26508-33-8Relevant articles and documents
Helical magnetic structure and hyperfine interactions in FeP studied by 57Fe M?ssbauer spectroscopy and 31P NMR
Sobolev, Alexey V.,Presniakov, Igor A.,Gippius, Andrey A.,Chernyavskii, Ivan V.,Schaedler, Martina,Buettgen, Norbert,Ibragimov, Sergey A.,Morozov, Igor V.,Shevelkov, Andrei V.
, p. 277 - 285 (2016)
We report results of 57Fe M?ssbauer and 31P NMR studies of a phosphide FeP powder sample performed in a wide temperature range including the point (TN ≈ 120 K) of magnetic phase transitions. The 57Fe M?ssbauer spectra at low temperatures T N present a very complex Zeeman pattern with line broadenings and sizeable spectral asymmetry. It was shown that the change of the observed spectral shape is consistent with the transition into a space-modulated helicoidal magnetic structure. Analysis of the experimental spectra was carried out assuming an anisotropy of the magnetic hyperfine field Hhf at the 57Fe nuclei when the Fe3+ magnetic moment rotates with respect to the principal axis of the electric field gradient (EFG) tensor. The obtained large temperature independent anharmonicity parameter m ≈ 0.96 of the helicoidal spin structure results from easy-axis anisotropy in the plane of the iron spin rotation. It was assumed that a very low maximal value of Hhf(11 K) ≈ 36 kOe and its high anisotropy ΔHanis(11 K) ≈ 30 kOe can be attributed to the stabilization of iron cations in the low-spin state (SFe = 1/2). The 31P NMR measurements demonstrate an extremely broad linewidth reflecting the spatial distribution of the transferred internal magnetic fields of the Fe3+ ions onto P sites in the magnetically ordered state.
Superconductivity of the "1 1 1" type iron pnictide LiFeP
Deng,Wang,Liu,Zhang,Lv,Zhu,Yu,Jin
, p. S309-S310 (2010)
We report studies on a new iron based LiFeP superconductor. The compound takes the same structure to LiFeAs containing a "FeP" conduction layer. Superconductivity was achieved up to 6 K. The new superconductor is featured with itinerant behavior at normal
The Enhanced CO Tolerance of Platinum Supported on FeP Nanosheet for Superior Catalytic Activity Toward Methanol Oxidation
Wang, Yajing,Du, Chunyu,Sun, Yongrong,Han, Guokang,Kong, Fanpeng,Yin, Geping,Gao, Yunzhi,Song, Ying
, p. 36 - 43 (2017)
The inferior CO-like intermediates tolerance of Pt nanoparticle greatly hampered the MOR activity and durability. To alleviate this issue, tremendous efforts have been made to create oxygen-containing groups on neighbouring Pt site for oxidizing the poisonous carbonaceous species. Given this, two-dimensional FeP nanosheet with excellent HER activity was utilized as support and cocatalyst. FeP nanosheet with special Feδ+ and Pδ? active sites was conductive to mass transfer, fast charge transfer and facilitating water dissociation for generating OH species to removal CO-like intermediates on Pt sites. The XRD, XPS, SEM and TEM analysis demonstrated that the Pt nanoparticle with an average size of 3.68 nm was successfully deposited on the FeP nanosheet surface. The methanol oxidation experiments in acidic medium revealed that the as-prepared binary Pt/FeP nanosheet hybrid exhibited superior MOR activity with enhanced anodic peak current density of 0.994 mA/cm2, which was 2.74-fold greater than that of commercial Pt/C, and the intensive CO oxidation peak potential was negatively shifted about 100 mV with respect to that of Pt/C. The better CO tolerance of Pt/FeP nanosheet hybrid might be attributed to cooperative effect from down-shifted d-band center of Pt, abundant hydroxyls on the Pt/FeP and special activity of Feδ+ and Pδ?. In addition, this hybrid electrocatalyst also showed relatively higher HER activity compared with that of Pt/C. This study provides a promising application of metal phosphide in methanol oxidation for enhancing CO resistance capability of Pt-based catalyst.
De Haas-van alphen effect of FeP in double helical magnetic state
Nozue, Tatsuhiro,Kobayashi, Hisao,Kimura, Noriaki,Aoki, Haruyoshi,Kamimura, Takashi
, p. 192 - 198 (2001)
The de Haas-van Alphen (dHvA) effect has been investigated on high-quality single crystals of FeP in a double helical magnetic state with a 5c period in the magnetic fields up to 14 T and at temperatures down to 0.42 K. Single crystals were grown by the chemical transport technique using iodine as the transport agent. Nineteen branches were observed in three crystallographic planes (100), (010) and (001), and analyzed with simple analytic equations for the Fermi surfaces. Many of the dHvA branches have a characteristic angular dependence and are found to correspond to the orbits on surfaces beyond the Brillouin zone in the magnetic state which is reduced to 1/5 of the non-magnetic one with the MnP-type along the [001] direction. These branches originate from the orbits caused by a magnetic breakdown phenomenon under high fields. Cyclotron mass ratios were obtained to be up to 5.9, whereas the electronic specific heat coefficient is rather small, 2.86 mJK-2mol-1.
