Stability and regeneration of Cu–ZrO2 catalysts used in glycerol hydrogenolysis to 1,2-propanediol

A series of Cu–ZrO2 catalysts with different copper contents have been prepared by the coprecipitation method. Their catalytic behavior was studied for glycerol hydrogenolysis reaction to obtain 1,2-propanediol (1,2-PDO) joint to deactivation mechanism and regeneration protocols. A number of physical chemical techniques as X-ray diffraction (XRD), evolved gas analysis by mass spectrometry (EGA-MS), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS) and chemical analysis have been used to characterize the precursors, activated and spent catalysts. Cu–ZrO2 catalysts with higher atomic ratio Cu/Zr showed higher selectivity while glycerol conversion values were not significantly changed. In terms of stability a decreasing of yield to 1,2-PDO due to a decrease of its selectivity was observed with the number of cycles. The main cause of deactivation was associated to the progressive formation of organic deposits on the surface of catalyst. A regeneration process highly efficient, where almost complete recovery of yield to 1,2-PDO shown by the fresh catalyst was reached, has been identified.

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► Cu–ZrO2 catalysts with higher atomic ratio Cu/Zr showed higher selectivity while glycerol conversion values were not significantly changed.
► The deactivation of the catalysts observed after its reuse mainly affects to 1,2- PDO selectivity.
► The deactivation on this system is mainly attributed to the progressive formation of organic deposits on the metallic Cu species.
► A highly efficient regeneration process has been identified.