6047-25-2Relevant articles and documents
Concerning the cation distribution in MnFe2O4 synthesized through the thermal decomposition of oxalates
Gabal,Ata-Allah
, p. 995 - 1003 (2004)
A single phase manganese ferrite powder have been synthesized through the thermal decomposition reaction of MnC2O4·2H 2O-FeC2O4·2H2O (1:2 mole ratio) mixture in air. DTA-TG, XRD, Mo?ssbauer spectroscopy, FT-IR and SEM techniques were used to investigate the effect of calcination temperature on the mixture. Firing of the mixture in the range 300-500 °C produce ultra-fine particles of α-Fe2O3 having paramagnetic properties. XRD, Mo?ssbauer spectroscopy as well as SEM experiments showed the progressive increase in the particle size of α-Fe2O 3 up to 500 °C. DTA study reveals an exothermic phase transition at 550 °C attributed to the formation of a Fe2O 3-Mn2O3 solid solution which persists to appear up to 1000 °C. At 1100 °C, the single phase MnFe 2O4 with a cubic structure predominated. The Mo?ssbauer effect spectrum of the produced ferrite exhibits normal Zeeman split sextets due to Fe3+ions at tetrahedral (A) and octahedral (B) sites. The obtained cation distribution from Mo?ssbauer spectroscopy is (Fe0.92Mn0.08)[Fe1.08Mn0.92]O 4.
Cation-substituted LiFePO4 prepared from the FeSO4·7H2O waste slag as a potential Li battery cathode material
Wu, Ling,Wang, Zhixing,Li, Xinhai,Guo, Huajun,Li, Lingjun,Wang, Xiaojuan,Zheng, Junchao
, p. 278 - 284 (2010)
The purpose of this study is to utilize the huge FeSO4·7H2O waste slag produced by the titanium dioxide industry. FeC2O4·2H2O precursors are synthesized at various pH values by using the waste slag and H2C2O4·2H2O as raw materials, and without any purifying process. ICP analysis confirms that the impurity content of FeC2O4·2H2O increases with the pH value. Crystalline cation-substituted LiFePO4 are prepared from the FeC2O4·2H2O precursors. The cation dopants do not obviously change the structure of LiFePO4, and all the samples are single olivine-type phase and well crystallized. The lattice parameters of LiFePO4 decrease with the increased dopants contents. The dopants limit the size of LiFePO4 nanocrystals, LiFePO4 particles agglomeration and, consequently, improve the electrochemical performance of LiFePO4. The cation-substituted LiFePO4 prepared from the waste slag show much better electrochemical properties than the pure LiFePO4 at high current rates. The optimal pH value for synthesizing FeC2O4·2H2O from the waste slag is about 1.0, with 96.6% iron recovery. The cation-substituted LiFePO4 prepared from this precursor exhibits the best electrochemical properties, which delivers a capacity of 152, 142 and 126 mAh g-1 at 1C, 2C and 5C rate, respectively, and shows excellent cycling performance.
The low temperature synthesis of metal oxides by novel hydrazine method
Rane,Uskaikar,Pednekar,Mhalsikar
, p. 627 - 638 (2007)
The hydroxide, oxalate and citrate precursors of the metal oxides such as γ-Fe2O3, (MnZn)Fe2O4, Cu(K)Fe2O4, BaTiO3, La(Sr)MnO3, La(Sr)AlO3, La/Gd(Ca/Ba/Sr)C
Large-scale fabrication of porous carbon-decorated iron oxide microcuboids from Fe-MOF as high-performance anode materials for lithium-ion batteries
Li, Minchan,Wang, Wenxi,Yang, Mingyang,Lv, Fucong,Cao, Lujie,Tang, Yougen,Sun, Rong,Lu, Zhouguang
, p. 7356 - 7362 (2015)
A facile, cost-effective and environmentally friendly route has been developed to synthesise porous carbon-decorated iron oxides on a large scale via annealing iron metal-organic framework (MOF) precursors. The as-prepared C-Fe3O4 particles exhibit microcuboid-like morphologies that are actually composed of ultrafine nanoparticles and show a greatly enhanced lithium storage performance with high specific capacity, excellent cycling stability and good rate capability. The C-Fe3O4 electrodes demonstrate a high reversible capacity of 975 mA h g-1 after 50 cycles at a current density of 100 mA g-1 and a remarkable rate performance, with capacities of 1124, 1042, 886 and 695 mA h g-1 at current densities of 100, 200, 500 and 1000 mA g-1, respectively. The satisfactory electrochemical performance was attributed to the hierarchical architecture, which benefitted from the synergistic effects of the high conductivity of the carbon matrix, the cuboid-like secondary particles on the microscale, and the ultrafine primary nanoparticles on the nanoscale. This low-cost and simple method provides the possibility to prepare anode materials on a large scale and hence may have great potential applications in energy storage and conversion. This journal is
