The effect of textural properties of CeO2-SiO2 mixed oxides on NH3-SCO activity of Pt/CeO2-SiO2 catalyst

A series of CeO2-SiO2 (CS) mixed oxides with different textural properties were prepared by sol-gel methodology using different synthesis temperatures (STemps) in order to investigate the influence of the CS mixed oxide support on the NH3-SCO activity for Pt/CS catalysts. The results showed that the support material had a significant effect on catalytic activity. A Pt/CS catalyst, CS material synthesized at 40 °C (CS40) with a core-shell structure, high dispersion and good CeO2 crystallinity, showed excellent NH3 oxidation activity at low temperatures which was superior to the traditional Pt/Al2O3 tested. Characterization results showed that highly dispersed CeO2 on SiO2 with good CeO2 crystallinity was favorable towards the formation of surface /lattice oxygen and medium strong acid both of which were important for the NH3 oxidation reaction. This work suggests that the Pt/CS40 catalyst is a more suitable alternative to traditional lower layer Pt/Al2O3 catalyst for dual ammonia slip catalyst (ASC).