Synergistic mechanism of Cu-Mn-Ce oxides in mesoporous ceramic base catalyst for VOCs microwave catalytic combustion

Abstract

Cu-Mn-Ce mesoporous catalysts with different aperture distribution were prepared on ceramic bases by the impregnation method. The degradation process of volatile organic compounds (VOCs) (toluene, ethyl acetate, acetone, and their mixture) with different catalysts under microwave catalytic combustion was studied, and the synergistic mechanism of Cu-Mn-Ce matters during catalysis were identified. Under the condition of microwave power of 300 W and gas flow rate of 200 ml min−1, the TVOC removal efficiency of toluene (810.38 ± 24.05 mg m−3), ethyl acetate (759.55 ± 12.84 mg m−3), and acetone (795.35 ± 42.76 mg m−3) were 93.09%, 85.41%, and 97.14%, respectively, and their removal efficiencies could reach almost 100%. After 10 cycles (2100 mins), the Cu-Mn-Ce mesoporous catalysts still had adsorption and filtration effects, and the best catalyst showed excellent stability with a removal efficiency of 91.40% for the mixed TVOC. The reasons for the high catalytic performance of Cu-Mn-Ce mesoporous ceramic base catalyst include: 1) The catalyst was highly dispersed on the mesoporous carrier, and cerium further promotes catalyst dispersion. 2) Composite metal oxides could effectively react with each other in the synergistic process. 3) Composite metal oxides catalyst increased the Oβ and decreased the Oγ after synergizing with each other. 4) The hydrogen reduction temperature was significantly lower after metal oxide synergy. 5) The composite catalysts could work together to effectively maintain the unpaired electrons on the catalyst surface and replace the internal structural elements thus forming various defects. The trace amount of residual organics were less harmful to the environment.