Preparation Of Iron And Nitrogen Co-doped Nanometer Carbon Materials By Electrospinning And Their Properties For Oxygen Reduction Reaction

At present,in order to solve the problems of energy crisis and environmental pollution and so on,the development of renewable clean energy is an important research direction.Fuel cellis popular because of its high energy conversion efficiency and low pollution.Especially,low-temperature fuel cells are widely used in portable electronic equipment,residential,automobile and the centralized power supply system and so on.But the large-scale applications of the fuel cells are restricted by the current commercial cathode catalyst Pt/Cdue tothe less resource,high cost and poor stability.Therefore,the study of non-platinum electrocatalystsbeing used to catalyze oxygen reduction reaction?ORR?has become ahotspotin recent years.In this work,electrospinning was used to prepare Fe and N co-dopednanometercarbonmaterial.The spinning precursor solution was prepared by N,N-dimethylformamide?DMF? containing chlorhematin and Polyacrylonitrile?PAN?,and chlorhematin was used as iron and nitrogen sources.The influences of carbonization temperature and amount of chlorhematin on electrochemical properties of catalystswere studied.The Physical characterizations of the samples were analyzed by SEM,TEM,XPS and so on,and related electrochemical tests were performed.Fe-N-CNFswasobtained by preoxidizedat300°C in the air and carbonized at 850°C for 2h in N₂.And the doped amount of nitrogen was highly 5.56 at%.Fe-N-CNFs exhibited better electrocatalytic activity for ORR and better stability than those of commercial Pt/C in 0.1 M KOH.Besides,in 0.1 M HClO₄ the onset potential of Fe-N-CNFs for ORR was 0.834 V,slightly left shift about 6mV than that of Pt/C,and catalyzed ORR via 4e^-pathway;after i-t test,Fe-N-CNFs showed better stability and methanol tolerance than Pt/C.PAN nanofibers containing 0.1 wt%ferrocene?Fer-PAN?were produced by electrospinning.Then Fer-PAN were preoxidized at 300°C in the air and carbonized at900°C for 2 h in N₂.Finally,the iron and nitrogen codoped self-supporting porous carbon nanosheets?Fe-N-CNS?were prepared.The specific surface area of Fe-N-CNS was 835 m²g^-1.In both alkaline and acid media,Fe-N-CNS exhibited excellent catalytic activity for ORR due to high catalytic activity sites,such as Fe³⁺-N₄ moiety and pyridinic-N.Fe-N-CNS exhibited better electrocatalytic activity for ORR and better stability than those of commercial Pt/C in 0.1 M KOH.Also,Fe-N-CNS exhibited outstanding electrochemical activity for ORR through 4e^-pathway in 0.1 M HClO₄ and had better stability than Pt/C.And the methanol tolerance of Fe-N-CNS was better than that of Pt/C.