Photoactivity and band gap energies of Ta oxide/oxynitride mixed with SiO2
Ta2O5 and TiO2 are photocatalysts that have applications for water purification. The oxides when excited by ultraviolet light form hydroxyl radicals, which oxidize organics. Research shows that the mixed oxide of TiO2 and SiO2 with a mass ratio of 30% TiO2 and 70% SiO2 oxidized organic dyes three times faster than TiO2 alone (Anderson, 1995). Similarly, it is expected that a mixed oxide comprising of Ta2O5 and SiO2 will have elevated photoactivity. In this study, the mixed oxides of Ta2O5 and SiO2 were formed by ball milling and manually mixing different weight ratios of the respective powders. Heating the powders in ammonia shifted their absorbance edges into the visible. The photoactivity of the resulting powders was estimated from the breakdown of organic dyes adsorbed to the oxides/oxynitrides. In all combinations of powders that were photoactive, the mass ratio of 30% Ta2O5 and 70% SiO2 had the highest photoactivity.
School:
Indiana University
Department:
Chemistry
Research Advisor:
John Shapley
Department of Research Advisor:
Chemistry
Year of Publication:
2006