Understanding the role of Co in Co–ZnO mixed oxide catalysts for the selective hydrogenolysis of glycerol

• Co–ZnO mixed oxides are selective catalysts for the hydrogenolysis of glycerol.
• The Co–ZnO catalysts activity depends on Co to ZnO ratio.
• Well-dispersed Co and sufficient amount of ZnO are required for high activity.
• Different reaction parameters evaluated and a kinetics model is derived.

A series of Co–ZnO catalysts with varying Co to Zn ratio were prepared by co-precipitation method and these were characterized by X-ray diffraction, temperature programmed reduction, H2 chemisorption, X-ray photoelectron spectroscopy and transmission electron microscopy. The developed catalysts were evaluated for selective hydrogenolysis of glycerol to 1,2-propanediol. Glycerol conversion was found to be dependent on the ratio of Co to ZnO and a weight ratio Co/Zn of 50:50 was shown about 70% glycerol conversion with 80% selectivity to 1,2-propanediol. Glycerol hydrogenolysis activity was found to be related to Co metal area as well as amount of ZnO in the catalyst. The proposed catalysts were stable under the reaction conditions and reusable with consistent activity. Different reaction parameters were studied and optimum reaction conditions were established. A kinetic model for the hydrogenolysis reaction was also derived.

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