Síntese de estruturas tridimensionais de WO3 decoradas com nanopartículas de prata obtidas pelo método hidrotermal: aplicação na inativação bacteriana e degradação de corantes
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Data
2022-04-29
Autores
Silva, Regina Aparecida Capeli
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Universidade Estadual Paulista (Unesp)
Resumo
As estruturas de WO3/Ag foram sintetizadas com sucesso pela rota hidrotérmica, utilizando como precursores o ácido tunguístico, o peróxido de hidrogênio e nitrato de prata. A síntese de nanocompósitos de WO3/Ag foi feita nas concentrações de Ag (prata) igual a 0,01 M, 0,05 M e 0,20 M. A composição de 0,20M de Ag foi submetida à diferentes temperaturas de tratamento hidrotermal. Os materiais nanoestruturados sintetizados foram caracterizados por Difração de Raios-X (DRX), Espectroscopia Raman, Espectroscopia no Infravermelho com Transformada de Fourier (FTIR), Microscopia Eletrônica de Varredura (MEV/FEG), Microscopia Eletrônica de Transmissão (MET), Espectroscopia Ultravioleta-Visível (UV-Vis), Isotermas de adsorção (BET), Fotoluminescência (PL), Espectroscopia de Fotoelétrons Excitados por Raios-X (XPS) e Análise Termogravimétrica (TG-DSC). As amostras foram submetidas a testes fotocatalíticos e biológicos. Para os testes biológicos foram realizados os testes de Concentração Inibitória Mínima (CIM), sob diferentes concentrações. Para os testes de atividade fotocatalítica, a decomposição de um corante sintético, Rodamina B, sob irradiação de lâmpada LED 467 nm, foram estudados. Com a análise dos resultados obtidos foi possível se estabelecer correlações entre a atividade fotocatalítica e bactericida com as propriedades estruturais, morfológicas e de superfície. Como resultado, verificou-se que a quantidade de Ag e a temperatura de síntese são fatores cruciais na formação de várias arquiteturas hierárquicas 3D novas e complexas de WO3. Os resultados mostraram a melhora da cristalinidade e a redução da densidade de estados eletrônicos localizados com o aumento da temperatura de síntese. A amostra sintetizada com a maior concentração do sal de Ag e de maior temperatura de síntese apresentou melhores resultados fotocatalíticos. Os biotestes revelaram que as propriedades antibacterianas das estruturas hierárquicas 3D de WO3 decoradas com NPs de Ag foram efetivamente afetadas pela forma e tamanho.
WO3/Ag structures were successfully synthesized by the hydrothermal route, using tungstic acid, hydrogen peroxide and silver nitrate as precursors. The synthesis of WO3/Ag nanocomposites was carried out at Ag (silver) concentrations equal to 0.01 M, 0.05 M and 0.20 M. The 0.20M Ag composition was subjected to different hydrothermal treatment temperatures. The synthesized nanostructured materials were characterized by X-Ray Diffraction (XRD), Raman spectroscopy Scanning Electron Microscopy (SEM/FEG), Fourier Transform Infrared Spectroscopy (FTIR), SEM-FEG, Transmission electron microscopy (TEM), Ultraviolet-Visible Spectroscopy (UV-Vis), Adsorption isotherms (BET) method, Photoluminescence (PL), X-Ray Excited Photoelectron Spectroscopy (XPS) and Thermogravimetric Analysis (TG-DSC). The samples were submitted to photocatalytic and biological tests. For the biological tests, the Minimum Inhibitory Concentration (MIC) tests were applied, under different concentrations. For the photocatalytic activity tests, the decomposition of a synthetic dye, Rhodamine B, under 467 nm LED lamp irradiation, was studied. With the analysis of the obtained results, it was possible to establish correlations between the photocatalytic and bactericidal activity with the structural, morphological and surface properties. As a result, it was found that the amount of Ag and the synthesis temperature are crucial factors in the formation of several new and complex hierarchical 3D architectures of WO3. The results showed an improvement in crystallinity and a reduction in the density of localized electronic states with increasing synthesis temperature. The sample synthesized with the highest concentration of Ag salt and the highest synthesis temperature showed better photocatalytic results. Biotests revealed that the antibacterial properties of the 3D hierarchical structures of WO3 decorated with Ag NPs were effectively affected by shape and size.
WO3/Ag structures were successfully synthesized by the hydrothermal route, using tungstic acid, hydrogen peroxide and silver nitrate as precursors. The synthesis of WO3/Ag nanocomposites was carried out at Ag (silver) concentrations equal to 0.01 M, 0.05 M and 0.20 M. The 0.20M Ag composition was subjected to different hydrothermal treatment temperatures. The synthesized nanostructured materials were characterized by X-Ray Diffraction (XRD), Raman spectroscopy Scanning Electron Microscopy (SEM/FEG), Fourier Transform Infrared Spectroscopy (FTIR), SEM-FEG, Transmission electron microscopy (TEM), Ultraviolet-Visible Spectroscopy (UV-Vis), Adsorption isotherms (BET) method, Photoluminescence (PL), X-Ray Excited Photoelectron Spectroscopy (XPS) and Thermogravimetric Analysis (TG-DSC). The samples were submitted to photocatalytic and biological tests. For the biological tests, the Minimum Inhibitory Concentration (MIC) tests were applied, under different concentrations. For the photocatalytic activity tests, the decomposition of a synthetic dye, Rhodamine B, under 467 nm LED lamp irradiation, was studied. With the analysis of the obtained results, it was possible to establish correlations between the photocatalytic and bactericidal activity with the structural, morphological and surface properties. As a result, it was found that the amount of Ag and the synthesis temperature are crucial factors in the formation of several new and complex hierarchical 3D architectures of WO3. The results showed an improvement in crystallinity and a reduction in the density of localized electronic states with increasing synthesis temperature. The sample synthesized with the highest concentration of Ag salt and the highest synthesis temperature showed better photocatalytic results. Biotests revealed that the antibacterial properties of the 3D hierarchical structures of WO3 decorated with Ag NPs were effectively affected by shape and size.
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Estruturas hierárquicas, Hidrotermal, Óxido de tungstênio, Hierarchical structures, Tungsten oxide, Hydrothermal