The effects of Mn-based catalysts on the selective catalytic reduction of NOx with NH3 at low temperature: A review

Selective catalytic reduction technology has been widely used to remove NOx. However, the development of low-temperature selective catalytic reduction catalysts with high removal efficiency still faces severe challenges. This paper reviews the progress of research on Mn-based catalysts for selective catalytic reduction of NOx at low temperatures. Catalysts were divided into three categories: single manganese oxide catalysts, polymetallic oxide catalysts, and supported Mn-based catalysts. In the part of single manganese oxide catalysts, the effects of oxidation state, crystallinity, specific surface area, and species morphology on catalytic activity were systematically reviewed. In the part of polymetallic oxides catalysts, Mn-based catalysts were studied from the aspects of preparation strategy, catalytic performance, resistance to H2O and SO2, and broadening the operating temperature window. In the part of supported metal oxides, Mn-based catalysts supported on Al2O3, TiO2, CeO2, activated carbon fibers, and carbon nanotubes were reviewed. In addition, the mechanisms of hydrothermal deactivation, chemical deactivation, sulfur poisoning, and hydrocarbon poisoning of Mn-based catalysts were studied. Finally, the prospects and future directions for the development of Mn-based low-temperature selective catalytic reduction catalysts are presented.