Rare earth metal modified three dimensionally ordered macroporous MnOx-CeO2 catalyst for diesel soot combustion

Three dimensionally ordered macroporous (3DOM) Ce-based catalysts were successfully prepared via a surfactant-assisted colloidal crystal template (CCT) route. The as-synthesized catalysts showed well-ordered structures with macropores and small interconnected pore windows. The Raman results indicate that the catalyst persists pure fluorite cubic phases until the molar ratio of Mn exceeds 0.3, therefore MnOx particles form and impede the contact of the active site and the reagent and restraining soot combustion. The doping of Nd into MnOx-CeO2 enhances the catalytic activity because of increased oxygen vacancy, Mn4+ content and stronger redox ability. Nd-doping also improves thermal stability of the catalyst due to less sintering and none phase separation after thermal aging. The fresh and aged Mn0.3Ce0.6Nd0.1O2 catalysts show the maximum oxidation rate for soot at 331 and 355 degrees C in the O-2/N-2 atmosphere, achieving a nearly 100% CO2 selectivity. (C) 2018 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.