Insight into enhanced catalytic performance of alkali-treated Al2O3 supported Ag catalyst for toluene oxidation

Volatile organic compounds (VOCs) triggered severe air pollution and posed a threat to human health. Herein, the Ag/gamma-Al2O3 catalyst was investigated by post treatment with alkali for removal of VOCs. It was found that the dealumination process induced by alkali can effectively regulate the number of strong acid sites on the surface of alumina, which favored the formation of larger number of Ag+ species and more uniform silver particles (around 10 nm). The Ag/Al2O3(1.0) catalyst exhibited complete removal of toluene at a lower temperature of 290 degrees C. The higher ratio of Ag+/Ag0 were crucial for accelerating the formation of intermediates (benzaldehyde and benzoic acid) and activation of O2. This work provided an insight into control of the valence state of Ag species via acid sites modulation for improving catalytic performance of VOCs oxidation.