Preparation And Performance Of Copper-based Nanocomposites

Good conductivity,thermal conductivity and catalytic performance of metal nanomaterials have a wide range of applications in antibacterial,catalytic,sensing,biomedical,electromagnetic shielding and other fields.At present,nano-copper has a large specific surface area and high surface activity,but it is easy to be oxidized in the air.To improve its oxidation resistance,the research on the preparation and interface properties of copper-based composite nanomaterials has become a research hotspot.Carbon material has stable chemical properties,which is an important material for preparing high conductivity,high strength copper-based composite materials.In this thesis,the well-aligned Cu@C core-shell nanocubes were prepared by polymer coating in-situ carbonization,and their application performance in the field of electrochemical enzyme-free glucose detection and electromagnetic shielding was studied respectively,and then the electromagnetic shielding performance of the nano-copper composite biomass flexible conductive film was studied.The specific research contents are as follows:?1?Preparation and application of Cu@C core-shell nanocubes in enzyme-free glucose sensing.Unique and well-aligned Cu@C core-shell nanocubes were rationally designed for nonenzymatic glucose detection using cubic Cu₂O nanoparticles immersed in water-soluble polyvinyl pyrrolidone?PVP?coatings as the precursor.The optimum Cu@C nanocubes with a shell thickness of?6.48 nm were prepared by the initial coating of Cu₂O nanoparticles with 1.5 mg/m L PVP and subsequent annealing at 600°C.After the thermal annealing process,Cu₂O nanoparticles were reduced to Cu nanocubes;at the same time,PVP was pyrolyzed to carbon shell encapsulating the cubic Cu core.Due to efficient protection of the carbon shell of Cu core from oxidization and the advantageous inter-connected core-shell conductive networks,the hierarchical Cu@C core-shell nanocubes exhibit excellent electrocatalytic activity towards glucose oxidation.Under optimum condition,the resulted 600°C annealed 1.5 mg/m L-Cu@C/Nafion modified glassy carbon electrode displayed high efficient nonenzymatic glucose detection,offering a wide linear range of 40?M?40 m M,with low detection limit at 21.35?M?S/N=3?and high sensitivity peak of 2565?A/?m M·cm²?.More importantly,the well-designed Cu@C core-shell nanocubes could be utilized as a promising nonenzymatic sensor in practical biological applications for the detection of glucose concentration in human serum samples.?2?Preparation of Cu@C/MWCNTs composite films and study on their electromagnetic shielding properties.A series of composite films of Cu@C core-shell nanocubes and MWCNTs with different thicknesses of carbon shells were prepared by vacuum-assisted pressure filtration.Its thickness is between 52.2?77.06?M.1.5mg/m L-Cu@C/MWCNTs composite film?52.2?m?shows the best conductivity and the highest specific electromagnetic shielding value of 510.73 d B/mm,which is higher than pure MWCNTs film?439.50 d B/mm?.Besides,1.5mg/m L-Cu@C/MWCNTs composite films were further studied to explore the influence of different quality MWCNTs on the properties of composite films.When the mass ratio of 1.5 mg/m L-Cu@C/MWCNTs is 5:5,this composite film has the highest electromagnetic shielding efficiency,good mechanical properties,and good reproducibility.It is proved that MWCNTs with good mechanical properties can enhance the mechanical properties,electromagnetic shielding properties and electrical conductivity of Cu-based nanomaterials.?3?Preparation of Cu-PDA-CMF conductive films and study on their electromagnetic shielding properties.Through electrodeposition of nano copper uniformly wrapped in cellulose microfibrils?CMF?,the cellulose copper composite film was prepared by vacuum-assisted filtration,and further mechanical pressing treatment was used to make the connection between the conductive fibers closer and improve the electrical conductivity and electromagnetic shielding efficiency of the flexible cellulose copper composite film.The conductivity of 5 mg-Cu-PDA-CMF flexible composite film prepared by mechanical pressing is 1015 S/cm,and the electromagnetic shielding effectiveness?EMI-SE?value is 86.42 d B.Due to its special network structure,cellulose copper conductive film enhances the reflection ability and absorption efficiency of the electromagnetic wave in its interior.