Positive shift of the d-Band center in Cu nanoparticles facilitates electrocatalytic hydrogenation of furfural under mild pH conditions

Abstract

The electrocatalytic reduction of biomass-derived furfural represents a sustainable pathway for the production of furfuryl alcohol and 2-methylfuran, serving respectively as value-added chemicals and biofuels. However, the production of these high-value-added products under mild conditions is hampered by low Faradaic efficiency. In this study, we develop a strategy to establish strong metal-support interactions, enabling Cu/NC (nitrogen-doped carbon) catalysts to efficiently produce value-added products under mild conditions. Specifically, we prepare a cost-effective NC support with highly dispersed ultrafine nano-Cu particles of approximately 1 nm in diameter. Under mild pH conditions, our comparative experiments show that the Faradaic efficiency for value-added products (furfuryl alcohol and 2-methylfuran) is nearly four times higher than that of commercial foam copper. We elucidate the influence of nitrogen-doped supports on the behavior of the supported metal Cu. Comprehensive in-situ infrared reflection absorption spectroscopy characterization and DFT theoretical calculations reveal a positive shift in the d-band center of the Cu 3d orbitals. This shift enhances the adsorption of furfural C1=O1 bonds on the Cu/NC catalyst and improves its capacity to bind active hydrogen, thereby increasing the Faradaic efficiency of the value-added products. Our findings advance theoretical understanding and providing practical insights for electrocatalytic hydrogenation of furfural under mild pH conditions.