Chinese Journal of Catalysis

Chinese Journal of Catalysis ›› 2026, Vol. 88: 356-368.DOI: 10.1016/S1872-2067(26)65127-3

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Highly selective oxidation of methane to acetic acid enabled by deficient UiO-66 under mild conditions

Yaowen Weia, Jianwei Wanga, Hao Guoa,*(), Tao Bana, Yufeng Yuea, Di Hua,*(), Haibao Huanga,b,*()   

  1. a Xinjiang Key Laboratory of Coal Clean Conversion & Chemical Engineering Process, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830046, Xinjiang, China
    b School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
  • Received:2025-11-19 Accepted:2026-02-13 Online:2026-09-18 Published:2026-09-05
  • Supported by:
    The National Key Research and Development Program of China(2024YFC3713500);The Major Science and Technology Projects of Xinjiang(2024A03012);The National Natural Science Foundation of China(22276223);The support of the Key Research and Development Plan of Xinjiang(2022B03029-3);The “Tianchi Talents” Introduction Plan(TCBS202013);The Natural Science Foundation of Xinjiang Uygur Autonomous Region(2023D01C170)

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Abstract:

The direct conversion of methane (CH4) into higher-value C2 products is essential for the green and efficient conversion of clean energy. However, this conversion process faces significant challenges due to the difficulty in activating methane's C-H bonds and the complexity of controlling C-C coupling reactions. Herein, we design and construct the unsaturated metal Zr4+ site by introducing ligand defects in UiO-66 through treatment with trifluoroacetic acid (TFA), which enables the direct oxidation of methane to acetic acid using H2O2 under mild conditions. Remarkably, a volcano-shaped correlation was observed between the degree of ligand defects in UiO-66 and acetic acid selectivity. Under optimal conditions (150 °C), the catalyst achieved an outstanding acetic acid selectivity of 84% with a high yield of 1691 μmol·gcat.-1. Notably, the catalyst exhibited exceptional stability, maintaining its performance over at least five consecutive reaction cycles. Through TFA modulation, the d-band center of the Zr 3d orbital in Zr4+ sites exposed by UiO-66 shifts upward. This promotes the decomposition of H2O2, thereby facilitating the formation and stabilization of highly reactive Zr-OH species, which enhances the activation of C-H bonds in CH4. The resulting *CH3 species is further oxidized by *OH species into *COOH species, which undergo stable C-C coupling at exposed Zr4+ sites to produce acetic acid. This work provides novel insights into the design of highly efficient catalysts for the direct conversion of methane into C2 oxygenates compounds under mild conditions.

Key words: Methane, Selective oxidation, Acetic acid, UiO-66 catalyst, Defect engineering