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Reduction and carburization of iron oxides for Fischer–Tropsch synthesis

Journal of Energy Chemistry 2020年第12期29卷 48-61页

作者： Monia Runge Nielsen Asger Barkholt Moss Anton Simon Bjrnlund Xi Liu Axel Knop-Gericke Alexander YuKlyushin Jan-Dierk Grunwaldt Thomas LSheppard Dmitry EDoronkin Anna Zimina Thomas Eric Lyck Smitshuysen Christian Danvad Damsgaard Jakob Birkedal Wagner Thomas Willum Hansen DTU Nanolab Technical University of DenmarkDK-2800Kgs.LyngbyDenmark Department of Physics Technical University of DenmarkDK-2800Kgs.LyngbyDenmark SynCat@Beijing Synfuels China Technology Co.LtdBeijing 101407China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Inorganic Chemistry Fritz Haber Institute of the Max Planck SocietyD-14195 BerlinGermany Research Group Heterogeneous Reactions.Max Planck Institute for Chemical Energy Conversion D-45470 MulheimGermany Research Group Catalysis for Energy Helmholtz-Zentrum Berlin for Materials and Energy(BESSYⅡ)D-12489 BerlinGermany Institute for Chemical Technology and Polymer Chemistry Karlsruhe Institute of TechnologyD-76131 KarlsruheGermany Institute of Catalysis Research and Technology Karlsruhe Institute of TechnologyD-76344 Eggenstein-LeopoldshafenGermany

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.

关键词： In situ characterization Fischer–Tropsch Catalyst reduction and carburization iron oxides

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iron oxides and Their Relations to Colors in Some Soilsof Southern China

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Pedosphere 1998年第1期8卷 53-58页

作者： ZHANGMINGKUI M．J．WILSON 等 DepartmentofSoilScienceandWaterResource ZhejiangAgriculturalUniversityHangzhou310029（CHina） Soilsand

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.

关键词： Al substitution color iron oxides southern China

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Evolution of electrical conductivity and semiconductor to metal transition of iron oxides at extreme conditions

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Chinese Physics B 2022年第8期31卷 95-100页

作者： Yukai Zhuang Qingyang Hu Institute of Atomic and Molecular Physics Sichuan UniversityChengdu 610065China Center for High Pressure Science and Technology Advanced Research(HPSTAR) Beijing 100094China

iron oxides are widely found as ores in Earth's crust and are also important constituents of its *** polymorphism,composition changes,and electronic structures play essential roles in controlling the structure and geodynamic properties of the solid *** all-natural occurring iron oxides are semiconductors or insulators at ambient pressure,they start to metalize under *** in this work,we review the electronic conductivity and metallization of iron oxides under high-pressure conditions found in Earth's lower *** summarize that the metallization of iron oxides is generally controlled by the pressure-induced bandgap closure near the Fermi *** 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.

关键词： high pressure metallization iron oxides electrical conductivity

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A model for estimating the rate constant between CO_2-CO gas and molten slag containing iron oxides using optical basicity

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International Journal of Minerals,Metallurgy and Materials 2012年第8期19卷 685-688页

作者： Teng Zhang Xiao-jun Hu Qi-feng Shu Kuo-Chih Chou State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

A simple model for estimating the rate constant between CO2-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-SiO2, FeO-Na2O, FeO-CaO-SiO2, FeO-SiO2-P2O5, FeO-SiOE-Na2O, and FeO-CaO-SiOE-P2O5. A comparison between the predicted results and measured data showed that the model worked well.

关键词： smelting rate constants slag iron oxides optical basicity models

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Deciphering the structural evolution and real active ingredients of iron oxides in photocatalytic CO_(2)hydrogenation

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Chinese Journal of Structural Chemistry 2024年第8期43卷 27-37页

作者： Mengjun Zhao Yuhao Guo Na Li Tingjiang Yan Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province School of Chemistry and Chemical EngineeringQufu Normal UniversityQufu273165PR China College of Chemistry and Chemical Engineering Shaanxi University of Science and TechnologyXi'an710021PR China

Photocatalytic CO_(2)hydrogenation reactions can produce high-value-added chemicals for industry,solving the environmental problems caused by excessive CO_(2)*** oxides are commonly used in photocatalytic reactions due to their various structures and suitable band ***,the structural evolution and real active components during photocatalytic CO_(2)hydrogenation reaction are rarely ***,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 ***,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 ***,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)*** 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 *** 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).

关键词： iron oxides Photocatalysis CO_(2)hydrogenation Structural evolution

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Dissolution kinetics of iron oxides in clay in oxalic acid solutions

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International Journal of Minerals,Metallurgy and Materials 2012年第12期19卷 1083-1087页

作者： U.K. Sultana A.S.W. Kurny Department of Materials and Metallurgical Engineering Bangladesh University of Engineering and Technology

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.

