Preparation and activity study of monolithic three-dimensional ordered macroporous La0.7Ce0.3CoO3 with different loading methods

Abstract

The innovative mixed impregnation method was used to realize the combination of polymethylmethacrylate(PMMA) template, active components and cordierite carrier in the preparation of monolithic catalyst. Compared with the samples prepared by centrifugal deposition method and deposition curing method, three-dimensional ordered macroporous(3DOM) La0.7Ce0.3CoO3 cordierite catalysts prepared by mixed impregnation method have obvious advantages over other samples in morphology, microstructure, surface properties and redox capacity. Through a series of characterization, it was found that the active components of the catalyst prepared by mixed impregnation method(3DOM La0.7Ce0.3CoO3/MIM) were highly dispersed on the surface of cordierite carrier, and the most complete La0.7Ce0.3CoO3 perovskite crystal structure was formed. At the same time, 3DOM La0.7Ce0.3CoO3/MIM formed a macroporous-mesoporous structure, which provided a good diffusion environment for the reactants. In addition, catalysts prepared by mixed impregnation method had excellent catalytic activity (T50 = 103 ℃, T90 = 218 ℃) and good stability due to its large specific surface area (10.57 m2/g), high Oads/Olatt concentration and good redox ability. The apparent activation energy of 3DOM La0.7Ce0.3CoO3/MIM was 59.56 kJ·mol−1, which was lower than that of catalysts prepared by centrifugal deposition method (72.07 kJ·mol−1) and deposition curing method (71.38 kJ·mol−1). It can be concluded that the high activity of 3DOM La0.7Ce0.3CoO3/MIM can be attributed to the high dispersion of active components, permeable pore structure, high surface adsorbed oxygen concentration and good low temperature reduction.