Pd-Ti₃SiC₂ synergistic catalysis for highly selective hydrogenative rearrangement of biomass-derived furfural to cyclopentanone

Creating synergistic metal-acidic sites is essential for the enhancement of activity and selectivity in the hydrogenative rearrangement of furfural (FFL) to cyclopentanone (CPO) for efficient biomass upgrading. In this work, Ti₃SiC₂ as a novel two-dimensional material was adopted as the support to construct the interfacial structure with metal Pd. Using water as the solvent, the optimal 2% Pd/Ti₃SiC₂ catalyst exhibits 2933 h⁻¹ specific reaction rate and 93.8 % CPO selectivity as well as great recycling stability in the FFL hydrogenation reactions at 160 °C. The combining characterizations and catalytic results indicate that the Pd⁰ nanoparticles in high-loading catalysts can promote hydrogen activation and dissociation, facilitating the formation of furfuryl alcohol (FAL) in the first reaction step. The highly dispersed Pd²⁺ species on Ti₃SiC₂ support promote the further ring-opening and rearrangement of FAL to CPO. The DFT calculations demonstrate that FFL-to-CPO is thermodynamically feasible. The reaction rate constant with FAL as substrate is 1.87 times higher than that with FFL as substrate, which proves that the hydrogenation of FFL–to–FAL is rate-determining step of the FFL to FAL hydrogenation. This work has established the structure-performance relationship of the Pd/Ti₃SiC₂ catalyst and catalytically synergistic mechanism in the hydrogenative rearrangement of FFL to CPO.