Surface Engineering of WO3/BiVO4 to Boost Solar Water-Splitting

Single-phase photoanodes often suffer inferior charge transport, which can be mitigated by constructing efficient heterojunctions. Thus, we have fabricated a fluorine-doped tin oxide (FTO)/WO3/BiVO4 heterojunction using hydrothermal and spin-coating methods. Surface engineering was exploited to further accelerate the reaction kinetics, which was achieved via post-modification with NaOH solution. This treatment alters the surface chemical state of the BiVO4 nanoparticles, leading to enhanced charge transport and surface water oxidation processes. As a result, the optimized sample can produce a photocurrent more than two times that of WO3. The simple post-treatment provides a viable and cost-effective strategy for promoting the photoelectric properties of photoanodes.