Sn x .Ti 1‐x O 2 solid solution catalysts for nitrogen oxide selective catalytic reduction by propene in presence of oxygen

A series of SnO 2 ‐TiO 2 binary oxide catalysts prepared by co‐current precipitation method was found to be a novel and good system for the selective catalytic reduction of NO by propene in the presence of oxygen with high activity and good selectivity to N 2 . The NO conversion to N 2 over SnO 2 ‐TiO 2 oxide catalysts varied with SnO 2 content and attainted a maximum at 65% over the catalyst with SnO 2 content at 40wt% for a feed with 1186 ppm NO, 948 ppm propene and 2.23% O 2 , in He and a space velocity of 15000 h −1 at 350°C. The SnO 2 TiO 2 catalysts could sustain moderate activity in the presence of 10% steam. Because of the identical valence and the similar radius of Sn 4+ and Ti 4+ , SnO 2 ‐TiO 2 binary oxides can form solid solution in three different phases as proved by XRD, electron diffraction and TPR. Sn 4+ is the main active species in the SnO 2 ‐TiO 2 catalysts, and it is enriched on the solid solution surface as tested by XPS analysis. H 2 ‐TPR, NH 3 ‐TPD and BET tests show that SnO 2 ‐TiO 2 solid solution can dilute SnO 2 and suppress the activity of propene complete oxidation over SnO 2 . This may be beneficial to the reactivity enhancement of NO conversion.