Density Functional Theory Investigation of the Conversion of 5-(Hydroxymethyl)furfural into 2,5-Dimethylfuran over the Pd(111), Cu(111), and Cu₃Pd(111) Surfaces

The conversion of 5-(hydroxymethyl)furfural (5-HMF) into 2,5-dimethylfuran (2,5-DMF) via cascade hydrogenation and hydrogenolysis over metallic catalysts has been considered a promising method to produce high-energy-content biofuel. Understanding the adsorption reactants, reactions, desorption byproducts is essential for developing efficient selective catalysts. Herein, most plausible reaction mechanisms 5-HMF 2,5-DMF Pd(111), Cu(111), Cu3Pd(111) surfaces are investigated using density functional theory calculations. pathways formation intermediates (2,5-bis(hydroxymethyl)furan, 5-methylfurfural, 5-methylfurfuryl alcohol (5-MFA)), 2,5-DMF, (water, 2,5-dimethyltetrahydrofuran (2,5-DMTHF)) established. overall barrier on Pd(111) surface, which governed by C–OH bonds in 5-MFA, larger (1.96 eV) than that surface (1.68 eV). In addition, significantly higher energy (−2.47 (−0.18 eV), caused flat geometry with η2-(C–O)-aldehyde configuration, leads 2,5-DMTHF furan ring saturation. Even though Cu(111) (0.84 much lower those surfaces, weak perpendicular η1-(O)-aldehyde highly unfavorable dissociative H2 adsorption, high required H2O hinder its intermediates. favorable (−0.54 low barrier, facile 2.5-DMF render Pd–Cu alloy catalyst candidate 2,5-DMF.