| As a new ORR catalyst,nitrogen doped carbon materials have high catalytic activity,high stability and strong resistance to toxicity.The ORR catalytic activity can be improved by the addition of metal elements on the basis of nitrogen doping.The transition metal ferrite is rich in stability and low price as doping metal has good application prospect.In this paper,the preparation of a kind of good performance is more stable than platinum carbon catalyst,for the purpose of graphene as carbon carrier,by controlling the process of polyaniline growth,in the heat treatment after the preparation of different kinds of different temperature nitrogen doped graphene.Then,the iron doped graphene polyaniline materials were prepared by means of Hydrothermal and heat treatment.A series of characterization and ORR performance tests were performed on the materials.The specific contents are as follows:1)The nitrogen doped graphene with four different nitrogen levels was prepared by controlling the addition of aniline,and the nitrogen atmosphere was heat treated at the same temperature At 800?under nitrogen atmosphere heat treatment preparation5GO,10GO,20GO to 30GOfour different nitrogen content of nitrogen doped catalysts,in order to prove the influence of temperature on the 10GO after different heat treatment temperature were studied in the catalytic activity..Compare the appearance of the samples before and after heat treatment.Before heat treatment,polyaniline was uniformly grown on the surface of graphene and with the addition of aniline,the concentration of polyaniline particles on the surface of graphene increased,and the graphene sheets were completely wrapped up.After heat treatment,a large number of wrinkles and defects were formed on the graphene layer,and the increase of N content with the addition of aniline was proved to be decreased.Nitrogen mainly exists in the form of pyridine nitrogen and graphite-type nitrogen,indicating that N atom is successfully doped into the graphene skeleton.By electrochemical test comparison ORR catalytic activity of all material,prove under 800?treatment 10GO best performance but also has the very big disparity compared with 20%Pt/C.2)To improve the 10GO,in the process of growth of polyaniline introduced part of iron ion,introduced in the process of Hydrothermal again after part of iron ions,the final heat treatment at different temperatures,the preparation of the growth on the surface of the graphene,ferroferric oxide nano clusters.Through the Raman spectrum,X-ray diffraction pattern and X-ray electron spectroscopy analysis,the iron elements were doped into the graphene skeleton in two forms:iron atoms and tri-iron.Through to the material ORR catalytic activity to the electrochemical tests,10GO/Fe-700?has the best catalytic activity,for four electronic process.Compare with 20%Pt/C in the oxygen saturation 0.1m KOH alkaline system.The limit current density under 1600rpm is close to 7 mA·cm-2 high and 20%Pt/C,and the data of RRDE is kept at four at different potentials,and the yield of hydrogen peroxide is maintained at zero.By comparing the anti-methanol permeability of 10GO/Fe-700 by I-T,the decrease of 35.7%in the same time was significantly higher than 85.7%of 20%Pt/C,indicating that we successfully prepared an ORR catalyst with good catalytic activity and stability compared with platinum and low price. |
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