Study On The Preparation And Performance Of Fe And Ni Based Catalysts For Oxygen Reduction In Anion Exchange Membrane Fuel Cell

Anion exchange membrane fuel cells(AEMFCs)with an alkaline anion membrane as an electrolyte can not only improve the kinetics of oxygen reduction reaction,but also can be used non noble metal cathode as catalyst.Thus,the manufacturing cost is greatly reduced,and the commercialization process of the fuel cell is more competitive.ORR catalyst is one of the key components,its performance is directly related to the output performance of the battery.The development of new and low cost ORR catalyst has important theoretical and practical significance to promote the development of AEMFC.In this dissertation,the Fe/C,Ni/C and FeNi/C catalysts were prepared by temperature controlled carbonization process with starch as the carbon source,nano iron oxide and nickel oxide as the active center.Through Transmission Electron Microscope(TEM)analysis confirmed that shell is consists of a piece of graphite layer and core is metal nanoparticles.The particle size of Fe nanoparticles is about 25 nm,while the diameter of Ni particles and alloy particles are from tens of nanometers to several hundred nanometers.Three kinds of catalysts showed catalytic activity to O2.Fe/C,Ni/C and FeNi/C catalysts were prepared with the best catalytic activity,when the pyrolysis temperature to 800 ? and the heat preservation time is 4 h,control the quality ratio of starch and iron/nickel respectively:100:5,50:1 and 100:2:3(starch/Fe/Ni).Under the optimal conditions,the three catalysts were prepared.Polarization current density of oxygen reduction reaction at-0.6 V are reached 0.799 mA·cm-2,0.89 mA·cm-2,1.266 mA·cm-2,respectively.Found that the catalytic activity of the three catalysts for ORR was Fe/C>Ni/C>FeNi/C.The maximum flow density of the carbon supported FeNi alloy catalyst was about 1.266 mA·cm-2.Compared with Fe/C and Ni/C,the performance of and were increased by 58.4%and 42.2%respectively.The dynamic potential polarization curves of the rotating disk electrode showed that the number of electron transfer of Fe/C,Ni/C,FeNi/C 3.29 catalysts were 2.29,2.83 and three,respectively.It shows that the oxygen reduction reaction on the surface of these three catalysts is both 4e and 2e.After 500 times of cyclic voltammetry test,the performance of the three catalysts showed good stability.