Cerium-modified manganese octahedral molecular sieves as catalysts for selective catalytic reduction

摘要

Catalysts and articles useful for selective catalytic reduction (SCR) are disclosed. The catalyst comprises a cerium oxide and an octahedral molecular sieve (OMS) comprising manganese oxide. The catalysts, which comprise 0.1 to 50 wt. % of cerium, can be made by doping, ion-exchange, deposition, or other techniques. Also disclosed is an SCR process in which a gaseous mixture comprising nitrogen oxides is selectively reduced in the presence of a reductant and the cerium-modified OMS catalyst. The cerium-modified manganese oxide OMS catalysts offer unexpected advantages for selective catalytic reduction, especially NH₃-SCR, including improved thermal stability and improved activity for NOx conversion, especially at relatively low temperatures (100° C. to 250° C.).