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Composites of metal organic framework MOF-5 and conjugated polymer polyaniline (PANI) were synthesized for the first time. Two procedures, which avoid humidity during the synthesis in order to preserve the structure of MOF-5, were applied. In the first one, dissolved part of nonconducting emeraldine base form of PANI (PANI-EB) in N,N΄-dimethylformamide was mixed with MOF-5 in different mass ratios. In the second one, the composites were prepared mechano-chemically, by using powdered conducting emeraldine salt form of PANI (PANI-ES) and solid MOF-5, mixed in chloroform in different mass ratios. The composites were characterized by various techniques: scanning electron microscopy (SEM), FTIR spectroscopy, nitrogen sorption and electrical conductivity measurements, XRD, and flame atomic absorption spectroscopy (FAAS). The procedure which used PANI-EB led to microporous PANI/MOF-5 composites with very high BET specific surface area, SBET (the highest value SBET of c.a. 2700 m2 g−1, even higher than SBET of starting pure MOF-5, showed the composite which contains 89 wt.% of MOF-5) and low conductivity (∼10-7 S cm−1). The second procedure which used PANI-ES gave microporous PANI/MOF-5 composites which showed moderate conductivities (the highest conductivity of 1.0 ⋅ 10−3 S cm-1 exhibited the composite which contains 25 wt.% of MOF-5) and also high SBET values, but lower than those measured for the composites with PANI-EB (the highest SBET of c.a. 850 m2 g-1 showed the composite of PANI doped with HCl which contains c.a. 77 wt.% of MOF-5). XRD measurements confirmed that predominately cubic crystalline structure of MOF-5 was present in almost all composites. © 2020 Elsevier B.V.

Efficient and simple room temperature synthesis of pure phase metal-organic framework MOF-5 has been developed, based on the use of anhydrous zinc acetate, Zn(OAc)2, as a precursor, instead of zinc acetate dihydrate. Crucial influence of water on a reaction pathway was revealed. In order to obtain MOF-5, different amounts of water have been added into the solutions of Zn(OAc)2 in N,N-dimethylformamide (DMF) to prepare in situ zinc acetate hydrates with 0.25, 0.5, and 1.0 mol of water. Commercially available zinc acetate dihydrate was also used as a precursor for comparison. These solutions were mixed at room temperature with the solution of 1,4-benzenedicarboxylic acid in DMF in the absence of any base. Based on XRD, FTIR, and SEM measurements, it was shown that the optimal amount of water for the synthesis of completely pure, crystalline phase MOF-5 is 0.25–0.5 mol of water per one mole of Zn. The reaction systems with 1.0 and 2.0 mol of water per one mole of Zn also led to solids with MOF-5 as the dominant phase, but they also contain small amounts of another phase, formed due to the decomposition (hydrolysis) and/or distortion of the MOF-5 framework in the presence of excess amounts of water. The product synthesized in the system without any added water contains MOF-5 phase in a very small amount, while main phase is zinc 1,4-benzenedicarboxylate and/or zinc hydrogen 1,4-benzenedicarboxylate. Regular cubic submicro/microcrystal morphology exhibited the samples synthesized using 0.5 and 0.25 mol water per one mole of Zn (pure MOF-5), while for the samples synthesized at mole ratios H2O/Zn2+ = 1.0 and 2.0 other particle shapes are also seen. By nitrogen sorption measurements it was found that the highest values of BET specific surface area (1937 m2 g−1), micropore volume (0.83 cm3 g−1), and micropore area (1590 m2 g−1) showed MOF-5 prepared at mole ratio H2O/Zn2+ = 0.5, while the highest yield of MOF-5 is obtained with the theoretical mole ratio H2O/Zn2+ = 0.25. Th

A facile and fast aqueous phase-based strategy to synthesize silver-polyaniline-polyvinylpyrrolidone (Ag-PANI-PVP) nanocomposites, via chemical oxidative polymerization method is presented. In the presence of polyvinylpyrrolidone (PVP), which has an accelerating effect on the oxidation of aniline with silver nitrate, Ag nanoparticles (AgNPs) were in situ generated in aqueous solution during simultaneous formation of polyaniline (PANI), without any additional reducing agent or complicated treatment. We have demonstrated synthesis of three stabile Ag-PANI-PVP nanocomposites with different content, size, and morphology of Ag nanoparticles by varying the experimental parameters, such as pH and PVP concentration. As a result, this led to different Ag nanostructures (spherical and polyhedral NPs), and, consequently, different morphology of formed nanocomposites (granular and nanosheets). The physicochemical properties of nanocomposites were examined by using different analytical techniques (UV–Vis, TEM, FESEM, FT-IR, XRD, and Raman). It is found that optical properties, electrical conductivity and the content of Ag in the composites vary depending on the synthetic conditions. The electrocatalytic behavior of Ag-PANI-PVP nanocomposites was examined towards the oxygen reduction reaction in acidic and alkaline media. All tested nanocomposites showed high electrocatalytic activity, while the most active catalyst is the one with the highest electrical conductivity (≈0.6 S cm−1) and the lowest Ag content (3.4 wt%), synthesized in the solution without added acid. The simplicity of synthesis and good electrocatalytic efficiency of prepared nanocomposites combined with large-scale availability make them attractive as Pt-free electrocatalysts.

