Low temperature catalytic steam reforming of ethanol. 2. Preliminary kinetic investigation of Pt/CeO2 catalysts

Catalytic activity, selectivity and stability of a Pt/CeO2 (5wt% Pt) catalyst were investigated in the low temperature ethanol steam reforming reaction for hydrogen production. Experimental results showed that the catalyst is very active and selective, with negligible CO production and complete ethanol conversion already at 300 degrees C. The main promoted reactions are ethanol decomposition, ethanol steam reforming and CO water gas shift, and a preliminary kinetic investigation showed that the apparent reaction orders are 0.5 and 0 for ethanol and steam respectively, with an apparent activation energy of 18 kJ mol(-1) evaluated in the range 300-450 degrees C. Kinetic evaluations and temperature programmed desorption experiments suggest a surface reaction mechanism involving the following step: (i) ethanol dissociative adsorption on catalyst surface to form acetaldehyde intermediate, (ii) decarbonylation to produce mainly H-2, CH4 and CO, and (iii) WGS reaction of CO adsorbed on Pt sites to produce H-2 and CO2. (c) 2010 Elsevier B.V. All rights reserved.