Sulfur-defect-rich Bi2S3/ZnIn2S4 Z-scheme heterojunction for highly efficient H2O2 photosynthesis in pure water

Photocatalytic conversion of O2 and H2O provides a green and low-cost route for H2O2 synthesis; however, most reaction systems involve sacrificial agents, and achieving efficient photosynthesis of H2O2 in pure water remains a challenge. In this work, a Z-scheme Bi2S3/ZnIn2S4 heterojunction with rich sulfur defects was prepared by a one-step hydrothermal method. The combination of Bi2S3 with ZnIn2S4 greatly enhanced visible-light absorption. The intimate heterojunction interface bonded through sulfur bridge efficiently promoted the separation and migration of photogenerated carriers. Moreover, the enlarged specific surface area, the existence of sulfur defects and the increase of surface hydrophobicity facilitated the oxygen reduction reaction. As a result, the H2O2 production rate of the Bi2S3/ZnIn2S4 heterojunction in pure water under visible light reached 1,634 μmol·g-1·h-1, which was 5.3 and 43.0 times that of ZnIn2S4 and Bi2S3, respectively. This work provides new ideas for the construction of novel heterojunction photocatalysts for H2O2 production.