Preparation, Characterization, Electrocatalytic And Magnetic Properties Of CoNi Alloy Nanocomposite Based On Carbon Nanotubes

Due to the special structure,the extraordinary mechanical and unique electronic properties and the potential applications,carbon nanotubes have attracted considerable attention since they were discovered.To generate new functionalities,it is necessary to attach other nanostructure to the surface of carbon nanotubes.The combination of carbon nanotubes and nanocrystals are useful in field emission displays, nanoelectronic devices,novel catalysts and polymer or ceramic reinforcement,which have become the resesarch field of physics, chemistry,material science and other sciences.In this paper,CoNi alloy nanoparticles were coated on carbon nanotubes via wet chemical method. One-dimensional CoNi alloy nanocomposites based on carbon nanotubes with adjustable composition were prepared,which were characterized by FT-IR,XRD,TEM,HRTEM,SAED and EDX.The electrochemical and magnetic properties of the samples were studied by cyclic voltammetry and a vibrating sample magnetometer(VSM),respectively.The full text reads as follows.1.Co,Ni and CoNi alloy nanoparticles coated on carbon nanotubes were prepared using wet chemical method by adjusting nitrate composition in mixed solution,which were characterized by XRD,TEM, HRTEM,SAED and EDX.The results indicated that the Co,Ni and CoNi alloy nanoparticles with face centered cubic(fcc)structure and dispersed highly coated on carbon nanotubes surface.The formation mechanism of the CoNi alloy nanoparticles was yet discussed in the paper.2.The surface tension of nitrate(Co(NO₃)₂ and Ni(NO₃)₂)solution with different concentration,was measured at different temperature, which provided experimental evidence for filling carbon nanotubes.It was found that the surface tension of mixed nitrate solution decreases with increasing temperature,decreasing concentration and increasing Ni(NO₃)₂ concentration.3.The electrochemical behavior of the Ni and CoNi nanocomposites modifided glassy carbon electrode(GCE)was studied by cyclic voltammetry.The cyclic voltammetry showed the electron transfer of Ni-CNTs/GCE mainly is a diffusion-controlled quasi-reversible process and the electron transfer of CoNi-CNTs/GCE is mainly a surface-controlled quasi-reversible process; The Ni-CNTs/GCE possesses highly electrocatalytic activity towards methanol and glucose oxidation in alkaline solution.The CoNi-CNTs/GCE possesses higher activity towards glucose than Co-CNTs/GCE and Ni-CNTs/GCE,it is due to the synergistic action of Co^â…£,Ni^â…¢and CNTs in alkaline solution4.Magnetic properties of Co_1-xNi_x(x=0.2,0.5,0.6,0.8) nanocomposites based on carbon nanotubes were studied.It was found that the CoNi alloy with different composition based on carbon nanotubes show typical soft magnetic properties.The coercivity of Co_1-xNi_x alloy nanoparticles decreased with increasing nickel content.Alloy composition also has great influence on the saturation magnetization and squareness ratio(Mr/Ms)of the samples.