Catalytic Behavior of Ag-Mn Catalyst for Efficient Toluene Removal at Low Temperature: Effect of Redox Property

Ag-Mn bimetallic catalysts were prepared by liquid-phase redox method and discussed their synergistic effect on the catalytic oxidation of toluene. The activity order of the catalysts was: Ag-Mn > Mn > Ag-Mn-R > Mn-R. The addition of Ag caused some K+ to be substituted over Ag-Mn, which resulted in the collapse of the structure, and led to more lattice defects and increased the active species. Furthermore, the Ag-Mn catalyst contained a large amount of Mn4+ and Olatt species, the best low-temperature reducibility and the lowest oxygen desorption temperature. After the reduction treatment, the high-valent manganese ions decreased, and the lattice oxygen concentration was greatly reduced. Besides, the high concentration of high valence manganese, easily released lattice oxygen and oxidized silver of Ag-Mn could contribute to the superior catalytic performance. The mechanism followed by toluene → benzoate → benzoquinone → manganese carbonate → CO2 + H2O.