FeCO₃ Microparticle Synthesis by Fe-EDTA Hydrothermal Decomposition

Abstract

We developed a new procedure for synthesizing highly crystalline FeCO 3 by hydrothermal decomposition of the Fe(III)-EDTA complex in the presence of urea, starting from ferric ammonium sulfate and Na 4 EDTA as the main precursors. Single phase FeCO 3 microcrystals with a size in the range of 50−200 μm have been obtained after high pressure−temperature treatment time between 15 and 26 h at 230 and 250 °C. Without changing the concentrations of the precursors and synthesis temperature, we have investigated the kinetics of phase transitions between 2 and 40 h of high pressure−temperature treatment time. A transition from hematite (in the first 4 h) to magnetite microoctahedrons with superparamagnetic behavior at room temperature, via a single phase of iron carbonate microcrystals, has been recorded.

Rapid synthesis of Ag2Se dendrites with enhanced electrical performance by microwave-assisted solution method

“…As a commonly used complexing agent, EDTA can complex with many metal ions and decrease the concentration of free ions in the solution, then reduce the formation and growth speed of crystal nuclei, realizing regulation of the morphology of crystals. [25][26][27] In this study, to demonstrate the role of EDTA and the formation mechanism of the Ag 2 Se dendrites and nanoparticles, a series of comparative experiments were carried out. First, a controlled experiment was conducted in the absence of AgNO 3 .…”

Elucidating some issues regarding the synthesis of superparamagnetic-like single crystalline micrometric Fe3O4 during the hydrothermal process

“…The spectrometer (Wissel) was calibrated by means of a standard α-Fe foil and the isomer shift was expressed with respect to this standard at 293 K. The fitting of the spectra was performed with the help of the NORMOS program. An induction-type AC hysteresigraph [8] was used for magnetic characterization.…”

Recent Progress and Challenges of Micro‐/Nanostructured Transition Metal Carbonate Anodes for Lithium Ion Batteries

“…The low cost, high abundance and environmental benignity, as well as high electrochemical performance, endow FeCO 3 very promising candidate for high energy density and low cost LIBs. In very recent years, FeCO 3 has also been exploited as anode for LIBs , …”

“…The electrochemical catalytic activity of newly formed Fe nanoparticles was also observed in Fe 3 O 4 @C and Fe@Fe 3 C/C nanocomposites as anode materials in battery operation. To design FeCO 3 with complex hierarchical structures is a meaningful way for conquering the shortcoming such as poor capacity retention and volume expansion during charge/discharge. Rhombohedral FeCO 3 crystallites were synthesized and its lithium storage performances displayed that an initial specific discharge capacity of 1587 mAh g –1 was obtained at 200 mA g –1 , remaining a reversible value of 1018 mAh g –1 over 120 cycles.…”