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.