Elucidate the promotional effects of Sn on Ce-Ti catalysts for NH3-SCR activity

Through a facile hydrothermal method, a series of mesoporous Ce0.3-x-Sn-x-Ti catalysts with high surface area have been prepared. A lot of characterizations were used to elucidate the promotional effects of SnO2 on Ce-0.3-Ti catalysts for NH3-SCR activity. Compared with CeO2-TiO2 catalysts, the activity and SO2 resistance of the Ce-0.2-Sn-0.1-Ti catalyst were remarkably improved after doping Sn, and presented an excellent catalytic activity (above 90%) within 220-360 degrees C. The results suggested that Sn-doped Ce-Ti catalysts effectively increased lattice oxygen mobility, total acid amount accompanied with more Ce3+ and surface adsorbed oxygen species by insertion of doping ions. Furthermore, the reducibility of Ce0.2Sn0.1-Ti sample was greatly improved by the reaction of 2Ce(4+) + Sn2+ <-> 2Ce(3+) + Sn4+, and with the assistance of Ce2O3 to prevent the (NH4)(2)SO4, NH4HSO4 species and bulk-like sulfates from forming on the surface, leading to the better SO2 resistance. In addition, the in situ DRIFTS also illustrated that the NH3-SCR process occurred over Ce-0.2-Sn-0.1-Ti obeyed the Elye-Rideal mechanism. (C) 2019 Energy Institute. Published by Elsevier Ltd. All rights reserved.