Catalytic Oxidation of <i>n</i>-Decane, <i>n</i>-Hexane, and Propane over Pt/CeO<sub>2</sub> Catalysts
Xiaohui Gao, Yuting Bai, Hao Zhang, Xingyi Wang
Abstract
High Resolution Image Download MS PowerPoint Slide 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.