A serie of novel ZrO2/Polyaniline (PANI) hybrid nanocomposite powders were successfully synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate (APS) in water, in the presence of ZrO2 nanoparticles. Syntheses were performed at initial ZrO2/aniline mole ratios 50,100 and 150 to produce ZP-50, ZP-100 and ZP-150. The morphological, structural, and optical properties of the synthesized nano composites were studied using Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Raman, UV-Vis and Electron-paramagnetic resonance (EPR) spectroscopies. EPR spectra of ZP-50 and ZP-100 nanocomposites showed the presence of intensive peak at the g-values comparable to that for free electrons (2.0023) indicating the presence of oligo/poly (semiquinone radical cations), i.e. polarons as charge carriers in PANI part; ZP-150 showed weak polaron peak of PANI, and peak that can be assigned to defects in zirconia matrix (Zr3+, oxygen vacancies). The monoclinic crystal structure of ZrO2 nanoparticles in all nanocomposites was confirmed by XRD and by Raman spectroscopy. The photocatalytic activities of ZP nanocomposites were evaluated using the photocatalytic degradation of trichlorophenol (TCP) and Rhodamine B model compounds and compared with the activity of bare ZrO2 nanoparticles. Enhanced degradation efficiencies of nanocomposites regarding TCP degradation were observed. (C) 2017 Elsevier B.V. All rights reserved.

A serie of novel ZrO2/Polyaniline (PANI) hybrid nanocomposite powders were successfully synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate (APS) in water, in the presence of ZrO2 nanoparticles. Syntheses were performed at initial ZrO2/aniline mole ratios 50,100 and 150 to produce ZP-50, ZP-100 and ZP-150. The morphological, structural, and optical properties of the synthesized nano composites were studied using Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Raman, UV-Vis and Electron-paramagnetic resonance (EPR) spectroscopies. EPR spectra of ZP-50 and ZP-100 nanocomposites showed the presence of intensive peak at the g-values comparable to that for free electrons (2.0023) indicating the presence of oligo/poly (semiquinone radical cations), i.e. polarons as charge carriers in PANI part; ZP-150 showed weak polaron peak of PANI, and peak that can be assigned to defects in zirconia matrix (Zr3+, oxygen vacancies). The monoclinic crystal structure of ZrO2 nanoparticles in all nanocomposites was confirmed by XRD and by Raman spectroscopy. The photocatalytic activities of ZP nanocomposites were evaluated using the photocatalytic degradation of trichlorophenol (TCP) and Rhodamine B model compounds and compared with the activity of bare ZrO2 nanoparticles. Enhanced degradation efficiencies of nanocomposites regarding TCP degradation were observed. (C) 2017 Elsevier B.V. All rights reserved.

A simple bottom-up method for the preparation of novel and very efficient photocatalytic nanocomposite system based on carbonized form of polyaniline (PANI) and colloidal TiO2 nanocrystals has been developed. The carbonized PANI/TiO2 nanocomposites were synthesized in a two-step procedure. Firstly, non-carbonized PANI/TiO2 nanocomposites were synthesized by the chemical oxidative polymerization of aniline (ANI) with ammonium peroxydisulfate, in the presence of colloidal TiO2 nanoparticles (TiO2 NPs) (d 4.5 nm). Initial [TiO2 NANI] mole ratios were 20, 50, and 80. In the second step, following the polymerization process, the carbonization of PANI/TiO2 nanocomposites was performed by thermal treatment in an inert atmosphere at 650 degrees C. The morphological and structural properties of the carbonized nanocomposites were studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Raman spectroscopy. The accomplishment of complete carbonization of PANI in PANI/TiO2 nanocomposites was confirmed by Raman spectroscopy. The appearance of anatase and rutile crystal forms in TiO2 NPs upon carbonization, with mass ratio depending on the initial molar ratio of ANI and TiO2 NPs was revealed by XRD measurements, TEM, SEM and Raman spectroscopy. The photocatalytic activities of carbonized PANI/TiO2 nanocomposites were evaluated following the photocatalytic degradation processes of Rhodamine B and Methylene blue. Carbonized PANI/TiO2 nanocomposites showed higher photocatalytic efficacy compared to bare TiO2 NPs and non-carbonized PANI/TiO2 nanocomposites. The porosity and surface structure of carbonized PANI/TiO2 nanocomposites, as well as crystalline structure of TiO2, affect photocatalytic activity of nanocomposites. (C) 2017 Elsevier B.V. All rights reserved.

