Direct conversion of cellulose into polyols over Ni/W/SiO2-Al2O3

The direct conversion of cellulose into polyols over Ni/W/SiO2-Al2O3 catalysts with different Al molar fractions was examined. For comparison, Cu/W/SiO2-Al2O3, Fe/W/SiO2-Al2O3, and Co/W/SiO2-Al2O3 were also evaluated. The bulk crystalline structure was determined using X-ray diffraction (XRD). The surface acidity was probed via temperature-programmed desorption of ammonia (NH3-TPD). The textural properties were investigated using N2 physisorption. The metal contents were confirmed via inductively coupled plasma–atomic emission spectroscopy (ICP-AES). Among the various metal catalysts, Ni/W/SiO2-Al2O3 was confirmed to be the most favorable for hydrogenolysis of cellulose into polyols. The effect of the Al molar fraction in SiO2-Al2O3 on this reaction over Ni/W/SiO2-Al2O3 was also investigated. It was found that the polyol yield was closely related to the total acidity of the support. Compared to Ni/W/SBA-15, Ni/W/SiO2-Al2O3 (Al/(Al + Si) = 0.6) showed better stability during the recycling test. The catalyst deactivation was confirmed to be caused by metal leaching.