Issue 4, Volume 2 – 1 articles

Noble Metal Sites Modulated Cyano-COF for Boosted Photocatalytic O₂ to H₂O₂ Production

Photocatalytic O₂ reduction to hydrogen peroxide (H₂O₂) is a promising chemical synthesis pathway with green property. However, the development of efficient and stable photocatalysts that enable high selectivity and activity remains an urgent scientific challenge. Herein, cyano-based covalent organic framework (cyano-COF) photocatalysts modulated by noble metal sites (i.e., Pt, Pd, Au, and Ag), denoted as Pt/cyano-COF, Pd/cyano-COF, Au/cyano-COF, and Ag/cyano-COF, are designed and synthesized. The cyano-group (-C≡N), acting as a strong electron acceptor, interacts with the noble metal sites to establish an efficient electron transfer pathway, which facilitates the separation of photogenerated charges, optimizes the reaction pathway, and thus enables boosted generation of H₂O₂ via the two-step single electron oxygen reduction reaction (O₂→·O₂⁻→H₂O₂). Under visible irradiation, Pt/cyano-COF, Pd/cyano-COF, Au/cyano-COF, and Ag/cyano-COF deliver superior H₂O₂ production rates of 903 ± 24, 1073 ± 35, 963 ± 9, and 851 ± 56 μmol·g⁻¹·h⁻¹, respectively, much higher than that of pristine cyano-COF (577 ± 69 μmol·h⁻¹·g⁻¹). This study offers profound insights into the mechanism of noble metal sites in the solar-driven selective reduction of O₂ to H₂O₂ synthesis.