Istraživanja u oblasti sinteze, karakterizacije i primene nanokompozita na bazi nanočestica metala i provodnih polimera kao što je polianilin (PANI), sa jedinstvenim fizičkohemijskim svojstvima, veoma su aktuelna. Kombinovanjem karakterističnih svojstava obe komponente (nanočestica metala i PANI), mogu se sintetisati nanokompoziti poboljšanih optičkih, električnih, termičkih i drugih karakteristika u odnosu na polazne komponente, sa mogućom primenom ovih materijala kao senzora neorganskih i organskih jedinjenja, u katalizi, elektrokatalizi, mikrobiologiji i elektronici.Modifikacija i korišćenje specifičnih karakeristika nanočestica bakra (Cu) i zlata (Au), pojedinačno ili kao nanokompozita ovih čestica sa provodnim polimerom PANI, predmet su istraživanja ove doktorske disertacije. Pored toga, disertacija se bavi i ispitivanjem mogućnosti primene ovih sistema kao antimikrobnih i elektrokatalitičkih materijala. Nanočestice Cu i Au sintetisane su jednostavnim oksido–redukcionim reakcijama u vodi kao medijumu, dok su nanokompoziti ovih čestica sa PANI, sintetisani novim metodama, primenom reakcije oksidativne hemijske polimerizacije anilina koja se odvija istovremeno kada i formiranje nanočestica Cu ili Au ili se odvija u prisustvu prethodno sintetisanih nanočestica (Au) različitih veličina. Na osnovu istraživanja navedenih sistema, doktorska disertacija je tematski podeljena u četiri celine:1. Sinteza i karakterizacija nanočestica Cu i ispitivanje njihovog uticaja na razvoj tri jednoćelijska patogena mikroorganizma: Gram – negativne bakterije Escherichia coli, Gram – pozitivne bakterije Staphylococcus aureus i gljivice Candida albicans;2. Sinteza i karakterizacija nanokompozita PANI sa česticama Cu i ispitivanje njegove antimikrobne aktivnosti prema prethodno navedenim patogenim mikroorganizmima;3. Sinteza i karakterizacija nanokompozita PANI sa česticama Au sintetisanim ex situ i ispitivanje uticaja ovih nanočestica na svojstva i provodljivost PANI;4. Sinteza i karakt, Synthesis, characterization and application of nanocomposites based on metal nanoparticles and conductive polymers such as polyaniline (PANI), with unique physicochemical properties, is currently receiving tremendous attention. By combining the characteristics of these two components (metal nanoparticles and PANI), nanocomposites with improved optical, electrical, thermal and other characteristics with respect to the initial components can be created, with large variety of applications including catalysis, electrocatalysis, sensors of inorganic and organic compounds, as well as applications in microbiology and electronic devices.Modification and utilization of specific properties of copper (Cu) and gold (Au) nanoparticles, either individually or in the nanocomposites with conductive polymer PANI are the subjects of this PhD thesis. Moreover, potential applications of these systems as antimicrobial and electrocatalytic materials are investigated. Cu and Au nanoparticles were synthesized by simple oxidation–reduction reactions in water as a medium, while the nanocomposites of these particles with PANI were synthesized by novel methods, using chemical oxidative polymerization of aniline simultaneously with the formation of Cu or Au nanoparticles, or in the presence of preformed Au nanoparticles of different sizes.Topic of this work can be apart into four different units:1. Synthesis and characterization of Cu nanoparticles and assaying of their impact on the development of three pathogen microorganisms: Gram – negative bacteria Escherichia coli, Gram – positive bacteria Staphylococcus aureus and fungus Candida albicans;2. Synthesis and characterization of nanocomposite based on PANI and Cu nanoparticles and assaying of its antimicrobial activity against the above–mentioned pathogen microorganisms;3. Synthesis and characterization of nanocomposites based on PANI and ex situ synthesized Au nanoparticles, as well as investigation of their influence on PANI characteristics

Gold‒polyaniline (AuPANI) nanocomposite, with granular morphology of PANI and rod‒like Au nanoparticles (NPs) as dominate structure distributed in it, was prepared by interfacial polymerization method in an immiscible water/toluene biphasic system. Simultaneously with the aniline polymerization to polyaniline (PANI) by HAuCl4, as an oxidant, AuNPs are formed. AuPANI composite as green precipitate is collected from aqueous phase. Polyaniline in the composite is in the conductive emeraldine salt form (PANIES), with high amount of Au (28.85 wt %). Nanocomposite showed great electrocatalytic activity towards the electrochemical O2reduction reaction (ORR), with high ORR onset potential and high selectivity for O2reduction to water. This makes it a good candidate for a new class of Pt‒free ORR catalyst.

