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

摘要

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.