Characterization of the activity and stability of supported cobalt catalysts for the steam reforming of ethanol

This paper reports results of studies of the catalytic activity and stability of supported cobalt catalysts for steam reforming of ethanol. Co/Al2O3, Co/SiO2, and Co/MgO catalysts were prepared by an impregnation method and characterized by X-ray diffraction, atomic absorption spectroscopy, Raman spectroscopy, and temperature programmed reduction with hydrogen. The results showed the presence of Co3O4 and CoOx species interacting with Al2O3 or MgO and formed after a calcination step. It was evident that only Co0 sites are active for the steam reforming of ethanol. All materials showed high levels of ethanol conversion, with molar yields of about 70% of hydrogen and 30% of CO+CO2+CH4 in the gaseous mixture. The Co/Al2O3 catalyst also produced ethylene through a dehydration reaction of ethanol. It is proposed that the methane formation on Co/SiO2 catalysts occurs by methanation of CO and by ethanol decomposition. After 9 h of reaction, 14–24% (w/w) of carbon was deposited on all catalysts, indicating that a well characterized deactivation of the materials is due to coke deposition.