Preparation And Electrochemical Properties Of Modified Electrode Materials For Composite Copper Oxides

In recent years,life science detection and social energy crisis are several major problems that need to be solved urgently in the world.Aimed at the problem,a large number of researchers have begun to conduct extensive research on electrode materials for electrochemical sensors and supercapacitors.Copper oxide（Cu O）,as the most common oxide material,is often used as a catalyst and electrode active material for various chemical reactions because of its cheap price,low toxicity,and strong catalytic performance.And nano-silver（Ag）has electrophilicity and nucleo-philicity,and is the best and cheapest noble metal with conductivity.As a carrier of other nanoparticles,graphene materials can not only effectively increase the specific surface area of the entire electrode active material,but also solve the problem that bare nanoparticles are easy to agglomerate.Based on the advantages of the above materials,nanocomposites with specific structures were synthesized and used as modified materials for electrochemical sensors and supercapacitor electrodes.The specific research work is as follows:1.Honeycomb Ag@CuO nanocomposite was prepared by electrospinning and calcination processes.Electron microscopy showed that Ag nanoparticles were evenly loaded on the surface of Cu O particles,and the two were closely attached to form a unique honeycomb structure.The prepared composite material was used to modify the carbon paste electrode,and a H₂O₂ sensor with high sensitivity and low detection limit was constructed.Based on electrochemical detection and calibration curve calculation,the sensitivity is as high as 1982.14μA.m M^-1.cm^-2,the detection limit is0.01μmol.L^-1,and the linear response range can be divided into two sections of0.05～100μmol.L^-1and 100～1500μmol.L^-1,which can be directly used for the determina-tion of actual samples.2.A novel CuO@rGO nanocomposite was prepared by in situ-hydrothermal synthesis method by adjusting the amount of copper acetate and external environmental conditions.According to electron microscope image analysis,Cu O nanocrystals interpenetrate to form a hollow petal-like structure,which are arranged inside and outside the graphene.Based on the special arrangement and superposition of the material itself and the large specific surface area,loading and high conductivity of graphene,the contact area and diffusion distance with the electrolyte are improved.Electrochemical tests show that the Cu O@r GO modified electrode exhibits excellent rate characteristics and cycle charge-discharge stability,and has a specific capacity value as high as 1392F.g^-1at the optimal current density of 2.5m A.cm^-2.And the charge-discharge cycle can still maintain more than 88.76%of the highest capacity after 3000 cycles.3.The Ag@CuO@rGO nanocomposites were prepared by in situ-hydrothermal synthesis method and high-temperature calcination process,using Ag NO₃,Cu（NO₃）₂and Na OH as raw materials,and CTAB as template.Several different mixed structures were observed by electron microscopy.The best choice is Cu O-wrapped Ag nanoparticles to form a core-shell structure,and the crystal particles are arranged in a similar way to form a rock sugar block structure,which is tightly wrapped by r GO.The test shows that it has a specific capacitance of up to 1453F.g^-1 at a current density of 2.5m A.cm^-2;the capacitance has good stability at high sweep speed:74.9%;retention of specific capacitance:75.7%;the high-current charge and discharge cycle remained at 87.36%after 3000 cycles.By improving the microstructure and introducing Ag,the specific capacitance was further increased and the operating current range was extended.