Preparation And Hydrogen Evolution Performance Of Ruthenium Based Dual Component Heterostructure Catalysts

Hydrogen energy is an ideal clean energy.It has the advantages of extensive sources,non-polluting,high thermal value,renewable,and other advantages.The electrolytic water process is a reverse reaction of hydrogen burning,it is a sustainable hydrogen-making method.Cathode hydrogen evolution reaction is an important part of the electrolytic water process.Studying the catalyst at the cathode hydrogen evolution reaction is important to reduce the energy consumption in the electrolytic water process.Ru is similar to Pt on HER catalytic active volcanic maps,and has more suitable water dissociation energy barrier than Pt,the Ru based catalyst is often used in alkaline HER.This paper refers to the results of the DFT calculation results,the surface structure and electronic structure of the catalyst were designed and a series of ruthenium based dual component heterostructure catalysts were synthesized.A systematic study was conducted on the structure,composition,formation mechanism,and electrochemical performance of the catalyst by combining various testing and characterization techniques.The specific research content is as follows:1.Structural Design,Preparation,and Hydrogen Evolution Performance of Ru/NdOCl Heterostructure Catalysts.Firstly,the H and OH adsorption strengths and work functions of Ru and Ln OCl were studied through DFT calculations.It was found that Ln OCl has a strong hydrogen adsorption and weaker HER intrinsic activity.There is a significant work function difference（1.25 e V）between Ru and NdOCl,which,according to the Mott Schottky effect,leads to electron transfer from NdOCl to Ru.On this basis,aiming at the toxic effect of high concentration OH^-ions in alkaline environment,a catalyst with Ru/NdOCl heterostructure was designed and prepared by one-step sol-gel self propagating combustion method.XRD,SEM,HR-TEM,and STEM were used to demonstrate that uniform and dense Ru nanoparticles were embedded in the NdOCl matrix to form a heterojunction structure,and electron transfer was completed using the difference in the two-phase work function.Spectral data analysis and theoretical calculation results show that the formed heterojunction structure leads to the electron transfer of NdOCl to Ru nanoparticles,which increases the electron density of Ru site,which is conducive to*OH transfer and OH^-desorption.The electrochemical test results showed that the Ru/NdOCl catalyst exhibited excellent catalytic activity in 1 M KOH alkaline medium,with a hydrogen evolution overpotential of only 20 m V at a current density of 10 m A cm^-2,significantly superior to commercial Ru/C（75 m V）and Pt/C（48 m V）.In high concentration alkaline solutions of 3 M KOH and 6 M KOH,the catalytic activity of Ru/NdOCl catalyst is less affected and exhibits resistance to the toxicity of OH^-ions.The chronopotentiometry test under step current density showed good performance,indicating that the catalyst also has good stability.2.Design,preparation,and hydrogen evolution performance of ruthenium copper oxide electrodes.Firstly,it was demonstrated through DFT calculations that Cu doping can optimize the hydrogen adsorption free energy of Ru O2 and improve the intrinsic catalytic activity of the electrode.In view of the gas accumulation effect under high current density in alkaline hydrogen evolution reaction,a series of Ru Cu oxide electrodes grown on foam nickel and titanium felt were designed and prepared by thermal decomposition method with comprehensive consideration of catalytic activity and mass transfer effect.SEM,TEM,TG,XRD and other characterization methods proved that the small lattice mismatch between Ru O₂（101）and Cu O（002）led to the heterogeneous nucleation of epitaxy,and finally formed Cu doped Ru O₂nanorod arrays on foam nickel and titanium substrates.The RCO/NF electrode exhibits excellent catalytic activity in a 1 M KOH solution,with an overpotential of only 5 m V at a current density of 10 m A cm^-2.The liquid contact angle test and bubble release behavior indicate that the RCO/NF electrode has advantages in gas desorption and mass transfer processes,and still maintains excellent catalytic activity in chronopotentiometry testing at high current density.