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Wang RP, Huang MJ, Hariki A, Okamoto J, Huang HY, Singh A, Huang DJ, Nagel P, Schuppler S, Haarman T, Liu B, de Groot FMF. Analyzing the Local Electronic Structure of Co 3O 4 Using 2p3d Resonant Inelastic X-ray Scattering. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:8752-8759. [PMID: 35655938 PMCID: PMC9150098 DOI: 10.1021/acs.jpcc.2c01521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/27/2022] [Indexed: 06/15/2023]
Abstract
We present the cobalt 2p3d resonant inelastic X-ray scattering (RIXS) spectra of Co3O4. Guided by multiplet simulation, the excited states at 0.5 and 1.3 eV can be identified as the 4 T 2 excited state of the tetrahedral Co2+ and the 3 T 2g excited state of the octahedral Co3+, respectively. The ground states of Co2+ and Co3+ sites are determined to be high-spin 4 A 2(T d ) and low-spin 1 A 1g (Oh ), respectively. It indicates that the high-spin Co2+ is the magnetically active site in Co3O4. Additionally, the ligand-to-metal charge transfer analysis shows strong orbital hybridization between the cobalt and oxygen ions at the Co3+ site, while the hybridization is weak at the Co2+ site.
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Affiliation(s)
- Ru-Pan Wang
- Debye
Institute for Nanomaterials Science, Utrecht
University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
- Department
of Physics, University of Hamburg, Luruper Chaussee 149, G610, 22761 Hamburg, Germany
| | - Meng-Jie Huang
- Karlsruhe
Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76021 Karlsruhe, Germany
- Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Atsushi Hariki
- Department
of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - Jun Okamoto
- National
Synchrotron Radiation Research Center, No. 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Hsiao-Yu Huang
- National
Synchrotron Radiation Research Center, No. 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Amol Singh
- National
Synchrotron Radiation Research Center, No. 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Di-Jing Huang
- National
Synchrotron Radiation Research Center, No. 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Peter Nagel
- Karlsruhe
Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76021 Karlsruhe, Germany
| | - Stefan Schuppler
- Karlsruhe
Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76021 Karlsruhe, Germany
| | - Ties Haarman
- Debye
Institute for Nanomaterials Science, Utrecht
University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Boyang Liu
- Debye
Institute for Nanomaterials Science, Utrecht
University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Frank M. F. de Groot
- Debye
Institute for Nanomaterials Science, Utrecht
University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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2
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Cagan DA, Bím D, Silva B, Kazmierczak NP, McNicholas BJ, Hadt RG. Elucidating the Mechanism of Excited-State Bond Homolysis in Nickel-Bipyridine Photoredox Catalysts. J Am Chem Soc 2022; 144:6516-6531. [PMID: 35353530 PMCID: PMC9979631 DOI: 10.1021/jacs.2c01356] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ni 2,2'-bipyridine (bpy) complexes are commonly employed photoredox catalysts of bond-forming reactions in organic chemistry. However, the mechanisms by which they operate are still under investigation. One potential mode of catalysis is via entry into Ni(I)/Ni(III) cycles, which can be made possible by light-induced, excited-state Ni(II)-C bond homolysis. Here, we report experimental and computational analyses of a library of Ni(II)-bpy aryl halide complexes, Ni(Rbpy)(R'Ph)Cl (R = MeO, t-Bu, H, MeOOC; R' = CH3, H, OMe, F, CF3), to illuminate the mechanism of excited-state bond homolysis. At given excitation wavelengths, photochemical homolysis rate constants span 2 orders of magnitude across these structures and correlate linearly with Hammett parameters of both bpy and aryl ligands, reflecting structural control over key metal-to-ligand charge-transfer (MLCT) and ligand-to-metal charge-transfer (LMCT) excited-state potential energy surfaces (PESs). Temperature- and wavelength-dependent investigations reveal moderate excited-state barriers (ΔH‡ ∼ 4 kcal mol-1) and a minimum energy excitation threshold (∼55 kcal mol-1, 525 nm), respectively. Correlations to electronic structure calculations further support a mechanism in which repulsive triplet excited-state PESs featuring a critical aryl-to-Ni LMCT lead to bond rupture. Structural control over excited-state PESs provides a rational approach to utilize photonic energy and leverage excited-state bond homolysis processes in synthetic chemistry.
