Clay samples containing 8.15% iron oxides and 27.49% alumina were leached in oxalic acid. Leaching experiments were per-formed in aqueous solutions of oxalic acid of 0.2-2 mol/L at 40-80 C for up to 90 min. The mixed ...Clay samples containing 8.15% iron oxides and 27.49% alumina were leached in oxalic acid. Leaching experiments were per-formed in aqueous solutions of oxalic acid of 0.2-2 mol/L at 40-80 C for up to 90 min. The mixed kinetic mechanism, i.e., t/τ=[（1 2X/3） （1 X）2/3 ]＋b[ 1 （1 X）1/3], seemed to be the most appropriate one to fit the kinetic data of leaching iron oxides contained in clay in the aqueous oxalic acid solutions. The Arrhenius activation energy for leaching in the 1.8 mol/L oxalic acid was found to be 41.035 kJ/mol.展开更多
The activation of iron oxide Fischer–Tropsch Synthesis(FTS) catalysts was investigated during pretreatment: reduction in hydrogen followed by carburization in either CO or syngas mixture, or simultaneously reduction ...The activation of iron oxide Fischer–Tropsch Synthesis(FTS) catalysts was investigated during pretreatment: reduction in hydrogen followed by carburization in either CO or syngas mixture, or simultaneously reduction and carburization in syngas. A combination of different complementary in situ techniques was used to gain insight into the behavior of Fe-based FTS catalysts during activation. In situ XRD was used to identify the crystalline structures present during both reduction in hydrogen and carburization. An increase in reduction rate was established when increasing the temperature. A complete reduction was demonstrated in the ETEM and a grain size dependency was proven, i.e. bigger grains need higher temperature in order to reduce. XPS and XAS both indicate the formation of a small amount of carbonaceous species at the surface of the bulk metallic iron during carburization.展开更多
A simple model for estimating the rate constant between CO_(2)-CO gas and molten slag containing iron oxides was developed using optical basicity only.In this model,the temperature dependence of the rate constant can ...A simple model for estimating the rate constant between CO_(2)-CO gas and molten slag containing iron oxides was developed using optical basicity only.In this model,the temperature dependence of the rate constant can be described by the Arrhenius law,and the activation energy can be expressed with a linear function of the slag's optical basicity.The model was applied to some molten slag systems,such as FeO,FeO-CaO,FeO-SiO_(2),FeO-Na_(2)O,FeO-CaO-SiO_(2),FeO-SiO_(2)-P_(2)O_(5),FeO-SiOE-Na_(2)O,and FeO-CaO-SiO_(2)-P_(2)O_(5).A comparison between the predicted results and measured data showed that the model worked well.展开更多
The removal of organic matter and iron oxides could increase and decrease soil CEC in tropical and subtropical regions, but the quantitative information is insufficient so far about the change of soil CEC, the influen...The removal of organic matter and iron oxides could increase and decrease soil CEC in tropical and subtropical regions, but the quantitative information is insufficient so far about the change of soil CEC, the influence factors and their contribution. In this study, the subhorizon soils of 24 soil series in the tropical and subtropical China were used, pH, particle size composition, organic matter, iron oxides of these samples were measured, and also CECs were measured and compared for the original soils and after the removal of organic matter and iron oxides. The results showed that, compared with CEC of the original soil, the eliminating organic matter increased soil CEC significantly by 2.28% - 56.50% with a mean of 24.02%, but the further obliterating iron oxides decreased soil CEC significantly by 0.75% - 20.30% with a mean of 7.73%. CEC after the removal of organic matter and iron oxides had positive correlation with iron oxides (p < 0.01) and negative correlation with sand content (p < 0.01 and p < 0.05). CEC after organic matter eliminated was mainly decided by iron oxides (51.68%), followed by silt content (22.19%);while CEC after iron oxides obliterated was mainly determined by iron oxides (50.55%). The increase of CEC after organic matter eliminated was co-affected by the contents of clays, slits, iron oxides and pH (22.00% - 27.34%), while the decrease of CEC after iron oxides obliterated further was dominated by the content of organic matter (66.92%). More other soil parameters should be considered for higher predicting accuracy in the regression model of soil CEC after the removal of organic matter and iron oxides, and the recommended optimal models obtained in this study were as follows: for soil CEC after organic matter eliminated, CEC = 1.665 <span style="white-space:nowrap;">−</span> 0.546pH <span style="white-space:nowrap;">−</span> 0.024OM + 0.053Fe<sub>x</sub>O<sub>y</sub> <span style="white-space:nowrap;">−</span> 0.001Silt + 0.007Clay + 0.972CEC<sub>original</sub> (R<sup>2</sup> was 0.923, RSME was 1.55 cmol(+)<span style="white-space:nowrap;"><span style="white-space:nowrap;">∙</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>, p < 0.01), while for soil CEC after iron oxides further obliterated, CEC = 1.665 <span style="white-space:nowrap;">−</span> 0.546pH <span style="white-space:nowrap;">−</span> 0.024OM + 0.053Fe<sub>x</sub>O<sub>y</sub> <span style="white-space:nowrap;">−</span> 0.001Silt + 0.007Clay + 0.972CEC<sub>original</sub> (R<sup>2</sup> was 0.923, RMSE was 1.55 cmol(+)<span style="white-space:nowrap;"><span style="white-space:nowrap;">∙</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>, p < 0.01). Further research is needed in the future as for exploring internal functional mechanism in view of soil electrochemistry and mineralogy.展开更多
