Study On Structure Regulation And Electrocatalytic Performance Of Pt-based Alloy Nanoparticles

With the continuous development and use of traditional energy sources(such as coal,oil,natural gas,etc.),the problem of environmental pollution has become increasingly serious.Therefore,finding green and non-polluting new energy sources has become the core of international energy shortages.Among many new energy sources,fuel cell and electrolytic water hydrogen evolution are considered to be the most promising new energy sources due to their environmental protection and high energy conversion rate.Currently,Pt catalysts are mainly used in fuel cells and electrolyzed water devices.However,due to the slow reaction rate of the catalyst and the high price of Pt,the cost of the catalyst remains high,which severely hinders widespread commercial applications.In recent years,with the continuous exploration of scientific researchers,there has been a qualitative leap in Pt-based catalysts,but there is still a considerable gap from widespread commercial applications.Therefore,there is an urgent need to prepare nanocatalysts with high activity,high stability,and low Pt.In this paper,four kinds of Pt-based catalysts were prepared by the polyol reduction method,and their oxygen reduction and hydrogen evolution from electrolytic water were studied.The research results obtained in this paper are as follows:By using the polyol reduction method,Fe_1-xPt_x nano-alloys with different components were synthesized by adjusting the molar ratio of precursors,and then the morphology and structure of Fe_1-xPt_x NPs were adjusted.After compounding it with carbon black,it was characterized by XRD,SEM and TEM.The XRD image was compared with a standard PDF card.The data showed that a part of the Fe_1-xPt_x alloy with fct phase was prepared.The electrochemical workstation was used to test and compare all Fe_1-xPt_x NPs and commercial Pt/C to explore the optimal molar ratio of ORR activity of Fe_1-xPt_x NPs.Through detailed calculation and analysis of electrochemical data,Fe₇₀Pt₃₀ NPs have better ORR catalytic performance than commercial Pt/C.Determine the optimal molar ratio of Fe:Pt:Cu=45:35:20 in the precursor,and change the Fe source(Fe(acac)³ and Fe Cl₂)to prepare Fe with the same composition and different Fe in hexadecylamine.Source of Fe₄₅Pt₃₀Cu₂₀ ternary alloy nanoparticles.The XRD characterization results show that the more Fe Cl₂ as the Fe source,the more obvious the fct phase and the larger the particle size of Fe₄₅Pt₃₀Cu₂₀ nanoparticles.When Fe(acac)₃ is used as the Fe content,the more the Fe₄₅Pt₃₀Cu₂₀ nanoparticles exhibit fcc phase,the smaller the particle size becomes and becomes uniform.After passing the HER performance test,we found that when Fe(acac)₃=0.18 mmol and Fe Cl₂=0.27 mmol,Fe₄₅Pt₃₀Cu₂₀ showed better HER catalytic activity and stability in 0.5M H₂SO₄.Its overpotential at a current density of 10m A/cm² is 10 m V and a low Tefel slope of 24 m V/dec,which is better than the commercial Pt/C overpotential of 30 m V and a Tefel slope of 30 m V/dec.By changing the Fe source to change the size,morphology,and structure of FePtCu nanoparticles,its HER performance is superior to commercial Pt/C catalysts,providing a new idea for the preparation of low-Pt high-efficiency electrolytic hydrogen evolution catalysts.In order to further reduce the cost of Pt-based catalysts and improve the reactivity of the catalysts.We tried to explore the molar ratio of high-performance Pd Pt Cu nanocatalysts.First,we prepared a series of Pt Cu nano-alloys with different components.Through physical property characterization and electrochemical performance tests,it was determined that when Pt:Cu=1:3,the acid electrolyte ORR activity was the best.Subsequently,the Pd content was increased on the basis of Pt₁Cu₃ to prepare a series of Pd Pt Cu nanocatalysts.Subsequent physical property characterization and electrochemical performance tests were performed.Analysis of the CV and LSV data confirmed that ORR had the best catalytic activity when Pd:Pt:Cu=3:1:3.In subsequent accelerated stability tests,the Pd₃Pt₁Cu₃ nanocatalyst showed superior stability and durability compared to commercial Pt/C.