Nanofibrous polyanilines (PANIs) were synthesized by several oxidative polymerization pathways that have in common the presence of excess oxidant(s) (ammonium peroxydisulfate and its mixture with hydrogen peroxide), the absence of added acid, and the absence of external template (self-assembly process). Conducting forms of the synthesized PANI nanofibers (re)doped with various acids were further used as precursors for carbonization process to obtain nanofibrous carbonaceous materials (Carb-PANIs). Morphology, molecular structure, surface properties and electrical characteristics of PANI nanofibrous precursors and their carbonized counterparts were studied by scanning electron microscopy, Raman spectroscopy, by measurements of zeta-potential and determination of isoelectric points, as well as by measurements of electrical conductivity. (C) 2016 Elsevier B.V. All rights reserved.

U poslednjih 30 godina nanokristalni TiO2 je privukao veliku paţnju kako kao fotokatalizator za različite praktične primene, tako i kao deo fotohemijskih sistema, kao što je Grecelova ćelija. Zbog svog velikog energetskog procepa (Eg=3,2 eV), TiO2 apsorbuje manje od 5 % dostupnih fotona sunčeve svetlosti, što ga čini relativno neefikasnim fotokatalizatorom. Takođe, glavni energetski gubitak nastaje usled procesa radijativne ili neradijativne rekombinacije naelektrisanja nastalih fotoekscitacijom TiO2, što se manifestuje kao relativno nizak prinos dugo-ţivećih razdvojenih naelektrisanja. Dakle, uspešna fotohemijska konverzija energije i reakcije koje slede zahtevaju produţeno vreme ţivota razdvojenih fotostvorenih naelektrisanja kao i apsorpciju u vidljivom delu spektra..., In the last 30 years nanocrystalline TiO2 has attracted widespread attention as a photocatalyst in various practical applications as well as the part of photoelectrochemical systems, such as Grätzel cells. Due to its large band gap (Eg = 3,2 eV), TiO2 absorbs less than 5% of the available solar light photons, being a relatively inefficient photocatalyst. Also, the main energy loss is due to the process of radiative or nonradiative recombination of charges generated upon photoexcitation of TiO2, which is manifested as the relatively low yield of long-lived separated charges. Hence, the successful photochemical energy conversion and subsequent chemical reactions require both the extended lifetime of separated photogenerated charges and the response in the visible spectral region...

Polyester fibers gained significant share from all other man-made fibers, but despite numerous advantages a characteristic static electricity generation is still seeking innovative solutions. In order to improve electrical properties of poly(ethyleneterephthalate) (PET) fabric, coating consisting of polyaniline/TiO2 (PANI/TiO2) nanocomposite was deposited on its surface. Coating was synthesized in acidic medium by the chemical oxidative polymerization of aniline with ammonium peroxydisulfate CAPS) in the presence of colloidal TiO2 nanoparticles (d similar to 4.5 nm) and PET fabric. The morphology, molecular structure and dielectric properties of PANI/TiO2 nanocomposites were studied by scanning electron microscopy (SEM), Raman and dielectric spectroscopies. SEM analysis revealed the formation of non-uniform PANI coating on the reference PET sample. In contrast, uniform PANI/TiO2 coating on the surface of PET fabric was generated when TiO2 nanoparticles were engaged. The existence of conductive emeraldine salt form of PANI and phenazine units was confirmed by Raman spectroscopy. Formation mechanisms of PANI and PANI/TiO2 coatings on PET fabrics were proposed. The presence of TiO2 nanoparticles significantly affected the dielectric properties (permittivity and loss tangent) and AC conductivity of PANI/TiO2 coated PET fabrics. PET fabrics coated by PANI/TiO2 nanocomposite showed up to two orders of magnitude higher conductivity in the measured frequency region compared to PANI coated PET fabric.

We report on the possibility to build hierarchically organized three-dimensional (3D) titania spherical particles having high surface-to-volume-ratio, by aerosol processing of nanotubular building blocks. Morphology and crystal structure of titania based spherical assemblies, obtained in the temperature range from 150 to 650 degrees C, were characterized by means of scanning and transmission electron microscopy, x-ray powder diffraction and Raman spectroscopy. Initial shape of 1D building units, nanotubes, was well preserved in the spherical assemblies processed at 150 and 450 degrees C. Processing at 650 degrees C resulted in a collapse of the nanotubular building blocks and formation of the assemblies of irregularly shaped TiO2 nanoparticles. Structural analysis revealed several phase transitions in titania spherical assemblies in course with the temperature increase indicating possibility of in-situ phase composition adjustment during aerosol processing.

Gold-polyaniline (Au-PANI) nanocomposite was prepared using a simple interfacial polymerization method, performed in an immiscible water/toluene biphasic system using tetrachloroaurate, AuCl4- as an oxidant. The formation of Au+ nanoparticles (AuNPs) or Au-PANI nanocomposite can be controlled to a certain degree by varying the ratio of initial Au+ and aniline concentrations. Under optimal condition (HAuCl4/aniline ratio is 1:2), green dispersion of Au-PANI nanocomposite is produced in aqueous phase, whose morphology, structure and physicochemical properties are investigated in details. The nanocomposite shows granular morphology with mostly rodlike AuNPs embedded in polymer. It was found that polyaniline in the composite is in the conducting emeraldine salt form, containing high amount of Au (28.85 wt %). Furthermore, the electrical conductivity of the nanocomposite was found to be four-fold higher than that of the polymer itself. In addition, the nanocomposite powder, isolated from the as-prepared aqueous dispersion, can later be easily redispersed in water and further used for various applications. Moreover, the obtained Au-PANI nanocomposite showed excellent electrocatalytic performance toward the electrochemical oxygen reduction reaction (ORR), with high ORR onset potential and good selectivity. This makes it a promising candidate for a new class of Pt-free ORR. catalyst.

