In-situ Reconfigured Copper Electrodes For Electrocatalytic Furfural Hydrogenation

Electrochemical transformation offers an efficient alternative to synthetic chemistry.Remarkable progress has been made recently in the electrocatalytic hydrogenation reduction of biomass-derived compounds,but challenges remain in Faradaic efficiency and product selectivity.This dissertation focuses on copper-based electrocatalysts,and improves the electrocatalytic hydrogenation reduction performance of furfural（FAL）by regulating the surface state of the copper electrode.1.Defect engineering of copper via O₂-plasma treatment is introduced for the efficient electrocatalytic hydrogenation of FAL to furfuryl alcohol（FOL）.Experiments and theory investigations indicate that the electrocatalytic hydrogenation rate is positively correlated with the difference in binding energies of H_ads and FAL_ads for competitive adsorption,and the higher difference in defective Cu compared to defect-free Cu enables fast electrocatalytic hydrogenation.Meanwhile,the experimental results show that Cu Ox produced on copper foil etched by oxygen plasma for 5 min（OP-Cu）is rapidly in situ reduced to Cu with high roughness and abundant defects during the initial electrocatalytic.Therefore,OP-Cu provides a high Faradaic efficiency（FE91%）of FOL at-0.56 V（vs.RHE）,which is superior to that of electropolished copper（EP-Cu;FE:～30%）or Ar plasma treated Cu（AP-Cu;FE:47%）.2.The valence state of the copper electrode surface is changed in situ by step-potential electrolysis,and used to promote electrocatalytic FAL hydrogenation.With the increase of the oxidation potential,the FOL Faradaic efficiency and the rate of formation per unit time(r _FOL)showed a volcano-type trend.When the oxidation potential was 0.64 V,the FOL Faradaic efficiency reached 94%,and the r _FOL was 4.18 m M/h,while under the constant potential condition,the FOL Faradaic efficiency was 40%,and the r _FOL was 1.2 m M/h.By changing the duty cycle,it is found that as the duty cycle increases,the FOL Faraday efficiency exhibits a volcano-shaped curve,reaching a maximum of 94%when the duty cycle is 50%,while r _FOLgradually decreases.Combining in-situ Raman and quasi-in-situ AFM tests,we believe that with the increase of anodic oxidation potential,the copper surface is continuously oxidized and reduced to generate edge defect sites,thereby improving the Faradaic efficiency and r _FOL.When the potential is too high,the reduction of copper oxide on the electrode surface forms a competitive reaction with fal hydrogenation,which reduces the catalytic performance.In summary,this dissertation investigates the structure of the copper electrode surface and microenvironment control to improve the electrocatalytic hydrogenation performance of organic compounds,which provided new ideas for electrochemical refining of organics.