Low temperature denitrification and mercury removal of Mn/TiO₂-based catalysts: A review of activities, mechanisms, and deactivation

Mn-Ce/TiO2 series catalysts have become a hot spot in the research of low temperature NH3-SCR catalyst for denitrification and mercury removal due to good catalytic activity at low temperature. The introduction of Ce effectively solves the problems of poor N-2 selectivity and toxic deactivation of MnOx/TiO2 catalysts due to its excellent redox performance and ability to enhance the sulfur resistance of catalyst. This work reviews the recent researches on MnOx/TiO2 catalysts modified by Ce in NO reduction and mercury removal. The preparation methods of catalyst have been briefly described. The effects of Mn-Ce/TiO2 catalysts modified by transition metal elements have been comprehensively analyzed in terms of catalytic activity, N-2 selectivity and catalyst microstructure. The reaction mechanisms related to the Mn-Ce/TiO2 low-temperature catalysts were investigated by combining quantum mechanical methods. In addition, the deactivation mechanisms of the catalysts by deactivating substances, such as SO2, HCl, and alkali metal ions, were summarized in depth, and it is shown that the doping of transition metals can effectively improve the resistance of the catalysts. Finally, based on the catalytic effects of the Mn-Ce/TiO2 low-temperature catalysts and the problems it faces, it is pointed out that improving the catalyst's efficiency in removing various flue gas pollutants and enhancing its anti-deactivation will be the focus of future research.