In order to elucidate the role of B, N, and P dopants in carbon materials on the kinetics of oxygen reduction reaction (ORR) and to provide a fair comparison of the effects of each dopant, a series of ordered mesoporous carbons (OMCs) with low concentration of heteroatoms ( LT 1 at%) has been prepared. Doped OMCs were characterized using X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), Raman spectroscopy, X-ray powder diffraction (XRD), and N-2 physisorption measurements. Comparative study of the ORR activity of these materials in alkaline solution was performed using rotating disk electrode voltammetry. The experiments evidenced that, compared to non-doped OMC, charge transfer kinetics was improved independently on the nature of the heteroatom. The decrease of the ORR overvoltage and the increase of the mass activity upon doping are similar for B and P and less prominent for N. On the other hand, OMCs doped with low levels of B and N were found to be selective for O-2 reduction to peroxide, while for P-doped OMCs, the apparent number of electrons consumed per O-2 molecule was up to 3.1. Experimental measurements were complemented by density functional theory (DFT) calculations.

Composites consisting of polyaniline (PANI) and gold nanoparticles (AuNPs) with an average size of 17 and 30 nm were synthesized by an interfacial method performed in an immiscible water/toluene biphasic system. The effect of embedded AuNPs on the morphology, structure and physicochemical properties of Au/PANI nanocomposites was investigated using scanning and transmission electron microscopies, UV-vis, FTIR, Raman and ICP-AES spectroscopies, X-ray diffraction, elemental analysis and conductivity measurements. Microscopy studies indicated nanofibrous morphology for pure PAN! and Au/PANI nanocomposites, while FTIR and Raman spectroscopies were confirmed emeraldine salt form of PANI chains and the presence of phenazine units. Also, Raman spectroscopy measurements revealed an inherent structural inhomogeneity at the macromolecular level that exist in PANI chains in its pure form as well as in Au/PANI nanocomposites. In addition, the increase of the electrical conductivity observed in the nanocomposites was discussed. (C) 2014 Elsevier B.V. All rights reserved.

Резиме: Утицај електромагнетног зрачења на једнослојне угљеничне нанотубе јепредмет интензивног проучавања. У оквиру ове докторске дисертације испитаноје дејство електромагнетног зрачења из видљиве, инфрацрвене и микроталаснеобласти на танке слојеве једнослојних угљеничних нанотуба депонованихвакуумском филтрацијом. У оквиру дисертације су коришћене нанотубе двапроизвођача, које су добијене методом хемијске депозиције из парне фазе али узупотребу различитог катализатора. Танки слојеви угљеничних нанотубадепоновани методом вакуумске филтрације су испитани раманскомспектроскопијом помоћу три ексцитациона ласера: 532, 633 и 780 nm имикроскопијом атомских сила. Установљено је да 532 nm ласер испитује стање наповршини узорка, док са друге стране ласер на 780 nm испитује целу запреминуузорка. Последице озрачивања ОПО ласером различитих таласних дужина изобласти видљивог зрачења су декомпозиција, фотооксидација и издвајање изснопова. Издвајање из снопова и уклањање угљеничних нечистоћа се јављајунакон динамичке оксидације. Осим тога, приликом динамичке оксидације можедоћи до сагоревања нанотуба мањих пречника. Изотермална оксидација имаразличит утицај на нанотубе коришћене у склопу ове дисертације, што јепоследица различитих катализатора коришћених за време синтезе. Озрачивањемикроталасима изазива повећање температуре узорка током озрачивања, али недоводи до селективне деструкције једног типа нанотуба. Дејство микроталаса наструктуру угљеничних нанотуба се махом манифестује у издвајању појединихнанотуба из снопова., The influence of electromagnetic waves upon single wall carbon nanotube isthe subject of great scientific interest. In this PhD thesis a detailed study of the influenceof electromаgnetic radiation from visible, infrared and microwave regions upon thinfilms of single wall carbon nanotubes prepared by vacuum filtration is presented. In thisPhD thesis carbon nanotubes from two different suppliers were used; both weresynthesized by chemical vapor deposition method but with different catalyst. Thin filmsof carbon nanotubes deposited by vacuum filtration method are characterized by Ramanspectroscopy using three excitation lines: 532, 633 and 780 nm and by atomic forcemicroscopy. It was established that the 532 nm excitation line probes the surface ofnanotube films, while the 780 nm excitation line probes the bulk of films. The effects ofOPO laser with radiation of different wavelengths upon thin films of carbon nanotubesare decomposition, photooxidation and debundling. Debundling and deffective carbonremoval is the major effect of dynamic oxidation. Also, dynamic oxidation can causethe removal of small diameter nanotubes. Isothermal oxidation causes different effectson carbon nanotubes from different suppliers, which is the consequence of the catalystsused during synthesis. Microwave irradiation upon carbon nanotubes results intemperature increase of the samples during irradiation, but selective destruction of onetype of SWCNT was not observed. Major effect of microwave irradiation wasdebundling.

