Molecular-level design of S-scheme COF/Ce-MOF heterojunctions for efficient photocatalytic H₂O₂ generation

In situ synthesis of S-scheme COF/Ce-MOF heterojunctions significantly enhances photocatalytic H₂O₂ production under ambient conditions. The directional charge separation, precise band alignment, and synergistic dual active sites of the heterojunction enable efficient, stable, and selective H₂O₂ generation. The CRM (Ce-MOF/COF) heterojunction delivers an H₂O₂ yield that is 11.2-fold higher than pristine Ce-MOF and 3.1-fold higher than pure COF. Moreover, the CRM heterojunction maintains excellent productivity over a 6-h reaction period. In situ X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses revealed not only the elemental composition and chemical states at the heterojunction interface but also the interfacial electronic redistribution and band alignment responsible for the enhanced photocatalytic performance. Specifically, the combined experimental and theoretical results confirmed the presence of strong interfacial coupling, the formation of an internal electric field, and the establishment of an S-scheme charge transfer pathway, all of which contribute to efficient charge separation and the preservation of high redox potentials, thereby enabling superior H₂O₂ generation activity. Overall, this work not only deepens the understanding of MOF-based photocatalysts but also provides valuable design principles for constructing next-generation heterojunction materials with superior efficiency in photocatalytic H₂O₂ production for environmental remediation.