De Haas-van Alphen effect and transverse magnetoresistance in FeP
Nozue, Tatsuhiro,Saito, Akira,Kobayashi, Hisao,Yamagami, Hiroshi,Kamimura, Takashi
, p. 1509 - 1510 (2000)
The 3d transition metal monopnictides show various interesting electric and magnetic properties. In this study, we have measured the dHvA effect and the transverse magnetoresistance in FeP which has the MnP-type structure and is antiferromagnetic below 12
Preparation of iron phosphide particles from an aqueous solvent of oxygen-contained precursors using spray pyrolysis
Koo, Kee Young,Park, Seung Bin
, p. 3767 - 3772 (2007)
Iron phosphides were prepared by an economically feasible spray pyrolysis method, in which nontoxic and inexpensive precursors are used in an aqueous solution. The addition of NaCl to the precursor solution promoted crystal growth at a low temperature and helped to avoid sintering during posttreatment. The key conclusion is that the stoichiometry, shape, and size of the particles are related to the NaCl/Fe molar ratio and the posttreatment temperature. Below the melting temperature of NaCl, the shape and stoichiometry of the particles depended on the NaCl/Fe molar ratio, while above the melting temperature, they were dominated by the posttreatment temperature. Wire-like particles were formed at a NaCl/Fe molar ratio over 15.
Design and fabrication of Fe2O3/FeP heterostructure for oxygen evolution reaction electrocatalysis
Ahmad, Iqbal,Ahmed, Jawad,Batool, Saima,Dahshan, Alaa,Hanif, Amna,Idrees, Muhammad,Jabeen, Uzma,Nazar, Muhammad Faizan,Shehzadi, Syeda Aalia,Ul-Hamid, Anwar,Zafar, Muhammad Nadeem,Zahidullah
, (2021/11/01)
The production of an inexpensive, highly active electrocatalyst for a simple oxygen evolution reaction (OER) based on earth-abundant transition metals is still a major challenge. In addition, the ambiguity of the water splitting reaction (hydrogen evolution and OER) is a hurdle in the manufacture of suitable catalysts for the efficient water electrolysis process. Here, the synthesis of iron oxide/iron phosphide (Fe2O3/FeP) heterostructure and its counterparts Fe2O3 and FeP as cheap electrocatalysts for water electrolysis is presented. Characterization techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to analyze the structure of these electrocatalysts. Heterostructure Fe2O3/FeP has been shown to be a more active electrocatalyst than its counterparts. It initiates OER at a remarkably low potential of 1.49 V vs. reverse hydrogen electrode (RHE). For this electrocatalyst, a current density of 10 mA/cm2 is achieved at an overpotential of 264 mV for OER in 1.0 M potassium hydroxide solution and the value of the Tafel slope is 47 mV dec?1, outperforming its complements (Fe2O3 and FeP) under similar conditions. The results obtained are superior to those of previously reported Fe-based OER electrocatalysts. The Fe2O3/FeP electrocatalyst has proven its long-term stability by driving OER at 1.65 V (vs. RHE) for about 12.5 h.
Lattice Matched Carbide-Phosphide Composites with Superior Electrocatalytic Activity and Stability
Regmi, Yagya N.,Roy, Asa,King, Laurie A.,Cullen, David A.,Meyer, Harry M.,Goenaga, Gabriel A.,Zawodzinski, Thomas A.,Labbé, Nicole,Chmely, Stephen C.
, p. 9369 - 9377 (2017/11/20)
Composites of electrocatalytically active transition-metal compounds present an intriguing opportunity toward enhanced activity and stability. To identify potentially scalable pairs of a catalytically active family of compounds, we demonstrate that phosphides of iron, nickel, and cobalt can be deposited on molybdenum carbide to generate nanocrystalline heterostructures. Composites synthesized via solvothermal decomposition of metal acetylacetonate salts in the presence of highly dispersed carbide nanoparticles show hydrogen evolution activities comparable to those of state-of-The-Art non-noble metal catalysts. Investigation of the spent catalyst using high resolution microscopy and elemental analysis reveals that formation of carbide-phosphide composite prevents catalyst dissolution in acid electrolyte. Lattice mismatch between the two constituent electrocatalysts can be used to rationally improve electrochemical stability. Among the composites of iron, nickel, and cobalt phosphide, iron phosphide displays the lowest degree of lattice mismatch with molybdenum carbide and shows optimal electrochemical stability. Turnover rates of the composites are higher than that of the carbide substrate and compare favorably to other electrocatalysts based on earth-abundant elements. Our findings will inspire further investigation into composite nanocrystalline electrocatalysts that use molybdenum carbide as a stable catalyst support.
