Novel Fe-W-Ce Mixed Oxide for the Selective Catalytic Reduction of NOx with NH3 at Low Temperatures

A set of novel iron doped cerium-tungsten catalysts were prepared by sol-gel method with a view to their application for low temperature selective catalytic reduction (SCR) of NOx with NH3 in power plants. With a molar ratio Fe/W/Ce of 0.5:1:1, a NOx reduction of >90% at 200 degrees C was achieved. In Fe-W-Ce catalysts with low iron oxide content, it was found that the iron compounds were highly dispersed and formed a solid solution within the cerium oxide lattice, which promoted the SCR activity. Large amounts of iron in the catalysts might form a layer of Fe2O3 on the catalyst surface, which induced the synergistic inhibition effect among Fe, Ce and W species. Moreover, the Fe-W-Ce catalysts possessed a high resistance to changed operation parameters as well as to deactivation by SO2 and/or H2O. The novel catalyst showed to be competitive among recently developed low-temperature SCR catalysts.