Predmet istraživanja ove doktorske disertacije podrazumeva sintezunanokompozita na bazi polianilina (PANI) i nanočestica titan (IV)‐oksida (TiO2)različitih oblika novom metodom, njihovu karakterizaciju većim brojemfizičkohemijskih metoda, kao i ispitivanje mogućnosti njihove primene ufotokatalizi.PANI/TiO2 nanokompoziti sintetisani su novim, ekonomičnim postupkomhemijske oksidativne polimerizacije anilina amonijum peroksidisulfatom u vodi,bez dodatka kiseline, kalupa i površinskih modifikatora, a u prisustvu nanočesticaTiO2. Optimizacijom sinteze nanokompozita kroz variranje polaznog molskogodnosa anilina i TiO2 pronađeni su uslovi za dobijanje PANI/TiO2 nanokompozita ukojima su prisutne polianilinske nanostrukture. U disertaciji je ispitan uticajnanočestica TiO2 na tok, brzinu i prinos reakcije polimerizacije anilina kao i namorfologiju, strukturu, provodljivost i magnetna svojstva polianilina. U ciljuizučavanja potencijalne primene sintetisanih nanokompozita, ispitivana jesposobnost polianilina da senzitizira i pospeši fotokatalitičke procese na površininanočestica TiO2.Rad se tematski može podeliti u tri celine i to:1. Sinteza i karakterizacija nanokompozita na bazi polianilina i koloidnihnanočestica TiO2;2. Sinteza i karakterizacija nanokompozita na bazi polianilina i nanotubaTiO2;3. Ispitivanje fotokatalitičke aktivnosti nanokompozita na bazi polianilina ikoloidnih nanočestica TiO2.Prvi deo teze odnosi se na ispitivanje svojstava nanokompozita sintetisanihhemijskom oksidativnom polimerizacijom anilina, uz pomoć amonijumperoksidisulfata, u prisustvu koloidnih nanočestica TiO2 (d = 4, 5 nm), bez dodatka..., The subject of this PhD thesis is the synthesis of nanocomposites based onpolyaniline (PANI) and titanium (IV) oxide (TiO2) by a novel method, withoutadded acids, templates and surfactants, their characterization by variousphysicochemical methods, as well as an investigation of their potential applicationin the field of photocatalysis.PANI/TiO2 nanocomposites were synthesized by a novel, economicalmethod of oxidative polymerization of aniline with ammonium peroxydisulfate inwater, without added acid, in the presence of shaped TiO2 nanoparticles. Theoptimization of polymerization process was done by varying initial mole ratio ofaniline/TiO2. The aim was to find optimal conditions for the synthesis ofPANI/TiO2 nanocomposites containing polyaniline nanostructures. Influence ofTiO2 nanoparticles on the course, rate and yield of polymerization process ofaniline, as well as their influence on the morphology, structure, electricalconductivity and magnetic properties of polyaniline is examined. Moreover,potential application of PANI/TiO2 nanocomposites in photocatalysis and ability ofpolyaniline to sensitize TiO2 nanoparticles are investigated.Topic of this work can be divided into three main units:1. Synthesis and characterization of nanocomposites based on polyanilineand colloidal TiO2 nanoparticles;2. Synthesis and characterization of nanocomposites based on polyanilineand TiO2 nanotubes;3. The study of photocatalytic activity of nanocomposites based onpolyaniline and colloidal TiO2 nanoparticles.The first part of the thesis refers to the investigation of properties ofnanocomposites synthesized by the chemical oxidative polymerization of anilinewith ammonium peroxydisulfate, in the presence of colloidal TiO2 nanoparticles(d=4, 5 nm), without added acid. As a reference sample, pure polyaniline...

