Investigations on development of ZnObased oxynitrides for photocatalytic applications

Abstract

Photocatalysts have emerged as one of the solutions for addressingenergy demands and environmental pollution, through their unquestionablepotential in generating Hydrogen as green energy by splitting water and alsoby degrading organic pollutants from water. Visible light activity of thephotocatalysts is the most sought after aspect so as to utilize sunlight forenergy generation as well as water treatment. A semiconductor material newlinequalifies as a visible light photocatalyst when it possesses a narrow bandgap(lt 3 eV), together with appropriate band-edge positions and photostability.Metal oxides are proven to be potential photocatalysts with their costeffectiveness and stability, but with activity limited to UV region of spectra,owing to the O2p levels lying at a potential of ~ 3 eV forming the top ofvalence band. Tailoring of the bandgap of metal oxides hence could offer aplausible way to realize visible light active photocatalysts. The bandgap of newlineZnO, one of the most versatile metal oxides, could be tuned and reduced byforming oxynitrides with GaN, InN, AlN, AlGaN etc. The formation ofoxynitride results in the introduction of N2p level at the top of valence band,thereby reducing the bandgap. newline newline