Vanadium promoted ZnO films: Effects on optical and photocatalytic properties

Abstract

The effect of electrodeposition temperature, vanadium doping, and oxidation state of vanadium on the photocatalytic activity of ZnO thin films over ITO substrates were investigated. NH 4 VO 3 aqueous solution was used as precursor to dope ZnO thin film samples with V 5+ by dip coating method and oxalic acid was used as reducing agent to synthesize V +4 doped samples. UV-Vis spectroscopy was used to determine the direct and indirect band gap values of thin film samples. Methylene blue (MB) degradation assays were used to evaluate the photocatalytic activity. XPS analysis was used to determine the analyse oxidation state of vanadium over the samples. Photocatalytic activity studies revealed that ZnO samples electrodeposited at 70°C have higher band gap and MB degradation activity under artificial solar irradiation. The presence of vanadium also enhances the photocatalytic activity of ZnO and samples doped with V +4 have higher photocatalytic activity than the samples doped with V +5 sites.