Construction Of Noble Metal Nanoparticle Composite Materials And Research Of Electrocatalytic Performance

With the increasingly serious energy crisis and environmental pollution,the use of efficient energy storage and conversion technology has become a way to alleviate the energy crisis.Hydrogen produced by electrolysis of water,and the produced hydrogen is used as a fuel for hydrogen fuel cells to complete energy storage and conversion.This process involves two half reactions of Hydrogen evolution reaction(HER)and Oxygen reduction reaction(ORR).The high potential greatly limits the development of its technology.Although platinum-based catalysts have the advantages of low overpotential and fast reaction kinetics,their expensive price prevents large-scale applications.The development of high-efficiency and low-cost catalysts is of great significance.This thesis has done certain research mainly in the following three aspects:First,an in-situ synthesis method is adopted,using dicyandiamide and D-glucosamine hydrochloride as the nitrogen source and carbon source,respectively,to fully combine palladium chloride,dicyandiamide,and D-glucosamine hydrochloride(GAH).Mix and use the reducing atmosphere in the pyrolysis process to reduce the palladium chloride to generate palladium chloride nanoparticles in situ to obtain a nitrogen-doped porous carbon nanosheets supported palladium particle catalyst,which is used to catalyze the ORR reaction.The initial potential and the half-wave potential are respectively It is 0.97 V and 0.82 V,which provides an environment-friendly catalyst preparation method for ORR.In order to obtain a more uniform particle size,more stable and efficient precious metal nanocluster catalyst,this paper synthesized Au₄Pd₂(PET)₈ nanoclusters,and then evenly dispersed the gold palladium nanoclusters on the carbon nanosheets,using high temperature to remove the complex.To obtain a carbon nanosheet supported gold-palladium nanocluster catalyst.Compared with nanoparticles,nanoclusters have a more precise structure and more precise active sites,which is conducive to the construction of catalysts.The carbon nanosheet-loaded gold-palladium nanoclusters were applied to catalyze the ORR reaction.The initial potential and half-wave potential were 0.95 V and 0.81 V,respectively.When applied to the HER reaction,the overpotential was 129 m V at 10 m A/cm².The catalyst is applied to the self-made zinc-air battery,and the zinc-air battery exhibits excellent charge and discharge stability.In order to study the effect of single-atom doping on the electrocatalytic activity of gold nanoclusters,this paper further uses MAu₂₄(PET)₁₈(M=Au,Pd,Pt)nanoclusters instead of Au₄Pd₂(PET)₈ nanoclusters,by comparison The effect of different heteroatom doping Au₂₅clusters on performance,the ORR catalytic activity is Pt Au₂₄>Pd Au₂₄>Au₂₅,and the HER catalytic activity is Pt Au₂₄>Pd Au₂₄>Au₂₅;different loadings of Pt Au₂₄ are studied,when the amount of noble metal doping When it is 10%,the catalytic performance is the best.The initial potential of the catalytic ORR reaction is 0.96 V,and the half-wave potential is 0.82V;the overpotential of the catalytic HER reaction is only 9 m V at 10 m A/cm2.It has high-efficiency catalytic ORR and HER performance.In this thesis,metal nanoparticles with definite structure,definite composition and mono-dispersity are used to realize the catalytic process of each metal atom as an active site.This procedure not only improves the catalytic activity of the catalyst,but also reduce the cost of the catalyst.The electronic structure of the metal clusters can be changed by replacing one atom of the single atom doped-bimetallic clusters,which provides an ideal catalyst model for understanding the relationship between catalytic activity and structure.As a catalytic material with high economic benefits,it also has a certain practical application value.