Visible Light-Driven BiOI/ZnO Photocatalyst Films and Its Photodegradation of Methomyl Insecticide

Abstract

Bismuth oxyiodide/zinc oxide (BiOI/ZnO) composite photocatalyst films were successfully prepared by a simple low temperature co-precipitation method coupled with a reflux procedure. Mole ratios of BiOI and ZnO were varied from 0, 0.125, 0.25 and 0.50 mol% while X-ray diffraction patterns confirmed characteristic peaks of BiOI and ZnO in all composite samples. Optimal photocatalytic efficiency of methomyl photodegradation under visible light irradiation was recorded for 0.25 mol% BiOI/ZnO photocatalyst at 58%. Increase in BiOI content resulted in higher photocatalytic activity than for pure ZnO and commercial ZnO. Optimal heterojunction content at 0.25 mol% BiOI/ZnO was recorded between hexagonal wurtzite ZnO and tetragonal BiOI, with high crystalline particles leading to enhanced specific surface light absorption capacity in the visible region. Based on these good characterization results for interfacial surface and X-ray Photoelectron Spectroscopy (XPS), the combination of both semiconductors generated more electrons, resulting in enhanced photocatalytic performance of methomyl degradation under visible light irradiation.