Support effects in cobalt-based ethanol steam reforming catalysts: Reaction of ethanol on Co/CeO2/YSZ(1 0 0) model catalysts

In order to provide insight into how the support affects the reactivity of cobalt-based ethanol steam reforming catalysts, the reaction of ethanol on Co/CeO2/YSZ(1 0 0) model catalysts was investigated using a combination of X-ray photoelectron spectroscopy (XPS) and Temperature Programmed Desorption (TPD). Consistent with previous studies, metallic cobalt was found to be active for decarbonylation of ethoxide groups, while partially oxidized cobalt containing both Co0 and Co2+ was found to be active for ethoxide dehydrogenation to produce acetaldehyde. This partially oxidized active form of the cobalt was found to be readily formed via the reaction of vapor-deposited Co films with the reducible CeO2 support at temperatures as low as 300 K. Comparisons of these results to those obtained in our previous studies of the reactivity of Co/ZnO(0 0 0 1) and Co/YSZ(1 0 0) model catalysts are also presented, and the role of the support for enhancing ethanol steam reforming activity is discussed.

Partially oxidized cobalt containing both Co0 and Co2+ is formed via reaction with a ceria support at 300 K. This partially oxidized Co species, in contrast to metallic or fully oxidized cobalt, is active for the selective oxidation of adsorbed ethoxide groups to produce acetaldehyde at 345 K.Figure optionsDownload high-quality image (227 K)Download as PowerPoint slideHighlights
► Partially oxidized cobalt is active for selective oxidation of ethanol to acetaldehyde.
► Transfer of oxygen from ceria to supported Co is facile and occurs at 300 K.
► The support may help to maintain Co in a partially oxidized state.