Controllable Synthesis, Structure Characterization And Electrochemical Properties Of PtNi Based Nanocrystals

With the rapid development of society,the shortage of petrochemical energy and its environmental pollution have become more and more serious,so it can not be ignored.Traditional fossil fuels(natural gas,coal and oil)have limited reserves and are not renewable.They will produce large amounts of polluting gases,which will have a great impact on the environment.In order to solve the above problems,fuel cells without combustion process have become the focus of research.Fuel cells have the advantages of no pollution and high energy conversion rate.It directly transforms chemical energy into electric energy by electrochemical way.Its fuel sources are abundant,renewable,convenient for storage and transportation.Fuel cells become an ideal choice for future energy conversion devices.Precious metal platinum is widely studied and applied because it plays an important catalytic role in the electrode reaction of fuel cells.Platinum is expensive and its reserves are limited,furthermore,platinum has the problems of high reaction potential and easily poisoning by carbon monoxide(CO)in the catalytic alcohols oxidation.With the rise of nanoscience,the research of platinum based nanocrystalline as a catalyst for fuel cell electrode has made great progress.Platinum nickel nanocrystals have reduced the amount of precious metal platinum and have good electrochemical properties,which have become an important direction for the research of platinum based nanocrystals.In this paper,the aim is to synthesize platinum nickel nanocrystals with uniform morphology and excellent electrochemical performance.Various platinum nickel nanocrystalline alloys were designed and synthesized,then their morphology,structure,composition and electrochemical properties were explored.(1)Using platinum(II)acetylacetonate and nickel(II)acetylacetonate as precursor,polyvinylpyrrolidone(PVP,Mw=8000)as reducing agent,sodium chloride(Na Cl)as structure directing agent,N,N-dimethyl acetamide(DMAC)as solvent in the reaction pressure under 180 ? for 8 hours,Pt3 Ni dendritic platinum nickel nanoalloy was successfully prepared.Under alkaline conditions,the electrocatalytic oxidation of ethylene glycol and glycerol is better than commercial platinum black(Pt black),and it shows high sensitivity,low detection limit,excellent anti-interference and very short reaction time in the application of dopamine biosensor.(2)With polyvinylpyrrolidone(PVP,Mw=8000)as reducing agent,sodium iodide(Na I)as structure directing agent,N,N-dimethyl acetamide(DMAC)as solvent,platinum(II)acetylacetonate and nickel(II)acetylacetonate as metal precursors in high pressure reactor at the temperature of 180 ? for 8 hours,the preparation of sub-4 nm grade platinum nickel nanocrystals was successful.On the basis of above,adding graphene(high-quality carbon materials)to sub-4 nm grade platinum nickel nanocrystals,graphene loaded sub-4 nm grade platinum nickel nanocrystals were successfully prepared.The electrocatalytic oxidation performance of ethanol was tested under alkaline conditions.The sub-4 nm grade platinum nickel nanocrystals and graphene loaded sub-4 nm grade platinum nickel nanocrystals exhibited much higher catalytic oxidation performance and stability than commercial platinum black(Pt black)and commercial carbon supported platinum(Pt/C).