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The reduction of NOx using NH₃ has been successfully practiced for stationary sources and more recently, for passenger cars and heavy-duty applications in the US and Europe. Due to the up-coming Euro 6 regulations (2014) for passenger cars and light-duty trucks, NH₃-SCR catalyst technologies are extensively studied by OEMs, catalysts manufacturers and raw materials suppliers, all looking for technologies very efficient at low temperatures, thermally stable up to 800°C and with a limited impact of the NO₂/NOx ratio on activity. Among the new emerging SCR catalytic systems, non-zeolitic zirconia-based mixed oxides were introduced recently in SAE 2008 as promising new SCR catalysts. This paper reports the progress made on these materials. "Synthetic Gas Bench Tests" performed on powder catalysts show a significant increase of the NOx conversion, in comparison with that previously reported.

Acidic zirconia materials have been tested as catalysts for the Selective Catalytic Reduction of nitrogen oxides (NOx) by ammonia (NH3-SCR). This paper focuses on the promotion of acidic zirconia by ceria. The introduction of ceria increases the NOx conversion, the selectivity to N2 and the durability and makes acidic zirconia materials attractive for Diesel after treatment systems.

The reduction of NOx from Diesel Engines or Lean-burn Gasoline Engines is a major issue in automotive catalysis. Over the last several years, many solutions to remove NOx under lean operating conditions have been considered. Attention is now focused on two main technologies: (i) Selective Catalytic Reduction using ammonia as reductant (urea SCR) and (ii) NOx-Storage Catalyst (NSC). This paper deals with materials for NOx storage catalysts. NSC catalysts show high efficiency as fresh, but their durability is low due to a fast deactivation of the active sites [1,3]. This issue relates to a drastic sintering of the materials after ageing, especially during the regeneration and the desulfation [3, 4 and 5]. Moreover, the current materials are sensitive to SOx poisoning [1,3,4]. In this paper, ceria based oxides have been examined as NOx-storage materials and Pt carriers as well. These oxides contain high ceria loading and are thermally stable up to 900°C.

Acidic doped zirconia catalyst supports with high thermal stability and high SOx resistance have been tested in Diesel exhaust. This paper focuses on the optimization of these materials to get the best trade-off between acidity and thermal stability. These materials were tested as a Platinum support for Diesel Oxidation Catalysts (DOC). Preliminary data are also discussed concerning their ammonia adsorption properties for the Selective Catalytic Reduction of NOx by ammonia (SCR).

The reduction of NOx from Diesel Engines or Lean-burn Gasoline Engines is a major issue in automotive catalysis. Over the last several years, many solutions to remove NOx under lean operating conditions have been considered. Attention is now focused on two main technologies: (i) Selective Catalytic Reduction using ammonia as reductant (urea SCR) and (ii) NOx-Storage Catalyst (NSC). This paper deals with materials for NOx storage catalysts. Even if the fresh NSC shows high efficiency, its durability is low due to a fast deactivation of the active sites [1,3]. This problem relates to a drastic sintering of the materials after ageing, especially during the regeneration and the desulfation [3, 4 and 5]. Moreover, the current materials are sensitive to SOx poisoning [1,3, 4]. In this paper, modified Ba-alumina oxides used as NOx-Storage materials have been investigated. These oxides contain high Ba loading (such as 20 wt% Ba) and are thermally stable.