The role of impregnation medium on the activity of ceria-supported cobalt catalysts for ethanol steam reforming

s The effect of impregnation medium on the activity of Co/CeO2 catalysts in ethanol steam reforming was investigated using various characterization techniques including temperature programmed calcination, temperature programmed reduction, X-ray diffraction, laser Raman spectroscopy, X-ray photoelectron spectroscopy, and diffuse reflectance infrared fourier transform spectroscopy. The steady-state reaction experiments showed that catalysts that were prepared in an organic medium (e.g.. ethanol) during impregnation gave higher H-2 yields than those prepared in aqueous media. Characterization results showed the presence of oxygenated carbonaceous species left on the surface from the impregnation step. These species, which were stable through oxidation and reduction pre-treatment steps, may possibly contribute to the activity, selectivity and stability of the catalysts by keeping the Co particles segregated and by blocking the sites for side reactions. (C) 2009 Elsevier B.V. All rights reserved.