BiVO4-Dotted WO3 Photoanode with an Inverse Opal Underlayer for Photoelectrochemical Water Splitting

Developing an efficient photoanode is critical for obtaining sustainable hydrogen energy by photoelectrochemical (PEC) water splitting. The performance of a photoanode is usually determined by charge separation and optical absorption efficiency, which can be enhanced by constructing a solid-state junction and applying an inverse opal (IO) structure, respectively. 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 WO3 photoanode with an onset potential of 0.80 VRHE and a photocurrent of 0.13 mA/cm2 at 1.23 VRHE, the BiVO4/WO3-IO photoanode exhibited much better PEC performance with an onset potential of 0.46 VRHE and a photocurrent of 0.94 mA/cm2 at 1.23 VRHE. Such a successful combination of two kinds of modification provides a promising approach to effectively utilize solar energy in visible-light-responsive photoanodes.