Preparation Of Transition Metal Carbide/B, N-doped Nanocarbon And Its Electrocatalytic Properties

In order to meet the highly need of human towards the sustainable energy,it is necessary to develop of novel energy storage and conversion devices,such as fuel cells and metal-air batteries.However,the commercial application is limited by the sluggish kinetics of cathodic oxygen reduction reaction(ORR).Compared with Pt-based noble metal catalysts,non-precicous metal catalysts is more important due to the advantages of high-efficient and low-cost.It has been found that both transition metals-nitrogen-carbon(M-N-C)composites and heteroatoms doped carbon materials could exhibit excellent ORR performance.Therefore,based on the synergistic effec of 1+1>2,combined of transition metal carbide with B-doped,N-doped carbon composites would play better ORR activity.In this thesis,a series of transition metal carbide and B,N-codped(or N-doped)nanocarbon composites were succesfully synthesized derived from melamine with abundant carbon and nitrogen sourcel.The detailed research content is as follows:1.Synthesis of vanadium carbide/N-doped nanocarbon composite.The ion reaction of ammonium vanadate firstly reacted with cobalt nitrate,then the precursor was formed by impregnation with melamine.Finally,the vanadium carbide and N-doped nanocarbon composite could be obtained by a high temperature carbonization process.The synthetic composites show good catalytic activity and stability towards ORR in alkaline electrolyte.It also exhibits a four electronic process and high methanol telarance ability.2.Synthesis of iron(cobalt)carbide/N doped nanocarbon composite.By using prussian blue analogues as precursor and melamine as nitrogen and carbon source,respectively,could prepare iron(cobalt)carbide/N doped nanocarbon composite.The composite could exhibit excellent ORR performance in alkaline electrolyte.Compared with commercial Pt/C catalyst,it shows a higher kinetic current density,better stability and methanol tolerance.3.Preparation of Fe-Fe3C/B,N co-doped graphitic nanocarbon composite.By using boric acid,melamine and ferric nitrate to synthesize the precursor,then Fe-Fe3C/B,N co-doped graphitic nanocarbon composite could be prepared after carbonization the precursor.As for non-precious metal catalyst,Compared with commercial Pt/C catalyst,the composite has showed superior ORR performance comparable to Pt/C catalyst in alkaline electrolyte,and it also exhibits well stability and methanol tolerance ability.