Low Temperature Formation of Iron Carbide from Iron Oxide with CO-H2Gas Mixtures

2007 ◽  
Vol 78 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Alberto N. Conejo ◽  
Raul S. Estrada
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Iron Carbide

Utilizing the Oxygen Carrier Property of Cerium Iron Oxide for the Low-Temperature Synthesis of 1,3-butadiene from 1-butene

2021 ◽  
Author(s):  
Aswathy T. Venugopalan ◽  
Prabu Kandasamy ◽  
Pranjal Gogoi ◽  
Jha Ratneshkumar ◽  
Raja Thirumalaiswamy
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Oxygen Carrier ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis

scholarly journals Influence of Phase Composition and Pretreatment on the Conversion of Iron Oxides into Iron Carbides in Syngas Atmospheres

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 773
Author(s):  
Aleks Arinchtein ◽  
Meng-Yang Ye ◽  
Michael Geske ◽  
Marvin Frisch ◽  
Ralph Kraehnert
Keyword(s):  
Phase Composition ◽  
Iron Oxide ◽  
Self Assembly ◽  
Iron Carbide ◽  
Active Phase ◽  
Physicochemical Analysis ◽  
Carbide Formation ◽  
Iron Carbides ◽  
Carbide Phases ◽  
Higher Hydrocarbons

CO2 Fischer–Tropsch synthesis (CO2–FTS) is a promising technology enabling conversion of CO2 into valuable chemical feedstocks via hydrogenation. Iron–based CO2–FTS catalysts are known for their high activities and selectivities towards the formation of higher hydrocarbons. Importantly, iron carbides are the presumed active phase strongly associated with the formation of higher hydrocarbons. Yet, many factors such as reaction temperature, atmosphere, and pressure can lead to complex transformations between different oxide and/or carbide phases, which, in turn, alter selectivity. Thus, understanding the mechanism and kinetics of carbide formation remains challenging. We propose model–type iron oxide films of controlled nanostructure and phase composition as model materials to study carbide formation in syngas atmospheres. In the present work, different iron oxide precursor films with controlled phase composition (hematite, ferrihydrite, maghemite, maghemite/magnetite) and ordered mesoporosity are synthesized using the evaporation–induced self–assembly (EISA) approach. The model materials are then exposed to a controlled atmosphere of CO/H2 at 300 °C. Physicochemical analysis of the treated materials indicates that all oxides convert into carbides with a core–shell structure. The structure appears to consist of crystalline carbide cores surrounded by a partially oxidized carbide shell of low crystallinity. Larger crystallites in the original iron oxide result in larger carbide cores. The presented simple route for the synthesis and analysis of soft–templated iron carbide films will enable the elucidation of the dynamics of the oxide to carbide transformation in future work.

Microstructural comparison of calcined and uncalcined gold/iron-oxide catalysts for low-temperature CO oxidation

2002 ◽  
Vol 72 (1-2) ◽  
pp. 133-144 ◽  
Author(s):  
N.A Hodge ◽  
C.J Kiely ◽  
R Whyman ◽  
M.R.H Siddiqui ◽  
G.J Hutchings ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Co Oxidation ◽  
Oxide Catalysts ◽  
Low Temperature Co Oxidation

scholarly journals Pre-Reduction of Au/Iron Oxide Catalyst for Low-Temperature Water-Gas Shift Reaction Below 150 °C

Catalysts ◽  
2011 ◽  
Vol 1 (1) ◽  
pp. 175-190 ◽  
Author(s):  
Shinji Kudo ◽  
Taisuke Maki ◽  
Takashi Fukuda ◽  
Kazuhiro Mae
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Oxide Catalyst ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Iron Oxide Catalyst ◽  
Shift Reaction ◽  
Water Gas ◽  
Temperature Water

Synthesis and crystallogenesis at low temperature of Fe(III)-smectites by evolution of coprecipitated gels: experiments in partially reducing conditions

Clay Minerals ◽  
1986 ◽  
Vol 21 (5) ◽  
pp. 861-877 ◽  
Author(s):  
A. Decarreau ◽  
D. Bonnin
Keyword(s):  
Crystal Growth ◽  
Iron Oxide ◽  
Low Temperature ◽  
Oxide Phase ◽  
Octahedral Sheet ◽  
Reducing Conditions ◽  
Iron Oxide Phase

AbstractSyntheses of ferric smectites were performed at low temperature (75° C by aging coprecipitated gels of silica and Fe2+-sulphate under initially reducing then oxidizing conditions. Under strictly reducing conditions only nuclei of a trioctahedral ferrous stevensite were observed and crystal growth did not take place. When a spontaneous oxidization, in contact with air, was effected, the ferrous smectite nuclei transformed rapidly into a ferric, nontronite-like, smectite. Crystallogenesis of the ferric smectite was studied by XRD, IR, DTA, Mössbauer and EPR spectroscopies. The end-synthesis smectite contained only Fe3+ions, all located in the octahedral sheet. This clay was mixed with a cryptocrystalline iron oxide phase containing one-third of the iron atoms and undetectable by XRD.

Electron Energy Loss Spectroscopy (EELS) of Iron Fischer–Tropsch Catalysts

2006 ◽  
Vol 12 (2) ◽  
pp. 124-134 ◽  
Author(s):  
Yaming Jin ◽  
Huifang Xu ◽  
Abhaya K. Datye
Keyword(s):  
Iron Oxide ◽  
Energy Loss ◽  
Electron Energy ◽  
Amorphous Carbon ◽  
Electron Energy Loss Spectroscopy ◽  
Iron Carbide ◽  
Iron Catalysts ◽  
Fischer Tropsch ◽  
Iron Phase ◽  
Electron Energy Loss

Electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy have been used to study iron catalysts for Fischer–Tropsch synthesis. When silica-containing iron oxide precursors are activated in flowing CO, the iron phase segregates into iron carbide crystallites, leaving behind some unreduced iron oxide in an amorphous state coexisting with the silica binder. The iron carbide crystallites are found covered by characteristic amorphous carbonaceous surface layers. These amorphous species are difficult to analyze by traditional catalyst characterization techniques, which lack spatial resolution. Even a surface-sensitive technique such as XPS shows only broad carbon or iron peaks in these catalysts. As we show in this work, EELS allows us to distinguish three different carbonaceous species: reactive amorphous carbon, graphitic carbon, and carbidic carbon in the bulk of the iron carbide particles. The carbidic carbon K edge shows an intense “π*” peak with an edge shift of about 1 eV to higher energy loss compared to that of the π* of amorphous carbon film or graphitic carbon. EELS analysis of the oxygen K edge allows us to distinguish the amorphous unreduced iron phase from the silica binder, indicating these are two separate phases. These results shed light onto the complex phase transformations that accompany the activation of iron catalysts for Fischer–Tropsch synthesis.

The role of iron oxide in the highly effective Fe-modified Co3O4 catalyst for low-temperature CO oxidation

RSC Advances ◽  
2013 ◽  
Vol 3 (30) ◽  
pp. 12409 ◽  
Author(s):  
Jie Li ◽  
Guanzhong Lu ◽  
Guisheng Wu ◽  
Dongsen Mao ◽  
Yanglong Guo ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Co Oxidation ◽  
Highly Effective ◽  
Low Temperature Co Oxidation
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