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

Abstract

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.