Polyaniline/TiO2 nanocomposite powders were successfully synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in water without the addition of acid, in the presence of colloidal TiO2 nanoparticles (d similar to 4.5 nm). The morphological, structural, and optical properties of the synthesized nanocomposites prepared at initial TiO2/aniline mole ratios of 50,100, and 150 were studied using transmission electron microscopy, X-ray powder diffraction, Raman and UV-vis spectroscopies. The presence of emeraldine salt and the base form of linear polyaniline (PANI) chains as well as the presence of phenazine units, branched PANI chains, oligomeric structures and short PANI chains in PANI/TiO2 nanocomposites was confirmed by Raman spectroscopy. The anatase crystal structure of TiO2 nanopartides in all the nanocomposites was confirmed by X-ray powder diffraction measurements and by Raman spectroscopy. The photocatalytic activities of PANI/TiO2 nanocomposites were evaluated using the photocatalytic degradation of Rhodamine B and Methylene blue as model compounds and compared with the activity of bare colloidal TiO2 nanoparticles. Enhanced degradation efficiencies in the dyes used were observed. A possible explanation for the PANI/TiO2 photocatalytic activities was suggested, taking into account the influence of the molecular structures of the used dyes and PANI in PANI/TiO2 nanocomposites. (C) 2013 Elsevier B.V. All rights reserved.

Nanocomposites consisting of self-assembled polyaniline (PANI) nanostructures and titania nanotubes (TiO2-NT) were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous dispersion of TiO2-NT (outer diameter similar to 10 nm), without added acid. The influence of initial mole ratio of aniline to TiO2 (80, 20, and 5) on the morphology, electrical conductivity, molecular structure, crystallinity, and magnetic properties of synthesized PANI/TiO2 nanocomposites was studied. Transmission electron microscopy, Raman spectroscopy, and X-ray powder diffraction proved that the shape and structure of TiO2-NT in the final nanocomposites were preserved. The shape of PANI nanostructures formed in the nanocomposites was influenced by the initial aniline/TiO2-NT mole ratio. Nanotubes and nanorods are predominant PANI nanostructures in the nanocomposite prepared with the highest aniline/TiO2 mol ratio of 80. The decrease of aniline/TiO2 molar ratio induced more pronounced formation of nanorod network. The electrical conductivity of PANI/TiO2 nanocomposites was in the range (1.3-2.4) x 10(-3) S cm(-1). The nanocomposites exhibit weak ferromagnetic behavior. Approximately order of magnitude lower values of coercive field and remanent magnetization were obtained for nanocomposite samples in comparison to pure PANI.

Single phase tungsten carbide nanoparticles (WC-NPs), (mean particle diameter 5.4 nm), distributed over carbonized polyaniline (C-PANT) nanotubes/nanosheets were synthesized by a solid state reaction between WO3 and nitrogen-rich carbonized polyaniline at 1000 degrees C in a reducing atmosphere. The resulting composite was characterized by X-ray diffractometry, electron microscopy, thermogravimetry in oxidizing and reduction atmospheres and elemental analysis. We suggested that the synthesis of WC as a single phase was facilitated by reactive C atoms with dangling bonds, formed upon nitrogen removal. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Microporous conducting nitrogen-containing nanostructured carbon with excellent catalytic activity for the electrochemical synthesis of hydrogen peroxide was synthesized by the carbonization of self-assembled polyaniline 3,5-dinitrosalicylate nanorods. Carbonization was carried out by means of gradual heating in a nitrogen atmosphere up to 800 degrees C. Carbonized polyaniline nanorods containing 9.8 wt.% of nitrogen had a conductivity of 0.35 S cm(-1). The electrical characteristics, morphology, textural parameters, elemental composition, molecular structure and crystallinity of novel carbonized nanostructured polyaniline were investigated by conductivity measurements, scanning and transmission electron microscopies, nitrogen adsorption-desorption measurements, elemental microanalysis, XPS, FTIR and Raman spectroscopies, and XRD, respectively. The electrocatalytic activity of carbonized polyaniline nanorods towards oxygen reduction in alkaline conditions has been studied by the voltammetry with the rotating disk electrode. (C) 2011 Elsevier Inc. All rights reserved.

Nitrogen-doped carbon nanomaterials were synthesized by the carbonization of three different nanostructured polyaniline (PANI) salt precursors: PANI 3,5-dinitrosalicylate nanorods, PANI 5-sulfosalicylate nanorods/nanotubes, and PANI hydrogen sulfate nanorods/nanotubes/nanosheets. A comparative study of the electrocatalytic activity of these materials for oxygen reduction reaction (ORR) in alkaline solution was performed by using rotating disk electrode voltammetry. The electrochemical data were correlated to the structural and textural data obtained by Raman spectroscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, elemental analysis and nitrogen sorption analysis. A fine interplay of textural characteristics, overall content of surface nitrogen and content of specific surface nitrogen functional groups were found to be responsible for a considerable variations in electrocatalytic properties toward ORR, involving variations in apparent number of electrons exchanged per O-2 molecule (from 2 to nearly 4) and variations in onset potential. The catalyst loading was found to influence remarkably the ORR kinetics. The excellent electrocatalytic activity was found for carbonized PANI 5-sulfosalicylate. Namely, it exhibited the most positive onset potential amounting to -0.05 V vs. SCE at a catalyst loading of 500 mu g cm(-2). The interrelation between the electrocatalytic activity and the electrical double layer charging/discharging characteristics of the investigated N-doped nanocarbon materials was revealed. (C) 2012 Elsevier B.V. All rights reserved.

