Effects of reduction conditions on the cycling performance of hydrogen storage by iron oxides: Storage stage

In the present work, reduction of iron oxides as a hydrogen storage material by the reaction of Fe₃O₄+4H₂→3Fe+4H₂O was conducted at 673 K under different hydrogen partial pressures. A shrinking-core model with reaction control was well fitted to the experimental data obtained by thermogravimetric analysis. Since the oxidation state of iron showed a very steep reaction front along the length of the tube reactor during the reduction, metallic iron was exposed to hydrogen until all the iron oxides in the reactor were sufficiently reduced. A simulated moving bed-type reactor was proposed to solve this problem, and the calculation was made using the reaction model based on the assumption of irreversible reaction, isothermality, and plug flow. The calculation results indicate that the simulated moving bed-type reactor can achieve high hydrogen storage efficiency without over-exposure of metallic iron to hydrogen.     

In situ Raman and other studies of electrochemically oxidized iron and iron-9% chromium alloy

It has been intensively attempted to record the in situ Raman spectrum of the passive layer of iron and Fe-Cr 9% alloy without result. Raman active bands of thin films of oxides and hydroxides on the passivated alloy could be observed after the electrodeposition of Ag on the prepassivated electrode. Thicker corrosion products on iron in HNO₃ are observed to be formed by a mechanism of reductive precipitation at −0.8 V vs sce. On a stationary electrode Fe₃O₄ is originally formed whereas with electrode rotation at 1400 rpm an amorphous precipitate of Fe(OH)₂ results. Upon oxidation of these products higher defect oxides/hydroxides result, which are characterized by a broadening of the Raman peak at 680 cm⁻¹ due to Fe₃O₄ towards higher wavenumbers. Electrochemically controlled formation of α-Fe₂O₃ is not observed in agreement with previous in situ investigations.     

Effect of Li ions on reduction of Fe oxides in aqueous alkaline medium

It has long been known that the performance of the Fe negative electrode in Fe/Ni or Fe/air batteries is improved by the presence of lithium ions in the electrolyte. This work therefore investigated quantitatively the effect of Li⁺ on the reduction of some Fe^II and Fe^III oxides, as possible intermediates of Fe reduction/oxidation cycles, by comparing the extent of the reduction in pure 6.0 M KOH with that in lithiated alkaline media. Fe oxides were studied as pressed powder samples embedded in Ni foam. It was found that, in 6.0 M KOH, only FeO is electrolytically reduced at room temperature, whereas Fe₂O₃ and, to an even greater extent Fe₃O₄, are very recalcitrant to the reduction process. The situation dramatically changes in, for instance, 4.0 M KOH + 2.0 LiOH electrolyte, in which the extent of the reduction, even at room temperature, becomes significant for all compounds. This behaviour is very probably due to the reduction of Li⁺ within the oxide lattice to produce Li_xFe_yO_z intercalation-compound intermediates, which are then reduced to metallic Fe and Li hydroxide.     

Development of iron oxide sorbents for Hg removal from coal derived fuel gas: Sulfidation characteristics of iron oxide sorbents and activity for COS formation during Hg removal

The aim of this study is to develop a process for the removal of Hg⁰ using H₂S over iron oxides sorbents, which will be located just before the wet desulfurization unit and catalytic COS converter of a coal gasification system. It is necessary to understand the reactions between the iron oxide sorbent and other components of the fuel gas such as H₂S, CO, H₂, H₂O, etc. In this study, the sulfidation behavior and activity for COS formation during Hg⁰ removal from coal derived fuel gas over iron oxides prepared by precipitation and supported iron oxide (1 wt% Fe₂O₃/TiO₂) prepared by conventional impregnation were investigated. The iron oxide samples were dried at 110 °C (designated as Fe₂O₃-110) and calcined at 300 and 550 °C (Fe₂O₃-300 and Fe₂O₃-550). The sulfidation behavior of iron oxide sorbents in coal derived fuel gas was investigated by thermo-gravimetric analysis (TGA). COS formation during Hg⁰ removal over iron oxide sorbents was also investigated using a laboratory-scale fixed-bed reactor. It was seen that the Hg⁰ removal activity of the sorbents increased with the decrease of calcinations temperature of iron oxide and extent of sulfidation of the sorbents also increased with the decrease of calcination temperature. The presence of CO suppressed the weight gain of iron oxide due to sulfidation. COS was formed during the Hg⁰ removal experiments over Fe₂O₃-110. However, in the cases of calcined iron oxides (Fe₂O₃-300, Fe₂O₃-550) and 1 wt% Fe₂O₃/TiO₂, formation of COS was not observed but the Hg⁰ removal activity of 1 wt% Fe₂O₃/TiO₂ was high. Both FeS and FeS₂ were active for Hg⁰ removal in coal derived fuel gas without forming any COS.     

