Synergy between hydrogen and ceria in Pt-catalyzed CO oxidation: An investigation on Pt–CeO2 catalysts synthesized by solution combustion

Abstract Pt–CeO 2 catalysts were prepared by solution combustion synthesis (SCS), a simple and fast one-pot method, using glycine or oxalyl dihydrazide (ODH) as the fuel and Pt chloride or nitrate as the metal precursor. The samples were characterized by ICP-OES, N 2 volumetry, XRD, XPS, aberration-corrected (S)TEM, CO-DRIFTS and microRaman spectroscopy. The SCS catalysts were evaluated in CO oxidation and preferential oxidation (PROX) of CO in H 2 excess, and compared to Pt/CeO 2 and Pt/Al 2 O 3 catalysts prepared by incipient wetness impregnation. The glycine fuel yields better results than ODH in terms of Pt dispersion and catalytic performance. The fresh Cl-containing catalysts consist of PtO nanoparticles poorly active in CO oxidation, while the catalysts synthesized from Pt nitrate contain highly active Pt δ+ (0  2 -free CO oxidation is the one synthesized from glycine and Pt nitrate. For PROX, the selectivity to CO 2 is 100% at low temperature and decreases in a similar way for all the Pt–CeO 2 catalysts above ca . 100 °C. With respect to H 2 -free conditions, the CO PROX activity of the Pt–CeO 2 catalysts is considerably enhanced (activity multiplied by up to 60 at 110 °C), while the activity gain is comparatively minor for Pt/Al 2 O 3 . We conclude that hydrogen, by increasing the mobility of oxygen species at the surface of ceria, promotes the support-assisted pathway of CO oxidation.