Hydrogenolysis of cellulose into polyols over Ni/W/SiO2 catalysts

• The hydrogenolysis of cellulose was examined over Ni/W/SiO2 catalysts.
• The crystallite size of W increased with average pore size of support.
• The crystallite size of W increased with reduction temperature.
• The yield of polyols increased on decreasing the crystallite size of W.
• The amount of surface acid site decreased with increasing crystallite size of W.

The direct conversion of cellulose into polyols in the presence of hydrogen was examined over Ni/W/SiO2 catalysts to establish the effects of average pore size of support and reduction temperature on the catalytic performance. The crystalline particle size of W, determined by X-ray diffraction (XRD), generally increased with increase in the average pore size of support and reduction temperature for Ni/W/SiO2. The yield of polyols such as sorbitol, mannitol, erythritol, ethylene glycol, and 1,2-propanediol increased on decreasing the crystalline particle size of W in Ni/W/SiO2. The individual catalytic activity of Ni/W/SiO2 was much better than that of the combined catalyst systems, i.e., Ni/SiO2 + W and Ni/SiO2 + WO3. The oxidation state effect of nickel and tungsten in Ni/W/SiO2 catalyst on the catalytic performance was also investigated. The reduced and oxidized Ni/W/SiO2 catalysts were found to be effective in forming polyols and organic acids, respectively.

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