Production of hydrogen from ethanol using Pt/hydrotalcite catalysts stabilized with tungsten oxides

An stabilization effect of WOx over the Pt/hydrotalcite catalysts to produce H₂ by ethanol steam reforming at low concentration was studied. The catalysts were characterized by N₂ physisorption, X-ray diffraction, Infrared (IR), and UV-vis spectroscopy. The catalytic tests were made in a fixed bed reactor. The catalysts showed porous with the shape of parallel layers with a monomodal mesoporous distribution. By IR spectroscopy it was found superficial chemical such as: -OH, H₂O, Al-OH, Mg-OH, and CO₃^2-. The reaction products were; H₂, CO ₂, CH₃CHO, CH₄ and C₂H₄. These catalysts did not produce CO and showed low selectivity to C ₂H₄. By XRD we found that catalysts having Pt and the lowest W concentration showed the highest crystallinity and the highest stability during the reaction of ethanol steam reforming. A possible thermal stabilization effect of W in the hydrotalcite crystal structure leading to prevent the Pt sintering is proposed. By IR the hydrotalcite hydroxil groups coordinated with Mg and Al decreased by the presence of WOx. We found that catalysts with low W concentration and Pt having high crystallinity showed the highest stability after ethanol steam reforming. It could be a possible thermal stabilization effect of W in the hydrotalcite crystal structure leading to prevent the Pt sintering.