BiVO₄‑Dotted WO₃ Photoanode\nwith an Inverse Opal Underlayer for Photoelectrochemical Water Splitting

Abstract

Developing an efficient photoanode\nis critical for obtaining sustainable\nhydrogen energy by photoelectrochemical (PEC) water splitting. The\nperformance of a photoanode is usually determined by charge separation\nand optical absorption efficiency, which can be enhanced by constructing\na solid-state junction and applying an inverse opal (IO) structure,\nrespectively. Following such principles, we developed a BiVO₄/WO₃-IO photoanode with a BiVO₄/WO₃ junction and an IO layer as an underlayer. Compared with a bare\nWO₃ photoanode with an onset potential of 0.80 V_RHE and a photocurrent of 0.13 mA/cm² at 1.23 V_RHE, the BiVO₄/WO₃-IO photoanode exhibited much\nbetter PEC performance with an onset potential of 0.46 V_RHE and a photocurrent of 0.94 mA/cm² at 1.23 V_RHE. Such a successful combination of two kinds of modification provides\na promising approach to effectively utilize solar energy in visible-light-responsive\nphotoanodes.