Enhancement of visible light photocatalytic activity of tantalum oxynitride and tantalum nitride by coupling with bismuth oxide; an example of composite photocatalysis

Abstract

ABSTRACTComposite photocatalysts comprised of two semiconducting oxides, with suitable band gaps and band positions, have been reported as an effective approach to enhance photocatalytic activity in the visible region of the electromagnetic spectrum. Here, we report the synthesis, characterization, and photocatalytic evaluations of semiconducting composites made by combing bismuth oxide with either tantalum oxynitride or tantalum nitride. Visible light active composites were synthesized using solution chemistry synthesis method. The composites were characterized by powder X- ray diffraction (PXRD), diffuse reflectance UV-Vis spectroscopy, and photoluminescence (PL). Their photocatalytic activities were evaluated for generation of hydrogen from an aqueous methanol solution under visible light irradiation (λ≥ 420 nm). The as-prepared composite catalysts are found to have longer photogenerated charge-carrier life time, resulting in enhanced photocatalytic activities.