Investigation of Co–Mn–Ce Ternary Composite Oxide Catalyst for Low-Temperature Selective Catalytic Reduction of NOx with NH3

Abstract

In this paper, the CoxMn1Cey composite oxide catalyst was synthesized by the co-precipitation method. The structure–activity relationship of the catalyst was analyzed by characterization methods such as XRD, Raman, H₂-TPR, NH₃/NO_x-TPD, XPS, and in situ DRIFTS. The results showed that the Co3Mn1Ce1 catalyst resisted high space velocity, water, and sulfur. In addition, Ce doping could effectively increase the specific surface area of the catalyst. In a sulfur-containing atmosphere, Ce could preferentially react with SO₂ and act as a sacrifice site to protect the active components from toxicity. Co-doping greatly enhanced the redox capacity of the catalyst and increased the chemisorbed oxygen (O_S) content on the surface of catalysts. Co-presence of Co and Ce increased the content of surface-active Mn species, which further effectively improved the adsorption capacity of the catalyst for NH₃ and NO reactants. In situ DRIFTS results showed that the reaction on the Co3Mn1Ce1 catalyst followed both the Langmuir–Hinshelwood and Eley–Rideal mechanisms.