Effect of A-site element on the performance of three-dimensionally ordered macroporous manganese-based perovskite catalyst

Three-dimensionally ordered macroporous manganese-based perovskite catalyst (3DOM AMnO3, A = Ce, La, Ni) were synthesized by PMMA hard-templating and impregnation method. Physicochemical properties of the samples were characterized by means of various techniques including XRD, BET, SEM, TEM, XPS and H2-TPR, and their catalytic activities were evaluated by toluene combustion. It was found that the 3DOM AMnO3 in each of the samples was perovskite in crystal structure, and only the samples possessed a good quality 3DOM architecture with a surface area of 48.8 m2/g. Due to the highest adsorbed oxygen species concentration (Oads/Olatt = 2.330), the best low-temperature reducibility (The low-temperature reduction peaks of 3DOM CeMnO3 catalysts occur at 425 °C) and the strong interaction between CeO2 and MnOx formed during calcination. The 3DOM CeMnO3 sample showed lower apparent activation energy (34.51 kJ·mol−1, SV = 15,000 h−1) and the best catalytic activity for toluene combustion, with the reaction temperatures (T50%, and T90%) required for achieving toluene conversions of 50%, and 90% being 100 °C, 172 °C at SV = 15,000 h−1, respectively.