Catalytic combustion of methane conducted on La–B–O–C (B Co, Mn, Fe) composites: The effects of B-sites cation properties

Abstract The novel La–B–O–C composites were fabricated as catalysts for methane catalytic combustion at low temperature, and considering the effect of newly C–O bond on B-site ions as active sites, three metal ions (Co, Mn, Fe) were selected for experiment. XRD, N2-physisorption, XPS and H2-TPR measurements were used to characterize the physicochemical properties of catalysts, which showed that the newly established C–O–B bond reduced the ionic valence of the B-site, and the redox capacities were increased or decreased to different degrees, respectively. Catalytic tests showed that T50 of La–Co–C–O composites (LC-C) and La–Fe–C–O composites (LF-C) are 377 °C and 482 °C, much lower than that of unmodified catalyst, respectively. But T50 of La–Mn–C–O composites (LM-C) increases to 507 °C from 493 °C. The superior performance of LC-C could be attributed to the high oxygen vacancies and enhanced redox property, and the better performance of LF-C was mainly benefited from the increase in lattice oxygen. For LM-C, the sacrifice of Mn4+ weakened the catalytic activity. There are more obvious mechanistic differences for different B-site elements in the La–B–O–C. The study will bring innovative insights into the design of excellent composites catalysts for methane oxidation.