Direct conversion of methane to synthesis gas using lattice oxygen of CeO2–Fe2O3 complex oxides

Three kinds of complex oxides oxygen carriers (CeO₂–Fe₂O₃, CeO₂–ZrO₂ and ZrO₂–Fe₂O₃) were prepared and tested for the gas–solid reaction with methane in the absence of gaseous oxidant. These oxides were prepared by co-precipitation method and characterized by means of XRD, H₂-TPR and Raman. The XRD measurement shows that Fe₂O₃ particles well disperse on ZrO₂ surface and Ce–Zr solid solution forms in CeO₂–ZrO₂ sample. For CeO₂–Fe₂O₃ sample, only a small part of Fe³⁺ has been incorporated into the ceria lattice to form solid solutions and the rest left on the surface of the oxides. Low reduction temperature and low lattice oxygen content are observed over ZrO₂–Fe₂O₃ and CeO₂–ZrO₂ samples, respectively by H₂-TPR experiments. On the other hand, CeO₂–Fe₂O₃ shows a rather high reduction peak ascribed to the consuming of H₂ by bulk CeO₂, indicating high lattice oxygen content in CeO₂–Fe₂O₃ complex oxides. The gas–solid reaction between methane and oxygen carriers are strongly affected by the reaction temperature and higher temperature is benefit to the methane oxidation. ZrO₂–Fe₂O₃ sample shows evident methane combustion during the reducing of Fe₂O₃, and then the methane conversion is strongly enhanced by the reduced Fe species through catalytic cracking of methane. CeO₂–ZrO₂ complex oxides present a high activity for methane oxidation due to the formation of Ce–Zr solid solution, however, the low synthesis gas selectivity due to the high density of surface defects on Ce–Zr–O surface could also be observed. The highly selective synthesis gas (with H₂/CO ratio of 2) can be obtained over CeO₂–Fe₂O₃ oxygen carrier through gas–solid reaction at 800 °C. It is proposed that the dispersed Fe₂O₃ and Ce–Fe solid solution interact to contribute to the generation of synthesis gas. The reduced oxygen carrier could be re-oxidized by air and restored its initial state. The CeO₂–Fe₂O₃ complex oxides maintained very high catalytic activity and structural stability in successive redox cycles. After a long period of successive redox cycles, there could be more solid solutions in the CeO₂–Fe₂O₃ oxygen carrier, and that may be responsible for its favorable successive redox cycles performance.     

Mechanism study of iron-based catalysts in co-liquefaction of coal with waste plastics

The state and active site of iron-based catalysts in co-liquefaction of coal with low-density polyethylene (LDPE) have been discussed. The catalysts used were sulfur-promoted iron oxides (Fe₂O₃+S), ferrous sulfide (FeS), ferrous sulfate (FeSO₄·7H₂O) and the mineral pyrite (FeS₂). It was found by X-ray photoelectron spectrometry that the active site in the working state of Fe₂O₃+S catalyst was not Fe_1−XS and the main form of sulfur existing in the spent Fe₂O₃+S catalyst was sulfate, followed by sulfite (SO₃²⁻). A finding from autoclave tests was that the ferrous sulfate before and after oxidation treatments showed sufficiently high activity for the co-liquefaction of coal with LDPE. It was concluded that an active site of the iron-based catalysts was sulfate species formed on the catalyst surface during the hydroliquefaction process of coal.     

