Selective reduction of nitric oxide by methanol and dimethyl ether over promoted alumina catalysts in excess oxygen

Selective catalytic reduction (SCR) activity for NO conversion to N₂ over γ-alumina, vanadia/alumina and molybdena/alumina catalysts has been investigated with methanol (MeOH) and dimethyl ether (DME) as reductants under lean conditions. Molybdena/alumina catalysts showed high efficiency for NO reduction with either reductant, especially at low temperature, which may involve surface formyl produced by oxidative dehydrogenation. Sulphated γ-alumina remains active for NO reduction with MeOH, while sulphated 5 wt.% MoO₃/Al₂O₃ remains active with both MeOH and DME over a broad temperature range.