Study On The Electrochemical Hydrogenation Reaction Of Furfural Compounds Over Cu-based Catalyst

With the excessive development of fossil fuels and the increasingly serious problem of environmental pollution,the development and utilization of green and environmentally friendly renewable resources into high value-added products is an inevitable trend.The biomass platform compounds furfural（FF）and 5-hydroxymethylfurfural（HMF）have attracted the attention of researchers due to their rich functional groups,which can be converted into high-value products through oxidation-reduction,dehydration and condensation reactions.Furfural compounds can be extracted from plants with abundant sources and are a green and renewable resource.The traditional hydrogenation reaction of furfural compounds is a thermal catalytic reaction.The hydrogenation reaction in the thermal catalytic reaction process usually needs to be carried out in the environment of H₂ and under high temperature and pressure conditions.However,the electrochemical hydrogenation conditions are mild,and an electrolyte can be used instead of H₂ as the hydrogen source.In addition,electrochemical hydrogenation reaction can achieve product selectivity by adjusting the potential,catalyst or reaction conditions,and is one of the green,safe,and sustainable chemical production methods.In this thesis,copper metal with abundant reserves,low price,and corrosion resistance was used as a catalyst.Cu based metals with different crystal planes were synthesized through regulation and their performance in the electrochemical hydrogenation of furfural was studied,exploring the effect of Cu crystal planes on FF electrohydrogenation of FAL.At the same time,CuZn bimetallic catalysts were synthesized for the electrochemical hydrogenation reaction of HMF.The activity of bimetallic catalysts in HMF reaction was studied,and the effect of electrolyte on HMF hydrogenation reaction was further studied.The main content is as follows:（1）Oxide derived copper（OD-Cu）catalysts with different ratios of Cu（100）and Cu（111）crystal planes were prepared for FF electrochemical hydrogenation reaction,and the catalytic performance and selectivity of Cu（100）and Cu（111）crystal planes in FF electrochemical hydrogenation reaction were studied.The experimental results indicate that the OD-Cu catalyst with a high proportion of Cu（100）crystal planes exhibits higher activity in the hydrogenation of furfural to furfuryl alcohol.The selectivity of furfuryl alcohol（FAL）on the OD-Cu-0 catalyst is 97.7%,which is much higher than that on the OD-Cu-11 catalyst（63.0%）.Density functional theory（DFT）calculation results show that the aldehyde C=O bond length（1.34?）in FF adsorbed on Cu（100）surface is larger than that in Cu（111）surface（1.28?）and FF（1.24?）,indicating that the aldehyde group is effectively activated on Cu（100）surface;The adsorption energy of Cu（100）crystal surface-1.03 eV is higher than that of Cu（111）crystal surface -0.83eV,indicating that Cu（100）crystal surface has stronger adsorption capacity for furfural hydroxyl groups.This confirms that Cu（100）crystal surface is superior to Cu（111）crystal surface in FF electrohydrogenation to generate FAL.（2）CuZn bimetallic catalyst was synthesized and its catalytic performance in the electrochemical hydrogenation of HMF and the effect of electrolyte on Product selectivity were studied.The results showed that the CuZn-15 catalyst with an electrodeposition time of 15minutes exhibited the highest Faraday efficiency of 5-methyl-2-furan methanol（MFA）（49.5%）,indicating that the CuZn bimetallic catalyst can promote the activity of electrochemical hydrogenation of HMF to prepare MFA.In addition,electrolyte significantly affected Product selectivity,and CuZn catalyst produced 2,5-hexanedione（HD）,a ring opening product,in 0.5 M sulfuric acid solution（p H=2.0）.Overall,this study expands the system of electrochemical hydrogenation of HMF and provides a further understanding of the electrolyte dependence of HMF and its reduction products.