Mechanism of B-site modulation in LaBO3 perovskites (B = Fe, Co, Ni) promoting CO catalytic oxidation

Perovskite (ABO3) catalysts have garnered significant attention in the field of catalytic oxidation due to their high structural stability, low cost, and excellent thermal stability. However, limited research has been conducted on the differences in CO oxidation activity among perovskites with different B-site elements and the underlying reasons for these variations. In this study, a series of LaBO3 (B = Fe, Co, and Ni) perovskites were synthesized using the sol-gel method, and their CO oxidation activity was evaluated. The results showed that LaNiO3 (designated as LNO) exhibited the best CO oxidation activity, with a temperature (T90) of only 192 degrees C required to achieve a 90 % conversion rate. Characterization by XRD, XRD Rietveld refinement, and EPR revealed differing levels of oxygen vacancies on the surfaces of the three perovskite catalysts. XPS and H2-TPR analyses further confirmed that LNO possesses superior low-temperature redox properties and an abundance of surface-adsorbed oxygen. The B-site element in perovskites influences the concentration of oxygen vacancies, which facilitate the adsorption and activation of oxygen from the gas phase. These characteristics contribute to LNO's outstanding CO catalytic oxidation performance. The B-site adjustment strategy reported in this study could facilitate the advancement of perovskite-based catalysts in the field of catalytic oxidation and purification.