Preparation Of N-Doped Fe@C And Fe@Si@C Nanocomposites And Investigation Of Their Performance

In this thesis,the anodes were prepared by the compacting method with the mixture of Fe₂O₃ and graphite powders,or Fe₂O₃,SiO₂ and graphite powders at a certain mass ratio as the raw materials,respectively.The N-doped Fe@C nanocomposites and N-doped Fe@Si@C nanocomposites were prepared by DC arc discharge,respectively.The products were characterized by TEM,HRTEM,EDX,SEM,EELS,XRD,TG-DSC and Raman.The effects of the diameter of anode and the ratios of raw materials on the morphology,structure and yield of the N-doped composite shell encapsulated iron nanoparticles?N-CEINPs?and iron@graphene nanocomposites?N-Fe@GNCs?were investigated and the corresponding magnetic,optical properties,adsorption performance and photocatalytic activity were investigated,respectively.The effects of the diameter of anode,the ratios of raw materials and the discharge voltage on the preparation of N-doped Fe@Si@C nanocomposites were also investigated and the magnetic,optical properties were investigated.The formation mechanism of the products were discussed and a simple model was proposed.The anodes were prepared with the mixture of graphite and Fe₂O₃?the quality ratio of 1:9?as raw materials.The product B₃,prepared by DC arc discharge using the anode with a diameter of 6.6 mm,mainly consists of N-CSEINPs.The average diameter of the N-CSEINPs is about 20.8 nm;the core mainly consists of iron and iron carbide;the shell is composite one,which contains C,Fe,O and N elements.The iron content of product B₃ is 86.4 wt.%and it shows typically ferromagnetic behavior at room temperature.The N-CSEINPs were employed to remove MB from its aqueous solution and exhibited high adsorption abilities and photocatalytic activity.The product C_IC-3 mainly consists of N-Fe@GNCs.The iron content of product C_IC-3 is 79.8 wt.%and it shows nearly superparamagnetic behavior at room temperature.The suspension of N-Fe@GNCs in ethanol emits green luminescence under the irradiation of UV light.The anode?diameter of 6.6 mm?was prepared with a mixture of graphite and Fe₂O₃?the quality ratio of 1:5?as raw materials.The product B₄ contains both CSEINPs and CEINPs.The iron content of product B₄ is 58.4 wt.%and it shows ferromagnetic behavior at room temperature.And the product C_IC-4 also mainly consists of N-Fe@GNCs and shows nearly superparamagnetic behavior at room temperature.The anode?diameter of 6.6 mm?was prepared with a mixture of graphite,Fe₂O₃and SiO₂?the quality ratio of 1:5:4?as raw materials.The product B₇,prepared by DC arc discharge under the discharge voltage of 80 V,mainly contains both N-doped core-shell nanowires and nanoparticles.The diameter and shell thickness of nanowires are 6-18 and 2-6 nm,respectively.The particle size and shell thickness of nanoparticles are 7-25 and 3-5 nm,respectively.The phase composition of product B₇mainly includes graphite carbon,FeSi,SiC.The product B₇ shows typical ferromagnetic behavior at room temperature.And the product C_IC-7 mainly consists of N-Fe@Si@GNCs and is very close to superparamagnetism at room temperature.The suspension of N-Fe@Si@GNCs in ethanol emits yellow green luminescence under the irradiation of UV light.The results of this thesis have importantly practical significance and some theoretical significance on the development of the arc discharge chemistry and the design,preparation and basic research of application of the novel inorganic?composite?nanomaterials.