Local magnetic moments in the (Fe1-xNix)4N (0 ≤ x ≤ 0.6) compounds
Yang, Jinbo,Xue, Desheng,Li, Fashen
, p. 2781 - 2785 (1997)
Moessbauer and magnetic measurements have been performed on the single-phase γ′-Fe4N and (Fe1-xNix)4N compounds. The local magnetic moments of iron and nickel atoms are evaluated by combining hyperfine fields an
Intrinsic and extrinsic proton conductivity in metal-organic frameworks
Tominaka,Cheetham
, p. 54382 - 54387 (2014)
Metal-organic frameworks (MOFs), a new class of solid-state materials, have recently been investigated as proton conductors, but little is known about their mechanisms. Since most of the conductivities reported so far were measured using powder samples, there is uncertainty as to whether they exhibit intrinsic proton transport through frameworks and/or micropores, or extrinsic transport through interparticle phases. Herein, we re-visit ferrous oxalate dihydrate [Fe(ox)(H2O)2] (ox = oxalate anion), which is a dense MOF and recognized as a model system for MOF-based proton conductors. By single-crystal measurements using microelectrodes, we show that protons do not transport through the crystals (-9 S cm-1), but that the conductivity observed in powder samples originates from interparticle phases. This result raises a question as to how general is this phenomenon? We have comprehensively surveyed the literature on solid-state proton conductors and found that large numbers of MOFs, including [Fe(ox)(H2O)2], have a similar activation energy to those of gels and interparticle conductors in classical solid-state materials. This indicates a considerable contribution from interparticle phases towards proton conductivity in MOFs, and single crystal analysis or special methods for powder analysis are clearly necessary to confirm intrinsic conductivity. This journal is
Peculiarities of polythermic decomposition of iron, cobalt and nickel oxalates within pores of photonic crystals based on SiO2 in atmosphere with oxygen lack
Zakharov,Mayorova,Perov
, p. 747 - 750 (2008)
Iron(II), cobalt(II) and nickel(II) oxalates were synthesized as nanofractals inside the voids of the photonic crystals based on SiO2. Guest substances undergone polythermic decomposition within the pores of the photonic crystals in helium atmo
Soft magnetic Fe5C2-Fe3C@C as an electrocatalyst for the hydrogen evolution reaction
Ye, Zhantong,Qie, Yaqin,Fan, Zhipeng,Liu, Yixuan,Shi, Zhan,Yang, Hua
, p. 4636 - 4642 (2019)
Herein, cubic iron carbides encapsulated in an N-doped carbon shell (ICs@NC) were prepared by a simple two-step method. The two-step method included the preparation of iron oxalate dihydrate and the process of calcination with ethylenediamine. By changing the calcination temperature, we could control the type of iron carbide formed. Moreover, the prepared iron carbide@N-doped carbon core-shell particles exhibited regular cubic shapes and soft magnetic properties with high saturation magnetization. More importantly, we investigated the electrocatalytic activity of the iron carbide@N-doped carbon catalysts for the hydrogen evolution reaction (HER). The results show that the Fe5C2-Fe3C@NC catalyst has efficient HER catalytic activity with an overpotential of 209 mV@10 mA cm?2.
Method for synthesizing high-purity ferrous oxalate
-
Paragraph 0037-0038, (2019/11/04)
The invention discloses a method for synthesizing high-purity ferrous oxalate. The method comprises the following steps: (1) fully dissolving a ferrous salt in reverse osmosis water, and carrying outfiltering; (2) preparing an oxalyl dihydrazide solution and carrying out filtering; and 3) mixing the ferrous salt solution with the oxalyl dihydrazine solution, then carrying out a reaction, and subjecting the obtained precipitate to filtering, washing, filtering and drying successively so as to obtain high-purity ferrous oxalate dihydrate. The method of the invention has the beneficial effects that oxalyl dihydrazide is used as a reaction raw material, and can be used both as a reactant and a reducing agent after decomposition so as to achieve the purpose of impurity removal, and impurity removal of oxalyl dihydrazide itself is simple, so the purity of the product is improved; the purity of the synthesized ferrous oxalate dihydrate can reach 99.99%, so the added value of the product is high, and the needs of synthesizing lithium iron phosphate can be met; and the method is simple in synthesis process, mild in reaction conditions, friendly to environment and energy-saving, can realizeindustrial production, and has great application value.