Preparation And Catalytic Performance Of Graphene Supported Platinum Nickel Alloy Catalyst

With the increasingly severe environmental and energy issues,the application of fuel cell as a new energy source is of great significance in alleviating environmental pressure and energy crisis.Moreover,the research of catalysts is very important for the practical application of fuel cells.In this paper,platinum-nickel alloy(Pt-Ni/G)catalyst was synthesized with graphene as earrier by galvanic cell replacement.On this basis,core?shell Pt-Ni alloy(Pt-Ni@Pt/G)catalyst was prepared by acid etching method,and the action of the Lorentz force and magnetizing force of the magnetic field to change the composition and morphology of Pt-Ni/G.Investigating the catalytic performance of the catalyst,an effective method to improve the catalytic activity was proposed.The specific work includes the following aspects:(1)Pt-Ni/G catalyst was prepared by changing the molar ratio of Pt ions and nano-Ni particles with graphene as carier in solution by galvanic cell replacement.The structure,composition,morphology and catalytic properties of Pt:Ni catalyst were characterized by XRD,XPS,TEM,EDS and electrochemical tests.The results show that the Pt-Ni alloy nanoparticles are uniformly distributed on graphene.When the molar ratio of Pt:Ni is 8:1,the Pt-Ni/G catalyst has a large mass activity ratio of 0.53A/mgPt and a higher onset potential of 0.96V for oxygen reduction reaction,showing a better catalytic performance.(2)Based on the preparation of Pt-Ni/G catalyst by galvanic cell replacement method,and then Pt-Ni@Pt/G catalyst was obtained by acid etching.The effects of acid etching times on the structure,composition and catalytic properties were investigated.The results show that the Pt-Ni@Pt/G catalyst has a high initial potential of 1.02V and the mass activity ratio of 0,65 A/mgpt which of 4,5 times that of commercial Pt/C catalyst for oxygen reduction reaction(ORR),due to the stress effect between the core and shell of Pt-Ni@Pt/G catalyst and the effect of Pt and Ni hgand;the hydrogen evolution reaction(HER)shows that it is more efficient for hydrogen production from electrolytic water;methanol oxidation reaction(MOR)has strong resistance to CO poisoning.(3)Pt-Ni/G catalyst was prepared in different magnetic fields strengths by galvanic cell replacement method.XRD,XPS,TEM,EDS,ICP and electrochemical measurements were used to characterize the effect of magnetic field intensity on the catalyst.The results show that with the increase of magnetic field,the displacement rate of platinum and nickel increases,and Pt-Ni alloy nanoparticles gradually agglomerate to form dendritic porous nanostructures.When the magnetic field strength is 2T,the mass specific activity of the prepared Pt-Ni/G catalyst is 0.68 A/mgpt,which is 4.6 times higher than that of commercial Pt/C catalyst,and the initial potential is 0.99V in ORR.HER shows that it is more efficient for hydrogen production from electrolytic water;MOR has strong resistance to CO poisoning.