Determination of the Oxidation States of Cu and Ru in the System La2−xSrxCu1−yRuyO4−δ by XANES-Measurements

Ebbinghaus, Stefan G.; Hu, Z.; Reller, Armin

doi:10.1006/jssc.2000.8981

Cited by 36 publications

(38 citation statements)

References 18 publications

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“…The obtained edge energies are almost identical with previously reported data [26,27,[46][47][48][49][50][51]. In the left frame of Fig. 14 the normalized spectra of the Ru-L III absorption edge are shown.…”

Section: Valence Determination Using Xanessupporting

confidence: 89%

“…14. In addition, the energy spacing between the two pseudo-Voigt maxima is in good agreement with the value of 2.6(1) eV typically found for Ru 4+ [47]. For La 2 Ru 0.75 Mn 0.25 O 5 absorption spectra for both edges Mn-K and Ru-L III were also measured for temperatures down to 110 K which is significantly below the transition temperature.…”

Section: Valence Determination Using Xanessupporting

confidence: 87%

“…In the left frame of Fig. 14 the normalized spectra of the Ru-L III absorption edge are shown. The determination of the edge energy was performed by fitting the first derivative of the absorption edge with two pseudo-Voigt and one arctangent function [47] using the program WINXAS [52]. For the reference compounds the obtained energies of the maxima of the two pseudo-Voigt functions are marked by the dashed lines in the left frame of Fig.…”

Section: Valence Determination Using Xanesmentioning

confidence: 99%

“…The spectra remain almost identical for all measured temperatures indicating constant valence and the absence of charge ordering, which could have been caused by the phase transition. [28,47], the full width at half maximum (FWHM) of the two pseudo-Voigt peaks utilized for the Ru-L III fit can be used to estimate the distortion of the RuO 6 octahedra. While the FWHM of pV1 (which can be assigned to a transition to empty orbitals of dominantly t 2g character) remains almost constant (≈1.8 eV), the second pseudo-Voigt peak (transition to e g -type orbitals) broadens with increasing Mn substitution level.…”

Section: Valence Determination Using Xanesmentioning

confidence: 99%

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Synthesis, crystal structure, and valence states of Mn-substitutedLa2RuO5

et al. 2014

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Polycrystalline samples of layered perovskite-related La 2 Ru 1−y Mn y O 5 (0 y 0.25) were prepared by a soft-chemistry synthesis based on the thermal decomposition of a citrate precursor. The crystal structures of the compounds were determined by Rietveld analysis of x-ray diffraction patterns recorded at different temperatures. Additional neutron diffraction patterns for La 2 Ru 0.75 Mn 0.25 O 5 were recorded between 1.5 K and 300 K. A structural phase transition from a monoclinic room-temperature to a triclinic low-temperature phase was observed for y 0.20, while for y = 0.25 a phase separation at low temperatures was identified. The structural phase-transition temperatures decrease with increasing Mn concentration. Selected area electron diffraction of La 2 Ru 0.75 Mn 0.25 O 5 documented the absence of cationic ordering of Ru and Mn. The Mn and Ru oxidation states were determined using x-ray absorption spectroscopy and showed a stable +4 valence for both elements in all samples investigated, at room temperature as well as at 110 K.

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Section: Valence Determination Using Xanessupporting

confidence: 89%

Section: Valence Determination Using Xanessupporting

confidence: 87%

Section: Valence Determination Using Xanesmentioning

confidence: 99%

Section: Valence Determination Using Xanesmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis, crystal structure, and valence states of Mn-substitutedLa2RuO5

et al. 2014

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“…In contrast to the preliminary work of some of us [24] -in which only the main peak in Cu L 3 XAS spectra were presented and the satellite structures for the 2p 3d 9 final state were not shown -now we measured both the Cu L 3 and Cu L 2 spectra, thus not missing out on any important information. CuO was used for energetic calibration at the Cu L 2;3 and O K thresholds after each injection into the storage ring.…”

Section: Methodsmentioning

confidence: 77%

The distribution of the doped holes in La2−xSrxCu1−yRuyO4−δ

Golden

Ebbinghaus

et al. 2002

Chemical Physics

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We present a systematic study of the perovskite-related system La 2Àx Sr x Cu 1Ày Ru y O 4Àd using Cu L 2;3 ; Ru L 2;3 , and O K X-ray absorption spectroscopy (XAS), magnetic and electrical measurements. This system can be regarded as hole-doped via substitution of La by Sr and to be electron-doped via substitution of Ru by Cu, and thus the question as to the distribution of the charge carriers and the interaction between Cu and Ru ions are central to our understanding of these novel systems. The comparison of the experimental data with the crystal-field-multiplet calculations shows clearly that the charge balance for x=2y > 1 is predominantly achieved by an increase of the Ru valence from Ru(IV) to Ru(V), while Cu remains in the Cu(II) oxidation state. Ó

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Super‐Exchange Interaction Induced Overall Optimization in Ferromagnetic Perovskite Oxides Enables Ultrafast Water Oxidation

Dai

Zhu

Yin

et al. 2019

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Oxygen evolution reaction (OER) is crucial in many renewable electrochemical technologies including regenerative fuel cells, rechargeable metal–air batteries, and water splitting. It is found that abundant active sites with favorable electronic structure and high electrical conductivity play a dominant role in achieving high electrocatalytic efficiency of perovskites, thus efficient strategies need to be designed to generate multiple beneficial factors for OER. Here, highlighted is an unusual super‐exchange effect in ferromagnetic perovskite oxide to optimize active sites and enhance electrical conductivity. A systematic exploration about the composition‐dependent OER activity in SrCo1x Rux O3−δ (denoted as SCRx) (x = 0.0–1.0) perovskite is displayed with special attention on the role of super‐exchange interaction between high spin (HS) Co3+ and Ru5+ ions. Induced by the unique Co3+–O–Ru5+ super‐exchange interactions, the SCR0.1 is endowed with abundant OER active species including Co3+/Co4+, Ru5+, and O22−/O−, high electrical conductivity, and metal–oxygen covalency. Benefiting from these advantageous factors for OER electrocatalysis, the optimized SCR0.1 catalyst exhibits a remarkable activity with a low overpotential of 360 mV at 10 mA cm−2, which exceeds the benchmark RuO2 and most well‐known perovskite oxides reported so far, while maintaining excellent durability. This work provides a new pathway in developing perovskite catalysts for efficient catalysis.

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Determination of the Oxidation States of Cu and Ru in the System La2−xSrxCu1−yRuyO4−δ by XANES-Measurements

Cited by 36 publications

References 18 publications

Synthesis, crystal structure, and valence states of Mn-substitutedLa2RuO5

Synthesis, crystal structure, and valence states of Mn-substitutedLa2RuO5

The distribution of the doped holes in La2−xSrxCu1−yRuyO4−δ

Super‐Exchange Interaction Induced Overall Optimization in Ferromagnetic Perovskite Oxides Enables Ultrafast Water Oxidation

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