Effect of composition on rheological behavior of iron oxides produced by hydrothermal method

The aim of the present work was to investigate the rheological properties of different iron oxides (Fe₃O₄, NiFe₂O₄, ZnFe₂O₄ and Ni_0.5Zn_0.5Fe₂O₄) aqueous suspensions. The oxides were produced through mixing the respective metallic sulfates within a closed isothermal reactor at 100 °C and at pH ≈12, in an oxidant environment (provided by H₂O₂ 0.63% w/v). The reactor was coupled with an adequate real-time data (RTD) acquisition system enabling measurement of temperature, pH and pressure. Obtained RTD data showed that once the isothermal conditions are reached, the pressure slowly decreases over time, which is a result of O₂ consumption through oxidation of Fe²⁺ to Fe³⁺. To characterize the suspensions as a function of temperature and shear rate, the steady rheology was used. The results revealed that the effect of temperature on viscosity of all suspensions was insignificant while steady rheology showed pseudoplastic behavior for all ferrites. The magnitude of viscosity and pseudoplasticity turned out to be in agreement with the hydrodynamic diameters of particles complying with the order: NiFe₂O₄>Fe₃O₄>Ni_0.5Zn_0.5Fe₂O₄>ZnFe₂O₄. Finally, the rheological behavior of suspensions was attributed to the concentration of OH groups on the surface of particles and this hypothesis was effectively supported by DRX, FTIR and TGA/DTA measurements.     

In-situ grown Ag on magnetic halloysite nanotubes in scaffolds: Antibacterial,biocompatibility and mechanical properties

A novel design of antibacterial and magnetic halloysite nanotubes loaded with Ag and Fe₃O₄ was reported. In detail, magnetic nanoparticles (Fe₃O₄) were immobilized on the surface of halloysite nanotubes (HNTs) via electrostatic adsorption (termed as HNTs/Fe₃O₄). The magnetic HNTs/Fe₃O₄ was then modified by polydopamine to in-situ grow Ag nanoparticles by a redox reaction, forming a composite nanostructure of HNTs/Fe₃O₄@Ag. The HNTs/Fe₃O₄@Ag was incorporated into poly-l-lactic acid (PLLA) scaffold fabricated via selective laser sintering, with the intent to endow the scaffold with robust antibacterial function and favorable cell activity. The results showed that the released Ag⁺ from the scaffold significantly against E. coli activity, with bacterial inhibition rate above 99%. Moreover, ion release behavior showed a scaffold enable to sustain release Ag⁺ over 28 days. Furthermore, Fe₃O₄ nanoparticles constructed magnetic microenvironment greatly enhanced cell activity and promoted cell proliferation. In addition, tensile strength of the scaffold increased by 52.9% compared with PLLA scaffold. These positive results suggested that the HNTs/Fe₃O₄@Ag nanostructure possessed potential in facilitating bone repair.     

Effectiveness factor of fast (Fe3+/Fe2+), moderate (Cl2/Cl?) and slow (O2/H2O) redox couples using IrO2-based electrodes of different loading

The effectiveness factor, E _f, (fraction of the electrode surface that participates effectively in the investigated reaction) of fast (Fe³⁺/Fe²⁺), moderate (Cl₂/Cl⁻) and slow (O₂/H₂O) redox couples has been estimated using IrO₂-based electrodes with different loading. The method of choice was linear sweep voltammetry (measurement of the anodic peak current) for the Fe³⁺/Fe²⁺ redox couple and steady-state polarization (determination of the exchange current) for the O₂ and Cl₂ evolution reactions. The results have shown that the effectiveness factor depends strongly on the kinetics of the investigated redox reaction. For the Fe³⁺/Fe²⁺ redox couple, effectiveness factors close to zero (max 4%) have been obtained contrary to the O₂ evolution reaction where effectiveness factors close to 100% can be achieved, all being independent of IrO₂ loading. For the Cl₂ evolution reaction, intermediate values of the effectiveness factor have been found and they decrease strongly, from 100% down to about 60%, with increasing loading.     

Photocatalytic degradation of organics in water in the presence of iron oxides: Influence of carboxylic acids

The effects of four carboxylic acids: malic, citric, tartaric and oxalic acids on the leaching of iron from two commercial iron oxides (hematite, α-Fe₂O₃, and magnetite, Fe₃O₄) have been investigated. The variables studied were the doses of iron oxides and carboxylic acids used as well as aqueous pH, temperature and the presence of hydrogen peroxide and/or UV-A radiation. On the whole, Fe₃O₄ led to higher amounts of leached iron than α-Fe₂O₃, and oxalic acid was the most effective carboxylic acid used. The importance of iron leaching has been considered to explain the photodegradation of bisphenol A (BPA) by UV-A/iron oxides systems. The influence of the presence of hydrogen peroxide and/or titania on the efficiency of these oxidation systems was also investigated. At the conditions tested, advanced oxidation with the UV-A/iron oxide/oxalic acid/H₂O₂/TiO₂ system led to the lowest BPA half life (<15 min) among those processes studied.     

