Photocatalytic conversion of CH4 and CO2 to acetic acid over Cu/ZnO catalysts under mild conditions

The conversion of methane (CH 4 ) and carbon dioxide (CO 2 ) into high-value products under mild conditions is crucial for addressing the greenhouse effect and advancing C1 chemistry. In this study, Cu/ZnO catalysts were prepared through a one-step wet reduction process, and the catalytic conversion of CH 4 and CO 2 into acetic acid molecules (CH 3 COOH) was achieved via photon activation at ambient temperature. The yield of acetic acid was 411.6 μmol/Lg cat −1 h −1 with a selectivity of 89.5 % under optimal conditions (100 mWcm −2 light intensity, 25 ± 2 °C, 2 MPa pressure, and a 1:1 CH 4 :CO 2 volume ratio). Enhanced solubility of CH 4 in aqueous under increased pressure and temperature was observed to improve acetic acid production. Additionally, the catalytic mechanism involved surface chemisorption of CH 4 and CO 2 , facilitated by ZnO and Cu in the catalyst, leading to C-C coupling and subsequent acetic acid formation, driven by photogenerated electron-hole migration. This study provides a foundational understanding for the synthesis of value-added chemicals through CH 4 and CO 2 conversion via C-C coupling in mild environments.