Controllable Synthesis Of Gold Palladium Nanoparticles Catalyst And Its Electrocatalytic Oxidation Of HMF

Every development of human society is inseparable from the application of"energy".The first three industrial revolutions have brought great development to mankind.At the same time,mankind is also facing an unprecedented global energy crisis and ecological crisis.In order to reduce the consumption of fossil fuels,electrolytic hydrolysis has received attention as a sustainable and clean hydrogen production strategy.The oxygen evolution reaction steps occurring on the anode are complex and require a high potential to drive,resulting in low energy conversion efficiency.Biomass platform molecules and similar organic matter oxidation have been used as substitutes for oxygen evolution reactions,which can not only obtain high value-added biomass oxidation refining products and hydrogen,but also effectively improve the energy conversion efficiency of the entire reaction device.In the context of the green industrial revolution,developing an efficient biomass platform molecular conversion system and coupling biomass electric reforming with green hydrogen production is a more economical strategy.Lignocellulose,widely present in biomass,generates5-hydroxymethylfurfural（HMF）through hydrolysis,isomerization,and dehydration.HMF is oxidized to obtain 2,5-furanedicarboxylic acid（FDCA）,which can replace petroleum product terephthalic acid to produce polyester compounds,greatly reducing dependence on petroleum products.Therefore,converting biomass into chemical products has broad application prospects.Compared with traditional thermal catalytic oxidation methods,electrocatalytic oxidation is a green and efficient conversion method.Its mild reaction conditions,controllable reaction rate,and simple operating platform have attracted widespread attention from researchers.Researchers from various backgrounds have entered this industry and started using or researching electrochemical tools,which has led to rapid development in the entire field of electrocatalysis.（1）Controllable synthesis of different ratios of Au,Pd,and Au-Pd bimetallic nanoparticles catalysts using sol-gel fixation method,and the synthesized catalysts are applied to the electrocatalytic oxidation reaction of HMF.The morphology and structural composition of the material were analyzed through a series of physical and chemical characterization methods.The synthesized catalyst has a smaller nanoparticle size,high dispersion,and a higher number of surface atoms.Under constant voltage electrolysis at 0.865 V for 60 minutes,the oxidation products at different time periods were detected by high-performance liquid chromatography.The Au₃Pd₇/C-CP catalyst showed the highest HMF conversion rate of 15.28%and FDCA yield of 2.7%within 1 hour.Compared to single metal catalysts,the bimetallic system of Au and Pd will improve electrocatalytic performance,reduce initial potential,and increase anode current for HMF oxidation.The metal structure on the surface of catalysts with different proportions has changed,resulting in different oxidation effects.According to the results,the Pd content in alloy catalysts plays a more important role.（2）On the basis of the catalyst in the previous chapter,by improving the hydrophilicity of carbon paper and enhancing its catalytic activity,it was applied to the electrocatalytic oxidation reaction of HMF.Compared with untreated carbon paper,H₂O₂ is used to treat the carbon paper to enhance the adsorption capacity of the catalyst for HMF and OH^-,thereby improving its electro catalytic oxidation capacity.This may be that the energy of the Au atom d orbital center deviates from the Fermi energy level far,and the Pd atom d orbital center energy deviates from the Fermi energy level near,so the hydrophilicity of the carbon paper is enhanced,The adsorption trend of OH^-on Au far away from the Fermi level is more significant than that on Pd near the Fermi level.Through the detection of oxidation products at different time periods by high-performance liquid chromatography,it was found that the Au₅Pd₅/C-CP-H₂O₂ catalyst has excellent electrocatalytic oxidation performance.After 60 minutes of reaction at 0.865 V,the HMF conversion rate was 15.4%and the FDCA yield was 3.9%.In the reaction system,due to the strong adsorption capacity of the catalyst for aldehyde groups,HMF electrocatalytic oxidation first generates HMFCA by oxidizing the aldehyde group,and then oxidizes the side chain alcohol group.The experimental results indicate that Au/C catalyst oxidizes aldehyde groups faster,while Pd/C catalyst oxidizes alcohol groups faster.Au in Au-Pd bimetallic catalysts can only promote the adsorption and oxidation of aldehydes,but Pd in the alloy region can promote both the adsorption and oxidation of aldehydes and the adsorption and oxidation of alcohols.At the same time,Pd not only serves as an adsorption site,but also can quickly remove electrons from the catalyst surface,promoting the oxidation reaction of Au in the alloy region.The close contact of the alloy region provides a dual functional surface for the oxidation of aldehydes and alcohols,promoting the occurrence of electrocatalytic oxidation reactions.