Highly Efficient Catalytic Soot Combustion Over Potassium‐Promoted Pine Needles‐Like CoMnO Nanoarray Monolithic Catalysts

Abstract

AbstractHerein, we report the high catalytic activity of the potassium‐promoted pine needles‐like Co2.7Mn0.3O4 nanoarray catalysts supported on the monolithic three‐dimensional macroporous (3‐DM) Ni foam substrate (xK/Co2.7Mn0.3O4−NF) by hydrothermal process and wet impregnation method for soot combustion. The 3‐DM structure of Ni foam and the macroporous nanostructure created by Co2.7Mn0.3O4 nano‐composites greatly improve the contact opportunities between soot particulates and catalysts. Our characterization results show that the addition of potassium promotes the mobility of oxygen species due to the low melting point of K‐containing compounds, and the strong interaction between potassium species and Co2.7Mn0.3O4 nano‐composites not only increases the number of active oxygen species but also improves the oxidizability of the xK/Co2.7Mn0.3O4−NF catalysts for soot oxidation. The impact of the K loadings on the catalysts displays a volcano‐type on the performance of soot oxidation and the catalyst loaded with 8 wt.% potassium species shows the highest activity with T50 at 314 °C in 600 ppm NO/O2/N2 flow, as well as high stability and water resistance. Simultaneously, the electron transfer and oxygen transfer mechanisms for soot combustion are discussed in detail. The strategy employed in this work has potential application prospects in other catalytic oxidation systems.