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Catalytic performance of iron carbide for carbon monoxide hydrogenation

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Journal of Natural Gas Chemistry 2010年第5期19卷 468-470页

作者： Minglin Xian Juan Zou Qinghua Li Xichun She Hunan Changling Petrochemical S＆T Developing Co. Ltd. Yueyang 414012 Hunan China

Novel iron carbide and potassium-promoted iron carbide catalysts were prepared and investigated for CO hydrogenation. The iron carbide showed high activity for CO hydrogenation under high pressures; with the addition of potassium, activity and selectivity to C5＋ hydrocarbons were greatly enhanced, and the selectivity to methane was suppressed under high pressure.

关键词： iron carbide potassium carbon monoxide hydrogenaion

Boosting CO_(2) hydrogenation to high-value olefins with highly stable performance over Ba and Na co-modified Fe catalyst

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Journal of Energy Chemistry 2023年第5期80卷 614-624,I0014页

作者： Joshua Iseoluwa Orege Na Liu Cederick Cyril Amoo Jian Wei Qingjie Ge Jian Sun Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

CO_(2)hydrogenation has been considered to be a highly promising route for the production of high-value olefins(HVOs)while also mitigating CO_(2)***,it is challenging to achieve high selectivity and maintain stable performance for HVOs(ethylene,propylene,and linear a-olefins)over a prolonged reaction time due to the difficulty in precise control of carbon coupling and rapid catalyst ***,we present a selective Ba and Na co-modified Fe catalyst enriched with Fe_(5)C_(2)and Fe_(3)C active sites that can boost HVO synthesis with up to 66.1%selectivity at an average CO_(2)conversion of 38%for over 500 *** to traditional NaFe catalyst,the combined effect of Ba and Na additives in the NaBaFe-0.5 catalyst suppressed excess oxidation of FeCxsites by H_(2)*** absence of Fe3O4phase in the spent NaBaFe-0.5 catalyst reflects the stabilization effect of the co-modifiers on the *** study provides a strategy to design Fe-based catalysts that can be scaled up for the stable synthesis of HVOs from CO_(2)hydrogenation.

关键词： CO_(2)hydrogenation High-value olefins Barium additive iron carbide Catalytic stability

First-principles calculations of high pressure and temperature properties of Fe_(7)C_(3)

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Chinese Physics B 2023年第7期32卷 625-630页

作者：范莉莉刘勋高畅刘中利李艳丽黄海军 School of Science Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Eckstrom-adcock iron carbide(Fe_(7)C_(3))is considered to be the main constituent of the Earth’s inner core due to its low shear wave ***,the crystal structure of Fe_(7)C_(3)remains controversial and its thermoelastic properties are not well constrained at high temperature and *** on the first-principles simulation method,we calculate the relative phase stability,equation of state,and sound velocity of Fe_(7)C_(3)under core *** results indicate that the orthorhombic phase of Fe_(7)C_(3)is stable under the core *** Fe_(7)C_(3)does reproduce the low shear wave velocity and high Poisson’s ratio of the inner core,its compressional wave velocity and density are 12%higher and 6%lower than those observed in seismic data,***,we argue that carbon alone cannot completely explain the thermal properties of the inner core and the inclusion of other light elements may be required.

关键词： iron carbide phase stability thermoelastic properties sound velocities inner core

Hetero-Epitaxial Diamond Single Crystal Growth on Surface of cBN Single Crystals at High Pressure and High Temperature

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Chinese Physics Letters 2008年第6期25卷 2273-2276页

作者：高峰贾晓鹏马红安郭玮刘晓兵 National Lab of Superhard Materiai Jilin University Changchun 130012 Institute of Materials Science and Engineering Henan Polytechnic University Jiaozuo 454000

We report a new diamond synthesis process in which cubic boron nitride single crystals are used as seeds, FesoNi20 alloy powder is used as catalyst/solvent and natural flake-like graphite is used as the carbon source. The samples are investigated using laser Raman spectra and x-ray diffraction （XRD）. Morphology of the sample is observed by a scanning electron microscope （SEM）. Based on the measurement results, we conclude that diamond single crystals have grown on the cBN crystal seeds under the conditions of high temperature 1230℃ and high pressure 4.8 GPa. This work provides an original method for synthesis of high quality hereto-semiconductor with cBN and diamond single crystals, and paves the way for future development.

关键词： HEXAGONAL BORON-NITRIDE ELECTRONIC-STRUCTURES iron carbide INTERFACE

Active Fischer-Tropsch synthesis Fe-Cu-K/SiO_2 catalysts prepared by autocombustion method without a reduction step

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Journal of Energy Chemistry 2018年第2期27卷 432-438页

作者： Suthasinee Pengnarapat Peipei Ai Prasert Reubroycharoen Tharapong Vitidsant Yoshiharu Yoneyama Noritatsu Tsubaki Program in Petrochemistry Faculty of ScienceChulalongkorn University Department of Applied Chemistry School of EngineeringUniversity of Toyama Department of Chemical Technology Faculty of ScienceChulalongkorn University

The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis（FTS） without a reduction step. The effect of different citric acid（CA）：iron nitrate（N） molar ratios and acid types on the FTS performance of catalysts were investigated. The CA：N molar ratios had an important influence on the formation of iron active phases and FTS activity. The iron carbide（FexC）, which is known to be one of the iron active phases, was demonstrated by the X-ray diffraction and X-ray photoelectron spectroscopy. Increasing the CA：N molar ratios up to 0.1 increased CO conversion of catalyst to 86.5%, which was then decreased markedly at higher CA：N molar ratios. An excess of CA resulted in carbon residues covering the catalyst surface and declined FTS activity. The optimal catalyst（CA：N molar ratio = 0.1） achieved the highest CO conversion when compared with other autocombustion catalysts as well as reference catalyst prepared by impregnation method, followed by a reduction step. The autocombustion method had the advantage to synthesize more efficient catalysts without a reduction step. More interestingly, iron-based FTS catalysts need induction duration at the initial stage of FTS reaction even after reduction, because metallic iron species need time to be transformed to FexC. But here, even if without reduction, FexC was formed directly by autocombustion and induction period was eliminated during FTS reaction.

