Preparation of Cu/Co/M (M=Al, Fe, Cr, NiFe) mixed metal oxides and their catalytic activity on selective catalytic reduction of NOx by hydrocarbon

Abstract

Cu/Co/M (M=Al, Fe, Cr, NiFe) mixed metal oxides (Cu/Co/M-MMOs) were prepared by calcination of Cu/Co/M layered double hydroxide (Cu/Co/M-LDHs) precursors. Their composition, thermal stability, structure and morphology were characterized by ICP, TGA, XRD, IR, BET and SEM, respectively. The results indicated that all precursor samples show good hydrotalcite structure with carbonate inside the layer, and the carbonate is removed by calcination at 773 K. While the mixed metal oxides have spinel structure with specific areas of 20-110 m2 g−1. Cu/Co/M-MMOs have hexagon structure with particle size in the range of 50-100 nm. The order of catalytic activities of Cu/Co/M-MMOs on selective catalytic reduction of NOx is: Cu/Co-MMOs>Cu/Co/Ni/Fe-MMOs>Cu/Co/Fe-MMOs>Cu/Co/AlMMOs∼Cu/Co/Cr-MMOs.