Study on Catalytic Oxidation of Soot by Sn-Ce Composite Oxide: Adsorbed oxygen and defect sites synergistically enhance catalytic activity

Herein, SnxCe1-xO2 (x= 0, 0.1, 0.2, 0.3, 0.4, 0.5, 1) catalysts have been synthesized by co-precipitation method and to investigate the catalytic performance for soot oxidation with the existence of water. Results show that the catalyst with the optimal mole ratio (Sn: Ce =4:6) exhibits the best catalytic performance, giving a T90 of 413℃ and 92.8% CO2 selectivity. The characterization results indicate that the incorporation of Sn4+ into the lattice of CeO2 can result in the decrease of crystallite size and the improvement of Oα (the chemisorbed oxygen) and Ce3+ content, which is beneficial to the enhancement of catalytic performance. The mesoporous structure and increased specific surface area enhance the contact condition between the catalyst and soot. The presence of Sn converts Ce4+ to Ce3+, which increases the adsorbed oxygen content of the catalyst. The improvement of redox activity and defective sites enhances the adsorption and activity properties of oxygen species. Moreover, repeat experiment was carry out to explore the durability.