges Yachay Tech University and its authorities for their support in the performance of the experiments at Instituto de Fisica Gleb Wataghin in Campinas, Brazil Abstract: Surface diffusion, molecular conformation, and on-surface coupling reactions are key processes for building tailored molecular nanostructures such as graphene nanoribbons, polycyclic aromatic hydrocarbons, and one-dimensional/two-dimensional (2D) polymers. Here, we study the surface diffusion and coupling in situ of a chlorinated porphyrin, namely 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin (Cl4TPP), using a combined scanning tunneling microscopy (STM), density functional theory (DFT), and X-ray photoelectron spectroscopy approach. Using STM, we obtain surface migration and rotation barriers Delta E of 0.77 +/- 0.09 and 0.93 +/- 0.28 eV, respectively, indicative of covalent binding to the surface. In fact, we find that the precursors as well as all the reaction species exclusively (approximate to 100%) adopt a peculiar "inverted" conformation covalently bonded to Cu(111). Using DFT, we have mapped two coupling reaction pathways: direct dechlorination and Cu adatom-mediated Ullmann coupling. We find that the latter is essentially barrierless, whereas the former faces a barrier of about 0.9 eV for inverted Cl4TPP on Cu(111). Our STM measurements show that C-Cu-C organometallic species are the main final products in the presence of Cu adatoms, which is explained by our DFT reaction profile when heat dissipation to the substrate is taken into account. This work not only highlights the relevance of surface adatoms in selecting the reaction pathway but also opens the possibility of precisely tailoring 2D molecular assemblies by controlling the supply of Cu adatoms CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: Authors are grateful to FAPESP (2010/13033-6, 2012/01484-9, 2015/14703-9, 2016/00023-9, 2014/24547-1 and 2014/11410-8), INEO (CNPq) for financial support, and also Bernhard Gross Polymer Group (IFSC–USP), Aˆ ngelo L. Gobbi and Maria Helena O. Piazzetta at Laboratory of Microfabrication (LNNano/CNPEM) for the cooperation in microelectrodes fabrication. This research also used the computing resources and assistance of the John David Rogers Computing Center (CCJDR) in the Institute of Physics ‘‘Gleb Wataghin,’’ University of Campinas Abstract: The production of large-area interfaces and the use of scalable methods to build up designed nanostructures generating advanced functional properties are of high interest for many materials science applications. Nevertheless, large-area coverage remains a major problem even for pristine graphene, and here we present a hybrid, composite graphene-like material soluble in water that can be exploited in many areas such as energy storage, electrodes fabrication, selective membranes and biosensing. Graphene oxide (GO) was produced by the traditional Hummers' method being further reduced in the presence of poly(styrene sulfonate) sodium salt (PSS), thus creating stable reduced graphene oxide (rGO) nanoplatelets wrapped by PSS (GPSS). Molecular dynamics simulations were carried out to further clarify the interactions between PSS molecules and rGO nanoplatelets, with calculations supported by Fourier transform infrared spectroscopy analysis. The intermolecular forces between rGO nanoplatelets and PSS lead to the formation of a hybrid material (GPSS) stabilized by van der Waals forces, allowing the fabrication of high-quality layer-by-layer (LbL) films with poly(allylamine hydrochloride) (PAH). Raman and electrical characterizations corroborated the successful modifications in the electronic structures from GO to GPSS after the chemical treatment, resulting in (PAH/GPSS) LbL films four orders of magnitude more conductive than (PAH/GO) FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: We gratefully acknowledge funding by the German Research Foundation (DFG) through Research Unit FOR 1878 (funCOS), the Cluster of Excellence EXC 315 "Engineering of Advanced Materials" (EAM), and the Collaborative Research Center SFB 953 at the Friedrich-Alexander-Universitat Erlangen-Nurnberg. L.Z. thanks the Alexander von Humboldt Foundation for a research fellowship. H.M., M.L., and A.d.S. are grateful for travel grants from DAAD and CAPES Abstract: The reaction rate of the self-metalation of free-base tetraphenylporphyrins (TPPs) on Cu(111) increases with the number of cyano groups (n=0, 1, 2, 4) attached at the para positions of the phenyl rings. The findings are based on isothermal scanning tunneling microscopy (STM) measurements. At room temperature, all investigated free-base TPP derivatives adsorb as individual molecules and are aligned with respect to densely packed Cu substrate rows. Annealing at 400K leads to the formation of linear dimers and/or multimers via CN-Cu-CN bonds, accompanied by self-metalation of the free-base porphyrins following a first-order rate equation. When comparing the non-cyano-functionalized and the tetracyano-functionalized molecules, we find a decrease of the reaction rate by a factor of more than 20, corresponding to an increase of the activation energy from 1.48 to 1.59eV. Density functional theory (DFT) calculations give insights into the influence of the peripheral electron-withdrawing cyano groups and explain the experimentally observed effects COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Aberto

