Electronic structure of La2−xSrxNiO4+δ studied by soft X-ray absorption and emission spectroscopies

Butorin, Sergei M.; Guo, Jinghua; Duda, Laurent; Wassdahl, N.; Nordgren, Joseph; Kurmaev, E.Z.; Tolochko, S.P.

doi:10.1016/0921-4534(94)91748-5

Cited by 7 publications

(5 citation statements)

References 6 publications

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“…4. 20 The lower spectral weight of the pre-edge peak in the TY spectrum in comparison with the FY spectrum reflects a lower concentration of oxygen hole states in the sample surface. The XAS data measured in the FY mode from single crystals, 7 with surfaces prepared ex situ, revealed a slowing down in the growth of the ligandhole peak approaching the maximum doping level studied (xϭ0.6).…”

Section: A O-k Xas Spectramentioning

confidence: 99%

Hole distribution between the Ni3dand O2porbitals inNd2−x
Hu
¹
,
Golden
²
,
Fink
³

et al. 2000
Phys. Rev. B
51
3
35
0
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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We present a joint experimental and theoretical study of x-ray absorption at the O-K and Ni-L 2,3 thresholds of Nd 2Ϫx Sr x NiO 4Ϫ␦ providing an analysis of the distribution of doped holes induced by Sr substitution between Ni 3d and O 2p orbitals. The preedge peak in the O-K x-ray absorption ͑XAS͒ spectra, reflecting holes located in the O 2p orbitals, increases monotonically with the degree of Sr doping up to the maximum doping level studied (xϭ1.4). The saturation in the relative intensity of the O-K preedge peak in the analogous lanthanum nickelate reported in the literature is shown to be most likely due to surface oxygen deficiency. Furthermore, the experimental Ni-L 2,3 XAS spectrum of the Ni͑III͒ nickelate Nd 1.1 Sr 0.9 NiO 3.95 was simulated by a cluster approach, including charge-transfer and complete multiplet interactions, and compared with the corresponding spectrum of the Ni͑III͒ system Nd 2 Li 0.5 Ni 0.5 O 4 . The 3d 7 weight in the ground state of Nd 1.1 Sr 0.9 NiO 3.95 was found to be 42%, somewhat smaller than the value of 51% found for Nd 2 Li 0.5 Ni 0.5 O 4 . This indicates the influence of nonlocal effects in x-ray-absorption spectroscopy, which, in this case is due to the increased covalency in the Sr-doped system as a result of inter-NiO 6 -cluster interaction. Such interactions are absent in Nd 2 Li 0.5 Ni 0.5 O 4 , which is characterized by having isolated NiO 6 clusters.

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Section: A O-k Xas Spectramentioning

confidence: 99%

Hole distribution between the Ni3dand O2porbitals inNd2−x
Hu
¹
,
Golden
²
,
Fink
³

et al. 2000
Phys. Rev. B
51
3
35
0
View full text Add to dashboard Cite

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“…However, resonant inelastic scattering from diamond suggested the presence of a correlation between the absorption and emission processes. 11 Such energy dependence at the C K-edge was also observed from the x-ray fluorescence of condensed C 60 , and the strong intensity modulation of constituent spectra is detected with varying excitation energy up to 10 eV above threshold. 18 A recent work from Feng et al observed the exciton-photon coupling (EPC) with two different phonons in graphite and a significantly different coupling strength was reported for the first time.…”

Section: Introductionmentioning

confidence: 58%

“…[7][8][9] The introduction of selectively excited soft x-ray emission has opened a new field of study by disclosing many new possibilities of resonant inelastic soft x-ray scattering (RIXS). With this technique one can measure resonantly excited Ti L-edge and N K-edge signals in TiN 10 and site selectivity in high-T c superconducting materials, [10][11][12] low-energy excitations in correlated materials, 13 femtosecond dynamics 14 and chemical bonding mechanism [15][16][17] by detuning from, for example, resonance. Soft x-ray absorption and consequent decay through x-ray emission at the C K-edge was assumed to be two independent one-photon processes.…”

Section: Introductionmentioning

confidence: 99%

In situ/operando soft x-ray spectroscopy of chemical interfaces in gas and liquid environments

et al. 2021

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Many energy-storage and energy-conversion systems are based on the complexity of material architecture, chemistry and interfacial interactions. To understand and thus ultimately control the energy applications calls for in situ/operando characterization tools. Over the years, in situ/operando soft x-ray spectroscopy has been developed for the studies of gas molecules, molecular liquids, catalytic, and electrochemical reactions. Soft x-ray spectroscopy offers electronic structure characterization of materials in energy conversion, energy storage, and catalysis regarding functionality, complexity of material architecture, and chemical interactions. It has been shown how to use the powerful in situ/operando soft x-ray spectroscopy characterization techniques of interfacial phenomena and how to reveal the mechanism of charge transfer and chemical transformation of solid/gas and solid/liquid interfaces of energy storage and catalytic materials in a realistic environment. It has been demonstrated how to overcome the challenge that soft x-rays cannot easily peek into the high-pressure catalytic or liquid 1 MRS Bulletin Article Template Author Name/Issue Date electrochemical reactions. The unique design of in situ/operando soft x-ray spectroscopy instrumentation and fabrication principle and examples of experiments are presented.

