Effect of rhodium on the properties of bifunctional MxOy/ZrO2 catalysts in the reduction of nitrogen oxides by hydrocarbons

The catalytic proper-ties of transition metal oxides (Cr, Ce, and Co) supported on ZrO2 synthesized by various methods, as well as the effect of rhodium on the performance of the MxOy/ZrO2 Oxide systems in NO reduction with hydrocarbons (methane, propane-butane mixture, and propene) were studied. Scanning electron microscopy, ammonia thermoprogrammed desorption (NH3-TPD), XPS, and IR spectroscopy were used to study the physicochemical indices of rhodium-promoted MxOy/ZrO2 oxide catalysts. The enhancement of the redox properties of the oxide catalysts upon the introduction of rhodium does not alter their bifunctional nature in SCR activity: these catalysts have both redox and strong acid Bronsted-sites. (c) 2006 Elsevier B.V. All rights reserved.