Redox-Based Visible-Light-Driven Z-Scheme Overall Water Splitting with Apparent Quantum Efficiency Exceeding 10%

Abstract

The performance of photocatalytic Z-scheme overall water splitting (ZOWS) is intrinsically dependent on not only the charge separation of H2-evolving photocatalyst (HEP) and O2-evolving photocatalyst (OEP), but also the electron transfer between HEP and OEP. The cocatalyst strategy is effective in accelerating the electron transfer and surface catalysis. BiVO4 has unique spatial charge separation between the {010} and {110} facets in bulk. In this study, the Au cocatalyst is demonstrated to be highly favorable for electron transfer from BiVO4 to [Fe(CN)6]3−, and Au and CoOx dual cocatalysts with site-selective deposition make a synergetic promotion on the charge separation of BiVO4, leading to an unprecedentedly efficient ZOWS system. Furthermore, the [Fe(CN)6]3−/[Fe(CN)6]4− redox mediator with lower redox potential is more favorable for storage of solar energy.