Influence of Synthesis Conditions on Catalytic Performance of Ni/CeO2 in Aqueous-Phase Hydrogenolysis of Glycerol without External Hydrogen Input

The aqueous-phase hydrogenolysis of glycerol was studied in Ni/CeO₂ catalytic systems prepared by incipient wetness impregnation. The operating conditions were 34 bar, 227 ºC, 5 wt.% of glycerol, and a W/m_glycerol = 20 g catalyst min/g glycerol without a hydrogen supply. The effect of the catalyst preparation conditions on the catalytic activity and physicochemical properties of the catalysts was assessed, particularly the calcination temperature of the support, the calcination temperature of the catalyst, and the Ni content. The physicochemical properties of the catalysts were determined by N₂ adsorption, H₂-TPR, NH₃-TPD, and XRD, among other techniques. A relevant increase in acidity was observed when increasing the nickel content up to 20 wt.%. The increase in the calcination temperatures of the supports and catalysts showed a detrimental effect on the specific surface area and acid properties of the catalysts, which were crucial to the selectivity of the reaction. These catalysts notably enhanced the yield of liquid products, achieving global glycerol conversion values ranging from 17.1 to 29.0% and carbon yield to liquids ranging from 12.6 to 24.0%. Acetol and 1,2-propanediol were the most abundant products obtained in the liquid stream.