The Preparation,Characterzation And Application Of Graphene Oxide/Layer Double Hydroxides Composite

Graphene oxide(GO)is the product of graphite powder after chemical oxidation peeling,it has excellent application prospect in the field of adsorption because of rich surface active groups as well as large specific surface area,and it can becomes reduced graphene oxide(RGO)after the reduction reaction of GO,meanwhile RGO can be used as electrode material in the field of electrochemistry because of excellent electrical conductivity,however GO and RGO are extremely easy to agglomerate,which seriously hinder its performance.The layered double hydroxides(LDH)material which can be used as adsorption material consist of positivelycharged main laminate as well as negatively-charged exchangeable interlayer anion,and it plays an important role in the field of electrochemistry,because it can be used for reversible Faraday reactions,and the redox activity is high as well as the cost is low.GO flakes are negatively charged and LDH laminates are positively charged,therefore we can prepared GO/LDH composite by using the electrostatic interaction between GO and LDH,which can effectively reduce the agglomeration of GO therefore enhance its adsorption performance,and the GO/LDH composite can be reduced by chemical methods to prepared RGO/LDH composite which can enhance its electrochemical performance.In this paper,GO/LDH composite was prepared by peeling reassembly method and characterized by XRD,FTIR,Roman,UV,SEM,TG,DSC test methods.The results showed that the GO/LDH composite possessed more excellent thermal stability than GO and LDH,and the strength of the C-H bond in the composite increased with the increasing of the GO content,meanwhile the structure of the LDH and the oxygen-containing functional groups of GO were preserved in the GO/LDH composite.In this paper,the adsorption performance of methylene blue(MB)solution by GO/LDH composite was studied and the effects of the type of adsorbent,the adsorption time,the amount of adsorbent added,the initial concentration of MB solution,and the p H of the solution were investigated.The results showed that GO/LDH composite had better adsorption effect on MB than GO and LDH,more importantly,the GO/LDH composite can naturally precipitated after the adsorption was completed,which overcomes the solid-liquid separation problem of GO as adsorbent.The removal rate of MB by GO/LDH composite increased with the increasing of the adsorption time as well as the amount of adsorbent added,however the removal rate of MB decreased with the increasing of the initial concentration of the MB solution,meanwhile it was not beneficial for the adsorption process under acidic conditions,however it was beneficial for the adsorption process under alkaline conditions.The adsorption kinetics conformed to the pseudo-second-order dynamic equation model,the adsorption rate conformed to the chemical reaction model,and the adsorption isotherm conformed to the Freundlich model.In this paper,GO/LDH composite was reduced by trisodium citrate to prepared RGO/LDH composite and characterized by XRD,FTIR,Roman,UV,and SEM.The results showed that the oxygen-containing functional groups were effectively removed after reduction reaction.Furthermore,the electrochemical properties of RGO,LDH,and RGO/LDH composite were studied,the results showed that Faraday redox reaction and pseudo-capacitance characteristics existed in RGO,LDH,and RGO/LDH composite,meanwhile RGO/LDH composite had more excellent electrochemical performance,higher specific capacitance than GO as well as LDH,and RGO/LDH composite had excellent charge and discharge cycle stability.