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

Abstract

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.

Keywords

Covalent organic framework / Noble metal / Photocatalysis / Oxygen reduction reaction / Hydrogen peroxide

Supplementary Materials

The following supporting information can be found at: https://www.sciepublish.com/article/pii/632, Figure S1: XRD pattern of cyano-COF; Figure S2: Wide scan XPS spectra of cyano-COF and metal/cyano-COF; Figure S3: Tauc plots of cyano-COF and metal/cyano-COF; Figure S4: Mott-Schottky curves of cyano-COF and metal/cyano-COF; Figure S5: Photoluminescence spectra of cyano-COF and metal/cyano-COF.

Author Contributions

Y.Y. (Yepeng Yang): Methodology, Validation, Investigation, Writing-review & editing. B.F.: Methodology, Validation, Investigation. C.W.: Investigation. C.Y.: Investigation. J.W.: Validation. Y.Y. (Yao Yuan): Validation. R.T.: Writing-review & editing, Supervision, Funding acquisition, Conceptualization.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data will be made available on request.

Funding

This work was supported by Yunnan Fundamental Research Project (202401AU070013), Cooperative Research Program of Yunnan Provincial Undergraduate Universities’ Association (Grant 202401BA070001-117, 202301BA070001-128), Talent Introduction Project of Kunming University (Grant YJL23018), Yunnan Key Laboratory of Metal-Organic Molecular Materials and Device Independent Research Projects (Grant YNMO-ZD-2405, YNMO-ZD-2407), Education Department Project of Yunnan Province (Grant 2025Y1068, 2025Y1073, 2025Y1059), College Students’ Innovative Entrepreneurial Training Plan Program (202411393002, 202411393008), and the Frontier Research Team of Kunming University 2023.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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