Cis-trans adsorption configuration influenced high-efficient hydrogenation of furfural over zeolite-encapsulated PtCu bimetallic catalyst

Abstract

Bimetallic catalysts are promising materials for high-efficient conversion of lignocellulose to value-added chemicals, but synthetic methods with reasonable generality are still lacking. Herein, we report a novel method for synthesizing bimetallic catalyst PtCu@S-1(S-1, silicalite‑1) via zeolite encapsulation with the aid of protecting chelating ligands. PtCu@S-1 displays remarkable activity for the hydrogenation of furfural (FUR) to furfuryl alcohol (FOL), and its apparent turnover frequency (TOF) values reach up to 735 mmolFUR·mmolPt−1·h−1 and 88 mmolFUR·mmolCu−1·h−1, which are ∼ 16 and ∼ 4 times higher than that of Pt@S-1 and Cu@S-1. Interestingly, we for the first time find that OO-trans FUR is a preferable adsorption configuration over OO-cis FUR on PtCu@S-1 due to the Pt sites coordinating with the carbon atom on the furan ring. More importantly, the adsorption ability of OO-trans FUR is stronger than that of OO-cis FUR, which increases the concentration of adsorbed species on PtCu@S-1 and accelerates the hydrogenation of FUR.