Co@Pd–Co Core–Shell Nanoparticles as Catalysts for the Selective Hydrogenation of Furfural to Furfuryl Alcohol

The surface structure of bimetallic catalysts is critical in determining their performance in hydrogenation reactions. In this study, we have developed a deep eutectic solvent-assisted solvothermal method to synthesize a highly efficient Pd 0.1 Co/CNTs-DES-40 nanocatalyst with a Co@Pd–Co core–shell structure. This Pd 0.1 Co/CNTs-DES-40 nanocatalyst demonstrated superior catalytic performance in the selective hydrogenation of furfural (FAL) to furfuryl alcohol (FOL) compared to other Pd–Co/CNT nanocatalysts with different structures (Janus type and alloy type), which were synthesized using successive impregnation and coimpregnation methods. The highest >99% FOL yield was achieved over the Pd 0.1 Co/CNTs-DES-40 catalyst. The arrangement of Pd and Co species in these systems was fully characterized, and detailed characterization revealed that the Co@Pd–Co core–shell nanostructure significantly increased the exposure of active sites and enhanced hydrogen adsorption and activation. Stability tests indicated a slight decrease in activity after six cycles, primarily due to the deposition of carbonaceous species and nanoparticle growth. This work highlights the importance of catalytic structure design for bimetallic catalysts in the selective hydrogenation of biomass-derived platform molecules and provides a strategy for synthesizing bimetallic catalysts.