Equilibrium composition of ethanol steam reforming reaction to produce H2 applied to Ni, Co and Pt/hydrotalcite–WOx catalysts

• Experimental and calculated mole fractions in H2 production were compared.
• Pt/hydrotalcite catalyst showed the best performance to produce H2 from ethanol.
• At 450 °C and a ratio water/ethanol of 4 these catalysts did not produce CO.
• Calculated equilibrium composition in H2 production was useful to select catalysts.
• The equilibrium constants for six reactions in H2 production were calculated.

The purpose of this work was to investigate the difference between the experimental molar fractions of products obtained during the evaluation of Pt, Co and Ni/Hydrotalcites–WOx catalysts and the calculated composition in equilibrium for the ethanol steam reforming reaction. Mole fractions of H2, CO2, CH3CHO, CH2CH2, CH4 and H2O were calculated using the stoichiometric and the minimization of the Gibbs free energy methods. The difference between calculated and experimental mole fractions was used to determine the intermediate and final compounds in the reaction mechanism and also how close to equilibrium are the reactants and final products. In addition, by comparing H2 and the conversion, it was possible to distinguish which series of catalysts were more active. From our experimental results, the conversion order of these catalysts was as follows: Pt > Ni > Co and the reaction rate per g-atm of metal was: Pt ≫ Ni ≈ Co.