关键词： clay iron oxides leaching oxalic acid kinetics activation energy

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iron oxides particles in human brain

Iron oxides particles in human brain

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第十七届国际生物物理大会;第十二届中国生物物理大会

作者： Martin Kopani Julius Dekan Marcel Miglierini Lubomir DIhan Roman Boca Department of Pathology Faculty of MedicineComenius UniversityBratislavaSlovakia St.Elizabeth University of Health and Social Sciences BratislavaSlovakia Department of Nuclear Physics Faculty of Electrical Engineering and Information TechnologySlovak University of TechnologyBratislavaSlovakia Academy of Science Institute of Inorganic ChemistryHusinec-RezCzech Republic Department of Inorganic Chemistry Faculty of Chemical and Food TechnologySlovak University of TechnologyBratislavaSlovakia

iron is central element in physiological and pathological *** can be found in human body mainly in the form of ferritin,but it can be found in various iron *** magnetite was found in physiological human *** investigated magnetic properties globus pallidus of human brain without any clinico-pathological findings on a disease of central nervous *** quantum interference device(SQUID) showed dominating diamagnetism and/or paramagnetism superimposed by a ferromagnetic

关键词： iron oxides brain particles magnetic field

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Quantitative Estimation of the Changes in Soil CEC after the Removal of Organic Matter and iron oxides

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Agricultural Sciences 2021年第11期12卷 1244-1254页

作者： Xiangzheng Kong Decheng Li Xiaodong Song Ganlin Zhang State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing China University of Chinese Academy of Sciences Beijing China

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 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 − 0.546pH − 0.024OM + 0.053FexOy − 0.001Silt +

关键词： Soil CEC Quantitative Estimation Removal Organic Matter iron oxides

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Redox reactions of iron and manganese oxides in complex systems

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Frontiers of Environmental Science & Engineering 2020年第5期14卷 3-14页

作者： Jianzhi Huang Huichun Zhang Department of Civil and Environmental Engineering Case Western Reserve UniversityClevelandOH 44106USA

Conspectus:Redox reactions of Fe-and Mn-oxides play important roles in the fate and transformation of many contaminants in natural *** to experimental and analytical challenges associated with complex environments,there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems,and most of the studies so far have only focused on simple model *** bridge the gap between simple model systems and complex environmental systems,it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant *** this Account,we primarily focused on(1)the oxidative reactivity of Mn-and Fe-oxides and(2)the reductive reactivity of Fe(Ⅱ)/iron oxides in comolex model systems toward contaminant *** effects of common metal ions such as Mn2+,Ca2+,Ni2+,Cr3+and Cu2+,ligands such as small anionic ligands and natural organic matter(NOM),and second metal oxides such as A1,Si and Ti oxides on the redox reactivity of the systems are briefly summarized.

关键词： iron oxides Manganese oxides Reduction Oxidation Complex systems Reaction kinetics and mechanisms

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Sandwich-structured nanocomposites of N-doped graphene and nearly monodisperse Fe304 nanoparticles as high-performance Li-ion battery anodes

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Nano Research 2017年第9期10卷 2923-2933页

作者： Wen Qi Xuan Li Hui Li Weikang Wu Pei Li Ying Wu Chunjiang Kuang Shaoxiong Zhou Xiaolin Li Beijing Key Laboratory of Energy Nanomaterials Advance Technology & Materials Co. Ltd. China Iron & Steel Research Institute Group Beijing 10008 I China School of Materials Science and Engineering Tianjin University Tianjin 300072 China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education Shandong University Jinan250061 China Department of Stationary Energy Storage Pacific Northwest National Laboratory Richland Washington 99354 USA

iron oxides have attracted considerable interest as abundant materials for high-capacity Li-ion battery anodes. However, their fast capacity fading owing to poorly controlled reversibility of the conversion reactions greatly hinders their application. Here, a sandwich-structured nanocomposite of N-doped graphene and nearly monodisperse Fe3O4 nanoparticles were developed as high-performance Li-ion battery anode. N-doped graphene serves as a conducting framework for the self-assembled structure and controls Fe3O4 nucleation through the interaction of N dopants, surfactant molecules, and iron precursors. Fe3O4 nanoparticles were well dispersed with a uniform diameter of ~15 nm. The unique sandwich structure enables good electron conductivity and Li-ion accessibility and accommodates a large volume change. Hence, it delivers good cycling reversibility and rate performance with a capacity of ~1,227 mA·h·g–1 and 96.8% capacity retention over 1,000 cycles at a current density of 3 A·g–1. Our work provides an ideal structure design for conversion anodes or other electrode materials requiring a large volume change.

关键词： N-doped graphene iron oxides self-assembly Li-ion battery density functional theory

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