2D/3D BiVO4@ZnIn2S4 Hierarchical Heterojunction for Enhanced One-Electron Oxygen Reduction Kinetics of H2O2 Artificial Photosynthesis

Hydrogen peroxide (H2O2) artificial photosynthesis converts low-density solar energy into storable clean chemical energy, which is an important hot topic in green chemistry. Constructing heterojunctions is an effective tactic to enhance the oxygen reduction kinetics of H2O2 photosynthesis, however, the actual source of activity remains ambiguous. Here, a series of BiVO4@ZnIn2S4 hierarchical heterojunctions (BZ-x, x = 0.4, 0.8, 1.2) were elegantly designed through piecing two-dimensional (2D) BiVO4 nanosheets onto the surface of three-dimensional (3D) ZnIn2S4 flower-like microspheres by a straightforward ethanol ultrasound-induced self-assembly strategy. These BZ-x photocatalysts exhibit significantly enhanced photocatalytic H2O2 production rates across a wide pH range (3–13) compared with those of pristine BiVO4 and ZnIn2S4, with the optimal BZ-0.8 showing an excellent photocatalytic H2O2 production rate as high as 1585.99 μmol g–1 h–1. Comprehensive analysis reveals that 2D BiVO4 nanosheets and 3D ZnIn2S4 flower-like microspheres form a Z-scheme hierarchical heterojunction, which can deliver a favorable energy coupling between photogenerated electrons and the chemical adsorption of O2 at the interface of hierarchical heterojunctions, thereby accelerating the two-step one-electron kinetic process. This study provides a new perspective for improving photocatalytic H2O2 production by introducing hierarchical heterojunction strategies.