1345-25-1Relevant academic research and scientific papers
Reduction of FeO/Pt(1 1 1) thin films by exposure to atomic hydrogen
Knudsen, Jan,Merte, Lindsay R.,Grabow, Lars C.,Eichhorn, Falk M.,Porsgaard, Soeren,Zeuthen, Helene,Vang, Ronnie T.,L?gsgaard, Erik,Mavrikakis, Manos,Besenbacher, Flemming
, p. 11 - 20 (2010)
Using scanning tunneling microscopy (STM), X-ray photoemission spectroscopy (XPS) and density functional theory (DFT) calculations we have studied the reduction of ultra-thin films of FeO(1 1 1) grown on Pt(1 1 1) after exposure to atomic hydrogen at room temperature. A number of new ordered, partly-reduced FeOx structures are identified and as a general trend we reveal that all the reduced FeOx structures incorporate 2-fold coordinated Fe atoms as opposed to the original 3-fold coordinated Fe atoms in the FeO film. We find that when all the Fe atoms are 2-fold O-coordinated the FeOx surface structure is resistant to further reduction at room temperature. We observe that water easily dissociates on the most heavily reduced FeOx, structure in contrast to the initially inert FeO film, and reveal that it is possible to partially re-oxidize the FeOx film by heating the surface slightly in the presence of water.
Studies on structural, magnetic and thermal properties of xFe 2TiO4-(1-x)Fe3O4 (0≤x≤1) pseudo-binary system
Sorescu, Monica,Xu, Tianhong,Wise, Adam,Díaz-Michelena, Marina,McHenry, Michael E.
, p. 1453 - 1462 (2012)
The xFe2TiO4-(1-x)Fe3O4 pseudo-binary systems (0≤x≤1) of ulv?spinel component were synthesized by solid-state reaction between ulv?spinel Fe 2TiO4 precursors and commercial Fe3O
Radiative lifetimes of the FeO orange system
Son,Lee,Shin,Ku
, p. 658 - 664 (2000)
The ground-state FeO molecules are generated from photolysis of Fe(CO)5 in a Fe(CO)5/M(O2 or N2O)/Rg(He or Ar) mixture using an unfocused weak UV laser beam. The formation of ground-state FeO molecules is identified by a laser-induced fluorescence (LIF) method. The LIF signal from FeO molecules is stronger in O2 than in N2O at the same partial pressures. The radiative lifetimes for seven bands in the FeO orange system are measured. They are substantially different depending on the excited band ranging from 260±30 ns to 590±50 ns.
REACTION PROCESS BETWEEN alpha -IRON(III) OXIDE AND SULFUR DIOXIDE IN THE PRESENCE OF CARBON.
Araki,Ryoo,Eguchi,Matsuzaki,Saeki
, p. 2271 - 2274 (1980)
The reaction products obtained by heating a mixture of alpha -Fe//2O//3 and carbon in a SO//2 stream at various temperatures were examined. The possible reactions during the above process were also examined The solid products obtained by heating a mixture of alpha -Fe//2O//3 and carbon in a SO//2 stream were Fe//3O//4 at 500 - 700 degree C, pyrrhotite and Fe//3O//4 at 750 degree C, and pyrrhotite (Fe//0//. //8//8S) alone at 800 degree C. Sulfur was obtained outside the heating zone throughout the temperature range. The reaction between carbon and SO//2 occurs even at 350 degree C to form sulfur, and the reaction proceeds markedly above ca. 700 degree C. Above ca. 500 degree C, the reductions of alpha -Fe//2O//3 with carbon and sulfur occur to form Fe//3O//4. Above ca. 750 degree C, pyrrhotite is formed by the reaction between Fe//3O//4 and sulfur. These results were supported by the thermodynamical consideration based on the chemical potential diagram for the Fe-S-C-O system.
