Structure Sensitivity of the Reaction of Methanol on Ceria

Temperature programmed desorption was used to study the reaction of CH 3 OH on several different ceria-based model catalysts. These catalysts consisted of a CeO 2 (111) single crystal and thin ceria films supported on α-Al 2 O 3 (0001) and yttria-stabilized zirconia (100). The results of this study demonstrate that the reaction of CH 3 OH on CeO 2 surfaces is highly structure sensitive and depends on crystallographic orientation, the concentration of surface oxygen vacancies, and the oxidation state of surface cerium cations. The primary decomposition pathway for methoxide intermediates adsorbed on surface oxygen vacancy sites is dehydrogenation to produce H 2 CO and surface hydroxyl groups. The surface hydroxyl groups then either react with additional methoxides to reform CH 3 OH or react to produce H 2 O. In contrast, methoxides adsorbed on partially reduced ceria surfaces, possibly on Ce 3+ sites, undergo complete dehydrogenation to CO and H 2 .