| Nano-sized iron oxide is a functional material with various excellent performances and widespread applications. With the increasing development of science and technology for nanoparticles, a lot of methods for preparation this particles having been come forth, electrochemical method is an advanced way to prepare for metal oxide particles. In this paper, the iron oxide nanoparticles prepared by using an iron plate as sacrificing anode and a sheet of stainless steel as cathode in non-aqueous medium with electrolytic cell without separating membranes are studied, which is composed of three sections as followed:1. Systematic studying on the reaction technologies for preparing the nanoparticles of iron oxide. Through the research on electrochemical performance of metallic iron electrode in DMF solution firstly, it indicates that iron plate can be dissolved when the potential is higher than a certain value, say the suitable electrolysis should be carried out. Secondly, the optimum reaction condition is set up by comparison the experiments by changing the affecting factors, as the results show that under condition of 0.08mol/L Bu4NBr, 2% H2O based on DMF solution, 5mm distance between two electrodes, the reaction process is best. Lastly, the electrolysis techniques are optimized by orthogonal test, it shows that the current efficiency is reached up 90% more, when the current density is 12mA/cm2, the concentration of electrolyte is 0.08mol/L and the distance between two electrodes is 5 mm.2. Characterizing the structure of the products-iron oxide nanoparticle. The gel obtained from electrolysis is treated by concentrating, washing and drying, then calcing to get the nano-sized particles. Through analysis the results of their FT-IR, TG-DSC, XRD, TEM and Particle Size Distribution it is found that the amorphous FeOOH is prepared by drying at 40℃in vacuum, in turn converted toγ-Fe2O3 with average size 22.0nm andα-Fe2O3, 35.2nm through calcining at 320℃C, 540℃respectively. Furthermore, its magnetic properties are tested by VSM and good soft magnetism is displayed with the less coercive force compared with that of normal particle.3. Researching and Exploring the dynamics and mechanism for preparation of nano-sized iron oxide by electrochemical method. From the experimental results of Fe electropolar reaction, the rate is fairly slow and its constant (K0) is ranged from 9.74×10-9～2.05×10-8, the transfer coefficient (β) is also small. Their Tafel formular can be expressed as follow at optimum condition:η=4.60+1.352. lgi. Upon the basis, the dynamics model is set up, the kinetic experimental results are quite consistent with mathematical deduction, and the reaction ratio (v) is merely related with time (t) showing the feature of a zero-order reaction. Its dynamical equation is described as following: [Fe2+]=k't. In addition, the relevant reaction mechanism is explored on the basis above and corresponding conclusion is put forward below:Anodic reaction:Fe(?)Fe2++2eCathodic reaction:Fe2++2e(?)[Fe]*In solution:[Fe]*+[S](?)[Fe]*/[S] (Absorption)[Fe]*/[S]+O2(or Air)(?)Fe2O3/[S] (Oxidation)As H2O present:[Fe]*+H2O+O2(?)FeOOH+H2 (Hydro-Oxidation)Overall Chemical formulation:4Fe+6H2O+O2→4FeO(OH)+4H2... |
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