Active Sites for the Reaction of Ethanol to Acetaldehyde on Co/YSZ(100) Model Steam Reforming Catalysts

Structure–activity relationships for the reaction of ethanol on model Co/YSZ(100) (YSZ = yttria-stabilized ZrO 2 ) steam reforming catalysts were investigated using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy and compared with those obtained previously for the reaction of ethanol on Co/ZnO(0001) and Co foils. Oxygen-free, metallic Co sites were found to be active for ethanol decarbonylation to form CO, H 2, and adsorbed CH 3 groups, whereas oxygen adatoms on metallic Co promoted ethoxide dehydrogenation to produce acetaldehyde at 330 K during TPD. In contrast, oxidized Co surfaces containing only Co 2+ sites were found to be less reactive for ethanol dehydrogenation producing acetaldehyde at 480 K. These results, along with comparisons with those from Co/ZnO(0001) and Co foils, provide new insights into the active sites for ethanol steam reforming on Co-based catalysts and the influence of the support on both catalyst reactivity and stability.