The direct conversion of methane (CH 4 ) into higher-value C2 products is essential for the green and efficient conversion of clean energy. The current industrial process for producing acetic acid from methane is an indirect method that consumes enormous amounts of energy, requiring three steps: methane reforming, methanol synthesis, and methanol carboxylation. However, direct synthesis of C2 products from methane often presents challenges in activating the C–H bond and controlling C–C coupling reactions. To overcome these issues, it is crucial to design heterogeneous catalysts that can precisely regulate the microenvironment around active sites to enable controlled methane activation and selective conversion. Metal-organic frameworks, with their tunable structure, adjustable pores, and well-defined metal sites, offer an ideal platform for achieving this goal. The deficient sites in UiO-66 catalyst may provide efficiently activate the C–H bond of methane and to promote the highly selective formation of CH 3 COOH
Recently, a research team led by Prof. Haibao Huang (Xinjiang University at Urumqi, Sun Yat-sen University at Guangzhou), Dr. Hao Guo (Xinjiang University at Urumqi) & Dr. Di Hu (Xinjiang University at Urumqi) designed a UiO-66 based catalyst with abundant ligand defects for activated CH 4 conversion. UiO-66-XT synthesized by the competitive complexation effect of trifluoroacetic acid exhibits a higher specific surface area and a greater number of defect sites could synergistically promote CH 4 oxidation process and lead to excellent performance. The results were published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(26)65127-3 ).
The designed unsaturated metal Zr 4+ site by introducing ligand defects in UiO-66 through treatment with trifluoroacetic acid, which enables the direct oxidation of methane to acetic acid using H 2 O 2 under mild conditions. The d-band center of the Zr 3 d orbital in Zr 4+ sites exposed by UiO-66 shifts upward and promoting the decomposition and C–C coupling. 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 1,691 μmol·g cat. -1 . Notably, the catalyst exhibited exceptional stability.
The UiO-66-XT synthesized by the competitive complexation effect of trifluoroacetic acid exhibits a higher specific surface area and a greater number of defect sites. These defects expose numerous unsaturated Zr 4+ sites, which promotes the adsorption of methane and hydrogen peroxide. Efficient charge transfer at these sites then facilitates C–H bond activation, while defect-stabilized intermediates catalyze C–C coupling to form acetic acid. These finding offer novel insights into the field of material defect engineering and extend the current understanding of the partial oxidation of methane process, with the potential to generate high-value-added products.
About the journal
Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top six journals in Applied Chemistry with a current SCI impact factor of 17.2.
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Chinese Journal of Catalysis
Highly selective oxidation of methane to acetic acid enabled by deficient UiO-66 under mild conditions
7-Aug-2026