One-pot Synthesis And Property Studies Of Two Dimensional Carbon-based Nanocomposites

Graphene,with an intrinsic two dimensional single atomic layer structure,has attracted great attention since its discovery,due to its excellent properties such as large specific surface area,fast electrical conductivity,good thermal conductivity,outstanding flexibility.Even though graphene has so many advantages,the current methods for preparing graphene can not reach its ideal condition.For example,the chemical reduction method results in much lower electrical conductivity than perfect graphene.Conventional mechanical exfoliation and chemical vapor deposition methods possess low production,which makes it hard to produce in large scale;the chemical vapor deposition method needs rigor reaction condition of high temperature with high cost.What's more,the graphene especially few-layered graphene tends to stack because of ?-? interaction,leading to reduced actual surface area.So single graphene may not reach the demands for various applications.Two dimensional carbon nanosheets can overcome the shortcomings of graphene's easily accumulation,usually born with high specific area,can be used as the substitute of graphene for the preparation of two dimensional carbon-based nanocomposites.In this thesis,we explored a new route for in situ preparation of two dimensional carbon based metal nanocomposites and carbon nanocages,characterized and investigated the morphologies and performances of different carbon-based nanocomposites.The main contents are as follows:1.Carbon nanocages@ultrathin carbon nanosheets:One-step facile synthesis and application as anode material for lithium-ion batteries.As a kind of surfactant,1-hexadecylamine with long carbon chain would come to form lamellar structures.Using this surfactant as carbon resource and structure directing agent,cobalt ion as metal catalyst,KCl as the template,upon high energy ball mailing,when exposed to high temperature calcining,cobalt nanosheets supported by ultrathin carbon sheets were prepared.The magnetic property of this nanocomposite was investigated.In addition,by etching cobalt nanosheets with hydrochloric acid,a novel three dimensional(3D)structure of carbon nanocages supported by ultrathin carbon nanosheets(CNCs@CNSs)has been synthesized.The ultrathin carbon nanosheets possess a thickness of 1.6 nm with hollow carbon nanocages dispersing on them to prevent the stacking.As the first combination of carbon nanocages with two dimensional(2D)carbon nanosheets,the 3D hybrids show excellent LIB performances and exhibit a reversible capacity of 650 mAh·g-1 at 0.5 C with rarely capacity loss.Fast charging in 10 mins with a high capacity of 580 mAh.g-1 at 10 C after 500 cycles has also been exploited,which presents broad prospects for the advancement of LIBs.2.Synthesis of ultrathin carbon nanosheets supported well-ordered gold nanoparticles and their application in electrocatalysis.We realized the in situ preparation of ultrathin carbon nanosheets supported gold nanoparticles through ball mailing of 1-hexadecylamine and chloroauric acid precursor without the adding of graphene.The size of gold nanoparticles can be adjusted by changing the reactant ratios.When applied in hydrogen peroxide detection,the sample exhibited good catalysis performance.