Cu–Zn–Al mixed oxides as catalysts for the hydrogenolysis of glycerol to 1,2-propanediol

Abstract

This study is aimed to compare Cu–Al–Zn catalysts prepared by different methods and their effectiveness in glycerol hydrogenolysis to 1,2-propanediol. The preparation methods were: co-precipitation and thermal decomposition of hydrotalcite, co-precipitation by KOH and thermal decomposition of the precipitate, sol–gel auto-combustion method, oxalate–gel co–precipitation and thermal decomposition of the precipitate and finally, mechanical mixing of Cu, Zn, Al oxides. It was found that the activity of the catalysts correlates well with the size of Cu crystallites. The smaller Cu crystallites, the higher the activity. However, also the texture of the catalyst, which also depends on the preparation method, has an impact on the catalyst activity. On the other hand, no correlation between activity and acidity, as well as internal surface area was found.