Commissioning and first results of the LNLS XAFS beamline

Tolentino, H.; Cezar, J. C.; Cruz, Daniel; Compagnon-Cailhol, V.; Tamura, E.; Alves, Maria do Carmo Martins

doi:10.1107/s0909049597015264

Cited by 85 publications

(54 citation statements)

References 7 publications

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“…Air was used in the I o , I t , and I r chambers. Owing to the low critical energy of the LNLS storage ring (2.08 keV), third order harmonic contamination of the Si(111) monochromatic beam is expected to be negligible above 5 keV [17].…”

Section: Methodsmentioning

confidence: 99%

Electrochemical and physical characterization of Ni-Cu-Fe alloy for chlor-alkali hydrogen cathodes

Giz¹,

Marengo²,

Ticianelli³

et al. 2003

Eclet. Quím.

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This work describes the development of an alternative acetate bath for the electrochemical codeposition of Ni-Cu-Fe electrodes at low pH that is stable for several weeks and produces electrodes with good performance for chlor-alkali electrolysis. Physical characterization of the electrode surface was made using X ray absorption spectroscopy (XAS), scanning electron microscopy (SEM) and energy dispersive analysis (EDX). The evaluation of the material as electrocatalyst for the hydrogen evolution reaction (her) was carried out in brine solution (160 g L -1 NaCl + 150 g L -1 NaOH) at different temperatures through steady-state polarization curves. The Ni-Cu-Fe electrodes obtained with this bath have shown low overpotentials for the her, around 0.150 V at 353 K, and good stability under continuous long-term operation for 260 hours. One positive aspect of this cathode is that the polarization behavior of the material shows only one Tafel slope over the temperature range of 298 -353 K.

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Section: Methodsmentioning

confidence: 99%

Electrochemical and physical characterization of Ni-Cu-Fe alloy for chlor-alkali hydrogen cathodes

Giz¹,

Marengo²,

Ticianelli³

et al. 2003

Eclet. Quím.

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“…It is equipped with a Si (111) 113 channel cut monochromator calibrated at the inflexion point of the absorption edge for the pure 114 element Ni (8333 eV), obtained by transmission (Tolentino et al, 1998(Tolentino et al, , 2001). The spectra were 115…”

Section: Exafs Data Collection and Analysis 111mentioning

confidence: 99%

EXAFS and XRD studies in synthetic Ni-fluorohectorite

Michels

Ribeiro

Mundim

et al. 2014

Applied Clay Science

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16In the present work the synthetic clay mineral fluorohectorite was studied by means of extended X-17 ray absorption fine structure (EXAFS) in a powder sample with the intention to observe the number 18 of neighbouring atoms to the Ni interlayer cation. In addition X-ray Diffraction (XRD) was 19 performed in order to follow the hydration states of Ni-fluorohectorite in terms of basal-spacing 20 measurements. The sample conditions were the same for both types of experiments. The EXAFS 21 results show that Ni 2+ forms a Brucite-like structure in the form of Ni(OH)2, and that this structure 22 coexists with the clay mineral particles. This shows that the Ni atom observed by means of our 23 EXAFS measurements is predominantly the Ni which composes the Brucite-like structure and not 24 the interlayer Ni 2+ cation. In order to confirm the formation of the Brucite-like structure, the 25 EXAFS data from Ni-fluorohectorite were compared to Ni-salt water solutions at various pH.

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“…In the XAS measurements, x-ray absorption near edge (XANES) and extended x-ray absorption fine structure (EXAFS) spectra were acquired at the Co, Fe, and Cu K-edges using the XAS beam line facility at the Laboratório Nacional de Luz Síncrotron (LNLS). 16 The reference spectra of the Cu (fcc), Fe (bcc), and Co (hcp) standard foils were also measured for comparison and data analysis purposes. The spectra of the samples were measured in fluorescence mode using a Si͑Li͒ detector, with the x-ray beam polarization vector in the plane of the samples.…”

Section: Experimental Methodsmentioning

confidence: 99%

Structural modifications in FexCo1−x∕Cu multilayers induced by ion irradiation

Graff

Teixeira

Amaral

et al. 2004

Journal of Applied Physics

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The structural evolution of Fe 30 Co 70 / Cu multilayers under ion irradiation is investigated in detail using x-ray techniques. The samples were irradiated with two different ions, 50 keV of He + and 600 keV of Kr + , at room temperature. No substantial changes were observed after He + irradiation; the He + ions promote some disorder in the FeCo layers, an increase of the Cu͑111͒ texture, and grain size. After Kr + irradiation a structural phase transition from bcc to fcc occurs in the FeCo layers. A very pronounced increase of the Cu͑111͒ texture and grain size is also observed. According to the equilibrium phase diagrams such fcc phase is not expected for the FeCo alloy at the composition of Fe 30 Co 70 . This fcc phase is imposed by the Cu fcc structure of the adjacent layers, which induce the regrowth of the FeCo layers structure from bcc to fcc during the relaxation period of the atomic collision cascades. Also, after the Kr + irradiation a multilayer structure still persists, as showed by the x-ray reflectivity.

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Commissioning and first results of the LNLS XAFS beamline

Cited by 85 publications

References 7 publications

Electrochemical and physical characterization of Ni-Cu-Fe alloy for chlor-alkali hydrogen cathodes

Electrochemical and physical characterization of Ni-Cu-Fe alloy for chlor-alkali hydrogen cathodes

EXAFS and XRD studies in synthetic Ni-fluorohectorite

Structural modifications in FexCo1−x∕Cu multilayers induced by ion irradiation

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