Iron oxides from 33 samples of 25 soils derived from various parent materials in the southern China were studied using NaOH selective dissolution technique and X-ray diffraction (XRD). Goethite and hematite were the o...Iron oxides from 33 samples of 25 soils derived from various parent materials in the southern China were studied using NaOH selective dissolution technique and X-ray diffraction (XRD). Goethite and hematite were the only two crystalline Fe oxides occurring in a significant quantity. The goethite / (goethite + hematie )ratios ranged from 0 to 1, being the highest in yellow soil, some yellow-red soils and saprolite samples and the lowest in soils derived from purple sandstone where only hematite was present. Al substitution in goethite ranged from 6.6 to 29.9 mol % with a mean value of 16.7 mol %, while substitution of Al in hematite ranged from 0 to 12.1 mol %. The values of Al substitution of hematite in coexisting goethite and hematite were closely related with corresponding values of goethite (r=0.7292, P<0.01, n=27). The redness rating of soils increased linearly with increasing amount of hematite (r=0.8109, P<0.01). It was suggested that redness rating could be used to crudely estimate hematite contents of soils.展开更多
Iron oxides are widely found as ores in Earth's crust and are also important constituents of its interiors.Their polymorphism,composition changes,and electronic structures play essential roles in controlling the s...Iron oxides are widely found as ores in Earth's crust and are also important constituents of its interiors.Their polymorphism,composition changes,and electronic structures play essential roles in controlling the structure and geodynamic properties of the solid Earth.While all-natural occurring iron oxides are semiconductors or insulators at ambient pressure,they start to metalize under pressure.Here in this work,we review the electronic conductivity and metallization of iron oxides under high-pressure conditions found in Earth's lower mantle.We summarize that the metallization of iron oxides is generally controlled by the pressure-induced bandgap closure near the Fermi level.After metallization,they possess much higher electrical and thermal conductivity,which will facilitate the thermal convection,support a more stable and thicker D′′layer,and formulate Earth's magnetic field,all of which will constrain the large-scale dynamos of the mantle and core.展开更多
The optimal conditions on the plasma-forming gas flowrate, discharge current and voltage, distance between the plasma-torch nozzle and the metal plate surface for the process of penetration in and vaporization of stee...The optimal conditions on the plasma-forming gas flowrate, discharge current and voltage, distance between the plasma-torch nozzle and the metal plate surface for the process of penetration in and vaporization of steel plates by the contracted electric-arc air plasma torch accompanied by water quenching, were determined. The X-ray structural and phase studies as well as Mossbauer and electron microscope studies on the samples treated were performed. It was demonstrated that the vaporized elemental iron was oxidized by the oxygen present in the air plasma jet to form iron oxides （wiistite, magnetite, hematite）, which, depending on their mass ra- tios, determined the color of the iron oxide pigments, namely, beginning from light yellow, through deep yellow, light brown, deep brown, violet, red-violet, to black. A high degree of dispersity of the iron oxides is thus produced, with an averaged diameter of the particles below 500 nm, and their defective crystal structure form the basis of their potential application as components of iron-containing catalysts and pigments.展开更多
Objective： To study the growth and differentiation of superparamagnetie iron oxides（SPIOs） labeled neural stem cells （NSCs）. Methods： After NSCs were cultured and subcuhured from newborn rat brain, they were mag...Objective： To study the growth and differentiation of superparamagnetie iron oxides（SPIOs） labeled neural stem cells （NSCs）. Methods： After NSCs were cultured and subcuhured from newborn rat brain, they were magnetically labeled with ferumoxides （a kind of SPIOs ）. Growth, differentiation and other biology properties of the cells were investigated with immunocytochemistry, transmission electron microscopy （TEM） and Prussian blue staining. Results： Nestin positive cells were found in the culture and offspring clones. NSCs could be differentiated into positive GFAP and NF200 cells in serum culture. When NSCs incubated with ferumoxides, the iron particles were seen in intracellular as well as in offspring clones. With the increase in concentration of ferumoxides （5.6-11.2/μg/ml）, ferumoxides showed no significant difference effects on the growth and differentiation of NSCs. When the concentration of ferumoxides exceeded 22.4μg/ml ,there was significant difference（P〈0.05）. Conclusion： We successfully label NSCs with ferumoxides,it is useful for tracking of magnetic labeled NSCs in vivo with MRI.展开更多
Polymer-supported hydrous iron oxides(HFOs) are promising for heavy metals removal from aqueous systems.The ubiquitous inorganic ligands, e.g., sulfate, are expected to exert considerable impacts on pollutants removal...Polymer-supported hydrous iron oxides(HFOs) are promising for heavy metals removal from aqueous systems.The ubiquitous inorganic ligands, e.g., sulfate, are expected to exert considerable impacts on pollutants removal by these hybrid sorbents. Herein, we obtained a hybrid sorbent HFO-PS by encapsulating nanosized HFO into macroporous polystyrene(PS) resin. Both batch and column sorption experiments of Cu(Ⅱ) by HFO-PS were carried out in the presence of sulfate. Obviously, the presence of sulfate is favorable for Cu(Ⅱ) sorption onto HFO-PS.The performances of column Cu(Ⅱ) removal were fitted and predicted with Adams–Bohart, Clark, Thomas and BDST models. Thomas model is suggested best-fit to predict the breakthrough curves. Besides, a linear correlation is observed between breakthrough time and column length based on BDST model, which might be useful for predicting the breakthrough time for Cu(Ⅱ) removal by HFO-PS.展开更多
