Sulfur resistance and soot combustion for La0.8K0.2Co1-yMnyO3 catalyst

Abstract

Different Mn-substitution amounts of La0.8K0.2Co1-yMnyO3(y=0–0.5)catalyst were prepared using the sol-gel method to study the effect of SO2 on the catalytic combustion of soot. The TPO results show that the La0.8K0.2Co0.7Mn0.3O3 catalyst has the best catalytic performance. After presulfurization (500ppm SO2, 3h, 300°C), the catalytic performance weakens with higher Ti (310°C) and Tm (386°C), increasing by 34°C and 31°C. In this paper, the oxygen absorbed from the gas phase and further incorporation of oxygen atoms into a lattice classified as three kinds of oxygen species, O2−, O− and O2−. The results of XPS indicate that there are sulfates on the surface of the catalysts and the catalytic performance of catalysts presulfured weakens mainly due to the decrease of available oxygen source (O2− and O2−). However, the oxidation of soot is attributed to the reaction between soot and O2− in the surface active site of catalyst. Meanwhile, soot and SO2 may have a competitive relationship in reacting with O2−. These results have significance to research the relation of catalyst poisoning and active oxygen with the aim of improving the stability of perovskite-based catalyst.