Preparation Of Nitrogen-doped Three Dimensional Graphene Composite Materials And Their Applications In Electrochemistry

Three-dimensional graphene has attracted increasing attention because of its unique structure,excellent chemical and physical properties.Nitrogen doped three dimensional graphene(3DNG)was prepared by using poly(m-phenylenediamine)as the carbon source and cobalt nitrate as the template.Three dimensional graphene usually exhibit higher specific surface area than 2D graphene materials.Furthermore,graphene is an ideal support to improve the electrocatalytic activity because of their high electrical conductivity.The introduction of heteroatoms(such as N,P,S,etc.)into the graphene can also make it get more excellent electrochemical performance.Furthermore,Preparation of 3DNG-polymer nanocomposites can further expand the electrochemical application of 3DNG.This thesis includes the preparation and characterization of 3DNG and its composites,and their electrochemical applications in electrocatalytic water splitting and electrochemical capacitors.The main research works were as follows:(1)3DNG was prepared by carbonization using poly(m-phenylenediamine)as the carbon source and cobalt nitrate as the template.The as-prepared 3DNG was used as the supporter for synthesis FeP/3DNG composite material.The as-prepared FeP/3DNG material asHER electrocatalyst displayed excellent catalytic performance for electrochemical hydrogen generation.Especially,the composite material exhibited low onset overpotential,a small Tafel slope,high exchange current density and high electrochemical stability.(2)NiCoOH/3DNG composite was synthesized by using 3DNG as a supporter.The composite materials were used for the electrocatalytic oxygen evolution reaction and exhibited low onset overpotential,a small Tafel slope,and high exchange current density and good cycling stability.(3)The polyaniline nanowires/3DNG were prepared by in-situ polymerization of aniline in the presence of 3DNG.The polyaniline/3DNG serving as supercapacitor electrode material exhibited high specific capacitance,excellent rate capability,and outstanding cycling stability.