Nearly 100% Charge Transfer in BiVO4 via Conjugated Organic-Inorganic Interface Engineering for Photoelectrochemical Water Splitting.

Abstract

Photoelectrochemical water splitting is regarded as a promising strategy for the direct conversion of solar energy into hydrogen energy. However, detrimental bulk charge transport and surface trap-state-mediated carrier recombination result in low efficiency. Herein, we propose a dual hole transport layer strategy by combining a covalent organic polymer (CHN) framework and an inorganic NiOx layer to enhance the PEC performance of BiVO4 photoanode. The dual hole transport layers not only reinforce the built-in electric field but also reduce the surface-state-mediated charge recombination. The resulting BiVO4/CHN/NiOx/NiFeOx photoanode delivers a high photocurrent density of 4.45 mA/cm2 at 1.23 V versus RHE and excellent stability for continuous 24 h illumination. Overall, this work provides a versatile platform for interface engineering modulation of BiVO4 photoanodes, and sheds light on the mechanism of organic-inorganic hole transport layers for boosting PEC performance.