Surface immobilisation of the sandwich type Na14[Fe4(Ox)4(H2O)2(SbW9O33)2]·60H2O polyoxometalate

A functionalised Fe-substituted Keggin Na₁₄[Fe₄(C₂O₄)₄(H₂O)₂(SbW₉O₃₃)₂]·60H₂O type POM termed “Fe₄Ox₄” has been successfully immobilised onto carbon electrode surfaces through the employment of conducting polypyrrole films and the layer-by-layer (LBL) technique. For the POM doped polypyrrole films the redox systems associated with the POM's tungsten-oxo framework was not apparent upon redox cycling, however a reversible redox couple associated with the Fe^III/II redox system was clearly seen within the pH range 2–7. Organised multilayer assemblies were constructed by the employment of the layer by layer (LBL) technique through alternating anionic Fe₄Ox₄ layers and cationic Ru^II metallodendrimers with poly(diallyldimethylammonium chloride) (PDDA) employed as an initial base layer. Stable redox couples associated with both the Fe^III/II and tungsten-oxo framework, for the Fe₄Ox₄ POM, and the Ru^III/II for the metallodendrimer, were clearly observed upon layer construction and redox switching within the pH domain of 2–7. The resulting multilayer assembly showed good stability towards redox cycling. Further investigations into the multilayer assembly were undertaken by determining it is charge transfer resistance using AC-impedance voltammetry. The layer also showed catalytic ability towards the reduction of H₂O₂ at pH 6.5.     

Characterization of nickel-bearing ferrites obtained as by-products of hydrochemical wastewater purification processes

The efficiency of the ‘ferrite process’ for the purification of wastewater heavily contaminated with nickel is evaluated, and the solid residues formed are characterised. The efficiency of the purification process is always above 99.9% for Fe²⁺/Ni²⁺ ratios greater than 3. The tested Fe²⁺/Ni²⁺ molar ratios (15/1, 7/1 and 3/1) yielded three different nickel ferrites. Inductively-coupled plasma atomic emission spectroscopy (ICP-AES), potentiometric titration, X-ray fluorescence (XRF), X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) yielded Ni_xFe_1−x^IIFe₂^IIIO₄ (x=0.18, 0.40 and 0.65, respectively) as the most probable stoichiometry, and inverse spinel as the most probable structure. Heating at 600 °C causes the transformation of the solids into a mixture of NiFe₂O₄, α-Fe₂O₃ and NiO. Electrochemical analysis of the solid nickel ferrites was performed using carbon paste electrodes (CPEs) in HClO₄ and HCl media. In each case, the first cyclic voltammogram showed the participation of solid species in the electrochemical transformation process, since the shape of the redox peaks could be related to the structure and stoichiometry of the ferrites. In second and successive scans, the voltammograms indicated the redox couples Fe_ads³⁺+1e⁻⇔Fe_ads²⁺ (0.525 V vs. Ag/AgCl) and Ni_ads²⁺+2e⁻⇔Ni(s) (−0.470 V) in HClO₄, and FeCl_2,ads⁺+1e⁻⇔FeCl_ads⁺+Cl⁻ (0.475 V) and NiCl_x,ads^(x−2)−+2e⁻⇔Ni(s)+xCl⁻ (−0.550 V) in HCl.     

X-ray photoelectron spectroscopy of nitrogen oxides adsorbed on iron oxides

Adsorption of N₂O, NO, and NO₂ on Fe₂O₃ and Fe₃O₄ was studied by means of X-ray photoelectron spectroscopy (XPS) using an AEI ES 100 spectrometer at temperatures from ?100 to +250 °C. Adsorption isotherms and isobars of NO and NO₂ have been plotted for Fe₃O₄ and Fe₂O₃. Isotherms are Langmuir curves, and the adsorption isobar of nitrogen dioxide adsorbed on Fe₂O₃ shows a maximum at room temperature. No adsorption of nitrogen monoxide is detected with Fe₂O₃ (the detection limit is about 0.1 monolayer). With adsorbed nitrous oxide a simple peak is recorded in contrast to what is observed in the vapor phase. The N 1s binding energy of adsorbed NO is lower than that of the gaseous species, suggesting that significant electron transfer from the iron oxides to the adsorbed nitrogen oxide occurs; however, this back donation is not observed with adsorbed nitrogen dioxide. Adsorption does not cause changes in the binding energies of Fe₂O₃ core electrons, but shifts the Fe 3p line of Fe₃O₄ toward the higher binding energies, suggesting that Fe₃O₄ is oxidized by the adsorption of nitrogen oxides.     