The relationship between iron oxides and surface charge characteristics in variable charge soils ( latosol and red earth ) was studied in following three ways. ( 1 ) Remove free iron oxides ( Fed ) and amorphous iron ...The relationship between iron oxides and surface charge characteristics in variable charge soils ( latosol and red earth ) was studied in following three ways. ( 1 ) Remove free iron oxides ( Fed ) and amorphous iron oxides ( Feo ) from the soils with sodium dithionite and acid ammonium oxalate solution respectively. ( 2 ) Add 2% glucose ( on the basis of air-dry soil weight ) to soils and incubate under submerged condition to activate iron oxides, and then the mixtures are dehydrated and air-dried to age iron oxides. ( 3 ) Precipitate various crystalline forms of iron oxides onto kaolinite. The results showed that free iron oxides ( Fed ) were the chief carrier of variable positive charges. Of which crystalline iron oxides ( Fed-Feo ) presented mainly as discrete particles in the soils and could only play a role of the carrier of positive charges, and did little influence on negative charges. Whereas the amorphous iron oxides ( Feo ) , which presented mainly as a coating with a large specific surface area, not only had positive charges, but also blocked the negative charge sites in soils. Submerged incubation activated iron oxides in the soils, and increased the amount of amorphous iron oxides and the degree of activation of iron oxide, which resulted in the increase of positive and negative charges of soils. Dehydration and air-dry aged iron oxides in soils and decreased the amount of amorphous iron oxides and the degree of activation of iron oxide, and also led to the decrease of positive and negative charges. Both the submerged incubation and the dehydration and air-dry had no significant influence on net charges. Precipitation of iron oxides onto kaolinite markedly increased positive charges and decreased negative charges. Amorphous iron oxide having a larger surface area contributed more positive charge sites and blocked more negative charge sites in kaolinite than crystalline goethite.展开更多
Natural surface coatings collected from natural substances （NSCsNS） were employed to study the roles of the main chemical components （iron oxides, manganese oxides, and other components） in controlling the adsorpt...Natural surface coatings collected from natural substances （NSCsNS） were employed to study the roles of the main chemical components （iron oxides, manganese oxides, and other components） in controlling the adsorption of lead（Pb） and cadmium（Cd） in aquatic environments. The selective chemical extraction followed by the adsorption of Pb and Cd experiments and statistical analysis, were used to investigate the adsorption property of each component. Hydroxylamine hydrochloride was used to remove manganese oxides selectively, and sodium dithionite was used to extract iron oxides and manganese oxides. The result indicated that iron oxides and manganese oxides played an important role in the adsorption of Pb and Cd on NSCsNS, and the relative contribution was about two-thirds. The contribution of manganese oxides was the greatest, with a lesser role indicated for other components. The adsorption ability of manganese oxides for Pb and Cd was greater than that of iron oxides or other components for Pb and Cd. The Pb adsorption observed in each component was greater than Cd adsorption.展开更多
Mesostructured iron oxides（MIOs） were nanocasted from a plugged hexagonal templated silica（PHTS） with a Brunauer-Emmett-Teller（BET） surface area of 694 m 2 /g.Results of X-ray diffraction（XRD）,transmission ele...Mesostructured iron oxides（MIOs） were nanocasted from a plugged hexagonal templated silica（PHTS） with a Brunauer-Emmett-Teller（BET） surface area of 694 m 2 /g.Results of X-ray diffraction（XRD）,transmission electron microscopy（TEM） and N 2 adsorption-desorption suggest that the nanocasted MIOs are synthetic hematite（α-Fe2O3） with a wormhole-like mesoporous network.As（V） adsorption test shows that the selected MIO—MIO-500（calcinated at 500 °C） with a BET surface area of 82 m^ 2 /g has a maximum adsorption capacity of 5.39 mg/g for As（V）,which is 2.5 times as large as that of natural hematite adsorbent.The study suggests that MIOs could be potentially used as the adsorbent of As（V） in wastewater.展开更多
Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in hu...Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.展开更多
Photocatalytic CO_(2)hydrogenation reactions can produce high-value-added chemicals for industry,solving the environmental problems caused by excessive CO_(2)emissions.Iron oxides are commonly used in photocatalytic r...Photocatalytic CO_(2)hydrogenation reactions can produce high-value-added chemicals for industry,solving the environmental problems caused by excessive CO_(2)emissions.Iron oxides are commonly used in photocatalytic reactions due to their various structures and suitable band gaps.Nevertheless,the structural evolution and real active components during photocatalytic CO_(2)hydrogenation reaction are rarely studied.Herein,a variety of iron oxides including a-Fe_(2)O_(3),y-Fe_(2)O_(3),Fe_(3)O_(4)and FeO were derived from Prussian blue precursors to investigate the CO_(2)hydrogenation performance,structural evolution and active components.Especially,the typical a-andγ-Fe_(2)O_(3)are converted to Fe_(3)O_(4)during the reaction,while Fe/Fe_(x)O_(y)remains structurally stable.Meanwhile,it is confirmed that Fe_(3)O_(4)is the main active component for CO production and the formation of hydrocarbons(CH_(4)and C_(2)-C_(4))are highly dependent on the Fe/Fe_(x)O_(y)heterojunctions.The optimal yields of CO,CH_(4)and C_(2)-C_(4)hydrocarbons over the best catalyst(FeFe-550)can achieve 4 mmol g^(-1)h^(-1),350μmol g^(-1)h^(-1)and 150μmol g^(-1)h^(-1),respectively due to their suitable metal/oxide component distribution.This work examines the structural evolution of different iron oxide catalysts in the photocatalytic CO_(2)hydrogenation reaction,identifies the active components as well as reveals the relationship between components and the products,and offers valuable insights into the efficient utilization of CO_(2).展开更多
Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic ...Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.展开更多