Agradecimentos: The authors thank LNLS for beamtime at PGM beamline as well as PGM staff for technical support during the experiments. This work was financially supported by Fundaca¸ o de Amparo a ~ Pesquisa do Estado de Sao Paulo (FAPESP) under projects ~ 2007/54829-5, 2007/08244-5 and 2016/21402-8 and by CNPq under project 455807/2014-0. R.C.C.F. acknowledge CAPES for studentship and L.H.L. and L.B. acknowledge CNPq for the studentship funding Abstract: The interaction of Fe deposited on graphene grown on Ir(111) was studied in detail to better understand the growth, intercalation, and oxidation of Fe ultrathin films on and under graphene. The study has combined a multiple technique approach that allows extracting at once the chemical, topographic, and precise atomic structure of the system submitted to different conditions of growth and atmospheric environment. For instance, scanning tunneling microscopy (STM) measurements allowed us to follow the formation of Fe nanostructures during Fe deposition and intercalation. Synchrotron-based high-resolution X-ray photoelectron spectroscopy (HR-XPS) untangled the different chemical environments for C-Fe bonds. We have also used photoelectron diffraction experiments to site-specifically unravel the atomic structure of the intercalated Fe under graphene. Oxidation experiments were also performed for samples prepared under different conditions which revealed that indeed one can set the sample temperature to selectively protect or oxidize the intercalated/supported materials, which open interesting possibilities to engineer complex metal-oxide graphene-based devices FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The authors like to thanks to CNPq, Capes, Fapemig, Nacional de Grafite Ltda, FAPESP (2007/54829-5) and (2017/08602-0) to support this work Abstract: We report the development of flexible self-supported metal-free electrodes based on non-oxidized graphene multilayer (MLG) paper, utilized to assemble bendable electrochemical supercapacitors. Using a simplified production method various electrodes exhibiting high conductivity were prepared and its structural, morphological, chemical and electrical properties characterized. Measurements in supercapacitors assembled from MLG electrodes and PANI-coated MLG electrodes show excellent electrochemical characteristics, with specific capacitances of 58 mF cm(-2) and 451 F g(-1) with 84% and 103% of capacitance retention after 1000 cycles, respectively. The energy and power density obtained for the PANI/MLG flexible supercapacitor reached 17.0 Wh g(-1) and 3.61 kW kg(-1), respectively. Moreover, in bending tests, the supercapacitors displayed an excellent mechanical and electrochemical stability. As an important result of this study, MLG electrodes appear as an interesting material for flexible high performance energy storage devices CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: We would like to acknowledge the Brazilian research agencies Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP and Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq, for financial support, Fapeg-Pronem 07/2016 (23187), and the Brazilian Synchrotron Light Laboratory – LNLS (proposal # SGM 16978) Abstract: An ordered thin film of niobium oxide (NbO) was formed on the Nb(100) surface by heating the niobium single crystal at 1023 K for 2 min under an oxygen atmosphere. The surface composition was analyzed by X-ray photoelectron spectroscopy (XPS), and the surface structure was characterized by low energy electron diffraction (LEED) and X-ray photoelectron diffraction (XPD) generated by synchrotron radiation. Annealing at 1223 K in ultra-high vacuum yielded a reconstructed (3 x 1) LEED pattern. XPS measurements indicated that the surface comprised of metallic and oxidized niobium species. The comparison between experimental and theoretical XPD results indicated that 60% of the Nb(100) surface was covered by two-layered nanoislands of NbO, and 40% had bare patches FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE GOIÁS - FAPEG Fechado

