Research On Preparation And Properties Of Carbon-Encapsulated Metal/Metal Oxide Nanocomposites

As a new functional composite with core-shell structure,carbon-coated metal/metal oxide composite nanoparticles,because of its different combination of core and shell layer carbon,make composite materials show a lot of unique physical and chemical properties,its application prospects in biomedical,chemical,new energy and other fields.As a new type of functional materials,its preparation methods,performance and application have been widely concerned.The carbon-coated nanocomposites of metals and their oxide particles can be prepared in different ways.In this paper,carbon-encapsulated copper nanoparticles?Cu@C?,carbon-Nickel nanoparticles?NiO@C?and carbon coated iron oxide nanoparticles?Fe₃O₄@C?were prepared by DC arc plasma method and hydrothermal method,respectively.The microstructure,morphology and some physical and chemical properties of the nanoparticles were characterized by X-ray diffraction?XRD?,Raman spectroscopy?Raman?,transmission electron microscopy?TEM?and vibrating sample magnetometer?VSM?System characterization analysis.First of all,carbon-encapsulated copper nanoparticles?Cu@C?were prepared by DC arc plasma technique under the protection of inert atmosphere?Ar?,with the mixture of carbon powder and copper powder as the starting material.The results show that: the Cu@C nanoparticles are spherical or ellipsoidal and have good dispersibility.The composite nanoparticles exhibited some ferromagnetism at room temperature.The specific surface area and pore structure of the samples were studied.It was found that the isothermal adsorption curves of the nanoparticles were of the type ? due to capillary condensation.The pores between the grains were mainly mesoporous.Secondly,the core of Ni O@C nanoparticles were successfully prepared by DC arc plasma device,the carbon powder and nickel powder as the starting materials.The results show that the NiO@C nanoparticles are irregular spherical or ellipsoidal,and they are constructed into a core-shell structure.The core is cubic NiO?FCC-NiO?nanoparticles.Particle size is mainly distributed in the range of 20¹00nm.Raman spectra show a low degree of graphitization and a redshift phenomenon.The sample exhibits a certain ferromagnetism at room temperature The cyclic voltammetry curves show that the redox peaks have a good response to the current in the process of testing the samples with the CS350 electrochemical workstation.At the same time,the composites have good capacity characteristics and good electrochemical activity.In the application of supercapacitor,this sample has a good application prospect as an electrode material.At last,based on the reduction and carbonization of C6H12O6,the core of Fe₃O₄@C composite nanometer material containing core-shell structure was synthesized by hydrothermal method,using Fe3+ as the iron source.,and the reaction conditions were prepared by changing the reaction conditions.Fe₃O₄@C composite nanoparticles with smaller particle size and Fe₃O₄@C nanocomposites with good dispersion.In this process,the nanoparticles are not only affected by the C6H12O6 content,but also the alkali source has a significant effect on the product.In addition,the interfacial tension between the particles and the surrounding solution is gradually reduced while the C6H12O6 molecules play their own reducing ability and carbonization;C6H12O6 molecules can reduce the size of nanoparticles and increase the nucleation rate of Fe₃O₄ nanoparticles.