Novel ferromagnetic semiconducting polyaniline PANI/TiO2 nanocomposites were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium, in the presence of colloidal TiO2 nanoparticles (d similar to 4.5 nm), without added acid. The morphological, magnetic, structural, and optical properties of the PANI/TiO2 nanocomposites prepared at initial aniline/TiO2 mole ratios 80, 40, and 20 were studied by scanning electron microscopy, superconducting quantum interference device, X-ray powder diffraction, FTIR, Raman, and UV-Vis spectroscopies. The emeraldine salt form of linear PANI chains as well as the presence of phenazine units, branched PANI chains, and anatase crystalline structure of TiO2 in PANI/TiO2 nanocomposites was confirmed by FTIR and Raman spectroscopies. The electrical conductivity of synthesized composites was similar to 10-3 S cm-1. The room temperature ferromagnetic response with coercive field of Hc similar to 300 Oe and the remanent magnetization of Mr similar to 4.35 x 10-4 emu/g was detected in all investigated PANI/TiO2 nanocomposites. POLYM. COMPOS., 2012. (c) 2012 Society of Plastics Engineers

Self-assembled polyaniline (PANI) nanotubes, accompanied with nanoribbons, were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium, in the presence of colloidal titanium dioxide (TiO(2)) nanoparticles of 4.5 nm size, without added acid. The morphology, structure, and physicochemical properties of the PANI/TiO(2) nanocomposites. prepared at various initial aniline/TiO(2) mole ratios, were studied by scanning (SEM) and transmission (TEM) electron microscopies, FTIR, Raman and inductively coupled plasma optical emission (ICP-OES) spectroscopies, elemental analysis, X-ray powder diffraction (XRPD), conductivity measurements, and thermogravimetric analysis (TGA). The electrical conductivity of PANI/TiO(2) nanocomposites increases in the range 3.8 x 10(-4) to 1.1 x 10(-3) S cm(-1) by increasing aniline/TiO(2) mole ratio from 1 to 10. The morphology of PANI/TiO(2) nanocomposites significantly depends on the initial aniline/TiO(2) mole ratio. In the morphology of the nanocomposite synthesized using aniline/TiO(2) mole ratio 10, nanotubes accompanied with nanosheets prevail. The nanocomposite synthesized at aniline/TiO(2) mole ratio 5 consists of the network of nanotubes (an outer diameter 30-40 nm, an inner diameter 4-7 nm) and nanorods (diameter 50-90 nm), accompanied with nanoribbons (a thickness, width, and length in the range of 50-70 nm, 160-350 nm, and similar to 1-3 mu m, respectively). The PANI/TiO(2) nanocomposite synthesized at aniline/TiO(2) mole ratio 2 contains polyhedral submicrometre particles accompanied with nanotubes, while the nanocomposite prepared at aniline/TiO(2) mole ratio 1 consists of agglomerated nanofibers, submicrometre and nanoparticles. The presence of emeraldine salt form of PANI, linear and branched PANI chains, and phenazine units in PANI/TiO(2) nanocomposites was proved by FTIR and Raman spectroscopies. The improved thermal stability of PANI matrix in all PANI/TiO(2) nanocomposites was

Poly-(1-naphthylamine) films were synthesized potentiodinamically and potentiostatically from 1-naphthylamine in neutral acetonitrile medium using a platinum electrode. These polymer films were investigated by infrared spectroscopy. Contrary to earlier published results neglecting the stereochemistry of the poly-(1-naphthylamine), we predict on the basis of quantum stereochemical analysis of the possible structural subunits of the polymer, that the ordinary N–C(4) coupled product is not predominant in the polymer because it is far removed from the expected planarity. Based on the results of IR investigations and semiempirical quantum chemical calculations, it is proposed that the polymer products are formed via mixed N–C(4), N–C(5) and N–C(7) coupling routes. The heats of formation of the oxidized 1-naphthylamine dimers and hexamers were calculated., Poli-(1-naftilaminski) filmovi sintetisani su potenciostatski i potenciodinamički iz neutralnog acetonitrilnog rastvora 1-naftilamina na platinskoj elektrodi. Ovi polimerni filmovi ispitivani su IR spektroskopijom. Za razliku od ranije publikovanih rezultata koji su zanemarivali stereohemiju poli-1(-naftilamina), u ovom radu se predviđa na osnovu kvantne stereohemijske analize mogućih strukturnih jedinica polimera da uobičajeni N–C(4) kuplovani produkt nije predominantan u polimeru, jer njegova struktura nije planarna. Na osnovu rezultata IR ispitivanja i semiempirijskih kvantno-hemijskih proračuna mi pretpostavljeno je da se polimerni produkti formiraju kombinovanim N–C(4), N–C(5) i N–C(7) načinima vezivanja 1-naftilamina. U ovom radu su takođe izračunate toplote nastajanja oksidovanih dimera i heksamera 1-naftilamina.