New orthorhombic sodium iron(+2) titanate

The set of compositions with Fe²⁺ in the system Na_xFe_x/2Ti_2–x/2O₄ has been prepared by solid-state reactions in the inert atmosphere at 1050 °С. The oxidation state of iron was confirmed using the XANES method. Na_0.88Fe_0.44Ti_1.56O₄ is the new four-element compound in Na₂O–“FeO”–TiO₂ system. According to the X-ray powder data, it is orthorhombic, Pnma, a = 9.3624(1), b = 2.96718(4), c = 11.3435(1) Å and has the same structure as Na_0.9Fe_0.9Ti_1.1O₄ with Fe³⁺. The structure was refined by the Rietveld method. The 3D-framework of (Fe, Ti)O₆ octahedra contains quadruple rutile-like chains and sodium ions in double tunnels. Fe/Ti partial ordering in the framework and sodium distribution in the tunnels were studied additionally using the method of bond valence sums and Voronoi tessellation. The structure and composition of Na_0.88Fe_0.44Ti_1.56O₄ make it a promising material for cathode application.     

Effect of cathodic pretreatment on the passivation of iron in neutral solution

Pure iron specimens anodically oxidized at +600 mV (vs sce) for one minute were partially reduced with a cathodic current of 10 μA/cm² and then reoxidized at the same potential for one hour. The experiment was performed in a boric acid/borate buffer solution at pH = 8.43 at room temperature. Variation in the thickness of the oxide film during the experiment is discussed for an inner Fe₃O₄ and outer γ-Fe₂O₃ layers, with emphasis on the effect of cathodic treatment. In the discussion, the amounts of charges for anodic and cathodic processes and the amount of dissolved Fe²⁺ ions during the cathodic reduction are utilized.     

3D rectangular WO3 hybridized by PrFeO3 nanoparticles with efficient dual charge transfer for enhanced photo-Fenton-like activity

In this work, zero-dimensional (0D) high crystalline PrFeO₃ worm nanocrystals were loaded over a three-dimensional (3D) rectangular WO₃ to construct a 0D/3D PFO/W Z-scheme heterojunction by an in situ ultrasonic synthetic process. This heterojunction exhibited excellent photocatalytic activities towards the degradation of organic pollutants such as rhodamine B (RhB), Methylene blue (MB), and tetracycline hydrochloride (TC) in the presence of small amounts of H₂O₂ under visible-light irradiation. For example, the k value of PFO/W + H₂O₂ was about 67, 107, 45, 27, 11 and 14 times higher than pure H₂O₂, PrFeO₃, WO₃, PFO/W nanocomposite, PrFeO₃+ H₂O₂ and WO₃+H₂O₂ respectively during the degradation of MB. The trapping experiments and ESR measurements identified that the generated ·OH, ·O₂⁻, and h⁺ were the active species involved in the catalysis. Further, the ·OH radical could be continuously generated by Fe³⁺/Fe²⁺ and W⁶⁺/W⁵⁺ conversion and played the dominant role in the degradation of organic pollutants. The superior photocatalytic performance of the PFO/W + H₂O₂ system was derived from the synergistic effect of the Z-scheme heterostructure and dual photo-Fenton-like oxidation (Fe³⁺/Fe²⁺ and W⁶⁺/W⁵⁺). A possible mechanism was postulated based on the results obtained. In summary, this study provided new insights into synthesizing an effectively heterogeneous 0D/3D Z-scheme dual photo-Fenton-like catalyst for water clarification.     