The study focused on the effect of several typical competing solutes on removal of arsenic with Fe2O3 and Al2O3. The test results indicate that chloride, nitrate and sulfate did not have detectable effects, and that s...The study focused on the effect of several typical competing solutes on removal of arsenic with Fe2O3 and Al2O3. The test results indicate that chloride, nitrate and sulfate did not have detectable effects, and that selenium（Ⅳ） （Se（Ⅳ）） and vanadium（Ⅴ） （V（Ⅴ）） showed slight effects on the adsorption of As（Ⅴ） with Fe2O3. The results also showed that adsorption of As（Ⅴ） on A12O3 was not affected by chloride and nitrate anions, but slightly by Se（Ⅳ） and V（Ⅴ） ions. Unlike the adsorption of As（Ⅴ） with Fe2O3, that with Fe2O3 was affected by the presence of sulfate in water solutions. Both phosphate and silica have significant adverse effects on the adsorption of As（Ⅴ） adsorption with Fe2O3 and Al2O3. Compared to the other tested anions, phosphate anion was found to be the most prominent solute affecting the As（Ⅴ） adsorption with Fe2O3 and Al2O3. In general, Fe2O3 has a better performance than Al2O3 in removal of As（Ⅴ） within a water environment where multi competing solutes are present.展开更多
In this study,we reported on the concept and practical use of cation exchange resin(CER)for removing anions in water via pretreating the CER with metal salts.The cation exchange resinsupported iron and magnesium oxide...In this study,we reported on the concept and practical use of cation exchange resin(CER)for removing anions in water via pretreating the CER with metal salts.The cation exchange resinsupported iron and magnesium oxides/hydroxides composite(FeMg/CER)was synthesized and introduced as a new and potential adsorbent for selective removal of nitrate ion in the water environment.Characteristics of FeMg/CER were determined by techniques such as Fouriertransform infrared spectroscopy,scanning electron microscopy,and Xray diffraction.The results showed that FeMg/CER material had a high nitrate adsorption capacity of 200 mg NO_(3)^()·g^(1)with a fast equilibrium adsorption time of 30 min at pH 5.In addition,it had good durability of at least 10 times of regeneration,which could be applied to practical water and wastewater treatment.展开更多
Soil aggregates determine the basic structure of soil,and their composition and stability are influenced by the various types of cementitious substances occurring in soil.To explore the main limiting factors of soil a...Soil aggregates determine the basic structure of soil,and their composition and stability are influenced by the various types of cementitious substances occurring in soil.To explore the main limiting factors of soil aggregation in the process of vegetation succession with granite as the parent material,five stages of vegetation succession in an eroded area were selected:bare land(BL),grassland(GL),grassland shrub transition land(GS),shrubland(SL)and secondary forest(SF).Soil samples were collected to determine the composition and stability of aggregates.The contents of organic and inorganic cementitious substances,including organic matter components and iron aluminum oxides,were determined at five soil aggregate grain levels.The results indicated that the stability of soil aggregates and the>0.25 mm water-stable aggregate content(WR_(0.25))increased with vegetation succession.Based on the Le Bissonnais(LB)method,the mean weight diameter(MWD)of soil aggregates increased,and the relative dissipation index(RSI)and relative mechanical crushing index(RMI)decreased.The humic acid(HA)and fulvic acid(FA)contents in soil aggregates increased with vegetation succession,and the soil humus content at the SF stage increased by more than 13.54%over the BL level.Upon different vegetation succession stage,the iron and aluminum oxides for the SL and the SF were at a high level,and the contents of free-form iron oxide(Fe_(d))and amorphous iron oxide(Fe_(o))for BL were high.Correlation analysis indicated that the soil humic degree(PQ)and the contents of amorphous alumina(Al_(o))were positively correlated with aggregate stability to varying degrees.Redundancy analysis(RDA)revealed that PQ values of 1-2 mm(PQ_(2))and 0.25-0.5 mm(PQ_(4))aggregates,the contents of Fe_(o) of bulk soil(Fe_(oB)),>2 mm(Fe_(o1)),1-2 mm(Fe_(o2)),and<0.25 mm(Fe_(o5))aggregates,and the contents of Al_(o) of>2 mm(Al_(o1))aggregates could explain 99.4%of the changes in soil aggregate stability at different vegetation succession stages.Al_(o1) had a contribution rate of 71.2%and is the key factor for improving the stability of soil aggregates.展开更多
The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. Th...The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carder could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carders were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carrier： the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species （bulk lattice oxygen） that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction condition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.展开更多
Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures ...Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures are the focus of recent research activi- ties because of their wide applications in magnetic refrigeration, information storage, electronics, catalysts, Li-ion battery, pigment, gas sensors, etc. This review covers the recent progress in the synthesis, properties and applications of 1-D iron oxides nanostructures. The paper begins with the introduction to 1-D iron oxides nanostructures, followed by the typical synthetic methods developed for the synthesis of 1-D iron oxides nanostructures. Then, the typical 1-D iron oxides nanostructures, in- cluding nanowires/nanorods, nanotubes, nanobelts, nanochalns, and special 3-D structures built on 1-D building blocks, are introduced in detail. The properties of 1-D iron oxides nanostructures are then discussed, focusing on the magnetic, gas sensing, and electrochemical and photocatalytic properties. Finally, we draw conclusions and look at the prospects of 1-D iron oxides nanostructures.展开更多
文摘Clay samples containing 8.15% iron oxides and 27.49% alumina were leached in oxalic acid. Leaching experiments were per-formed in aqueous solutions of oxalic acid of 0.2-2 mol/L at 40-80 C for up to 90 min. The mixed kinetic mechanism, i.e., t/τ=[（1 2X/3） （1 X）2/3 ]＋b[ 1 （1 X）1/3], seemed to be the most appropriate one to fit the kinetic data of leaching iron oxides contained in clay in the aqueous oxalic acid solutions. The Arrhenius activation energy for leaching in the 1.8 mol/L oxalic acid was found to be 41.035 kJ/mol.
