MOF-Derived Z-Scheme Bi/BiVO4/MgIn2S4 Heterojunction with Oxygen Vacancies and Plasmonic Bi0 for Enhanced Photocatalytic H2O2 Production

Abstract

The photocatalytic production of hydrogen peroxide (H2O2) using renewable solar energy provides a more sustainable option compared to the energy-intensive anthraquinone process. The present study designed a Z-scheme heterojunction photocatalyst, Bi/BiVO4/MgIn2S4 (BOBVM), with rich oxygen vacancies. Utilizing Bi-MOF as a precursor, this material employs in situ topological conversion to prepare a BiVO4 framework that boasts a specific surface area, while oxygen vacancies and plasmonic metallic bismuth nanoparticles (Bi0) are subsequently achieved synchronously via a NaBH4 reduction strategy. The porous structure derived from Bi-MOF has been shown to significantly reduce the distances of charge transport during the photocatalytic reactions. Oxygen vacancies act as electron capture centers, reducing carrier recombination and serving as active sites for O2 adsorption, thereby lowering the activation energy. Meanwhile, the surface plasmon resonance of Bi0 broadens the spectrum of light absorption. Under visible-light irradiation, BOBVM achieved an H2O2 yield of 1.04 × 103 μmol·L–1 in pure water under ambient air, corresponding to approximately 53-fold and 2.9-fold enhancements compared with pure BiVO4 and BiVO4/MgIn2S4 heterojunctions, respectively. This work provides insight into the design of Z-scheme photocatalysts through heterojunction construction, defect engineering, and Bi0-assisted light absorption and interfacial charge regulation.