Iron(II) Sulfate(VI) from Titania Production as a Raw Material for Preparation of Hydrogen Sulfide Sorbents

A hybrid sorbent material for removal of hydrogen sulfide from air was developed. The material is based on activated carbon and iron compounds obtained from waste iron(II) sulfate(VI) heptahydrate. The iron salt is deposited on the carbonaceous support and subjected to oxidation (Fe²⁺ to Fe³⁺) using atmospheric oxygen under alkaline conditions. An effect of H₂O₂ addition to the process on the composition of the resultant material was also examined. X-ray diffraction (XRD) analyses confirmed easy conversion of waste FeSO₄·7H₂O to iron oxides Fe₃O₄ and FeOOH. The activated carbon supporting iron oxides revealed a higher efficiency in H₂S elimination from air compared to the commercial activated carbon, without any modification.     

Kinetic studies on the reactions involved in the hot gas desulfurization using a regenerable iron oxide sorbent—II: Reactions of iron sulfide with oxygen and sulfur dioxide

In the hot gas desulfurization process using iron oxide sorbent, the regeneration of the sulfided iron oxide sorbent consists of two reactions: the oxidation of iron sulfide with air, and its reaction with the sulfur dioxide formed during the air oxidation. This part describes the kinetic studies on the reactions of iron sulfide (formed by the reactions of Fe₂O₃ with H₂CO mixture and subsequendy with H₂S) with oxygen and sulfur dioxide. The experimental and analysis procedures used are similar to those outlined in Part I of this paper.The activation energies for the oxygen and the sulfur dioxide reactions are found to be 15.63 and 17.5 kcal/mol, respectively. Notably, the product oxides formed in the two cases are different. With air, the reaction is fast and the final product is Fe₂O₃, whereas with SO₂, the major product is Fe₃O₄, which slowly oxidizes to Fe₂O₃ in a secondary step. Also, in the latter reaction elemental sulfur is formed.     

Das redox-standardpotential von Co3+/Co2+

The standard potenial of the process Co³⁺+e=Co²⁺ has been calculated on the basis of the calorimetric determination of the thermal effect of the reaction Fe²⁺+Co³⁺=Fe³⁺+Co²⁺. The standard potential has also been estimated by extrapolating the cathode and anode tafel curves to intersection. The data available concerning the value of E^o_{Co³⁺/Co²⁺} have been thoroughly analysed, and the average value E^o from all independent methods of estimating the standard potential an acidic medium has been shown to be + 1·45. It has been found from the data on potentials of cobalt oxides in an alkali medium that the standard potential Co³⁺/Co²⁺ must be within the range 1·40–1·53 V. This value agrees with the value 1·45 V obtained in acidic media.     

Solution combustion synthesis of nanostructured iron oxides with controllable morphology,composition and electrochemical performance

Nanostructured iron oxides have emerged as promising materials for electrochemical energy storage and conversion devices due to their high theoretical capacity, eco-friendliness and earth abundance. Particularly, the morphology- and composition-controllable synthesis of nanostructured iron oxides is extremely important to optimize their electrochemical performance. However, the development of facile and effective synthetic method is still a great challenge. In this paper, we demonstrated a one-pot solution combustion synthesis (SCS) approach for the time- and energy-effective preparation of nanostructured iron oxides with controllable morphology and composition just by tuning the molar ratio (φ) of fuel (glycine) to oxidizer (ferric nitrate). Innovatively, the effects of φ value on the control of combustion reaction mechanism, morphology and composition of SCS products, and the electrochemical properties in relation to the morphology and composition have been systematically investigated. The results revealed that with the increase of φ value, the reaction mechanism varied from pyrolysis to combustion and the combustion phenomenon changed from volumetric mode to self-propagating mode. Correspondingly, the morphology of products evolved from uniform nanoneedles to porous nanosheets, and finally into aggregated nanoparticles. Meanwhile, the phase composition of these products changed from amorphous α-Fe₂O₃ to crystalline α-Fe₂O₃, and eventually into α-Fe₂O₃/Fe₃O₄ composites. When evaluated as lithium ion battery anode, the as-prepared α-Fe₂O₃/Fe₃O₄ porous nanosheets (φ = 1.0 product) exhibited the best electrochemical properties (a high reversible capacity of ~ 1200 mA h g^?1 and an excellent rate capability) among all the SCS products, which may be attributed to its mesoporous structure (supply favorable accessibility for electrons), nanosheet morphology (shorten the transport length of Li⁺) and appropriate proportion of Fe₃O₄ phase (enhance the electronic conductivity). Consequently, the facile SCS method demonstrated here might provide a new methodology for the morphology and composition-controllable synthesis of nanomaterials, for which a number of prospective applications in electrochemical fields can be envisioned.