A rhodium ultra-thin film was deposited on a Pd-supported a-Fe2O3 (0001) film by molecular beam epitaxy (MBE). The surface atomic and electronic structures were studied using X-ray photoelectron diffraction (XPD), X-ray photoelectron spectroscopy (XPS), and low energy electron diffraction (LEED). For an oxide thin film (~16.5 Å), an ordered (v3 × v3)R30° structure was observed. The multiple scattering calculation approach combined with a genetic algorithm for surface structure optimization was used to investigate precisely the atomic structure of the oxide support as well as the Rh nanoislands or nanoparticles (NPs). Rh exhibited 3D growth on an a-Fe2O3 thin film forming NPs with a lattice constant expanded by 5.26% relative to the Rh bulk value. The coexistence of 60° rotated domains and also evidence of Fe termination at the surface of a-Fe2O3 were observed CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: Funding by the Deutsche Forschungsgemeinschaft (DFG) within the Cluster of Excellence EXC 315 "Engineering of Advanced Materials'' (www.eam.uni-erlangen.de) and the Research Unit FOR 1878 (funCOS) is gratefully acknowledged. A. S. acknowledges funding from CAPES (PROBRAL 435/15) and FAPESP from Brazil. H. M. and M. L. are grateful for funding through DAAD PROBRAL projects 57143062 and 5735014 Abstract: Based on density functional theory calculations combined with experimental results, we report and discuss an extremely distorted, "inverted" adsorption geometry of free-base tetraphenylporphyrin on Cu(111). The current findings yield new insights into a well-studied system, shedding light on the peculiar molecule-substrate interaction and the resulting intramolecular conformation COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was supported by FAPESP (process 2007/54829-5), CNPq, and CNPEM/LNLS (SXS project no. 7074) Abstract: Ultra-thin films of Au were deposited on the Pd(111) surface and then characterized by X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), and X-ray photoelectron diffraction (XPD) generated by synchrotron radiation. The Au films were deposited at room temperature (300 K) and subsequently annealed at 400 °C (673 K) and 610 °C (883 K). XPD analyses indicated that the gold films were 7 and 6 ML thick, for the annealing temperatures of 400 °C and 610 °C, respectively. The film interlayer distances exhibited an oscillatory behavior, with a 5% contraction between the top and the second layers, a 3% expansion between the second and the third layers, for the film annealed at 400 °C, and a 2% expansion in the interlayer distance between the top and the second layers and a 4% contraction between the second and the third layers, for the film annealed at 610 °C. For both annealing temperatures, the interlayer distances between the third and the fourth layers and between the fourth and the fifth layers exhibited a 1% expansion and a 2% contraction. For the film annealed at 610 °C, XPD results revealed that the Pd(111) surface was covered by Au islands, with some bare patches exposed FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: We thank Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP-07/54829-5) and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) for financial support. Special thanks to Prof. G. Tremiliosi-Filho for lending the Au(332) crystal. M.J.P. and E.A.C. thank FAPESP and CNPq for the fellowships granted (Proc. FAPESP 2011/12.566-3; Proc. CNPq 150192/2014-2). We also thank the Brazilian Synchrotron Light Source for the beam time and the PGM-beamline staff for support during the experiments Abstract: The reactivity of the Pt/Au(332) surface was studied using high-resolution photoelectron spectroscopy and carbon monoxide adsorption at 3.5 x 10(-3) mbar. The characterization of Pt/Au(332) indicates the formation of a Au-Pt surface alloy at the topmost atomic layer of the (332) crystal due to an atomic exchange mechanism at both terrace and step edge. The amount of alloyed Au atoms has proven to be dependent on the amount of Pt deposited in the coverage range investigated. The activation of Au atoms by alloying is detected by comparing the ability of the surface to adsorb CO at high pressures. By analyzing the C 1s and O 1s photoemission lines it is possible to conclude that CO adsorption is both dissociative and molecular on the PtAu/Au(332) surface, differently from the behavior observed for Au and Pt single crystals. Also, by rising the temperature of the COads-PtAu/Au(332) surface, a dissociative reaction path is followed by the accumulation of graphitic carbon on the surface and the oxygen/carbon dioxide desorption. Thus, our results show not only the differential catalytic behavior of Pt@Au/Au(hkl) model surfaces but also that Au atoms have an active role on the reaction mechanism FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: This work received financial support from International programs for scientific cooperation (PICS 05918). We acknowledge LNLS for beamtime at the PGM beamline and the beamline staff for the efficient technical support Abstract: We studied by soft X-ray absorption spectroscopy the magnetization axis in a 4 nm thin CoO (111) layer exchange-coupled to an ultra thin L10 PtFe layer with perpendicular magnetic anisotropy. The angular dependence of the linear magnetic dichroism at 10 K and the relative variations of the spectral features provide a full description of the spin orientation in this antiferromagnetic layer. The spins are found in the film plane, pointing along the 110 direction. This results is discussed in relation to the film strain and the preferential occupation of t2g orbitals. The strong orthogonal coupling between Co and Fe spins should be at the origin of the robustness of the exchange bias effect found in this bilayer system Aberto

