Catalytic Oxidation of n -Decane, n -Hexane, and Propane over Pt/CeO 2 Catalysts.

Pt species with different chemical states and structures were supported on CeO 2 by solution reduction (Pt/CeO 2 -SR) and wet impregnation (Pt/CeO 2 -WI) and investigated in catalytic oxidation of n -decane (C 10 H 22 ), n -hexane (C 6 H 14 ), and propane (C 3 H 8 ). Characterization by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, H 2 -temperature programming reduction, and oxygen temperature-programmed desorption showed that Pt 0 and Pt 2+ existed on Pt nanoparticles of the Pt/CeO 2 -SR sample, which promoted redox, oxygen adsorption, and activation. On Pt/CeO 2 -WI, Pt species were highly dispersed on CeO 2 as the Pt-O-Ce structure, in which surface oxygen decreased significantly. The Pt/CeO 2 -SR catalyst presents high activity in oxidation of C 10 H 22 with a rate of 0.164 μmol min -1 m -2 at 150 °C. The rate increased with oxygen concentration. Moreover, Pt/CeO 2 -SR presents high stability on feed stream containing 1000 ppm C 10 H 22 at gas hour space velocity = 30,000 h -1 as low as 150 °C for 1800 min. The low activity and stability of Pt/CeO 2 -WI were probably related to its low availability of surface oxygen. In situ Fourier transform infrared results showed that the adsorption of alkane occurred through the interaction with Ce-OH. The adsorption of C 6 H 14 and C 3 H 8 was much weaker than that of C 10 H 22 , which resulted in the decrease in activity for C 6 H 14 and C 3 H 8 oxidation of Pt/CeO 2 catalysts.