Preparation and characterization of Cu-Mn composite oxides in N2O decomposition

A series of CuxMn composite oxide catalysts with different Cu/Mn molar ratios (x = 1, 1.5 and 2) was synthesized by the co-precipitation method. The catalytic performance of CuxMn in N2O decomposition has been studied with a continuous flowing microreactor system. The obtained catalysts were characterized by XRD, BET, Raman, FT-IR, ICP-AES and H-2-TPR. The catalytic tests show that the CuxMn catalysts exhibit more excellent N2O catalytic decomposition activity compared with the pure CuO and Mn2O3 catalysts, and the Cu1.5Mn shows the highest catalytic activity under the reaction conditions of N2O 0.1%, GHSV 10000 h(-1). The characterizations results suggest that bulk CuO and Mn2O3 existed in pure CuO and Mn2O3 catalysts, respectively. In the CuxMn catalysts, with the decreasing of x, the amount of bulk CuO gradually decreases until it disappears, while the amount of newly formed CuMn2O4 gradually increases. However, the amount of small crystal CuO increases first and then decreases, which might be considered as an important active phase that contributes to the excellent catalytic performance of CuxMn in N2O decomposition.