Ethanol steam reforming on Ni/Al-SBA-15 catalysts: Effect of the aluminium content

A series of Ni catalysts supported on Al-SBA-15 mesoporous materials (Si/Al = 20, 60, 140, 240, ∞) was prepared and tested in ethanol steam reforming. The catalysts were characterized by XRD, H2-TPR, NH3-TPD, TEM, ICP-AES, 27Al-MAS-NMR and N2-sorption measurements. It was found that the incorporation of Al atoms into SBA-15 structure is responsible for the formation of catalyst acid sites, an increase of the size of nickel species and stronger metal-support interaction between Ni and Al-SBA-15 carrier. Regarding ethanol steam reforming, catalysts with higher Al content keep ethanol conversion along time. However, Ni/Al-SBA-15 catalysts produce larger amounts of ethylene and coke, with slightly lower hydrogen selectivity than Ni/SBA-15. This is the consequence of ethanol dehydration in Ni/Al-SBA-15 acid sites, while ethanol dehydrogenation mechanism predominates in Ni/SBA-15 catalyst.