Synthesis And Application Of Ferrate

Ferrate(â…¥) compounds are composed of metal ions and FeO₄2-, mainly Na₂FeO₄, Li₂FeO₄, K_<sub>2FeO₄, Cs₂FeO₄, BaFeO₄, CaFeO₄, ZnFeO₄ and so on. In nature, iron typically occurs in valence states of Fe(0),Fe(â…¡),Fe(â…¢).But in potassium ferrate, the state is Fe(â…¥). Fe(â…¥) has high oxidation-reduction potential, large electrochemical capacity, the product itself and the discharge have no pollution to the environment so it can be used in water treatment and organic synthesis, and cathodic materials in"super-iron"batteries. This paper mainly talk about the preparation, preservation and the application of K_<sub>2FeO₄,BaFeO₄.In this paper, the solution is 12mol/L NaOH, established the Electrolytic Preparation of potassium ferrate and the use of spectrophotometric methods for the analysis. Study at current density,electrolytic time,electrolytic area,The influences of different additives, additive concentration and additive mixed proportion. In this paper the cyclic voltammograms (CVs) of iron electrode revealed a broad anodic wave between-1.40 and 0.70V versus HgO/Hg corresponding to iron dissolution and passivation of the electrode. Study at the stability of Fe(â…¥) in different kinds,concentration of alkali solution, and the additives, effects on the stability of Fe(â…¥).The preparation of BaFeO₄ is the same to K_<sub>2FeO₄, the different thing is the solution is composed of 12mol/L NaOH and Ba(OH)2, and the analysis method is dichromate titration , use high-speed centrifugal method of preparation of high-purity material, the purity is 95 percent. The crystalline structure of the samples particles are investigated by X-ray diffraction (XRD) and Infrared absorption spectroscopy (IR). Use BaFeO₄ for battery material, with the lithium electrode in to a battery, detecting its discharge performance.The study showed that the best condition to prepare for K_<sub>2FeO₄ is at room temperature,current density is 50mA/cm2,30min. The optimum mixed proportion was 1:1:1 the maximum current efficiency, obtained after 0.5h of electrolysis, was a value of 61.96%. In 2.5mol/L sodium hydroxide, when joined three stabilizer at the same time, the stability of Fe(â…¥) can exist in a long time. The CV is strikingly different in that anodic wave with previous papers, where was emerging the peak which was related to the inter-mediator of electro-oxidation of Fe(III) species in concentration basic aqueous solution. It should be FeO₄3-(Fe(V) species). Use the high-purity barium ferrate materials for batteries, and lithium battery electrode component for testing. The experiments showed that BaFeO₄ has 184.0mAh / g of the initial discharge capacity in the 0.3mA/cm2 charge-discharge current density at the low-voltage 2.5-0.5V. In the 4.2V-2.5V high voltage charge and discharge, the discharge capacity is only 24.02mAh / g, high-iron barium cathode material is not suitable.The crystalline structure of the samples particles are investigated by X-ray diffraction (XRD) and Infrared absorption spectroscopy (IR). The results prove that we have obtained samples for K₂FeO₄ and BaFeO₄.