Kai Li,Junqi Cai,Yue Tao,Yunhe Xing,Zuchao Zhu,Zhiqiang Lu,Xuming Zhang
The direct conversion of methane into the value-added chemical methanol using molecular oxygen was investigated via plasma catalysis under mild condition. An efficient synergistic effect between plasma and catalyst was achieved using an oxygen vacancy-rich ZnO/Al 2 O 3 catalyst. A high methanol selectivity of 48.5 % and a high synergy factor of 2.1 could be achieved simultaneously over ZnO/Al 2 O 3 R300 catalyst. The presence of oxygen vacancies played a crucial role in methanol formation. A close relationship between oxygen vacancy content and methanol selectivity was established. In situ DRIFT and optical emission spectra were employed to identify key intermediates, and a plausible reaction mechanism was proposed. The CH 3 and CH 3 O species were the key intermediates on the catalyst surface. The oxygen vacancy could efficiently adsorb the O radicals and accelerate the formation of CH 3 O species. This work offers insights into the rational engineering of efficient catalyst for plasma catalysis process.
The light-driven conversion of CO 2 to dimethyl carbonate (DMC) represents a promising green and sustainable pathway for achieving dual-carbon goals. However, the inherent difficulty in activating CO 2 molecules results in low DMC yields when synthesizing DMC from CO 2 and methanol (CH 3 OH) under light-driven conditions. In this study, the activation of CO 2 and CH 3 OH is enhanced by modulating the number of hydroxyl groups and the concentration of oxygen vacancies on the surface of spindle-like CeO 2-x through the introduction of cetyltrimethylammonium bromide (CTAB). Photothermal catalytic experiments show that the optimal CTAB-modified CeO 2-x achieves excellent DMC yield of 5.26 mmol·g −1 under mild conditions (0.1 MPa, 120℃). The X-ray photoelectron spectroscopy and CO 2 temperature-programmed desorption results demonstrate that CTAB modification increases the number of hydroxyl groups and oxygen vacancies on the CeO 2-x surface, which improves the effective activation of CO 2 to form the reactive intermediates such as *HCO 3 – and *CO 2 . Notably, the increased hydroxyl groups promote the dissociation of CH 3 OH into *CH 3 O. Meanwhile, isotopic labeling and in situ infrared characterization confirm the light-driven reaction pathway of CO 2 and CH 3 OH, involving the oxidation of CH 3 OH to *CH 2 OH via photogenerated holes, followed by rapid coupling with *CO 2 to generate the reactive intermediate (CH 3 OCOO*). These findings provide new insights into the rational design and construction of CeO 2 -based catalysts to achieve high yields of DMC under mild conditions.
危险品化学品经营许可证（带存储）