Synergistic Effects of Multicomponents Produce Outstanding Soot Oxidation Activity in a Cs/Co/MnO_x Catalyst

摘要

The control of soot emission from diesel vehicles is of extraordinary importance to the environment, and catalytic removal of soot is a highly effective and clean method. Here, we report a novel, non-noble metal catalyst for application in the catalytic combustion of soot with superb activity and resistance to H_2O and SO_2· MnO_x oxide was prepared via a hydrothermal method, and then, Cs and Co were loaded on MnO_x by impregnation. The 5%Cs/l%Co/MnO_x catalyst displayed excellent catalytic activity with values of T_(10) (332°C), T_(50) (371 °C), and T_(90) (415 °C) under loose contact. The as-prepared catalysts were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), H_2 temperature-programmed reduction (TPR), O_2 temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure (XAFS). The results suggest that, after the introduction of Cs and Co into the MnO_x oxide, more NO_2 molecules take part in soot oxidation, exhibiting higher NO_2 utilization efficiency; this is due to the synergistic effects of multiple components (Cs, Co, and Mn) promoting the generation of more surface-active oxygen and then accelerating the reaction between NO2 and soot. This study provides significant insights into the development of high-efficiency catalysts for soot oxidation, and the developed 5%Cs/1%Co/MnO_x catalyst is a promising candidate for application in diesel particulate filters.