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


Khan I., Sawwan H., Alsaikhan K., El Jery A., Iqbal K., Iqbal A., ...More

MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, vol.209, 2026 (SCI-Expanded, Scopus) identifier identifier

Abstract

The limited efficiency of water oxidation is a significant challenge in the photocatalytic production of hydrogen peroxide (H2O2) 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 H2O2 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 BiVO4 (Ov-BiVO4). 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 H2O2 production rate of 4550.4 mu mol g- 1 h- 1 in pure water, a 38-fold increase compared to the unmodified BiVO4. 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 O2 adsorption and activate the 2e- oxygen reduction reaction (ORR) pathway, crucial for efficient H2O2 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 H2O2 synthesis.