Transition metal modified manganese-based catalysts for soot oxidation promoted by noncompetitive adsorption of oxygen: Experiments and DFT calculations

Abstract

A series of manganese-based oxide catalysts were synthesized by the hydrothermal method. By adjusting the doping amounts of W and Cu in the system to study the catalytic performance of transition metal-doped manganese oxides on soot combustion. They were deeply studied through various characterizations and theoretical calculations. The results show that W and Cu doping modifications can significantly improve the activity of manganese-based oxides in soot oxidation. W-Cu0.1/MnOx prepared by co-modification of W and Cu at 395 °C can convert 90% of soot into CO2. The multiple characterization results show that by adjusting the doping amount of copper and tungsten, the nano-flower-like morphology can be obtained and the crystal plane can be reconstructed, which is helpful to increase the specific surface area, Mn3+ content, and oxygen vacancy content. The theoretical calculation results show that the oxygen vacancy on the surface of the catalyst shows the ability to activate O2 and H2O, and they show non-competitive adsorption. In addition, W-Cu0.1/MnOx has a good application prospect in the catalytic oxidation of soot because of its excellent catalytic stability. This work provides a reference for the design and preparation of non-noble metal-based catalysts for the elimination of soot particles from diesel engine exhaust.