Insights into the effect of Cu and Fe dispersion state over Ce0.1Al on the catalytic performance of NO reduction by CO

Abstract

In this paper, Cu and Fe dispersion states over Ce0.1Al were modified by different doping methods such as impregnation and co-precipitation. Cu and Fe were dispersed on the surface of Ce0.1Al carriers in Cu/Fe/Ce0.1Al sample, while for Cu/FeCe0.1Al catalyst, Fe was doped in the carriers and Cu was uniformly dispersed on the surface. The effects of dispersion states on the catalytic behaviors of NO reduction by CO were investigated. The resistance to O2 and SO2 was also verified. Cu/FeCe0.1Al catalyst owned superior denitrification activity and O2/SO2-tolerance performance than Cu/Fe/Ce0.1Al. For the front one, Fe was introduced by co-precipitation scheme. Small particle size and higher specific surface area was achieved. Thus its redox and adsorption performance were ameliorated. For the latter, more active species were enriched on the surface, which was conductive to the defects formation and the reduction of surface adsorbed oxygen. In combination with microstructure characterizations, the intrinsic mechanism was proposed. In essences, the interaction among Cu, Fe and Ce was modified owing to their different dispersion state of Cu and Fe. As a result, NO+CO reaction followed different mechanism over two catalysts. NO reduction by CO on Cu/Fe/Ce0.1Al catalyst followed E-R mechanism, while L-H mechanism was dominant over Cu/FeCe0.1Al catalyst.