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This work aims to evaluate the behavior of the FTO/m-BiVO4 photoanode in different electrolytes, pH, anions and cations, in order to investigate the influence of these parameters on their photoelectrochemical activity. The m-BiVO4 semiconductor was developed by combustion synthesis in solution (SCS) and deposited by dip-coating technique on fluorinated doped tin oxide (FTO) coated glass substrate. The morphological and structural characterization of the film was performed by XRD, UV-Vis and SEM measurements. The evaluation of the photosensitive behavior of the film was made by linear voltammetry and chronoamperometry in the presence of pulsed visible light. After photoelectrochemical parameters optimization, the study of photoelectrocatalysis in glucose degradation was performed. Thus, it was possible to evaluate the efficiency of the film in the photoelectrocatalytic processes, presenting itself as a potential material for such applications.

Made available in DSpace on 2022-04-28T19:44:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 This work presents the results obtained in the production of poly (vinyl alcohol) (PVA) nanofibers with different concentrations of polypyrrole (PPy) doped with dodecylbenzene sulfonic acid (DBSA) - PPy.DBSA. The morphology of the nanofibers was studied by scanning electron microscopy (SEM) technique. The nanofibers were deposited on interdigitated electrodes (IDEs) for direct current electrical characterization (DC) and tested as ammonia gas sensors. The results showed a rapid detection of ammonia gas for higher concentrations of PPy.DBSA and for several alternating cycles in atmospheric N2. Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) Departamento de Física, SP Universidade Federal de Santa Catarina Coordenadoria Especial de Engenharia de Materiais, SC Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) Departamento de Física, SP

Made available in DSpace on 2018-12-11T17:21:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A resistance detection device for dissolved molecular oxygen in aqueous solutions is prepared using a chemiresistor material as sensor platform. The chemiresistive circuit element is fashioned from a thin film of a cobalt-salen metallopolymer electrodeposited on a platinum electrode. Electrochemical impedance spectroscopy shows that the resistive and capacitive properties of the sensor platform depend on the presence of dissolved oxygen. The electrical circuit models are R(Q/R)(Q/R) and R(Q/R)(Q/RW) in the absence and presence of oxygen, respectively. The chemiresistor sensor exhibits good sensitivity (0.483 kΩ L mg−1), excellent reversibility and excellent linearity over a range of dissolved oxygen concentrations typically found under environmental conditions (2.72–40.9 mg L−1). The sensor fabricated in this work can potentially serve as an alternative sensor for the detection of dissolved oxygen in environmental samples. Department of Chemistry and Biochemistry School of Science and Technology - Sao Paulo State University (UNESP), Rua Roberto Simonsen 305, CEP 19060-900 Department of Chemistry and Biochemistry School of Science and Technology - Sao Paulo State University (UNESP), Rua Roberto Simonsen 305, CEP 19060-900 CNPq: 113827/2012-1 FAPESP: 2016/09017-1

Department of Chemistry and Biochemistry School of Science and Technology Sao Paulo State University (UNESP), Rua Roberto Simonsen, 305

Entidades de todo o mundo estão cada vez mais fortalecendo movimentos em prol de um planeta mais saudável e sustentável. Neste sentido, o intuito deste trabalho é a construção de nanofibras de C/BiVO4 via eletrofiação e posterior carbonização do polímero PVA. Obtendo assim, nanofibras com elevada área superficial quando comparados aos usais métodos de deposição. Possibilitando maior absorção dos fótons e consequentemente elevando a eficiência fotoeletrocatalítica na conversão energética e degradação de poluentes orgânicos. O BiVO4 sintetizado foi caracterizado e assim confirmado a formação da fase monoclínica. A técnica de eletrofiação apresentou fibras com diâmetros na escala nanométrica com a presença do carbono, aumentando consideravelmente a área superficial do material, confirmado pelas microscopias óptica e eletrônica de varredura.

Made available in DSpace on 2018-12-11T16:43:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Electropolymerization of a π-conjugated polymer from [N,N′-bis(salicylidene)-o-phenylenediamine]nickel(II) complex ([Ni(salophen)]) on the surface of indium-tin-oxide (ITO) was studied. Two structures of the polymer have been proposed based on the theorem of molecular columns. The highlighted structures are the molecular column of the central aromatic rings (MCCAR) and molecular column of the side aromatic rings (MCSAR). The molecular structures were obtained by control of the potential scan rate in the electropolymerization step. The MCCAR structures are stable and structurally compact, whereas the MCSAR structures are less compact. Electrochemical measurements, atomic force microscopy (AFM), UV–Vis spectroscopy, FTIR Raman spectroscopy and optical microscopy support the formation of the multiblock π-conjugated polymer. Department of Chemistry and Biochemistry Faculty of Science and Technology São Paulo State University (UNESP), Rua Roberto Simonsen 305 São Carlos Institute of Chemistry University of São Paulo (USP) Department of Chemistry Faculty of Science and Technology University of Coimbra Department of Chemistry and Biochemistry Faculty of Science and Technology São Paulo State University (UNESP), Rua Roberto Simonsen 305

