Preparation And Electrochemical Properties Of Iron And Nitrogen Doped Porous Carbon Materials

The doped porous carbon material with excellent chemical stability,good conductivity,abundant pore structure,high specific surface area,and nitrogen doping modification are favored in the application of oxygen reduction catalysts and supercapacitor electrode materials.The pursuit of low-cost raw materials,simple process preparation methods to synthesize porous carbon electrode materials with excellent electrochemical performance has been the goal pursued in this field.Biomass materials are rich in resources,rich in various elements and renewable resources which are ideal raw materials for the preparation of doped carbon materials.In this work,iron-nitrogen-doped porous carbon material?Fe-N-EWPC-900?was prepared by using of nitrogen-rich renewable biomass egg white as the carbon source and nitrogen source,and Fe?NO₃?₃ as iron source though 900?high-temperature carbonization.X-ray electron spectroscopy measurement showed that the doping amounts of nitrogen and iron in Fe-N-EWPC-900 are 2.69 at%and 0.63 at%,respectively.Moreover,The electron scanning transmission electron microscopy and corresponding the elemental mapping displayed that nitrogen and iron were uniformly distributed in the carbon structure.Used as an oxygen reduction catalyst,the Fe-N-EWPC-900 exhibited an excellent initial potential of 0.97 V?vs.RHE?which was12 mV higher than 20 wt%Pt/C.It also displayed a better stability and methanol resistance than the 20 wt%Pt/C catalyst and had close to 4 of electrons reaction.As a supercapacitor electrode material,the Fe-N-EWPC-900 exhibited a high specific capacitance(285.6 F?g^-1at 1 A?g^-1)and excellent stability(capacitance retention of 95.2%after 2000 cycles at 50 mV?s^-1).Fe-N-doped three-dimensional honeycomb-like hierarchical porous carbon?Fe-N-HPC-800?was prepared under 800?high-temperature carbonization though using NaCl as a template in synergy with ferric nitrate.The Fe-N-HPC-800 possessed a high specific surface area of 855.4 m²?g^-1.In a assembled symmetric two-electrode supercapacitor test,The Fe-N-HPC-800 electrode exhibited a specific capacity of360F?g^-1 at 0.5 A?g^-1,still reached 240.5 F?g^-1 at a current density of 20 A?g^-1,and kept the high capacitance retention of 88%after charging-discharging 5000 cycles at 200 mV?s^-1.Those results indicated that the Fe-N-HPC-800 had good electrochemical stability and excellent rate performance.When Fe-N-HPC-800 was tested for oxygen reduction performance,it had a high initial potential 0.92 V?vs.RHE?,half-wave potential 0.78 V?vs.RHE?which were better than 20 wt%Pt/C and closed to the four-electron reaction mechanism.The Fe-N-HPC-800 also showed a better stability than 20 wt%Pt/C.