Preparation Of Heteroatom-doped Carbon Nanomaterials And Study On Its Electrocatalytic Water Splitting Performance

Hydrogen has the advantages of clean,environmentally friendly,and recyclable and so on.Electrolytic water is one of the effective ways to obtain high-purity hydrogen.The use of precious metals as electrolyzed water catalysts can effectively reduce the reaction energy consumption and improve efficiency of production.However,precious metals have problems such as low scarce-reserves,high-cost and shortened durability,which have greatly limited their large-scale commercial use.Heteroatom-doped carbon materials have the advantages of easily tailored structure and strong acid–base durability in acidic/alkaline conditions.However,Electrolytic water activity of heteroatom-doped carbon materials is still far behind that of metal-based materials.Hence,this paper takes carbon nanotubes as the object to stutdy the new high-performance materials for electrocatalytic water splitting.N,S co-doped and N,P co-doped carbon materials were prepared using compounds such as thiocyanate,phytic acid and aniline as heteroatom sources with experimental technology of concentration,condensation-polymerization and subsequent heat-treatment in an inert gas.Heteroatoms are doped into the structure of carbon nanotubes or carbon layer on the surface of carbon nanotubes.The morphology and composition of doped carbon materials were adjusted by changing experimental parameters such as the amount of heteroatom sources added and pyrolysis temperature.The internal relationship and rule between the doping of heteroatoms and the activity for electrocatalytic water splitting of the material is mainly studied.The performance towards electrocatalytic water splitting of the prepared N,S co-doped carbon nanotubes and N,P co-doped carbon coated carbon nanotubes was systematically investigated.When driving HER to the current density of 10 mA cm^-2 in an acidic system(0.5 mol L^-1 H₂SO₄),the superior overpotential required for N,S co-doped carbon nanotube（NSCNT-900）and N,P co-doped carbon coated carbon nanotubes（CNT@NPC-900）were 206 and 167 mV,which are better than that of most of state-of-the-art metal-free catalysts for HER.In an alkaline system(1.0 mol L^-1KOH),the potential of NSCNT-900 and CNT@NPC-900 at a current density of 10 mA cm^-2 is 1.63 V and 1.58 V for OER,which is comparable to that of most reported metal-free electrocatalystsTheoretical models of N,P co-doped carbon coated carbon nanotubes for efficiently were constructed.And the mechanism of HER of materials was discussed.