Enhanced plasma-catalytic oxidation of methanol over MOF-derived CeO2 catalysts with exposed active sites

A series of CeO2-based catalysts synthesized by pyrolysis of Ce-MOF precursors under various calcination tem-peratures were combined with non-thermal plasma to evaluate the plasma-catalytic performance for methanol oxidation in details. The highest methanol conversion (100.0 %), CO2 selectivity (90.1 %), COx selectivity (97.7 %) and ozone suppression were obtained in CeO2-300 that was pyrolyzed at 300 degrees C. Various physicochemical property characterizations revealed that CeO2-300 possessed the highest specific surface area and the most oxygen vacancies. According to CH3OH-temperature programmed desorption, CeO2-300 catalyst displayed more exposed active sites for methanol adsorption and oxidation, which could principally contribute to the improved plasma-catalytic performance. In addition, ozone catalytic decomposition and oxidation experiments further suggested that CeO2-300 can provide abundant active sites for the conversion of ozone into active oxygen species on the catalyst surface and therefore promote the deep oxidation of methanol into CO2. Finally, plausible re-action mechanism was proposed based on the results of in-situ diffuse reflectance infrared transform spectroscopy (DRIFTS) experiments.

Automated summary

A series of CeO2-based catalysts synthesized by pyrolysis of Ce-MOF precursors under various calcination temperatures were combined with non-thermal plasma to evaluate their plasma-catalytic performance in methanol oxidation. The catalyst with the highest methanol conversion, selectivity, and ozone suppression was obtained at 300℃ pyrolysis temperature. Various characterizations revealed that this catalyst had the highest specific surface area and oxygen vacancies. It also provided more active sites for methanol adsorption and oxidation, contributing to the improved performance. Additionally, it promoted the deep oxidation of methanol by converting ozone into active oxygen species. Based on the experimental results, a plausible reaction mechanism was proposed.