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

Abstract

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 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 °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 reaction mechanism was proposed based on the results of in-situ diffuse reflectance infrared transform spectroscopy (DRIFTS) experiments.