Derivatives Of Cu Superstructures Reduced By Biomass Reductant:synthesis And Application In Glucose Detection

As one of the earliest used metals with wide application prospects,metallic copper(Cu)has raised much interests due to its advantages of good ductility,high conductivity,abundant reserves,non-toxicity and harmlessness.However,it is easy to be oxidized when micronano Cu is exposed in air,which results in poor stability.Currently,a series of strategies are devoted to improve the stability of this material,such as carbon-coating and compositing with other metals.The strategy of converting Cu into copper oxide or copper sulfide is more direct and convenient,compared with above conventional methods.Some studies have been reported about the Cu-based nanosheets,Cu-based nanowires,Cu-based nanospheres and so on.Among them,Cu-based nanosheets have attracted extensive attention due to their unique electronic and physical properties which attributes to their low dimension and quantum effects.In addition,Cu-based nanosheets also benefit from large specific surface area,rich active sites,good stability and biocompatibility,which make them a powerful competitor in the field of electrochemical sensing.Simultaneously,combined with the advantages of fast response,good selectivity and stability for glucose detection,Cu-based materials become the most promising electrode materials for enzyme-free glucose electrochemical sensor.In this study,in order to study the synthesis and morphology of Cu-based nanosheets with different sizes,Cu superstructures with interconnected and continuous structure were reduced by magnolia grandiflora leaves via one-step hydrothermal method.Then Cu/CuO,Cu/Cu2O and CuS nanosheets were fabricated with Cu superstructures as the substrate and the electrical sensing performance of these sensors were studied.1.The fabrication of Cu/CuO porous nanosheets-based glucose electrochemical sensor:Cu/CuO porous nanosheets were prepared by stirring method using Cu superstructure as precursor,deionized water as solvent and ammonium persulfate((NH4)2S2O8)as oxidants.The morphology of the material was observed by scanning electron microscope(SEM)and transmission electron microscope(TEM),and the effect of the feed ratio on the morphology was analyzed.In addition,the effect of the nanostructure on the electrochemical sensing performance was also studied.It was found that the CuO nanosheet with relatively compact and intact exhibited the best analytical performance for glucose electrochemical sensing.This may be attributed to the following features:(1)The Cu superstructure encapsulated with nanosheets structure guarantees the whole conductivity of Cu/CuO-3 and protects the substrate from directly contacting with air and electrolyte.(2)The multilayer nanosheets structure is conducive to providing fast ion transport path and improving the structural stability of materials.(3)The pores grown on CuO nanosheets assembled by nanowires are instrumental in increasing the specific surface areas and exposing more active sites.2.The fabrication of Cu/Cu2O nanosheets-based glucose electrochemical sensor:Cu/Cu2O nanosheets were prepared by a one-step solvothermal method using Cu superstructure as precursor,methanol(CH3OH)as solvent and polyvinyl pyrrolidone(PVP)as surfactant.The morphology of the material was observed by SEM and TEM,and the effect of the reaction temperature on the morphology was analyzed.In addition,the effect of the nanostructure on the electrochemical sensing performance was also studied.It was found that the Cu2O nanosheet obtained under 160? showed the best analytical performance for glucose electrochemical sensing.These can be attributed to the follow advantages:(1)The Cu superstructure with Cu2O nanosheets grown on it guarantees high conductivity and stability.(2)Cu2O nanosheet with small size(about 10 nm)is beneficial to improve the catalytic activity of the composite.3.The fabrication of CuS nanosheets-based glucose electrochemical sensor:CuS nanosheets were prepared by a one-step solvothermal method using Cu superstructure as precursor,ethanol(CH3CH2OH)as solvent and sublimated sulfur as sulfur source.The morphology of the material was observed by SEM and TEM,and the effect of the reaction temperature on the morphology was analyzed.In addition,the effect of the nanostructure on the electrochemical sensing performance was also studied.It was found that the CuS nanosheet obtained under 180? showed the best analytical performance for glucose electrochemical sensing.It can be concluded that the nanosheets remains intact structure under 180? and grow compactly with multilayer structure.This unique multilayer CuS nanosheet structure is instrumental in shortening the electronic transmission path and improvement of structural stability.