Research On Efficient Catalyst And Electrolyte For Furfural Electrochemical Hydrogenation

Biomass energy is a kind of sustainable non-fossil energy.Rational use and development of biomass resources can reduce the consumption of fossil energy to a large extent.Furfural（FF）is a kind of biomass platform molecule easily obtained from raw materials,and furfural alcohol（FA）can be obtained by hydrogenation,which has important applications in medicine,agriculture and dye fields.Compared with traditional furfural thermal catalytic hydrogenation,electrocatalytic hydrogenation（ECH）can directly utilizes protons in water,which is green and safe,and meets the background requirements of emission peak and carbon neutrality.Catalysts and electrolyte are important components of the ECH reaction of furfural.However,the active site of catalysts and the microenvironment of electrode/electrolyte remain to be further understood.Based on the consideration of above problems,this work explored the active site of efficient catalyst and the influence of electrolyte in furfural ECH.The main contents are as follows:（1）This work reveals the active sites of Cu-based catalysts in furfural ECH reaction.CuO nanowires with high hydrogenation activity were in situ grown on the surface of Cu foam,and it was pointed out by in-situ attenuated total reflection surface-enhanced infrared spectroscopy technique（ATR-SEIRAS）and in-situ synchrotron radiation X-ray absorption spectroscopy（XAS）that during the reaction process,Cu⁺and Cu⁰ co-existed on the surface of the catalyst.Poisoning experiments proved the necessity of Cu⁺for furfural ECH.The density functional theory（DFT）calculation suggests that the Cu⁰-Cu⁺synergistic effect is beneficial to both kinetics and thermodynamics:Cu⁺accelerates the second-step hydrogenation process of furfural,and Cu⁰ reduces the energy barrier for the desorption of furfuryl alcohol.This work demonstrates the synergistic effect of Cu⁰ and Cu⁺states for the electrochemical hydrogenation of furfural and provides a deeper understanding of the furfural hydrogenation mechanism.（2）In this work,electrodeposited copper（ED-Cu）was used to explore the effect of phosphate buffer solution（PBS）and KHCO₃ electrolyte on the reaction performance of furfural ECH.Electrochemical characterizations and product measurements showed that KHCO₃electrolyte has better performance for furfural ECH reaction than PBS electrolyte.The changes of morphology and composition of the catalysts before and after electrolysis were analyzed by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）and scanning electron microscopy（SEM）.In-situ synchrotron radiation fourier transform infrared spectroscopy（SR-FTIR）,and DFT calculations analyzed the adsorption modes of furfural at the two electrode/electrolyte interfaces.Furfural has different adsorption configurations in the two electrolytes:in KHCO₃ electrolyte,the carbonyl group of furfural is directly adsorbed on the surface of catalyst;In PBS electrolyte,furfural are indirectly adsorbed on the electrode surface through phosphate groups.The catalytic performance of ED-Cu for furfural ECH reaction was optimized by KHCO₃ electrolyte.This work deepens the understanding of the microenvironment of the electrode surface and provides new ideas for the optimization of electrocatalytic reactions.