Transition metal-aluminate catalysts for NO reduction by C 3H 6

Abstract

Transition metal-aluminum mixed oxide catalysts (Cu, Ni and Co–Al 2O 3), with spinel-type structure, were prepared by coprecipitation method. These catalysts showed high activity and selectivity for the selective reduction of NO by C 3H 6 in excess oxygen, and showed moderate activity even in the presence of 10% water. Among the catalysts tested, Cu–Al 2O 3 with 16 wt.% Cu content exhibited the highest activity at low temperature, though a bend over of NO conversion was significant at high level of O 2 concentration. At low level of O 2 concentration, Cu–Al 2O 3 exhibited higher activity than Cu-ZSM-5 below 623 K. In addition, Cu–Al 2O 3 showed higher hydrothermal stability than Cu-ZSM-5. The high activity and selectivity of M-Al 2O 3 were attributed to the surface aluminate phase, containing highly dispersed transition metal cations in Al 2O 3 matrix.