Catalytic performance of La-Mn-Fe-Cu/HZSM-5 catalysts for soot combustion from diesel exhaust

The catalysts of perovskite-type complex oxide loaded on HZSM-5 zeolite were synthesized. The catalysts were characterized by XRD, SEM, XPS and H₂-TPR, and their performance for combusting soot was evaluated in a fixed micro-reactor. The results show that when B-site ion was consisted of various metals, the catalytic performance was improved, the soot combustion temperature decrease, and the selectivity forming CO₂ increased. The performance of catalysts was affected by the species and component of B-site ion. The selectivity forming CO₂ increased and the temperature of soot combustion reduced when Cu and Co ion was in B-site, respectively. The temperature of soot combustion and selectivity forming CO₂ was improved with changing the mole ratio of Fe/Mn. Among them, LaMn_0.2Fe_0.7Cu_0.1O₃/HZSM-5 catalyst has better performance with lower combustion temperature of T_ig, T_m and T_f at 236.6, 419.0 and 458.7 ℃, respectively, and higher selectivity forming CO₂ of 88.3%。