Pt–Co Single-Atom Alloy toward Furfural Hydrogenation–Rearrangement Tandem Reaction in the Aqueous Phase

Aqueous-phase tandem reactions, as a fundamental aspect of green chemistry, hold a crucial position in the contemporary synthesis of fine chemicals, wherein the advancement of high-performance heterogeneous catalysts remains a formidable challenge. Herein, we report a Pt₁Co_n single-atom alloy (SAA) catalyst in which Pt single atoms are immobilized onto the surface of Co nanoparticles through Pt–Co coordination. The Pt₁Co_n SAA catalyst exhibits a high chemoselectivity for the aqueous-phase hydrogenation–rearrangement reaction of furfural (FAL) to cyclopentanol (CPL) (yield: >93%, considering the carbon loss), with a TOF value of 2257 h^–1 (based on Pt). A joint investigation based on reaction dynamics, isotope-label tracing experiments, EPR, and in situ FT-IR verifies a five-step consecutive tandem reaction pathway for the formation of CPL. Notably, during the reaction, the rapid exchange of hydrogen atoms would occur between activated hydrogen species and the water solvent. Furthermore, the water molecule does not serve as a H-donor but is involved in the rearrangement reaction in the side chain of the furan ring. Kinetic studies combined with DFT calculations substantiate that the Pt–Co interface sites effectively lower the energy barrier of the cyclopentanone (CPO) hydrogenation step via facilitating activation adsorption of the carbonyl group, accounting for the largely enhanced catalytic behavior. This study sheds light on the advancement of a highly efficient and stable heterogeneous catalyst for a biomass upgrading reaction in the aqueous phase.