基金supported by the “Villum Center for the Science of Sustainable Fuels and Chemicals” (V-Sustain, grant number 9455) research initiative funded by the VILLUM FONDEN。
文摘The activation of iron oxide Fischer–Tropsch Synthesis(FTS) catalysts was investigated during pretreatment: reduction in hydrogen followed by carburization in either CO or syngas mixture, or simultaneously reduction and carburization in syngas. A combination of different complementary in situ techniques was used to gain insight into the behavior of Fe-based FTS catalysts during activation. In situ XRD was used to identify the crystalline structures present during both reduction in hydrogen and carburization. An increase in reduction rate was established when increasing the temperature. A complete reduction was demonstrated in the ETEM and a grain size dependency was proven, i.e. bigger grains need higher temperature in order to reduce. XPS and XAS both indicate the formation of a small amount of carbonaceous species at the surface of the bulk metallic iron during carburization.
基金supported by the National Natural Science Foundation of China(Nos.50834007,50874128,and 50674012)
文摘A simple model for estimating the rate constant between CO_(2)-CO gas and molten slag containing iron oxides was developed using optical basicity only.In this model,the temperature dependence of the rate constant can be described by the Arrhenius law,and the activation energy can be expressed with a linear function of the slag's optical basicity.The model was applied to some molten slag systems,such as FeO,FeO-CaO,FeO-SiO_(2),FeO-Na_(2)O,FeO-CaO-SiO_(2),FeO-SiO_(2)-P_(2)O_(5),FeO-SiOE-Na_(2)O,and FeO-CaO-SiO_(2)-P_(2)O_(5).A comparison between the predicted results and measured data showed that the model worked well.
文摘The removal of organic matter and iron oxides could increase and decrease soil CEC in tropical and subtropical regions, but the quantitative information is insufficient so far about the change of soil CEC, the influence factors and their contribution. In this study, the subhorizon soils of 24 soil series in the tropical and subtropical China were used, pH, particle size composition, organic matter, iron oxides of these samples were measured, and also CECs were measured and compared for the original soils and after the removal of organic matter and iron oxides. The results showed that, compared with CEC of the original soil, the eliminating organic matter increased soil CEC significantly by 2.28% - 56.50% with a mean of 24.02%, but the further obliterating iron oxides decreased soil CEC significantly by 0.75% - 20.30% with a mean of 7.73%. CEC after the removal of organic matter and iron oxides had positive correlation with iron oxides (p < 0.01) and negative correlation with sand content (p < 0.01 and p < 0.05). CEC after organic matter eliminated was mainly decided by iron oxides (51.68%), followed by silt content (22.19%);while CEC after iron oxides obliterated was mainly determined by iron oxides (50.55%). The increase of CEC after organic matter eliminated was co-affected by the contents of clays, slits, iron oxides and pH (22.00% - 27.34%), while the decrease of CEC after iron oxides obliterated further was dominated by the content of organic matter (66.92%). More other soil parameters should be considered for higher predicting accuracy in the regression model of soil CEC after the removal of organic matter and iron oxides, and the recommended optimal models obtained in this study were as follows: for soil CEC after organic matter eliminated, CEC = 1.665 <span style="white-space:nowrap;">−</span> 0.546pH <span style="white-space:nowrap;">−</span> 0.024OM + 0.053Fe<sub>x</sub>O<sub>y</sub> <span style="white-space:nowrap;">−</span> 0.001Silt + 0.007Clay + 0.972CEC<sub>original</sub> (R<sup>2</sup> was 0.923, RSME was 1.55 cmol(+)<span style="white-space:nowrap;"><span style="white-space:nowrap;">∙</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>, p < 0.01), while for soil CEC after iron oxides further obliterated, CEC = 1.665 <span style="white-space:nowrap;">−</span> 0.546pH <span style="white-space:nowrap;">−</span> 0.024OM + 0.053Fe<sub>x</sub>O<sub>y</sub> <span style="white-space:nowrap;">−</span> 0.001Silt + 0.007Clay + 0.972CEC<sub>original</sub> (R<sup>2</sup> was 0.923, RMSE was 1.55 cmol(+)<span style="white-space:nowrap;"><span style="white-space:nowrap;">∙</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>, p < 0.01). Further research is needed in the future as for exploring internal functional mechanism in view of soil electrochemistry and mineralogy.
文摘Iron oxides from 33 samples of 25 soils derived from various parent materials in the southern China were studied using NaOH selective dissolution technique and X-ray diffraction (XRD). Goethite and hematite were the only two crystalline Fe oxides occurring in a significant quantity. The goethite / (goethite + hematie )ratios ranged from 0 to 1, being the highest in yellow soil, some yellow-red soils and saprolite samples and the lowest in soils derived from purple sandstone where only hematite was present. Al substitution in goethite ranged from 6.6 to 29.9 mol % with a mean value of 16.7 mol %, while substitution of Al in hematite ranged from 0 to 12.1 mol %. The values of Al substitution of hematite in coexisting goethite and hematite were closely related with corresponding values of goethite (r=0.7292, P<0.01, n=27). The redness rating of soils increased linearly with increasing amount of hematite (r=0.8109, P<0.01). It was suggested that redness rating could be used to crudely estimate hematite contents of soils.
