Synthesis of TixSn1-xO2 mixed metal oxide for copper catalysts as high-efficiency NH3 selective catalytic oxidation

A series of y Cu/Ti x Sn 1-x O 2 catalysts for selective catalytic oxidation (NH 3 -SCO) were synthesized using Ti x Sn 1-x O 2 as catalyst support and CuO as active species. Compared with pure TiO 2 support, the strong metal-support interaction between Cu active species and Ti x Sn 1-x O 2 was significantly promoted by the Sn-doping, thereby improving the catalytic activity and N 2 selectivity of the catalyst, which meets the demand of diesel vehicles to completely convert NH 3 . The results of XRD and HRTEM showed that the particle size of 20 Cu/TiSnO 2 sample is much more highly dispersed. The results of NH 3 -TPD and in-situ DRIFTS indicated that the copper species in 20 Cu/Ti x Sn 1-x O 2 can provide more Lewis acid sites than 20 Cu/TiO 2 , which is conducive to the adsorption and reaction of NH 3 . Meanwhile, XPS results proved that adsorbed oxygen on the catalyst surface is the main active oxygen species. Finally, in-situ DRIFTs and kinetic measurements found that the NH 3 -SCO reaction over 20 Cu/TiSnO 2 and 20 Cu/TiO 2 follow the i-SCR and imide (–NH) mechanisms, respectively. This catalyst will provide solutions for the future design and application of ammonia slip from mobile and stationary sources.