Catalytic combustion of lean methane over MnCo2O4/SiC catalysts: Enhanced activity and sulfur resistance

Abstract

The simultaneous control of catalytic activity and sulfur resistance is a challenging task for non-noble metal catalysts in the domain of heterogenous catalysis. Herein, by dispersing MnCo2O4 (MCO) nanoparticles on a SiC substrate, we develop a novel catalyst for methane combustion that exhibits excellent low-temperature catalytic activity as well as high sulfur resistance. Strong interactions between SiC and MCO reduce the crystallite size of MCO and increase the specific surface area of the catalyst and the concentration of the active species, namely, Co3+ and surface oxygen species. The 60%MCO/SiC sample shows the highest catalytic activity, with T10, T50, and T90 values of 335, 375, and 444 °C, respectively, at a space velocity of 45,000 mL∙g−1∙h−1. In-situ diffuse reflectance infrared spectroscopy experiments and physicochemical characterizations indicate that the enhancement of catalytic activity is mainly attributed to the abundant adsorbed oxygen and surface Co3+ species in the catalysts that accelerate the formation of carbonate and formic acid species during methane conversion. The 60%MCO/SiC sample also exhibits high sulfur resistance, which is mainly attributed to the inhibiting effect of SiC on the catalyst for bulk sulfate formation. The findings of this study provide insights for the fabrication of catalysts with high activity as well as high sulfur resistance.