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).