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“…Recently, many investigation on A2BO4 (A=La, Pr and Nd, B=Co, Fe and Ni) oxides with the K2NiF4-type structure were reported as a promising candidate of cathode materials for IT-SOFCs [ [124][125][126][127][128][129][130][131][132]. The ideal K2NiF4-type structure can be regarded as a combination of the ABO3 perovskite and Ln2O2 rock-salt layers stacked one upon the other along the c-axis as shown in Fig.…”

Section: Layered-perovskite Oxidesmentioning

confidence: 99%

Developing high performance and stable hetero-structured cathodes and fundamental understanding of oxygen reduction and reaction behavior

Zhang¹

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Developing High Performance and Stable Hetero-structured Cathodes and Fundamental Understanding of Oxygen Reduction and Reaction Behavior ByXinxin Zhang New hetero-structured La2NiO4+δ (LNO)/ (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ (LSCF) SOFC cathodes have been successfully fabricated by the infiltration technique for long-term stability and oxygen reduction reaction (ORR) kinetic consideration. The current comparative study of LSCF and LNO-infiltrated LSCF shows a significant reduction in polarization resistance by one order of magnitude and a 67% increase in maximum power density by using LNO-infiltrated LSCF cathodes at 750 o C in air. The electronic conductivity relaxation (ECR) results demonstrate that the remarkable improved oxygen exchange properties of LNO/LSCF hetero-structured cathodes are attributed to not only the increase of surface reaction area, but also the introduction of LNO surface and LNO-LSCF interface with rapid oxygen exchange behavior. A trace amount of Co, Sr and more oxygen defects stabilized in the LNO layer have been identified by TEM, EDXS, XPS, XRD and iodine titration experiments, giving rise to the enhancement of stability and surface catalytic activity. A low degradation rate of 0.39% at a constant current density of 250 mA•cm-2 can be still achieved for the fuel cell using LNO-infiltrated LSCF cathodes after long-term durability of about 500 h at 750 o C, accompanied by nanoparticles growth/aggregation, delamination and slight lanthanum enrichment on LNO surfaces. The benefits from the presence of the LNO nanoparticles demonstrate that LNO-infiltrated LSCF materials can act as high active surface oxygen exchange cathodes with promising fast ORR behavior and stability. To further enhance the long-term stability of infiltrated (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ (LSCF) cathode, two kinds of new hetero-structured cathodes, CeO2 & LNO co-infiltrated LSCF and La2-xNiO4+δ-infiltrated LSCF, have been designed. La2NiO4+δ (LNO), as an superior performance promoter, and CeO2, as a particle growth retardant due to the high melting point and good wettability, were co-infiltrated into the LSCF backbone to mitigate the delamination and growth/aggregation of in-situ formed nano-sized infiltrants. A more advantageous microstructure was confirmed in the co-infiltrated sample relative to those infiltrated with LNO alone. The original morphology was largely retained in the coinfiltrated sample after heat treatment, showing finer surface particles, better connection between the infiltrant network and the LSCF backbone. XPS and EIS results reveal that the substitution of stoichiometric La2NiO4+δ by A-site deficient La2-xNiO4+δ can effectively suppress lanthanum enrichment and enhance the stability after cathodic polarization treatment observed by measurement. The advantages of both modified hetero-structured cathodes suggest that CeO2 & La2-xNiO4+δ co-infiltrated LSCF is a promising heterostructured cathode to mitigate the LSCF electrode degradation. iv ACKNOWLEDGMENTS My deepest gratitude goes first and foremost...

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Electronic structure of La2−xSrxNiO4+δ studied by soft X-ray absorption and emission spectroscopies

Cited by 7 publications

References 6 publications

Hole distribution between the Ni3dand O2porbitals inNd2−x
Hu
¹
,
Golden
²
,
Fink
³

et al. 2000
Phys. Rev. B
51
3
35
0
View full text Add to dashboard Cite

Hole distribution between the Ni3dand O2porbitals inNd2−x
Hu
¹
,
Golden
²
,
Fink
³

et al. 2000
Phys. Rev. B
51
3
35
0
View full text Add to dashboard Cite

In situ/operando soft x-ray spectroscopy of chemical interfaces in gas and liquid environments

Developing high performance and stable hetero-structured cathodes and fundamental understanding of oxygen reduction and reaction behavior

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Electronic structure of La2−xSrxNiO4+δ studied by soft X-ray absorption and emission spectroscopies

Cited by 7 publications

References 6 publications

Hole distribution between the Ni3dand O2porbitals inNd2−xHu1, Golden2, Fink3 et al. 2000Phys. Rev. B513350View full textAdd to dashboardCite

Hole distribution between the Ni3dand O2porbitals inNd2−xHu1, Golden2, Fink3 et al. 2000Phys. Rev. B513350View full textAdd to dashboardCite

In situ/operando soft x-ray spectroscopy of chemical interfaces in gas and liquid environments

Developing high performance and stable hetero-structured cathodes and fundamental understanding of oxygen reduction and reaction behavior

Contact Info

Product

Resources

About

Hole distribution between the Ni3dand O2porbitals inNd2−x
Hu
¹
,
Golden
²
,
Fink
³

et al. 2000
Phys. Rev. B
51
3
35
0
View full text Add to dashboard Cite

Hole distribution between the Ni3dand O2porbitals inNd2−x
Hu
¹
,
Golden
²
,
Fink
³

et al. 2000
Phys. Rev. B
51
3
35
0
View full text Add to dashboard Cite