Research progress of Mn-based low-temperature SCR denitrification catalysts

Selective catalytic reduction (SCR) is a efficiently nitrogen oxides removal technology from stationary source flue gases. Catalysts are key component in the technology, but currently face problems including poor low-temperature activity, narrow temperature windows, low selectivity, and susceptibility to water passivation and sulphur dioxide poisoning. To develop high-efficiency low-temperature denitrification activity catalyst, manganese-based catalysts have become a focal point of research globally for low-temperature SCR denitrification catalysts. This article investigates the denitrification efficiency of unsupported manganese-based catalysts, exploring the influence of oxidation valence, preparation method, crystallinity, crystal form, and morphology structure. It examines the catalytic performance of binary and multicomponent unsupported manganese-based catalysts, focusing on the use of transition metals and rare earth metals to modify manganese oxide. Furthermore, the synergistic effect of supported manganese-based catalysts is studied, considering metal oxides, molecular sieves, carbon materials, and other materials (composite carriers and inorganic non-metallic minerals) as supports. The reaction mechanism of low-temperature denitrification by manganese-based catalysts and the mechanism of sulphur dioxide/water poisoning are analysed in detail, and the development of practical and efficient manganese-based catalysts is considered.