Deep eutectic solvent-derived carbon-based FeNi bimetallic catalysts for selective hydrogenation of furfural

In this paper, we report a simple alloying strategy to prepare carbon-based catalysts (FeNi4-NC-D) containing FeNi3 alloys with high specific surface area by employing deep eutectic solvents (DES) as catalyst precursors after a simple one-step calcination. Experimental data and characterization demonstrated that DES not only had an effect on the physical phase structure and promoted a substantial increase in the specific surface area and pore volume, but also effectively regulated the electronic environment of the carbon substrate in the catalyst. The selective hydrogenation of furfural was used as a probe reaction, while DFT calculations were employed as an auxiliary validation to explore the significant effects of the DES promoted formation of FeNi3 alloys and Ni dual active sites on the catalytic performance. [Display omitted] •By calcination of deep eutectic solvent, the FeNi4-NC-D catalyst with dual active site was synthesized.•The necessity of DES for the formation of FeNi3 alloys was demonstrated.•In comparison to the inactive of FeNi4-NC and 25.3 % of Ni-NC-D, FeNi4-NC-D catalyzed FF in 99.9 % yield with 110 °C.•FeNi complex phase promotes the activation of hydrogen and furfural. Cheap Ni catalysts have excellent catalytic hydrogenation activity, but also result in low selectivity. Ni-based alloy catalysts can improve performance, but controlling their preparation is a challenge. This paper reports an alloying strategy by using a deep eutectic solvent (DES) as the catalyst precursor, and carbon-based catalysts (FeNi4-NC-D) containing FeNi3 alloys with high specific surface area were prepared by a simple one-step calcination. The necessity of DES for the formation of FeNi3 alloys was demonstrated. In comparison to the inactive of FeNi4-NC and Fe-NC-D, as well as the 60.3 % of FeNi3-NC-D and 25.3 % of Ni-NC-D, the FeNi4-NC-D with dual active sites in the selective hydrogenation of furfural (FF) to furfuryl alcohol (FAL) achieved a yield of 99.9 % at a mild condition of 110 °C. According to serial characterization, the explanation for this difference is that DES not only promotes a substantial increase in specific surface area and pore volume, but also effectively modulates the electronic environment of the carbon substrate in FeNi4-NC-D. More significantly, DES forms a composite structure of Ni and FeNi3 alloy phase in FeNi4-NC-D. The FeNi3 and Ni double sites in this structure markedly enhance the dissociation of H2. Moreover, the formation and enha