Electrochemical hydrogenation of furfural under alkaline conditions with enhanced furfuryl alcohol selectivity by self-grown Cu on a Ag electrode

Abstract

Studies for improving product selectivity and reaction pathways in the electrocatalytic hydrogenation (ECH) of FF need to be developed. Herein, a self-assembled Cu catalyst on porous Ag foil (Cu/P_Ag) is synthesized by cyclic voltammetry (CV) ion-exchange followed by an electrodeposition method, which achieves high selectivity (97.4%) and faradaic efficiency (FE, 98.9%) for furfuryl alcohol (FAL) at −0.276 V vs. RHE. Electrochemical impedance spectroscopy illustrates the superior electron transfer and mass transfer capabilities of Cu/P_Ag. Thiol assembly experiments confirm that the electrochemical reduction of FF over Cu/P_Ag is mainly via the ECH pathway, which suppresses the polymerization of FF and results in a high selectivity of FAL. Moreover, combining operando Raman and CV tests demonstrates that the adsorbed hydrogen (H_ads) and FF (FF_ads) share the active sites on Cu/P_Ag. Furthermore, the concentration- and pH-dependent experiments imply that H_ads and FF_ads are well equilibrated on Cu/P_Ag, which not only greatly inhibits the polymerization reaction, but also suppresses the competing hydrogen evolution reaction, thus dramatically increasing the FE of FAL. This work provides important guidelines for the development of in situ engineered catalysts and the electrocatalytic conversion of biomass.