A novel insight into enhanced propane combustion performance on PtUSY catalyst

摘要

Platinum was supported on c-Al_2O_3 and ultrastable Y zeolite(USY) by an incipient wetness impregnation method. The catalysts were characterized by nitrogen physisorption, transmission electron microscopy(TEM),CO/C_3H_8 isothermal oxidations, NH_3 temperature-programmed desorption(NH_3–TPD) and infrared(IR) spectroscopy of adsorbed probe molecules(CO, C_3H_8 and C_3H_8+ O_2). Compared with Pt/Al_2O_3, Pt USY catalyst shows obviously higher activity for the combustion of propane. After estimating the size effect of Pt particles and propane adsorption capacity of USY, the excellent activity of Pt USY is also attributed to the strong interactions between the precious metal and the acidic zeolite. It inhibits the oxidation of Pt in an oxygen-rich atmosphere at high temperatures, which facilitate the initial oxidation step involving the C–H bond activation on metallic Pt as reflected by in situ diffuse reflectance infrared Fouriertransformed(DRIFT) spectra.