Structure sensitivity of the reaction of methanol on ceria

Temperature programmed desorption was used to study the reaction of CH3OH o n several different ceria-based model catalysts. These catalysts consisted of a CeO2(lll) single crystal and thin ceria films supported on alpha -Al2O 3(0001) and yttria-stabilized zirconia (100). The results of this study dem onstrate that the reaction of CH3OH on CeO2 surfaces is highly structure se nsitive and depends on crystallographic orientation, the concentration of s urface 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 H2CO and surface hydroxyl groups. The surface hydroxyl groups then either react with additi onal methoxides to reform CH3OH or react to produce H2O. In contrast, methi oxides adsorbed on partially reduced ceria surfaces, possibly on Ce3+ sites , undergo complete dehydrogenation to CO and H-2.