Catalysts for H sub(2) production using the ethanol steam reforming (a review)

This review aims to provide an overview of the main catalytic studies of H sub(2) production by ethanol steam reforming (ESR). The reaction is endothermic and produces H sub(2), CO sub(2), CH sub(4), CO and coke. The conversion and H sub(2) selectivity of these products depended greatly of the physicochemical properties of the catalysts, active metal, promoters, temperature, long-term reaction, water/ethanol ratio, space velocity, contact time, and presence of O sub(2). Initial total conversion has been reported in all catalysts evaluated between 300 and 850 degree C. The noble catalysts with high selectivity to H sub(2) (more than 80%) were: Rh, Ru, Pd and Ir and non-noble metal catalysts were: Ni, Co and Cu. The support materials include CeO sub(2), ZnO, MgO, Al sub(2)O sub(3), zeolites-Y, TiO sub(2), SiO sub(2), La sub(2)O sub(2)CO sub(3), CeO sub(2)-ZrO sub(2) and hydrotalcites. The impregnation method produced the best noble metal catalysts in terms of selectivity and conversion. The decrease of coke was related with the presence of basic sites on the support.