Catalytic Combustion of Toluene over Cu–Mn Mixed Oxide Catalyst

A series of copper manganese mixed oxide catalysts Cu1-xMnx (x = 0-1.0) with high surface area were synthesized by using the carbonate co-precipitation method and their performance in the catalytic combustion reaction of toluene was investigated by varying the mole ratio of Cu and Mn. TG, XRD, H-2-TPR, DRIFT, XPS and N-2 adsorption/desorption were used to characterize the structure and textural properties of catalysts. The resulting Cu1-xMnx catalyst showed higher catalytic activity than the mono-metal oxide catalyst, especially when a small amount of copper was doped into manganese oxide. With increasing the manganese content from 0 to 1.0, a volcanic tendency for catalytic activity was observed. Results of catalyst characterization revealed that the promoted catalytic activity can be associated with some interrelated factors, such as depressed crystallinity, highly dispersed oxide species onto the other, easier catalyst reducibility, more surface oxygen and enhanced surface area. It was difficult to attribute the promoted catalytic activity only to a single and specific factor. A synergistic effect between manganese and copper species was considered to be the most intrinsic reason.