Selective catalytic reduction (SCR) activity for NO conversion to N-2 over gamma-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 gamma-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.