Exploration of a novel Type II 1D-ZnO nanorods/BiVO4 heterojunction photocatalyst for water depollution

In this study, we reported on the successful fabrication of a novel heterojunction photocatalyst (in particulate system) with a Type II band alignment between 1D-ZnO nanorods and BiVO4 nanocrystals. Pristine 1D-ZnO nanorods and BiVO4 nanocrystals were first fabricated through hydrothermal reaction followed by heterojunction formation via the wet chemical reaction. The 1D-ZnO/xBiVO(4) heterojunction photocatalyst (x = weight ratio of BiVO4 in g) that found optimum when x = 0.08 g was used for the degradation of salicylic acid (SA) and Reactive Black 5 (RB5) resulting in high pseudo-first-order reaction rate constants of 0.0049 min(-1) and 0.0132 min(-1), respectively. Electrochemical studies proved that the 1D-ZnO/0.08BiVO(4) heterojunction photocatalyst demonstrated a fast charge mobility and the most efficient photogenerated charge carriers separation among other heterojunction samples as analysed from PL spectra. Besides, UV-vis spectroscopic measurement and optical characterisation showed that the improved photoactivity in 1D-ZnO/BiVO4 is attributed to the formation of a Type II heterojunction staggered arrangement that enables a broader visible-light harvesting ability. Finally, a postulation photocatalytic mechanism was proposed based on the theoretical band alignment diagram between the 1D-ZnO nanorods and BiVO4 nanocrystals as well as portraying the fundamental charge carriers transfer within the 1D-ZnO/BiVO4 heterojunction photocatalyst. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.