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Affiliation(s)
- David A. Cagan
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Daniel Bím
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Breno Silva
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States,Department of Chemistry and Biochemistry, Suffolk University, Boston, Massachusetts 02108, United States
| | - Nathanael P. Kazmierczak
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Brendon J. McNicholas
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Ryan G. Hadt
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States,Corresponding Author:
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3
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Kistanov AA, Rani E, Singh H, Fabritius T, Huttula M, Cao W. Discerning phase-matrices for individual nitride inclusions within ultra-high-strength steel: experiment driven DFT investigation. Phys Chem Chem Phys 2022; 24:1456-1461. [PMID: 34985487 DOI: 10.1039/d1cp05068k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-metallic inclusions play a decisive role in the steel's performance. Therefore, their determination and control over their formation are crucial to engineer ultra-high-strength steel. Currently, bare experimental approaches are limited in the identification of non-metallic inclusions within microstructural phases of complex steel matrices. Herein, we performed a density functional theory study on the characteristics of different nitride inclusions as observed in spectro-microscopy studies. As per the simulations, TiN inclusions preferentially formed in the austenite matrix, while the ferrite matrix generally hosts BN inclusions. Furthermore, although the presence of both BN and TiN inclusions in the Fe3C matrix is possible, their formation is impeded because of the strong inclusion-carbon interactions. The observed regularity in the formation of nitride inclusions in different phases of steel was also confirmed by the comparison of simulated and experimental K-edge XAS spectrum of nitride inclusions. Our work shed the light on the formation of nitride inclusions in different steel matrices and facilitates their further experimental identification.
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Affiliation(s)
- Andrey A Kistanov
- Nano and Molecular Systems Research Unit, University of Oulu, 90014 Oulu, Finland. .,Centre for Advanced Steels Research, University of Oulu, 90014 Oulu, Finland
| | - Ekta Rani
- Nano and Molecular Systems Research Unit, University of Oulu, 90014 Oulu, Finland.
| | - Harishchandra Singh
- Nano and Molecular Systems Research Unit, University of Oulu, 90014 Oulu, Finland. .,Centre for Advanced Steels Research, University of Oulu, 90014 Oulu, Finland
| | - Timo Fabritius
- Centre for Advanced Steels Research, University of Oulu, 90014 Oulu, Finland.,Process Metallurgy Research Unit, University of Oulu, 90014 Oulu, Finland
| | - Marko Huttula
- Nano and Molecular Systems Research Unit, University of Oulu, 90014 Oulu, Finland. .,Centre for Advanced Steels Research, University of Oulu, 90014 Oulu, Finland
| | - Wei Cao
- Nano and Molecular Systems Research Unit, University of Oulu, 90014 Oulu, Finland. .,Centre for Advanced Steels Research, University of Oulu, 90014 Oulu, Finland
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Vorwerk C, Sottile F, Draxl C. All-Electron many-body approach to resonant inelastic x-ray scattering. Phys Chem Chem Phys 2022; 24:17439-17448. [DOI: 10.1039/d2cp00994c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a formalism for the resonant inelastic x-ray scattering (RIXS) cross section. The resulting compact expression in terms of polarizability matrix elements, particularly lends itself to the implementation in...
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Shari'ati Y, Vura-Weis J. Polymer thin films as universal substrates for extreme ultraviolet absorption spectroscopy of molecular transition metal complexes. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1850-1857. [PMID: 34738939 DOI: 10.1107/s1600577521010596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Polystyrene and polyvinyl chloride thin films are explored as sample supports for extreme ultraviolet (XUV) spectroscopy of molecular transition metal complexes. Thin polymer films prepared by slip-coating are flat and smooth, and transmit much more XUV light than silicon nitride windows. Analytes can be directly cast onto the polymer surface or co-deposited within it. The M-edge XANES spectra (40-90 eV) of eight archetypal transition metal complexes (M = Mn, Fe, Co, Ni) are presented to demonstrate the versatility of this method. The films are suitable for pump/probe transient absorption spectroscopy, as shown by the excited-state spectra of Fe(bpy)32+ in two different polymer supports.
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Affiliation(s)
- Yusef Shari'ati
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Josh Vura-Weis
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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Maurel L, Herrero-Martín J, Motti F, Vasili HB, Piamonteze C, Heyderman LJ, Scagnoli V. Route to tunable room temperature electric polarization in SrTiO 3-CoFe 2O 4 heterostructures. JOURNAL OF MATERIALS CHEMISTRY. C 2021; 9:5977-5984. [PMID: 34094567 PMCID: PMC8118119 DOI: 10.1039/d0tc05821a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Utilizing the magnetostrictive properties of CoFe2O4, we demonstrate reversible room temperature control of the Ti electronic structure in SrTiO3-CoFe2O4 heterostructures, by inducing local and reversible strain in the SrTiO3. By means of X-ray absorption spectroscopy, we have ascertained the changes that take place in the energy levels of the Ti 3d orbitals under the influence of an external magnetic field. The observed Ti electronic state when the sample is subjected to moderately large external magnetic fields and the disappearance of the induced phase upon their removal indicates lattice distortions that are suggestive of the development of a net electric polarization.
