The importance of constructing Triple-functional Sr2P2O7/Ni2P catalysts for smoothing hydrogenation Ring-rearrangement of Biomass-derived Furfural compounds in water

Rational design of catalysts with multi-function was of great importance for speeding mechanism-complicated heterogeneous reaction. Herein, a series of Sr-Ni-P catalysts characterized in (Sr2P2O7)m/Ni2P composite structure (Sr:Ni molar ratio m = 0.15–0.60) were prepared and investigated for hydrogenation ring-rearrangement of four biomass-derived Furfural compounds (FALs) to their Cyclopentanone derivatives (CPOs) in water. By properly manipulate m at 0.40, the superior and reproducible CPOs yields up to 96% were achieved under mild conditions in particular under low-pressure (0.1 MPa) H2. Chemical adsorption measurements disclosed that the attachment of Sr2P2O7 with Ni2P in nanoscale was crucial to construct triple-functional catalytic interface with modulated hydrogen activation (7.5–47.4 µmol/g), acid (196.4–327.3 µmol/g) and base (108.0–214.5 µmol/g) sites. H2-D2 exchange, H2-IR experiments and DFT simulation implied that H2 could be activated through heterolytic dissociation on Sr2P2O7 to participate in reaction; H218O, D2O, D2 isotope-label tracing experiments and DFT mechanism calculation further clarified that besides of H2, H2O was also frequently present in hydrogenation, ring opening, rearrangement and ring re-closing steps and acted as dual donors to provide H and O for CPO; in the favorable thermodynamic feature, a new pathway (with unsaturated dicarbonyl compound as key intermediate) achieved on Sr2P2O7/Ni2P was demonstrated to be more feasible than the reported pathway. The importance of the triple-functional Sr2P2O7/Ni2P catalytic interface for smoothing the aqueous hydrogenation transformation, in particular the function of base site for speeding the transformation was illustrated and discussed.