Effect of Sm2O3 Doping of CeO2-Supported Ni Catalysts for H2 Production by Steam Reforming of Ethanol

Hydrogen is a priority energy vector for energy transition. Its production from renewable feedstock like ethanol is suitable for many applications. The performance of a Ni catalyst supported on samaria-doped ceria in the production of hydrogen by the reforming of ethanol is investigated, adding Sm2O3 to CeO2 in molar ratios of 1:9, 2:8, and 3:7. A CeO2-supported Ni catalyst was also evaluated for comparative purposes. The supports were prepared by the coprecipitation method and Ni was incorporated by incipient wetness impregnation to obtain catalysts with a Ni/(Ce+Sm) molar ratio of 4/6. The catalysts were characterized by a nitrogen adsorption isotherm, X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Increasing Sm2O3 content leads to a more homogeneous distribution of Sm2O3 and Ni particles on the support, and higher oxygen mobility, favoring the catalytic properties. The catalyst with a Sm2O3/CeO2 molar ratio of 3/7 showed outstanding behavior, with an average ethanol conversion of 97%, hydrogen yield of 68%, and great stability. The results suggest that the main route for hydrogen production is ethanol dehydrogenation, followed by steam reforming of acetaldehyde, and acetone and ethylene formation are promoted by increasing Sm content in the outer surface of the catalyst.