Surface State and Catalytic Performance of Ceria‐Supported Cobalt Catalysts in the Steam Reforming of Ethanol

The effect of the particle size and the addition of a K promoter on the oxidation state of Co/CeO 2 was investigated and correlated with selectivity for ethanol steam reforming performed with various H 2 O/EtOH molar ratios. Spectroscopic studies showed that the oxidation state of the catalyst components depends on the H 2 O/EtOH molar ratio. Surface oxygen‐containing species (OH and K δ + −O δ − ) are necessary to achieve a good catalyst selectivity, to decrease the amount of coke deposited and to change the nature of the product from fully dehydrogenated C=C to CH x . Besides the surface concentration of oxygen‐containing species, the catalyst morphology and the location at which oxygen‐containing species are chemisorbed may be equally important to their abundance; the selective ceria‐supported Co catalyst should have well‐dispersed Co particles deposited on a well‐dispersed support.