Study of the effect of Gd-doping ceria on the performance of Pt/GdCeO2/Al2O3 catalysts for the dry reforming of methane

This work studied the performance of Pt/Al2O3 and Pt/CexGd1-xO2/Al2O3 catalysts for the dry reforming of methane at 1073 K. Pt/Al2O3 catalyst underwent severe deactivation at the beginning of reaction, whereas the deactivation of Pt/Ce0.8Gd0.2/Al2O(3) and Pt/Ce0.5Gd0.5/Al2O3 catalysts was less significant. Pt/36Ce(0.8)Gd(0.2)/Al2O3 catalyst remained quite stable during reaction. in situ XRD and XANES experiments showed the formation of oxygen vacancies and Ce3+ species during the reduction of the mixed oxide, which promoted the mechanism of carbon removal from the Pt particle. In the absence of mixed oxide, carbon deposition led to the deactivation of Pt/Al2O3 catalyst. The cyclohexane dehydrogenation reaction revealed that Pt sintering is responsible for the deactivation of Pt/Ce0.8Gd0.2/Al2O3 and Pt/Ce0.5Gd0.5/Al2O3 catalysts. The stability of Pt/36Ce(0.8)Gd(0.2)/Al2O3 catalyst is likely due to the close contact between Pt and the CeGd mixed oxide because of the higher extent of alumina coverage by the mixed oxide. This promotes the mechanism of carbon removal from the surface of Pt particles and inhibits Pt particle size growth.