基金supported by the National Natural Science Foundation of China(Grant Nos.42150101 and 42150102)supported by the CAEP Research Project(Grant No.CX20210048)a Tencent Xplorer Prize(Grant No.XPLORER-2020-1013)。
文摘Iron oxides are widely found as ores in Earth's crust and are also important constituents of its interiors.Their polymorphism,composition changes,and electronic structures play essential roles in controlling the structure and geodynamic properties of the solid Earth.While all-natural occurring iron oxides are semiconductors or insulators at ambient pressure,they start to metalize under pressure.Here in this work,we review the electronic conductivity and metallization of iron oxides under high-pressure conditions found in Earth's lower mantle.We summarize that the metallization of iron oxides is generally controlled by the pressure-induced bandgap closure near the Fermi level.After metallization,they possess much higher electrical and thermal conductivity,which will facilitate the thermal convection,support a more stable and thicker D′′layer,and formulate Earth's magnetic field,all of which will constrain the large-scale dynamos of the mantle and core.
基金the National Science Fund of the Bulgarian Ministry of Education and Science(Project X-1504/2005)
文摘The optimal conditions on the plasma-forming gas flowrate, discharge current and voltage, distance between the plasma-torch nozzle and the metal plate surface for the process of penetration in and vaporization of steel plates by the contracted electric-arc air plasma torch accompanied by water quenching, were determined. The X-ray structural and phase studies as well as Mossbauer and electron microscope studies on the samples treated were performed. It was demonstrated that the vaporized elemental iron was oxidized by the oxygen present in the air plasma jet to form iron oxides （wiistite, magnetite, hematite）, which, depending on their mass ra- tios, determined the color of the iron oxide pigments, namely, beginning from light yellow, through deep yellow, light brown, deep brown, violet, red-violet, to black. A high degree of dispersity of the iron oxides is thus produced, with an averaged diameter of the particles below 500 nm, and their defective crystal structure form the basis of their potential application as components of iron-containing catalysts and pigments.
基金Supported by National Natural Science Foundation of Chi-na (330370500)Postdoctoral Science Foundation of China(2003033363)the CQUMS Excellent Doctoral Founda-tion
文摘Objective： To study the growth and differentiation of superparamagnetie iron oxides（SPIOs） labeled neural stem cells （NSCs）. Methods： After NSCs were cultured and subcuhured from newborn rat brain, they were magnetically labeled with ferumoxides （a kind of SPIOs ）. Growth, differentiation and other biology properties of the cells were investigated with immunocytochemistry, transmission electron microscopy （TEM） and Prussian blue staining. Results： Nestin positive cells were found in the culture and offspring clones. NSCs could be differentiated into positive GFAP and NF200 cells in serum culture. When NSCs incubated with ferumoxides, the iron particles were seen in intracellular as well as in offspring clones. With the increase in concentration of ferumoxides （5.6-11.2/μg/ml）, ferumoxides showed no significant difference effects on the growth and differentiation of NSCs. When the concentration of ferumoxides exceeded 22.4μg/ml ,there was significant difference（P〈0.05）. Conclusion： We successfully label NSCs with ferumoxides,it is useful for tracking of magnetic labeled NSCs in vivo with MRI.
基金Supported by the National Natural Science Foundation of China(21607080)the Natural Science Foundation of Jiangsu Province(BK20160946)Jiangsu Higher Education Institution NSF(16KJB610011)
文摘Polymer-supported hydrous iron oxides(HFOs) are promising for heavy metals removal from aqueous systems.The ubiquitous inorganic ligands, e.g., sulfate, are expected to exert considerable impacts on pollutants removal by these hybrid sorbents. Herein, we obtained a hybrid sorbent HFO-PS by encapsulating nanosized HFO into macroporous polystyrene(PS) resin. Both batch and column sorption experiments of Cu(Ⅱ) by HFO-PS were carried out in the presence of sulfate. Obviously, the presence of sulfate is favorable for Cu(Ⅱ) sorption onto HFO-PS.The performances of column Cu(Ⅱ) removal were fitted and predicted with Adams–Bohart, Clark, Thomas and BDST models. Thomas model is suggested best-fit to predict the breakthrough curves. Besides, a linear correlation is observed between breakthrough time and column length based on BDST model, which might be useful for predicting the breakthrough time for Cu(Ⅱ) removal by HFO-PS.
文摘The relationship between iron oxides and surface charge characteristics in variable charge soils ( latosol and red earth ) was studied in following three ways. ( 1 ) Remove free iron oxides ( Fed ) and amorphous iron oxides ( Feo ) from the soils with sodium dithionite and acid ammonium oxalate solution respectively. ( 2 ) Add 2% glucose ( on the basis of air-dry soil weight ) to soils and incubate under submerged condition to activate iron oxides, and then the mixtures are dehydrated and air-dried to age iron oxides. ( 3 ) Precipitate various crystalline forms of iron oxides onto kaolinite. The results showed that free iron oxides ( Fed ) were the chief carrier of variable positive charges. Of which crystalline iron oxides ( Fed-Feo ) presented mainly as discrete particles in the soils and could only play a role of the carrier of positive charges, and did little influence on negative charges. Whereas the amorphous iron oxides ( Feo ) , which presented mainly as a coating with a large specific surface area, not only had positive charges, but also blocked the negative charge sites in soils. Submerged incubation activated iron oxides in the soils, and increased the amount of amorphous iron oxides and the degree of activation of iron oxide, which resulted in the increase of positive and negative charges of soils. Dehydration and air-dry aged iron oxides in soils and decreased the amount of amorphous iron oxides and the degree of activation of iron oxide, and also led to the decrease of positive and negative charges. Both the submerged incubation and the dehydration and air-dry had no significant influence on net charges. Precipitation of iron oxides onto kaolinite markedly increased positive charges and decreased negative charges. Amorphous iron oxide having a larger surface area contributed more positive charge sites and blocked more negative charge sites in kaolinite than crystalline goethite.
