Alkali metal enhanced cerium manganese-based three-dimensional ordered macroporous catalyst for NO oxidation and soot combustion

Abstract

Alkali metal can control the redox potential of the reaction system, modify the surface electronic structure, improve the stability of catalyst. Herein, we dop the alkali metal into cerium manganese-based three-dimensional ordered macroporous (3DOM) catalyst for NO oxidation and soot combustion, which are synthesized using a self-sacrificing polymethyl methacrylate template and an excess impregnation method. The introduction of alkali metal can provide the rough pore surface, which increases the contact area between the catalyst and the reactant gas. Meanwhile the alkali metal dopping can promote the formation of more oxygen vacancies and unsaturated structures and increase the catalytic activity for NO oxidation and soot combustion. 5% K-doped CM-5K achieved an 81.9% NO conversion rate at 250°C and nearly 100% at 320 °C. The CM-5K also demonstrated remarkable stability in cyclic stability tests for NO oxidation and soot combustion. This work provides a promising catalyst candidate for NO oxidation and soot combustion catalyst in the practical application.