Hard magnetic nanocrystalline alloys of Fe-Fe2O3 system
Lileev,Yagodkin,Grishina,Khanenya,Nefedov,Popova
, p. 1217 - 1220 (2005)
The structure and magnetic properties of Fe2O3 and Fe powders as well as their mixtures, subjected to treatment in a high-energy ball mill, were studied. It was shown that the phase composition of all the starting materials (except that of the Fe powder) was changed in the milling process. The nanocrystalline composite alloys, containing FeO and α-Fe with an average crystallite size of 10-20 nm as well as an amorphous phase, were obtained as a result of the milling. Phase content in the milled powders depended on the composition of the starting materials. Unlike the starting materials, the milled powders (except of the milled Fe powder and Fe 2O3+90% Fe mixture) had the properties, which are characteristic for hard magnetic materials. Further improvement of the properties was achieved by low-temperature annealing of the milled powders. The annealed powders of the mixtures contained only nanocrystallites of α-Fe and Fe3O4. The amount of these constituents and the magnetic properties of the annealed powders depended on the composition of the starting materials. The sufficiently high properties of the produced powders may be explained by the formation of α-Fe and Fe3O4 single-domain particles.
Monolayer iron oxide film on platinum promotes low temperature CO oxidation
Sun,Qin,Lewandowski,Carrasco,Sterrer,Shaikhutdinov,Freund
, p. 359 - 368 (2009)
CO oxidation on a clean Pt(1 1 1) single crystal and thin iron oxide films grown on Pt(1 1 1) was studied at different CO:O2 ratios (between 1:5 and 5:1) and partial pressures up to 60 mbar at 400-450 K. Structural characterization of the model
Cyclic reduction-oxidation of haematite powders
Coombs, P. G.,Munir, Z. A.
, (1989)
The cyclic reduction-oxidation of haematite (Fe2O3) powders was investigated over the temperature range 723 to 873 K. The hydrogeon reduction had an approximate activation energy of 53 KJ mol-1. The air oxidation of the re
M?ssbauer and X-ray diffraction investigation of nanocrystalline Fe-O alloys
Lileev,Yagodkin,Reissner,Steiner
, p. 504 - 506 (2003)
X-ray and M?ssbauer investigations were carried out on powders produced by milling of Fe2O3 + α-Fe mixtures in a high-energy ball mill and subsequent low-temperature annealing. The nanocrystalline composite alloys obtained as a result of the milling, contained FeO and α-Fe with an average crystallite size of 15-20nm as well as an amorphous phase. Alloys subjected to subsequent annealing contained, however, only α-Fe + Fe3O4 with an average crystallite size of about 20nm. Unlike the starting materials the produced powders had properties, which are characteristic for hard magnetic materials.
Structural, magnetic and electrical properties of CoSi ferrites synthesized by sol-gel self-propagating method
Tao, Zheng-Xiong,Li, Le-Zhong,Wu, Xiao-Hui,Zhong, Xiao-Xi,Zhong, Zi-Chen
, (2021)
CoFe2O4 is mainly used in magnetic strain sensor, magnetic resonance imaging, supercapacitor, cryogen, high density magnetic recording medium and magneto-optical devices and so on. In this study, SixCo1-xFe
One-dimensional pyrazine bridged M(II)-saccharinato coordination polymers: Synthesis, characterization, crystal structures and thermal studies
Yilmaz, Veysel T.,Senel, Evrim,Kazak, Canan
, p. 3199 - 3204 (2007)
Three new coordination polymers with a general formula [M(sac)2(μ-pyz)(H2O)2]n [M = Mn(II) (1), Fe(II) (2), Co(II) (3), pyz = pyrazine, and sac = saccharinate] have been synthesized and characterized by elemental analyses, IR, UV-VIS, magnetic measurements, thermal analysis techniques and single crystal X-ray diffraction. All three complexes are isomorphous, crystallizing in the triclinic space group P over(1, ?) (No. 2). Each metal(II) ion in 1-3 is octahedrally coordinated by two sac, two pyz and two aqua ligands. The sac ligands are N-coordinated, while the pyz ligands bridge the metal centers leading to an one-dimensional linear chain structure. Intra-chain M-M separations in complexes 1, 2 and 3 are 7.381(2), 7.259(3) and 7.188(3) A?, respectively. The individual chains are linked into two-dimensional layers by O-H?O hydrogen bonds involving the hydrogens of aqua ligands and carbonyl and sulfonyl O atoms of sac ligands. The hydrogen bonded layers are further assembled into three-dimensional supramolecular networks by weak aromatic π?π stacking interactions between the phenyl rings of sac ligands or CH?π interactions involving pyz. These complexes exhibit similar decomposition characteristics. In the first stages, endothermic removal of the aqua and pyz ligand takes place leading to an intermediate probably in the form of [M(sac)2], which undergoes highly exothermic decomposition at higher temperatures to give corresponding metal oxides.