基金Supported by the National Natural Science Foundation of China(No.20477014).
文摘Natural surface coatings collected from natural substances （NSCsNS） were employed to study the roles of the main chemical components （iron oxides, manganese oxides, and other components） in controlling the adsorption of lead（Pb） and cadmium（Cd） in aquatic environments. The selective chemical extraction followed by the adsorption of Pb and Cd experiments and statistical analysis, were used to investigate the adsorption property of each component. Hydroxylamine hydrochloride was used to remove manganese oxides selectively, and sodium dithionite was used to extract iron oxides and manganese oxides. The result indicated that iron oxides and manganese oxides played an important role in the adsorption of Pb and Cd on NSCsNS, and the relative contribution was about two-thirds. The contribution of manganese oxides was the greatest, with a lesser role indicated for other components. The adsorption ability of manganese oxides for Pb and Cd was greater than that of iron oxides or other components for Pb and Cd. The Pb adsorption observed in each component was greater than Cd adsorption.
基金Supported by the National Natural Science Foundation of China(No.51002080)the Research Funds of Nanjing University of Information Science and Technology(NUIST),China(No.S8108179001)+1 种基金the College Students Practice Innovative Projects of Jiangsu Province,China(No.N1885010087)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Mesostructured iron oxides（MIOs） were nanocasted from a plugged hexagonal templated silica（PHTS） with a Brunauer-Emmett-Teller（BET） surface area of 694 m 2 /g.Results of X-ray diffraction（XRD）,transmission electron microscopy（TEM） and N 2 adsorption-desorption suggest that the nanocasted MIOs are synthetic hematite（α-Fe2O3） with a wormhole-like mesoporous network.As（V） adsorption test shows that the selected MIO—MIO-500（calcinated at 500 °C） with a BET surface area of 82 m^ 2 /g has a maximum adsorption capacity of 5.39 mg/g for As（V）,which is 2.5 times as large as that of natural hematite adsorbent.The study suggests that MIOs could be potentially used as the adsorbent of As（V） in wastewater.
基金supported by the National Key R&D Program of China,Nos.2017YFA0104302(to NG and XM)and 2017YFA0104304(to BW and ZZ)
文摘Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.
基金supported by the National Natural Science Foundation of China(Nos.22172086,22105117)Taishan Scholars Program of Shandong Province(No.tsqn202103064)the Major Basic Research Project of Shandong Province(No.ZR2021ZD06).
文摘Photocatalytic CO_(2)hydrogenation reactions can produce high-value-added chemicals for industry,solving the environmental problems caused by excessive CO_(2)emissions.Iron oxides are commonly used in photocatalytic reactions due to their various structures and suitable band gaps.Nevertheless,the structural evolution and real active components during photocatalytic CO_(2)hydrogenation reaction are rarely studied.Herein,a variety of iron oxides including a-Fe_(2)O_(3),y-Fe_(2)O_(3),Fe_(3)O_(4)and FeO were derived from Prussian blue precursors to investigate the CO_(2)hydrogenation performance,structural evolution and active components.Especially,the typical a-andγ-Fe_(2)O_(3)are converted to Fe_(3)O_(4)during the reaction,while Fe/Fe_(x)O_(y)remains structurally stable.Meanwhile,it is confirmed that Fe_(3)O_(4)is the main active component for CO production and the formation of hydrocarbons(CH_(4)and C_(2)-C_(4))are highly dependent on the Fe/Fe_(x)O_(y)heterojunctions.The optimal yields of CO,CH_(4)and C_(2)-C_(4)hydrocarbons over the best catalyst(FeFe-550)can achieve 4 mmol g^(-1)h^(-1),350μmol g^(-1)h^(-1)and 150μmol g^(-1)h^(-1),respectively due to their suitable metal/oxide component distribution.This work examines the structural evolution of different iron oxide catalysts in the photocatalytic CO_(2)hydrogenation reaction,identifies the active components as well as reveals the relationship between components and the products,and offers valuable insights into the efficient utilization of CO_(2).
基金supported by the Shenyang Municipal Science and Technology Project,China(23-409-2-03)the Liaoning Provincial Department of Science and Technology Project,China(Z20230183)the Liaoning Provincial Applied Basic Research Program,China(2022JH2/101300173).
文摘Both soil organic carbon (SOC) and iron (Fe) oxide content, among other factors, drive the formation and stability of soil aggregates.However, the mechanism of these drivers in greenhouse soil fertilized with organic fertilizer is not well understood.In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.To explore the impact of organic fertilizer on soil aggregates, we established four treatments:no fertilization (CK);inorganic fertilizer (CF);organic fertilizer (OF);and combined application of inorganic and organic fertilizers(COF).The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of>0.25 mm aggregate fractions.OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in>0.25 mm aggregates.Organic fertilizer application significantly increased the content of free Fe(Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.Both non-crystalline Fe and SOC were significantly positively correlated with>2 mm mean weight diameter.Overall, we believe that the increase of SOC, aromatic-C, and non-crystal ine Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.
