Effects of tin doping level on structure, acidity and catalytic performance of Ti-Ce-O_x catalyst for selective catalytic reduction of NO by ammonia

A series of tin-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and tested for selective catalytic reduction of NO_x with NH₃ (NH₃-SCR). Effects of tin additives on structure, acidity and catalytic performance of Ti-Ce-Ox for NH₃-SCR of NO were investigated through characterization of N₂ adsorption-desorption, H₂-TPR, XRD, NH₃-TPD and SEM. Results showed that tin additives extended the active temperature window especially toward lower temperatures and the NO conversion efficiency of Ti-Sn-Ce-O_x (the Ti/Sn is equal to 4) catalyst reached 92% at 200°C. The addition of tin not only inhibit grain growth of CeO₂ and TiO₂, but also expand unit cell and cause lattice distortion, which are especially beneficial to NH₃-SCR. Moreover the introduction of tin also improved redox property significantly and enhance the acidity of catalyst. The anti-sulfur and anti-influence of water performance of catalyst also improved by tin-doped, when injecting 300 ppm SO₂ and 10 vol.% H₂O, the NO conversion efficiency of Ti-Sn-Ce-O_x catalyst was still reached 85% at 200°C.