Catalytic conversion of glucose and cellobiose to ethylene glycol over Ni–WO3/SBA-15 catalysts

Abstract

Hydrogenolysis of glucose and cellobiose, used as the model feedstocks, over Ni–WO₃/SBA-15 catalysts has been investigated to probe the influencing factors for the conversion of cellulose to ethylene glycol (EG). The conversion of glucose and cellobiose to EG showed different dependencies on reaction temperature; a lower reaction temperature was needed for the former. Additionally, the surface atomic ratio of W to Ni on the Ni–WO₃/SBA-15 catalysts was the key factor for the product distribution. Both glucose and cellobiose had their own optimum W–Ni ratio for the production of EG, and the ratio of W to Ni for glucose was slightly lower than that of cellobiose. On the other hand, the Ni–WO₃/SBA-15 catalysts were thoroughly characterized by N₂ adsorption–desorption, X-ray diffraction (XRD), hydrogen-temperature programmed reduction (H₂-TPR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The results indicated that the reducibility of Ni–WO₃/SBA-15 catalysts with high Ni loading was more similar to that of pure NiO. More importantly, the change of surface atomic content of Ni and W of Ni–WO₃ catalysts with various Ni loadings resulted from the surface W species of the catalysts being gradually covered by Ni species with the increase of Ni loading.