Accurate modulation of NiS cocatalysts on the photoelectron transfer sites of BiVO4 for photocatalytic H2O2 generation

Abstract

Lacking effective active sites on the BiVO₄ surface severely restricts the photocatalytic H₂O₂-formation activity. As a promising and mainstream cocatalyst, NiS with rich active sites is widely applied to improve the catalytic activity of host photocatalysts. However, it is rarely reported to facilitate photocatalytic O₂ reduction to produce H₂O₂. In this study, a sulfur (S)-mediated photodeposition method is adopted to precisely modify a NiS cocatalyst at the photoelectron transfer sites of BiVO₄. Specifically, photoelectrons enrich a enough high concentration of Ni²⁺ ions on the (010) facet of BiVO₄, where the S molecules combine with them to in situ form NiS and deposit on its surface. Photocatalytic results show that 10 wt% NiS/BiVO₄ obtains optimal photocatalytic performance with a H₂O₂-production concentration of 975 μmol L⁻¹ (AQE = 4.8%), which is about 87 times that of pristine BiVO₄. The remarkable performance of the NiS/BiVO₄ photocatalyst can be ascribed to the accurate modification of an efficient NiS cocatalyst at the photoelectron transfer sites of BiVO₄, which can accelerate photogenerated charge migration, promote surface O₂ adsorption and boost the interfacial O₂ reduction reaction of BiVO₄. This work offers a novel approach for the precise modification of transitional metal-sulfide cocatalysts for high-efficiency photocatalytic H₂O₂ production.