The present research investigates the electrochemical behavior of a solar cell sensitized with Bismark Brown R azopolymer. This cell was developed from the electropolymerization of the dye on a conductive glass substrate coated with fluorine-doped tin oxide(FTO) by cyclic voltammetry. The photosensitive behavior of the obtained film was analyzed by cyclic voltammetry and chronoamperometry in the presence of pulsed light. The poly(azo-Bismarck R) exhibited reversible light-induced changes of electrical conductance, due to azo group photoisomerization. Electrochemical impedance spectroscopy was also carried out under a light source. This technique allowed to evaluate interfacial phenomena existing in the photovoltaic device, performing a Recebido em: 27/08/2018Aprovado em: 16/09/2018 52Colloquium Exactarum, v. 10, n.3,Jul-Set. 2018, p.51–65. DOI: 10.5747/ce.2018.v10.n3.e245detailed investigationof its photoelectrochemical properties. A decrease in electrical resistance was observed with the lightincidence on the polymer membrane indicating charge transfer to the polymer conduction band.Photo-responsive film of Bismarck Brown can be developed for advanced organic photovoltaic such as solar cells.

Made available in DSpace on 2018-12-11T16:52:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) In this study, we explore the fabrication and properties of a sensing electrochemical platform that is based on a novel 11-mercaptoundecyl-N′,N″,N‴-trimethylammonium hexacyanoferrate (MAH) and 6-(ferrocenyl)hexanethiol (FT)/glucose oxidase (GOx) on gold substrate. The hexacyanoferrate and ferrocene moieties that were immobilized on the gold surface were examined as electron transfer mediators with the oxidase glucose. The sensing platform, based on 11-mercaptoundecyl-N′,N″,N‴-trimethylammonium hexacyanoferrate (MAH) and 6-(ferrocenyl)hexanethiol (FT)/GOx modified gold electrode, shows the potential to work with two distinct mechanisms for electrochemical response. The hexacyanoferrate anion that was anchored at positive edge charge of the 11-mercaptoundecyl-N′,N″,N‴-trimethylammonium on the gold surface provided an efficient electron transfer. It was demonstrated that in the design of the GOx/MAH, the FT/Au electrode is facilitating the electron transfer from GOx toward the gold substrate. We believe that this study adds a new facet to nanobioelectronics with applications for biofuels and sensorial platforms. Department of Chemistry and Biochemistry School of Science and Technology Sao Paulo State University (UNESP), Rua Roberto Simonsen 305 São Carlos Institute of Chemistry University of São Paulo (USP) São Carlos Department of Physiotherapy School of Science and Technology Sao Paulo State University (UNESP) Department of Chemistry and Biochemistry School of Science and Technology Sao Paulo State University (UNESP), Rua Roberto Simonsen 305 Department of Physiotherapy School of Science and Technology Sao Paulo State University (UNESP) FAPESP: 2012/21703-7 CNPq: 234256/2014-1 CNPq: 302728/2012-0

The preparation and electrochemical characterization of a nickel hydroxide modified nickel electrode as well as its behavior as electrocatalyst toward the oxidation of hydrochlorothiazide (HCTZ) were investigated. The electrochemical behavior of the modified electrode and the electrooxidation of HCTZ were explored using cyclic voltammetry. The voltammetric response of the modified electrode in the detection of HCTZ is based on the electrochemical oxidation of the Ni(II)/Ni(III) and a chemical redox process. The analytical parameters for the electrooxidation of HCTZ by the nickel hydroxide modified nickel electrode were obtained in NaOH solution, in which the linear voltammetric response was in the concentration range from 1.39 × 10−5 to 1.67 × 10−4 mol L−1 with a limit of detection of 7.92 × 10−6 mol L−1 and a sensitivity of 0.138 μA L mmol−1. Tafel analysis was used to elucidate the kinetics and mechanism of HCTZ oxidation by the modified electrode.

Made available in DSpace on 2018-12-11T16:38:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-06-25 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Abstract This paper describes the development of a selective lithium ion sensor based on spinel-type manganese oxide doped with gallium and anions (Ga0.02Mn1.98O3.98X0.02, where X = S2- and F-). Investigation was made of the influence of cationic and/or anionic doping agents on the potentiometric response of the sensor. Experimental parameters evaluated included the effect of the lithium concentration on activation of the sensor by cyclic voltammetry, the pH of the electrolyte solution, and the selectivity towards Li+ compared to other alkali and alkaline-earth metal ions. There was an important influence of the unit cell size of the material on the linear range, detection limit, and selectivity of the sensor. Reduction in the size of the tunnel for insertion of the lithium in the porous structure of the oxide directly affected the potentiometric performance of the electrode. Sensor performance increased in the order: Ga0.02Mn1.98O4 > Ga0.02Mn1.98O3.98S0.02 > Ga0.02Mn1.98O3.98F0.02. The observed super-Nernstian response could be explained by a mixed potential arising from two equilibria (redox and ion exchange) in the spinel-type manganese oxide. Sensitivity and the influence of pH on the electrode response were directly related to the doping agents present in the oxide structure. Faculty of Science and Technology, São Paulo State University (UNESP) Department of Chemistry, Federal University of Sao Carlos Faculty of Science and Technology, São Paulo State University (UNESP) FAPESP: 2005/01296-4 FAPESP: 474367/2004-5