Copper modified manganese oxide with tunnel structure as efficient catalyst for low-temperature catalytic combustion of toluene

Copper-modified manganese oxide catalysts with tunnel, layer, and transitional structure were successfully prepared by a one-step hydrothermal method and investigated for the catalytic oxidation of toluene. The catalysts were characterized by XRD, SEM, TEM, BET, H-2-TPR, XPS and ICP-AES techniques. The tunnel-structured catalyst exhibited the best activity among the three Cu-Mn oxide catalysts and excellent water resistance. Abundant surface oxygen species, good low temperature reducibility, low average oxidation state of manganese, and high surface area lead to remarkable catalytic performance of this catalyst. The toluene catalytic combustion over these catalysts was found to follow the Mars-van-Krevelen mechanism and the unique copper states found in the tunnel-structured catalyst play a key role in promoting the cyclic redox process.