Hydrogen production via steam reforming of ethanol on phyllosilicate- derived Ni/SiO₂: Enhanced metal-support interaction and catalytic stability

This paper describes the design of Ni/SiO₂ catalysts obtained from a phyllosilicate precursor that possess high activity and stability for bioethanol steam reforming to sustainably produce hydrogen. Sintering of metal particles and carbon deposition are two major issues of nickel-based catalysts for reforming processes, particularly at high temperatures; strong metal-support interaction could be a possible solution. We have successfully synthesized Ni-containing phyllosilicates by an ammonia evaporation method. Temperature programmed reduction results indicate that the metal-support interaction of Ni/SiO₂ catalyst prepared by ammonia evaporation method (Ni/SiO _2P) is stronger due to the unique layered structure compared to that prepared by conventional impregnation (Ni/SiO_2I). With the phyllosilicate precursor nickel particles highly disperse on the surface, remaining OH groups in the unreduced phyllosilicates promote nickel dispersion and carbon elimination. We also show that high dispersion of Ni and strong metal-support interaction of Ni/SiO_2P significantly promote ethanol conversion and H₂ production in ethanol steam reforming. Ni/SiO _2P produces less carbon deposition compared to Ni/SiO_2I; for the latter, a surface layer of Ni₃C formed during the deactivation.