Remarkable synergy of borate and interfacial hole transporter on BiVO4 photoanodes for photoelectrochemical water oxidation

Abstract

Bismuth vanadate (BiVO₄) is one of the most fascinating building blocks for the design and assembly of highly efficient artificial photosynthesis devices for solar water splitting. Our recent report has shown that borate treated BiVO₄ (B-BiVO₄) results in an improved water oxidation performance. In this study, further improvement of both the photoelectrochemical (PEC) activity and stability of B-BiVO₄ was successfully achieved by introducing NiFeV LDHs as an oxygen evolution catalyst and interfacial hole transporter. Benefiting from the synergistic effect of co-catalyst and borate pretreatment, the as-prepared NiFeV/B-BiVO₄ exhibited a high photocurrent density of 4.6 mA cm⁻² at 1.23 V_RHE and an outstanding onset potential of ∼0.2 V_RHE with good long-term stability. More importantly, NiFeV was found to play a pivotal role in the critically efficient suppression of charge combination on the BiVO₄ surface and acceleration of charge transfer rather than a mere electrocatalyst for water oxidation.