Agradecimentos: This work was supported by FAPESP, CNPq, LNLS, CAPES, and FAPEMIG from Brazil. S.F. gratefully acknowledges FAPESP studentship 2012/16860-8 and 2013/04855-0. R.G.A.V. is thankful for the funding provided by the FAPESP grant 2011/19564-6 and 2014/10294-4. MJP is thankful for the funding provided by the FAPESP grant 2011/12566-3. This work used computational facilities provided by the Blue Gene/P supercomputer supported by the Research Computing Support Group (Rice University) and Laboratorio de Computacao Cientifica Avancada (Universidade de Sao Paulo) Abstract: The growth and self-assembling properties of nickel-tetraphenyl porphyrins (NiTPP) on the Cu(111) surface are analysed via scanning tunnelling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT). For low coverage, STM results show that NiTPP molecules diffuse on the terrace until they reach the step edge of the copper surface forming a 1D system with disordered orientation along the step edges. The nucleation process into a 2D superstructure was observed to occur via the interaction of molecules attached to the already nucleated 1D structure, reorienting molecules. For monolayer range coverage a 2D nearly squared self-assembled array with the emergence of chiral domains was observed. The XPS results of the Ni 2p3/2 core levels exhibit a 2.6 eV chemical shift between the mono- and multilayer configuration of NiTPP. DFT calculations show that the observed chemical shifts of Ni 2p3/2 occur due to the interaction of 3d orbitals of Ni with the Cu(111) substrate FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG Fechado

Agradecimentos: This work received financial support from FAPESP, CNPq and CAPES from Brazil. The authors would like to thank the DELTA staff for their technical support during beamtime and G. A. Viana for the SiC H2 etching. LHL and AS acknowledge the hospitality of Technische Universität Dortmund Abstract: A chemical-specific photoelectron diffraction structure determination of a carbon rich buffer layer on SiC is reported. In addition to the long-range ripple of this surface, a local buckling in the hexagonal sublattice, which breaks the local range order symmetry, was unraveled FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: We thank CICPBA, ANPCyT (PICT 2011–0238), and CONICET for their financial assistance, L. F. Gambino and O.R. Pardini for technical assistance, Christopher Young for reviewing and correcting the paper and Solvay Specialty Polymers S.p.A. (Italy) for the donation of the nanoPTFE dispersion. PSA and PJP are the members of CONICET and JIA is the member of CICPBA (Argentina) Abstract: Films from blends of polyurethane and nano-polytetrafluoroethylene aqueous dispersions (PU/nanoPTFE) were prepared, and the effect of the addition of different amounts of PTFE nanoparticles (50 nm) was studied. The changes in the superficial properties of the films were studied by means of XPS, ATR/FTIR, and contact angle measurements. SEM and TEM results are also included. The contact angle values confirm the surface hydrophobicity of composite films. Even though nanoparticles are present in the bulk, higher concentrations of particles appear at the surface in samples with lower nanoPTFE content (up to 10 wt%), as revealed by XPS. Higher amounts of nanoPTFE particles cause aggregation. The mechanical and thermal properties of composites are also discussed Fechado

Agradecimentos: We acknowledge the support given by the LNLS staff. This work is funded by the CNPq, the FAPESP and the CAPES. A. S. Kilian thanks CNPq for his Ph.D. fellowship Abstract: A detailed investigation concerning the surface atomic structure of the Au/Cr2O3 model catalyst deposited on a Pd(111) single crystal surface is presented. The system was prepared by molecular beam epitaxy (MBE) and characterized in situ by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD). The element-specific short-range order information was obtained from XPD experiments supported by a comprehensive multiple scattering calculation diffraction approach. Based on the experiments, we have strong evidence of Au island formation on the Cr2O3 surface. The experiments indicated that the islands are constructed of two Au monolayers and formed by the important structural relaxations in the three outermost atomic layers of the Au/Cr2O3 surface. Such a surface structure could explain the particular catalytic reactivity displayed by catalysts based on Au nanoparticles dispersed on several oxide matrices CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The authors thank CNPq, FAPEMIG, FAPESP, and CAPES, Brazilian research agencies, for financial support and