Preparation And Electrocatalystic Performance Of Heteroatom-doped Carbon-based Nano-tubes/Ribbons

The sustained consumption of unrenewable fossil fuels caused serious problems,including air pollution,global warming,energy depletion.Therefore,developing renewable energy is vital,such as solar cells,wind energy and hydrogen energy.Among these renewable energy,H2-O2 fuel cells received more attention due to non-geological restraint,high energy conversion efficiency,and zero pollution.However,the extensive application of fuel cells was greatly hindered by noble-metal catalysts because of their scarcity,high cost,poor stability and susceptible to methanol and CO.Therefore,developing non-noble catalysts with high activity,low cost,good stability played a significant role on the development of fuel cells.Herein,we developed two kind of non-noble catalyst.The main research contents and innovation in this work were summarized as follow:The nitrogen,phosphorus and iron tri-doped carbon nanotubes were prepared and used as bi-functional electrocatalyst for ORR and OER.The typical sample(N-P-Fe-CNTs)exhibited excellent ORR performance with an onset potential of 0.97 V and a half-wave potential of 0.84 V in 0.1M KOH solution,which were comparable to commercial Pt/C.The catalyst also showed good OER performance with an onset potential of 1.52 V,which was close to commercial RuO2.The oxygen electrode activity(?E)was just 0.74 V.The maximum power density of PEMFC assembled from N-P-Fe-CNTs electrode was 438.5 mW cm-2.The electrocatalytic and PEMFC performance of N-P-Fe-CNTs were firstly researched compared with other nitrogen,phosphorus and iron tri-doped carbon in the literature.Besides,the bi-functional performance of N-P-Fe-CNTs was still better than those of many kinds of M/N/C and S-M/N/C materials.The nitrogen,sulphur and boron co-doped carbon nanoribbons were prepared and used as metal-free electrocatalyst for ORR by a two-step route.The catalyst showed good ORR performance with a half-wave potential of 0.76 V,limited current density of 5.8 mA cm-2,and kinetics current density of 11.04 mA cm-2 at 0.7 V in alkaline medium.The ORR performance of NSB-NR was superior to previously reported one-dimensional(ID)N-S-B co-doped carbon-based electrocatalyst and many other carbon materials doped with B and another heteroatom.Through a series of control experiments,we found that two-step doping of N-S-B was better than one-step.The N-S-B tri-doped system for ORR was better than those of bi-doping and mono-doping system.