Mechanistic Understanding of Furan Hydrogenation to Tetrahydrofuran on Transition-metal Surfaces Using Density Functional Theory

Abstract

—One of the crucial processes in the upgrading of biomass and the generation of green solvents is the selective Hydrogenation of Furan to Tetrahydrofuran (THF). This study employed Density Functional Theory (DFT) to investigate the complete hydrogenation sequence of furan to THF on transition metal surfaces such as Pd (111), Pt (111), and Ni (111) surfaces. Furan adsorbs preferentially in a flat configuration at the fcc site, with binding energies of − 1.74 eV, − 1.91 eV, and − 1.46 eV on Pd, Pt, and Ni, respectively, while THF exhibits weaker interactions ( − 0.95 eV, − 0.85 eV, and − 0.68 eV), indicating physisorption and facile desorption. Hydrogenation proceeds through four sequential steps, with site preferences varying across metals. On Pd (111), the third hydrogen addition at the α -carbon (C4) is rate-determining, with an activation barrier of 1.10 eV. On Pt (111), the third hydrogenation at the β -carbon (C2) is rate-limiting, with a barrier of 1.02 eV, whereas on Ni (111), the fourth and final hydrogenation step at the β -carbon (C3) is the slowest, with a barrier of 0.89 eV. Bader charge analysis of key transition states further elucidates how electron redistribution between the reacting carbon and hydrogen stabilizes the transition states, rationalizing the metal-dependent pathways. Although Ni (111) appears to be the most active metal based on DFT energetics, this trend does not align with experimental observations, whereas Pd (111) and Pt (111) show excellent consistency with observed selectivity and activity. Overall, the investigation presents a clear mechanistic perspective on metal-dependent reactivity and develops a DFT-based framework for connecting surface energetics to experimental selectivity trends in furan hydrogenation.