文摘The study focused on the effect of several typical competing solutes on removal of arsenic with Fe2O3 and Al2O3. The test results indicate that chloride, nitrate and sulfate did not have detectable effects, and that selenium（Ⅳ） （Se（Ⅳ）） and vanadium（Ⅴ） （V（Ⅴ）） showed slight effects on the adsorption of As（Ⅴ） with Fe2O3. The results also showed that adsorption of As（Ⅴ） on A12O3 was not affected by chloride and nitrate anions, but slightly by Se（Ⅳ） and V（Ⅴ） ions. Unlike the adsorption of As（Ⅴ） with Fe2O3, that with Fe2O3 was affected by the presence of sulfate in water solutions. Both phosphate and silica have significant adverse effects on the adsorption of As（Ⅴ） adsorption with Fe2O3 and Al2O3. Compared to the other tested anions, phosphate anion was found to be the most prominent solute affecting the As（Ⅴ） adsorption with Fe2O3 and Al2O3. In general, Fe2O3 has a better performance than Al2O3 in removal of As（Ⅴ） within a water environment where multi competing solutes are present.
基金Vietnam National University-Ho Chi Minh City under grant number A2020-16-01.
文摘In this study,we reported on the concept and practical use of cation exchange resin(CER)for removing anions in water via pretreating the CER with metal salts.The cation exchange resinsupported iron and magnesium oxides/hydroxides composite(FeMg/CER)was synthesized and introduced as a new and potential adsorbent for selective removal of nitrate ion in the water environment.Characteristics of FeMg/CER were determined by techniques such as Fouriertransform infrared spectroscopy,scanning electron microscopy,and Xray diffraction.The results showed that FeMg/CER material had a high nitrate adsorption capacity of 200 mg NO_(3)^()·g^(1)with a fast equilibrium adsorption time of 30 min at pH 5.In addition,it had good durability of at least 10 times of regeneration,which could be applied to practical water and wastewater treatment.
基金financial support for the research provided by the Guangxi Natural Science Foundation(2021GXNSFBA075017)the National Natural Science Foundation of China(No.42007055,42107350)the Guangxi Science and Technology Base and talent Special project(No.AD20159031)。
文摘Soil aggregates determine the basic structure of soil,and their composition and stability are influenced by the various types of cementitious substances occurring in soil.To explore the main limiting factors of soil aggregation in the process of vegetation succession with granite as the parent material,five stages of vegetation succession in an eroded area were selected:bare land(BL),grassland(GL),grassland shrub transition land(GS),shrubland(SL)and secondary forest(SF).Soil samples were collected to determine the composition and stability of aggregates.The contents of organic and inorganic cementitious substances,including organic matter components and iron aluminum oxides,were determined at five soil aggregate grain levels.The results indicated that the stability of soil aggregates and the>0.25 mm water-stable aggregate content(WR_(0.25))increased with vegetation succession.Based on the Le Bissonnais(LB)method,the mean weight diameter(MWD)of soil aggregates increased,and the relative dissipation index(RSI)and relative mechanical crushing index(RMI)decreased.The humic acid(HA)and fulvic acid(FA)contents in soil aggregates increased with vegetation succession,and the soil humus content at the SF stage increased by more than 13.54%over the BL level.Upon different vegetation succession stage,the iron and aluminum oxides for the SL and the SF were at a high level,and the contents of free-form iron oxide(Fe_(d))and amorphous iron oxide(Fe_(o))for BL were high.Correlation analysis indicated that the soil humic degree(PQ)and the contents of amorphous alumina(Al_(o))were positively correlated with aggregate stability to varying degrees.Redundancy analysis(RDA)revealed that PQ values of 1-2 mm(PQ_(2))and 0.25-0.5 mm(PQ_(4))aggregates,the contents of Fe_(o) of bulk soil(Fe_(oB)),>2 mm(Fe_(o1)),1-2 mm(Fe_(o2)),and<0.25 mm(Fe_(o5))aggregates,and the contents of Al_(o) of>2 mm(Al_(o1))aggregates could explain 99.4%of the changes in soil aggregate stability at different vegetation succession stages.Al_(o1) had a contribution rate of 71.2%and is the key factor for improving the stability of soil aggregates.
基金the National Natural Science Foundation of China (50574046)National Natural Science Foundation of Major Research Projects (90610035)+1 种基金Natural Science Foundation of Yunnan Province (2004E0058Q)High School Doctoral Subject Special Science and Research Foundation of Ministry of Education (20040674005)
文摘The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carder could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carders were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carrier： the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species （bulk lattice oxygen） that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction condition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.
基金supported by the National Natural Science Foundation of China (Grant No. 51002059)the National Basic Research Program of China (Grant No. 2011CBA00700)+2 种基金the Natural Science Foundation of Hubei Province (Grant No. 2009CDB326)the Research Fund for the Doctoral Program of Higher Education (Grant Nos. 20090142120059, 20100142120053)the Director Fund of WNLO. Special thanks to the Analysis and Testing Center of HUST
文摘Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures are the focus of recent research activi- ties because of their wide applications in magnetic refrigeration, information storage, electronics, catalysts, Li-ion battery, pigment, gas sensors, etc. This review covers the recent progress in the synthesis, properties and applications of 1-D iron oxides nanostructures. The paper begins with the introduction to 1-D iron oxides nanostructures, followed by the typical synthetic methods developed for the synthesis of 1-D iron oxides nanostructures. Then, the typical 1-D iron oxides nanostructures, in- cluding nanowires/nanorods, nanotubes, nanobelts, nanochalns, and special 3-D structures built on 1-D building blocks, are introduced in detail. The properties of 1-D iron oxides nanostructures are then discussed, focusing on the magnetic, gas sensing, and electrochemical and photocatalytic properties. Finally, we draw conclusions and look at the prospects of 1-D iron oxides nanostructures.