the Laboratorio Nacional de Luz Sincrotron for beam time (SGM-10986 and SGM-12716) Abstract: We perform a systematic study on the evolution of the magnetic spin moment (ms) of epitaxial [100]- and [111]-magnetite films of increasing thickness. The ultrathin films are characterized by low-energy electron diffraction, x-ray absorption spectroscopy, and x-ray magnetic circular dichroism (XMCD). By employing sum rules on the XMCD spectra we obtain ms=3.6 µB/f.u. for samples of around 35 Å. This is considered a bulk value and has been reported only for films more than 10 times thicker. Moreover, we show that even 10-Å-thick magnetite already presents a significant magnetic moment. For both grown directions the moment increases similarly with the thickness. The ferromagnetic behavior for each iron ion site (Feocta2+, Feocta3+, Fetetra3+) of Fe3O4 is measured by monitoring XMCD peaks. The deduced hysteresis curves (per ion, per site) exhibit a coercive field of 300 Oe. Our results show that both the ferrimagnetic order and the bulk moment value are preserved at room temperature around the thickness of 2 unit cells CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: Authors thank Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP-07/54829-5) and Conselho Nacional de Pesquisa (CNPq) for financial support. Specially thank to L. H. Lima for experimental assistance with STM measurements and Prof. G. Tremiliosi-Filho for lending the Au(332) crystal. MJP, SF and EAC thank FAPESP and CNPq for the fellowships granted (Procs. FAPESP 2011/12.566-3 and 2012/16860-6; Proc. CNPq 160172/2011-0) Abstract: Two single crystalline surfaces of Au vicinal to the (111) plane were modified with Pt and studied using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) in ultra-high vacuum environment. The vicinal surfaces studied are Au(332) and Au(887) and different Pt coverage (yPt) were deposited on each surface. From STM images we determine that Pt deposits on both surfaces as nanoislands with heights ranging from 1 ML to 3 ML depending on yPt. On both surfaces the early growth of Pt ad-islands occurs at the lower part of the step edge, with Pt ad-atoms being incorporated into the steps in some cases. XPS results indicate that partial alloying of Pt occurs at the interface at room temperature and at all coverage, as suggested by the negative chemical shift of Pt 4f core line, indicating an upward shift of the d-band center of the alloyed Pt. Also, the existence of a segregated Pt phase especially at higher coverage is detected by XPS. Sample annealing indicates that the temperature rise promotes a further incorporation of Pt atoms into the Au substrate as supported by STM and XPS results. Additionally, the catalytic activity of different PtAu systems reported in the literature for some electrochemical reactions is discussed considering our findings FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: We thank the LNLS staff for their support. A.S. Kilian thanks CNPq for his Ph.D. fellowship. This work was funded by CNPq, CAPES, FAPERGS, and FAPESP Abstract: A detailed investigation concerning the atomic structure of Cr2O3 and Pd/Cr2O3 ultrathin films deposited on a Ag(111) single crystal is presented. The films were prepared by MBE (molecular beam epitaxy) and characterized in situ by LEED (low energy electron diffraction), XPS (X-ray photoelectron spectroscopy), and XPD (X-ray photoelectron diffraction). Evidences of rotated domains and an oxygen-terminated Cr2O3/Ag(111) surface were observed, along with significant contractions of the oxide’s outermost interlayer distances. The deposition of Pd atoms on the Cr2O3 surface formed a four-monolayer film, fcc packed and oriented in the [111] direction, which presented changes in monolayer spacing and lateral atomic distance compared to the expected values for bulk Pd. The observed surface structure may shed light on new physical properties such as the induced magnetic ordering in Pd atoms CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

We report on the exchange coupling and magnetic properties of a strained ultrathin CoO/PtFe double layer with perpendicular magnetic anisotropy. The cobalt oxide growth by reactive molecular beam epitaxy on a Pt-terminated PtFe/Pt(001) surface gives rise to a hexagonal surface and a monoclinic distorted CoO 3 nm film at room temperature. This distorted ultrathin CoO layer couples with the PtFe(001) layer establishing a robust perpendicular exchange bias shift. Soft x-ray absorption spectroscopy provides a full description of the spin orientations in the CoO/PtFe double layer. The exchange bias shift is preserved up to the Néel antiferromagnetic ordering temperature of TN = 293 K. This unique example of selfsame value for blocking and ordering temperatures, yet identical to the bulk ordering temperature, is likely related to the original strain-induced distortion and strengthened interaction between the two well-ordered spin layers Fechado

