Promoted Hydrogenolysis of Furan Aldehydes to 2,5-Dimethylfuran by Defect Engineering on Pd/NiCo2O4

Catalytic hydrogenolysis of biobased furan aldehydes (i. e., 5-methylfurfural, 5-hydroxymethylfurfural) to 2,5-dimethylfuran has gained extensive interest for biomass-derived fuels and chemicals. Herein, a class of NiCo2O4-supported palladium with considerable oxygen defects was synthesized by hydrogen plasma etching and phosphating methods. The oxygen defects not only promoted the hydrogenation of the C=O group but also enhanced the accessibility of coordinatively unsaturated metal cations with Lewis acidity for the hydrogenolysis of the C-OH group. Meanwhile, the additional Bronsted acidity in Pd/NiCo2O4-x obtained by phosphating could further strengthen the hydrogenolysis ability by the etherification route of C-OH. Finally, Pd/NiCo2O4-x exhibited the most effective performance with 2,5-dimethylfuran yields of 92.9 and 90.5 % from 5-methylfurfural and 5-hydroxymethylfurfural, respectively. These catalytic mechanisms were confirmed by in-situ infrared spectroscopy and control experiments. Furthermore, the catalyst showed outstanding recycling stability. This work shows powerful synergistic catalysis in the hydrogenolysis reaction by multifunctional active sites.

Automated summary

This study synthesized a NiCo2O4-supported palladium catalyst with oxygen defects through hydrogen plasma etching and phosphating methods. The catalyst not only promoted the hydrogenation of the C=O group, but also enhanced the hydrogenolysis of the C-OH group. Additionally, the phosphated catalyst exhibited extra Bronsted acidity which further strengthened the hydrogenolysis ability. The catalyst showed high activity and stability in the hydrogenolysis of biobased furan aldehydes.