Boosted NH3 Selective Catalytic Oxidation Activity over V-Pt-Ti Catalysts: Insight into Preparation Method Effects

In this work, V-Pt-Ti catalysts were synthesized employing impregnation (IP), precipitation (PC), sol-gel (SG), thermal decomposition (TD), and hydrothermal (HD) methods. A systematic study has been carried out to investigate impacts of various preparation methods on the performance of NH3 selective catalytic oxidation (SCO) at temperatures from 150 °C to 450 °C. N2 adsorption/desorption, XPS, XRD, H2-TPR, NH3-TPD, O2-TPD, SEM, TEM, and in situ DRIFTS were adopted to characterize the physico-chemical property of V-Pt-Ti catalysts. The results suggested that V-Pt-Ti catalysts synthesized by precipitation methods (denoted as VPT-PC) exhibited notably better SCO performance across the 150–450 °C temperature range compared with those produced by impregnation (IP), sol-gel (SG), thermal decomposition (TD), and hydrothermal (HD) methods. The outstanding performance of the VPT-PC catalyst could be ascribed to its larger surface area, higher relative contents of Pt0, V5+, and Oα, more abundant surface acid sites, and better redox property. In situ DRIFTS results suggested that NO2 species could participate in NH3 oxidation reaction on the surface of the VPT-PC catalyst, which was beneficial for improving the SCO activity.