Agradecimentos: Authors would like to thank Conselho Nacional de Pesquisa (CNPq) and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for financial support. Special thanks to L. H. Lima for discussions during STM measurements and Prof. G. Tremiliosi-Filho for lending the Au crystal. MJP thanks FAPESP for the fellowship granted (Proc. 2011/12.566-3). EAC thanks CNPq for the fellowship granted (Proc. 160172/2011-0) Abstract: Co nanoislands were grown on (332) vicinal surface of Au in UHV using the e-beam evaporation technique. Scanning tunneling microscopy results reveal that Co deposition occurs following an islanding mode for ?Co ranging from 0.17 to 0.64 ML. At low coverage nanoislands show a monolayer height, while at higher Co loadings, islands have a maximum bilayer height. XPS measurements rule out the possibility of alloy formation provided that binding energy of Co2p core lines remains unchanged as cobalt loading increases. Also, XPS data reveals that, when subjected to thermal annealing, Co atoms diffuse into Au crystal retaining its chemical nature as before the annealing. Finally, NO adsorption experiments show that Co nanostructures are partially oxidized upon adsorption, as evidenced by changes in core photoemission lineshapes of the Co2p lines. Also, NO adsorption seems to inhibit Co atom diffusion into Au crystal during moderate thermal treatment FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This work received financial supported from FAPESP, CNPq, CAPES, FAPEMIG, LNLS (SGM 8586 and SGM 10029) and INCT-Carbono from Brazil. The authors would like to thank the LNLS staff, especially G. Rodrigues, for their technical support during beamtime and George G. Kleiman for valuable discussions Abstract: We report a chemically specific x-ray photoelectron diffraction (XPD) investigation using synchrotron radiation of the thermally induced growth of epitaxial graphene on the 6H-SiC(0001). The XPD results show that the buffer layer on the SiC(0001) surface is formed by two domain regions rotated by 60? with respect to each other. The experimental data supported by a comprehensive multiple scattering calculation approach indicates the existence of a long-range ripple due the (6v3 × 6 v3)R30? reconstruction, in addition to a local range buckling in the (0001) direction of the two sublattices that form the honeycomb structure of the buffer layer. This displacement supports the existence of an sp2-to-sp3 rehybridization in this layer. For the subsequent graphene layer this displacement is absent, which can explain several differences between the electronic structures of graphene and the buffer layer FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG Fechado

Agradecimentos: TEM data were acquired at the LME-HRTEM (JEM-3010) of the Brazilian Synchrotron Light Laboratory (LNLS). Small-angle X-ray scattering data were acquired at beamline D11A-SAXS1-11663 and 11044 (Project 5988) at LNLS. Authors would like to thank N. M. Souza-Neto for helping with XANES measurements and LME/LNNano/CNPEM for the technical support during the electron microscopy work. The work at UNICAMP was supported by FAPESP and CNPq, Brazil. Abstract: In the present work, we have reported the effect of Ag NPs seeds on the growth and magnetic properties of Ag-Fe3O4 heterodimer nanoparticles prepared using a two step chemical approach. Three different Ag NPs concentrations have been tried and thoroughly characterized using small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), X-ray diffraction (XRD), dc magnetization, and X-ray absorption near edge spectroscopy (XANES). It is observed that at low concentration, the "flower" types of nanoparticles are more favorable whereas the higher concentration of Ag NPs seeds promotes the growth of dimer type of structures. Our dc magnetization results are well correlated to the structural ones. The sample with lower amount of starting Ag NPs seeds possesses highest blocking and irreversibility temperature. On the other hand, the sample with highest concentration of Ag NPs seeds, the blocking temperature is lowered FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors would like to thank Ana C. F. Felippi for her assistance in part of the experiments. Work supported by FAPESP, CAPES, CNPq, (Brazilian funding agencies), and LNLS (SXS project #5759) Abstract: Ultra-thin films (1 and 3 monolayers) of Pd were deposited on the Au(111) surface and then characterized by X-ray photoelectron spectroscopy (XPS), X-ray excited Auger spectroscopy (XAES), low-energy electron diffraction (LEED), and X-ray photoelectron diffraction (XPD). For the 1 ML Pd film annealed at 450 C, XPS and XAES results indicated that Pd had diffused into the Au substrate. For the 3 ML Pd film deposited at room temperature, the comparison between experimental and theoretical XPD results indicated approximately 30% of the surface was formed by 2 ML Au layers, and 70% of the surface, by 1 ML Au layers FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado