Low-temperature steam reforming of glycerol for hydrogen production over supported nickel catalysts

Al₂O₃, CeO₂, TiO₂ and MgO supported Ni catalysts were prepared by incipient impregnation. The activities in glycerol steam reforming to hydrogen production were evaluated at 300~500 ℃. The catalysts were characterized by XRD, N₂ adsorption, TEM, and H₂-TPR techniques. A strong effect of support on the activity of Ni catalyst was detected. Ni/CeO₂ catalyst gives the highest activity among all catalysts at 400 ℃and the following activity order is shown Ni/CeO₂> Ni/Al₂O₃ > Ni/TiO₂ ~ Ni/MgO. On Ni/CeO₂, there was almost no deactivation detected after 20 h reaction with 70% conversion of glycerol and 69.2% H₂ yield. Good activity and stability of the catalyst is attributed to the intrinsic property of CeO₂ and strong interaction between CeO₂ and active nickel species. Relatively high glycerol conversion (85.7%) with low H₂ selectivity on Ni/Al₂O₃ catalyst at 500 ℃ is achieved due to its high surface area and large pore volume. The formation of solid solution NiMgO₂ phase observed in Ni/MgO catalyst does not show the desired activity at low temperatures though it enhanced the interactions between active phase and the support. Base oxide supports (CeO₂, MgO) seem to be more effective than acid oxide supports in preventing the formation of CO and CH₄ as by-products.