Preparation And Properties Of Nitrogen Doped 2D Porous Carbon Material Oxygen Reduction Catalysts

Currently,the growing energy demand and sustainable development goals require more efficient,economical and environmentally friendly energy conversion systems.In the course of research,it is found that an efficient and clean fuel cell is one of the most ideal energy conversion devices.However,the commercial fuel cell cathode catalyst is mainly made of platinum metal,which has high cost and limits the development of the fuel cell.It is urgent to develop a low-cost,high-performance non-platinum catalyst to replace it.In this paper,GO was prepared by hummer modification method and modified by SBA-15 hard template.The prepared GO-SiO2 was used as the carrier and ferric nitrate was used as the metal source.The melamine and polymeric ions with low cost and wide source were selected.A non-noble metal doped carbon catalyst having high catalytic performance is prepared by liquid or the like.The main tasks as follows:1、The prepared GO-SiO2 was used as the carrier,the ferric nitrate was used as the metal source,and the melamine was used as the nitrogen precursor.The Fe-N(mela)/C catalyst was prepared by chemical impregnation method and high temperature pyrolysis method.According to the conditional screening,when the calcination temperature is 800℃,the doping amount of melamine is 0.8 g,and n(male):n(Fe(NO3)3)=15:1,The Fe-N(mela)/C catalyst exhibited the highest oxygen reduction reaction(ORR)catalytic performance,whether in acidic or alkaline conditions.Under acidic conditions,Eon reached 0.817 V and the limiting current density reached 4.5 mA·cm-2;slightly different from 20wt%Pt/C catalyst.Under alkaline conditions,Eon was 1.03 V and the limiting current density reached 4 mA·cm-2.This is attributed to the strong coordination of melamine with Fe3+in a slightly acidic solution and the formation of a stable Fe-N active site during pyrolysis.And the template method controls the mesoporous structure of the catalyst to promote the enhanced ORR catalytic activity,which directly produces OH-mainly through the 4e-pathway reaction.2、The prepared GO-SiO2 was used as the carrier,the ferric nitrate was used as the metal source,and the poly-l-vinyl-3-ethylimidazolium bromide was used as the nitrogen precursor.The Fe-N(PIL)/C catalyst was prepared by chemical impregnation and high temperature pyrolysis.According to the conditional screening,when the calcination temperature is 800 0C,the doping amount of the polymerized 1-vinyl-3-ethylimidazolium bromide salt P[[VEIM]Br]is 2.0 g,and when n(Fe(NO3)3·9H2O):n(PIL)=2:1,Fe-N(PIL)/C catalyst exhibits the highest oxygen reduction reaction(ORR)catalytic performance whether acidic or alkaline.Under acidic conditions,Eon=0.82 V,the limiting current density reaches 4.5 mA cm-2,and the performance is slightly worse than 20wt%Pt/C;under alkaline conditions,Eon=1.05 V,the limiting current density reaches 5.5 mA cm-2,slightly better than 20 wt%Pt/C.This is attributed to the interaction of PIL with Fe3+,resulting in the formation of a stable Fe-N active site in pyrolysis.And the template method controls the mesoporous structure of the catalyst,and the nitrate decomposes in the high temperature pyrolysis to generate a porous structure,so that the catalyst fully leaks the active site,and the ORR catalytic activity of the Fe-N(PIL)/C catalyst is enhanced.It produces OH-directly through the 4 e-pathway reaction.3、The prepared GO-SiO2 was used as a carrier,and ferric nitrate was used as a metal source.The composite nitrogen source:polymerized 1-vinyl-3-ethylimidazolium hexafluorophosphate/dicyandiamide was used as a nitrogen precursor,and was chemically impregnated.Fe-N/P(PIL/DCD)/C catalyst was prepared by high temperature pyrolysis.According to the conditional screening,when the calcination temperature is 800℃ and m(PIL):m(DCD)=4:1.2,whether in acidic or alkaline conditions,the catalytic performance of Fe-N/P(PIL/DCD)/C catalyst shows the highest in the oxygen reduction reaction.Under acidic conditions,Eon=0.8 V,the limiting current density reaches 4 mA·cm-2,and the performance is slightly worse than 20wt%Pt/C;under alkaline conditions,Eon=1.04 V,the limiting current density reaches 5 mA·cm-2,comparable to 20wt%Pt/C.This is attributed to the fact that PIL/DCD is a composite nitrogen source that not only has excellent electron conductivity,but also interacts with Fe3+,resulting in a stable Fe-N active site in high temperature pyrolysis.And the template method controls the mesoporous structure of the catalyst,and the nitrate decomposes in the high temperature pyrolysis to form a porous structure.The ORR catalytic activity of the porous structure Fe-N/P(PIL/DCD)/C catalyst is enhanced to pass the 4e’pathway reaction.Directly generate OH’.