The solution-phase process of a g-C3N4/BiVO4 dyad to a large-area photoanode: interfacial synergy for highly efficient water oxidation

The oxygen evolution reaction (OER) is the rate-limiting process for water splitting, and highly efficient large-area OER photoanodes have been considered as an essential part in photoelectrochemical water splitting reactors. The high hole-electron separation efficiency of photoanodes is highly required for real applications of photoanodes in sufficiently harvesting solar energy. Herein we show that the inactive g-C3N4 nanolayers can be self-assembled with BiVO4 into a highly coupled BV/CN dyad to significantly enhance the charge separation efficiency of BiVO4 photoelectrodes for the OER. The incident photon-to-current conversion efficiency (IPCE) of visible light (400 nm) provided by the scalable BV/CN-5 photoanode was estimated to be 50% at 1.23 V vs. RHE in 0.5 M Na2SO4 solution and significantly increased to 97% at a bias voltage of 1.6 V vs. RHE.