Enhanced catalytic performance of Cu/NC catalyst for hydrogenation of furfural to furfuryl alcohol: Effective stabilization of Cu+ with CaO promoter

The semi-hydrogenation of biomass-derived furfural (FAL) to furfuryl alcohol (FOL) has great significance for sustainable development of energy. Cu-based catalysts have been reported to be highly selective for FOL, but typically exhibit relatively low hydrogenation activity. Herein, Cu/xNC and Cu-Ca_y/6NC catalysts with different nitrogen contents and Cu/Ca molar ratios were prepared and applied to the FAL hydrogenation. The optimized Cu-Ca_2.0/6NC catalysts exhibited glorious catalytic performance with complete FAL conversion and 99.5 % FOL selectivity under 4 MPa and 150 ℃ and outstanding stability. It was found that the FAL conversion, as well as the FOL selectivity, is in good positive correlation with the Cu⁺ content. Additionally, the apparent activation energy for FAL hydrogenation was reduced by the addition of CaO, possibly ascribed to the strong electronic interaction between CaO and Cu species, which not only improved the Cu dispersion, but also stabilized the Cu⁺ species in the catalyst. This work could offer a potential strategy for the design of promising Cu catalyst for FAL hydrogenation.