Oxygen-vacancy-mediated enhanced electron–proton transfer in 2D/2D Ce,Er–BiVO4-based metal–organic framework heterostructures for efficient photocatalytic H2O2 production

The limited efficiency of water oxidation is a significant challenge in the photocatalytic production of hydrogen peroxide (H 2 O 2 ) without sacrificial agents. Among the different water oxidation reactions, the two-electron water oxidation reaction (2e− WOR) stands out as a promising route for direct H 2 O 2 generation, owing to its favorable kinetics. However, strategies to effectively activate 2e − WOR remain underdeveloped. In this work, we employ a molecular engineering approach to achieve a high density of oxygen vacancy sites on the surface of BiVO 4 (Ov-BiVO 4 ). These vacancies promote favorable interactions with the oxygen-rich ligands of MIL-101 through electrostatic self-assembly, resulting in enhanced growth and reduced formation energy of the material. The optimized photocatalyst demonstrates a remarkable initial photocatalytic H 2 O 2 production rate of 4550.4 μmol g −1  h −1 in pure water, a 38-fold increase compared to the unmodified BiVO 4 . Additionally, the apparent quantum yield (AQY) reaches 12.35% at 420 nm. This enhanced performance is attributed to the synergistic effects of oxygen vacancies, the incorporation of rare earth bimetallic centers, and the Z-scheme heterojunction, all of which facilitate the separation of photogenerated charge carriers. Notably, the unsaturated coordination sites of Ce and Er efficiently promote O 2 adsorption and activate the 2e − oxygen reduction reaction (ORR) pathway, crucial for efficient H 2 O 2 production. MIL-101 further improves the water oxidation reaction, optimizing the redox reaction matching within the system. This work introduces a straightforward molecular engineering method for dual-atom anchoring with tailored coordination environments, emphasizing the importance of redox dual-regulation for achieving efficient H 2 O 2 synthesis.