Dióxido de titanio autodopado, obtenido a partir de una ruta simple de síntesis, fotoactivo bajo luz visible
Date
2019
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Abstract
Nanopartículas de TiO2 fueron obtenidas a partir un método simple de síntesis sol-gel. Los sólidos
sintetizados fueron caracterizados mediante DRX, espectrofotometría UV-Vis, adsorción-desorción con
nitrógeno, y TEM. Los estudios permitieron confirmar la naturaleza mesoporosa de todas las muestras
y la existencia de una fase cristalina constituida únicamente por anatasa. Dado que no fue empleado un
agente plantilla durante la síntesis, no fue necesario someter los catalizadores a tratamientos finales con
elevadas temperaturas. No obstante, se estudió el efecto de la temperatura de calcinación en la
performance fotocatalítica de los materiales, en términos de la degradación del ácido naranja 7 (AO7)
en solución acuosa bajo luz visible LED. Se demostró que la ausencia de calcinación permite que el
sólido permanezca autodopado con especies de carbono, las cuales provienen de la misma fuente
utilizada para el titanio, y serían las responsables de la absorción hacia longitudes de onda
correspondientes al rango visible del espectro. Además, pudo determinarse que a 200 °C mejora la
actividad fotocatalítica, dado que logra retardarse la recombinación electrón/hueco positivo y más
carbono ingresa a la matriz. De esta manera, fueron precisadas las condiciones óptimas para obtener un
material mesoporoso susceptible de ser activado bajo luz visible.
TiO2 nanoparticles were obtained from a simple sol-gel synthesis method. The synthesized solids were characterized by XRD, UV-Vis DR, N2 adsorption-desorption, and TEM. The studies confirmed the mesoporous nature of all the samples and the existence of a crystalline phase constituted only by anatase. Given that a template agent was not used during the synthesis, it was not necessary to subject the catalysts to final treatments at high temperatures. However, the effect of the calcination temperature on the photocatalytic performance of the materials was studied, in terms of the acid orange 7 (AO7) degradation in aqueous solution under visible LED light. It was demonstrated that the absence of calcination allows the solid to remain self-doped with carbon species, which come from the same source used for titanium, and would be responsible for the absorption towards wavelengths corresponding to the visible range of the spectrum. In addition, it could be determined that at 200 °C the photocatalytic activity improves, given that the positive electron / hole recombination is slowed and more carbon enters the matrix. In this way, optimal conditions were established to obtain a mesoporous material that could be activated under visible light.
TiO2 nanoparticles were obtained from a simple sol-gel synthesis method. The synthesized solids were characterized by XRD, UV-Vis DR, N2 adsorption-desorption, and TEM. The studies confirmed the mesoporous nature of all the samples and the existence of a crystalline phase constituted only by anatase. Given that a template agent was not used during the synthesis, it was not necessary to subject the catalysts to final treatments at high temperatures. However, the effect of the calcination temperature on the photocatalytic performance of the materials was studied, in terms of the acid orange 7 (AO7) degradation in aqueous solution under visible LED light. It was demonstrated that the absence of calcination allows the solid to remain self-doped with carbon species, which come from the same source used for titanium, and would be responsible for the absorption towards wavelengths corresponding to the visible range of the spectrum. In addition, it could be determined that at 200 °C the photocatalytic activity improves, given that the positive electron / hole recombination is slowed and more carbon enters the matrix. In this way, optimal conditions were established to obtain a mesoporous material that could be activated under visible light.
Description
Keywords
Fotocatálisis, Titania, Autodopado, Remediación ambiental
Citation
XXI Congreso Argentino de Catálisis( 2919). X Congreso de Catálisis del Mercosur (2019)
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