关键词： Fischer-Tropsch synthesis iron-based catalysts Autocombustion iron carbide SiO2

Effect of hydrogen plasma treatment on the growth and microstructures of multiwalled carbon nanotubes

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Nano-Micro Letters 2010年第1期2卷 42-48页

作者： S.K.Srivastava V.D.Vankar V.Kumar Department of Physics Indian Institute of Technology Delhi National Physical Laboratory Dr.K.S.Krishnan Marg

The effect of hydrogen plasma treatment of iron oxide films on the growth and microstructure of carbon nanotubes(CNTs)by microwave plasma enhanced chemical vapor deposition process has been *** plasma was characterized in-situ using optical emission *** of the films was examined by scanning electron *** analysis was carried out by high resolution transmission electron microscopy(HRTEM)equipped with energy dispersive X-ray spectroscopy(EDS)and micro-diffraction *** is found that oxide films without H_2 plasma pretreatment or treated for lesser time resulted in CNT films with high percentage of carbonaceous particles and with embedded particles/nanorods distributed discontinuously in the cavity of the *** embedded particles were found to be of iron carbide(Fe-C)as confirmed by HRTEM,EDS and micro-diffraction *** observations suggested that the iron oxide particles had poor catalytic action for CNT growth and in-situ reduction of oxide clusters to Fe by hydrogen plasma plays a key role in discontinuous filling of the nanotubes by the catalytic particles.

关键词： Carbon nanotubes Chemical vapor deposition iron carbide MPECVD

XRD Synchrotron Study of carbide Precipitation in Martensitic Steels During Tempering

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Acta Metallurgica Sinica(English Letters) 2013年第5期26卷 553-557页

作者： C.Bellot P.Lamesle D.Delagnes Universit de Toulouse Mines Albi INSAISAE ICA(Institut Clment Ader) Campus Jarlard Aubert&Duval

In order to improve the knowledge of the precipitation mechanism in martensitic steels containing carbon,XRD synchrotron experiments were performed. Firstly, the influence of Ni,Co and Al were studied and it was found that the precipitation of iron carbides occurs in same way as in Fe-C steel. However, with the addition of molybdenum and chromium in same steels, XRD synchrotron investigations clearly showed alloyed carbides directly precipitate, thereby preventing the iron carbides formation.

关键词： Carbon Martensite iron carbide Cementite Precipitation mechanism

Research Trends in Fischer-Tropsch Catalysis for Coal to Liquids Technology

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Frontiers of Engineering Management 2016年第4期3卷 321-330页

作者： Emiel J.M.Hensen Peng Wang Wayne Xu Laboratory of Inorganic Materials Chemistry Schuit Institute of CatalysisDepartment of Chemical Engineering and ChemistryEindhoven University of Technology National Institute of Clean-and-Low-Carbon Energy (NICE) Shenhua NICEFuture Science & Technology City

Fischer–Tropsch Synthesis(FTS) constitutes catalytic technology that converts synthesis gas to synthetic liquid fuels and *** synthesis gas can be obtained from any carbonaceous feedstock,current industrial FTS operations are almost exclusively based on natural *** to the energy structure of China where cheap coal is abundant,coal to liquids(CTL) technology involving coal gasification,FTS and syncrude upgrading is increasingly being considered as a viable option to convert coal to clean transportation *** this brief paper,we review some pertinent issues about Fe-and Co-based FTS *** is better suited to convert synthesis gas derived from coal gasification into *** authors limit themselves to noting some important trends in the research on Fe-based *** focus on the preparation of phase-pure carbides and innovative cheap synthesis methods for obtaining active and stable *** approaches should be augmented by(1) computational investigations that are increasingly able to predict not only mechanism,reaction rates and selectivity but also optimum catalyst composition,as well as(2) characterization of the catalytic materials under conditions close to the operation in real reactors.

关键词： Fischer–Tropsch FTS CTL Fe catalyst iron carbide computational modeling

Theoretical study of the strain effects on CO activation by Fe_(2)C confined with graphene

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分子科学学报 2024年第3期40卷 233-238页

作者： ZHU Jialiang LI Zhe ZHANG Yuhua LI Yongxiu LI Jinlin Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education&Hubei Key Laboratory of Catalysis and Materials Science South-Central Minzu UniversityWuhan 430074China

The intrinsic strains at the confinement interface of iron carbide with graphene play important roles in the catalytic Fischer-Tropsch *** this study,we performed theoretical study of the biaxial strain effects on the CO adsorption and dissociation on the Fe_(2)C(121)surface covered by graphene(Fe_(2)C@graphene).By varying the lattice strains within a range of±5%,the apparent energy barriers(E_(a,app))correlate with the adsorption energies(E_(ad))in nonlinear scaling relations for the direct and H-assisted CO dissociation at the Fe_(2)C active sites,which is normal Br∅nsted-Evans-Polanyi relation for those at the graphene *** nonlinear scaling relations can be interpreted by the strain effects on the confinement distances in the adsorption and transition *** study provides a deep understanding of the intrinsic strain effects of Fe_(2)C@graphene for CO activation.

关键词： strain effect iron carbide confinement effect graphene Fischer-Tropsch synthesis