Is there any beam yet? Uses of synchrotron radiation in the in situ study of electrochemical interfaces

Abruña, Héctor D.; White, James H.; Albarelli, M. J.; Bommarito, G. M.; Bedzyk, M. J.; McMillan, Martin

doi:10.1021/j100336a005

Cited by 53 publications

(29 citation statements)

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“…The Fourier-filtered (0.i < r/nm < 0.32) data were analyzed by using a curve fitting method on the basis of the single scattering plane wave approximation as given in Eq. 3 [3] where k is a wave vector, and Ni, S~(k), ~, and ri represent a coordination number of the ith shell, an amplitude reduction factor, a Debye-Waller-like factor (DW factor) and an interatomic distance of the ith shell, respectively. Theoretical phase shift (~ (k)) and amplitude functions (F~ (k)) were used3 ~ Fitting was carried out between 35 and 135 nm -~.…”

Section: Methodsmentioning

confidence: 99%

In Situ X‐Ray Absorption Fine Structure Study on Structure Transformation and Electronic State of Various Pt Particles on Carbon Electrode

Yoshitake

Ota

1994

J. Electrochem. Soc.

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The structure and electronic state of fine Pt particles on the carbon electrode were investigated by XANES and extended x-ray absorption fine structure (EXAFS) spectroscopies. The white line intensities were processed into the parameter representing the density of unoccupied 5d state. They were described as kinds of voltammograms. It was different between the cathodic sweep and the anodic sweep even in the same potential. The small particle electrode showed large hysteresis of the d-density change. These changes by potential sweep are discussed in relation to the structure of the particle on the basis of the parameters of EXAFS. The large change in the small particle was explained by the ratio of the surface atoms in the whole particle. The thickness of the oxide layer and lattice disorder in subsurface was estimated from these structural parameters.Metal particles often change their physicochemical characteristics when the particle size becomes smaller. The effect in electric double layer has attracted attention recently because of the development of fuel-cell electrodes. Major contributions to exploring the particle size effect were the direct measurement of catalytic activities. One main interest has been the ORR (oxygen reduction reaction) activity per Pt atom when the particle becomes smaller. It is still unclear whether the activity increases with particle size decrease or whether it has an optimum value.1 The catalytic performance of the dispersed electrode often is considered to be closely related with the structure of the particle. 2 Additionally, the charge-transfer rate may be affected by the electronic state of the Pt particle or the surface. For these reasons, spectroscopic studies on dispersed Pt electrodes are required for the understanding of the particle size effect on the metal structure in double layer in addition to helping to develop commercial electrodes with good activities.X-ray absorption spectroscopy (XAS) has been widely used for in situ studies of electrochemical interfaces. 3' 4 It has also offered a deeper understanding of the state of the Pt particle on carbon electrodes. 5-7 The physicochemical parameters given by EXAFS and x-ray absorption nearend structure (XANES) can describe the dynamic transformation of fine particles as well as the structure and the electronic state in the double-layer region. In a previous paper 7 we investigated the relationship of the density of d state with parameters for the first coordination shell of Pt, the electrolyte, and functional groups on the support. The density of unoccupied d state was related to the roughness of the Pt particle lattice, although no Pt-O bond was observed. The reduction/oxidation of the surface functional groups on the support had no effect on the density of d states.The evidence of the oxidation and details of the oxidation process may be obtained by XAS when the particle size is smaller. In this sense, the extent of the oxidation near the surface and of the lattice roughening should be further confirmed by changing the part...

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Section: Methodsmentioning

confidence: 99%

In Situ X‐Ray Absorption Fine Structure Study on Structure Transformation and Electronic State of Various Pt Particles on Carbon Electrode

Yoshitake

Ota

1994

J. Electrochem. Soc.

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“…Conceptually, the most straightforward one is to determine geometry changes from x-ray or EXAFS structural studies of ET reactants and products and then obtain force constants by vibrational spectroscopy. 5,6 For intramolecular ET involving mixed-valence compounds, the reorganization energy can be estimated by measuring absorption bandwidths of intervalent charge transfer transitions. 7 Another elegant technique is resonant-enhanced Raman scattering with a reinterpretation of Raman cross sections in terms of time-dependent models.…”

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Probing the electronic structure of redox species and direct determination of intrinsic reorganization energies of electron transfer reactions

Wang

2000

The Journal of Chemical Physics

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An experimental technique capable of directly determining the intrinsic reorganization energies of bimolecular electron transfer reactions is described. Appropriate solution phase redox species are prepared in the gas phase using electrospray ionization and probed using photodetachment spectroscopy. Five metal complex anions involved in the Fe 2ϩ-Fe 3ϩ redox couple are investigated and the intramolecular reorganization energies are measured directly from spectral features due to removing the most loosely bound 3d electron from the Fe͑II͒-complexes. The photodetachment spectra also yield electronic structure information about the Fe 2ϩ-Fe 3ϩ redox couple and provide a common electronic structure origin for the reducing capability of the Fe͑II͒-complexes, the most common redox reagents.

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“…where E is the incident photon energy and E0 is the threshold energy typically close to the absorption edge (24,25). In wave vector form the EXAFS can be presented as a summation over the various coordination shells…”

Section: Methodsmentioning

confidence: 99%

EXAFS Study of Terbium Activated Zinc Sulfide Thin Films

Charreire

Marbeuf

Tourillon

et al. 1992

J. Electrochem. Soc.

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In order to establish the nature of luminescent centers in green-emitting electroluminescent thin film structures based on terbium-activated zinc sulfide, extended x-ray absorption fine structure (EXAFS) measurements were carried out using x-ray radiation from the 1.85 GeV-200 mA DCI storage ring in Orsay. Analysis of the EXAFS spectra at the Tb L~n edge gives direct evidence for the presence of Tb-containing clusters in films prepared by the Atomic Layer Epitaxy process. The polycations TbO § forming the clusters are very similar to those found in the crystal structure of Tb202S. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.174.255.116 Downloaded on 2015-06-02 to IP

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Is there any beam yet? Uses of synchrotron radiation in the in situ study of electrochemical interfaces

Abstract: was taken at the same time. The OWG electrode had sheet resistance of ca. 500 fi/cm1 2 and donor density of ca. 102O/cm3 ([SbCl3] in the spray solution = 2.5 wt %); the optical path length was 1 cm.

Cited by 53 publications

References 1 publication

In Situ X‐Ray Absorption Fine Structure Study on Structure Transformation and Electronic State of Various Pt Particles on Carbon Electrode

In Situ X‐Ray Absorption Fine Structure Study on Structure Transformation and Electronic State of Various Pt Particles on Carbon Electrode

Probing the electronic structure of redox species and direct determination of intrinsic reorganization energies of electron transfer reactions

EXAFS Study of Terbium Activated Zinc Sulfide Thin Films

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