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

The catalytic properties 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 Brønsted-sites.