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Affiliation(s)
- Laura Maurel
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich 8093 Zurich Switzerland
- Paul Scherrer Institute 5232 Villigen PSI Switzerland
| | | | - Federico Motti
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich 8093 Zurich Switzerland
- Paul Scherrer Institute 5232 Villigen PSI Switzerland
| | - Hari Babu Vasili
- ALBA Synchrotron Light Source 08290 Cerdanyola del Vallès Barcelona Spain
| | | | - Laura J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich 8093 Zurich Switzerland
- Paul Scherrer Institute 5232 Villigen PSI Switzerland
| | - Valerio Scagnoli
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich 8093 Zurich Switzerland
- Paul Scherrer Institute 5232 Villigen PSI Switzerland
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7
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Spectroscopic characterization of electronic structures of ultra-thin single crystal La 0.7Sr 0.3MnO 3. Sci Rep 2021; 11:5250. [PMID: 33664335 PMCID: PMC7933230 DOI: 10.1038/s41598-021-84598-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/18/2021] [Indexed: 11/08/2022] Open
Abstract
We have successfully fabricated high quality single crystalline La0.7Sr0.3MnO3 (LSMO) film in the freestanding form that can be transferred onto silicon wafer and copper mesh support. Using soft x-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) spectroscopy in transmission and reflection geometries, we demonstrate that the x-ray emission from Mn 3s-2p core-to-core transition (3sPFY) seen in the RIXS maps can represent the bulk-like absorption signal with minimal self-absorption effect around the Mn L3-edge. Similar measurements were also performed on a reference LSMO film grown on the SrTiO3 substrate and the agreement between measurements substantiates the claim that the bulk electronic structures can be preserved even after the freestanding treatment process. The 3sPFY spectrum obtained from analyzing the RIXS maps offers a powerful way to probe the bulk electronic structures in thin films and heterostructures when recording the XAS spectra in the transmission mode is not available.
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Al Samarai M, Hahn AW, Beheshti Askari A, Cui YT, Yamazoe K, Miyawaki J, Harada Y, Rüdiger O, DeBeer S. Elucidation of Structure-Activity Correlations in a Nickel Manganese Oxide Oxygen Evolution Reaction Catalyst by Operando Ni L-Edge X-ray Absorption Spectroscopy and 2p3d Resonant Inelastic X-ray Scattering. ACS APPLIED MATERIALS & INTERFACES 2019; 11:38595-38605. [PMID: 31523947 DOI: 10.1021/acsami.9b06752] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Herein, we report the synthesis and electrochemical oxygen evolution experiments for a graphene-supported Ni3MnO4 catalyst. The changes that occur at the Ni active sites during the electrocatalyic oxygen evolution reaction (OER) were elucidated by a combination of operando Ni L-edge X-ray absorption spectroscopy (XAS) and Ni 2p3d resonant inelastic X-ray scattering (RIXS). These data are compared to reference measurements on NiO, β-Ni(OH)2, β-NiOOH, and γ-NiOOH. Through this comparative analysis, we are able to show that under alkaline conditions (0.1 M KOH), the oxides of the Ni3MnO4 catalyst are converted to hydroxides. At the onset of catalysis (1.47 V), the β-Ni(OH)2-like phase is oxidized and converted to a dominantly γ-NiOOH phase. The present study thus challenges the notion that the β-NiOOH phase is the active phase in OER and provides further evidence that the γ-NiOOH phase is catalytically active. The ability to use Ni L-edge XAS and 2p3d RIXS to provide a rational basis for structure-activity correlations is highlighted.
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Affiliation(s)
- Mustafa Al Samarai
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , Mülheim an der Ruhr 45470 , Germany
| | - Anselm W Hahn
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , Mülheim an der Ruhr 45470 , Germany
| | - Abbas Beheshti Askari
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , Mülheim an der Ruhr 45470 , Germany
| | - Yi-Tao Cui
- Institute for Solid State Physics , The University of Tokyo , Kashiwa , Chiba 277-8581 , Japan
- Synchrotron Radiation Research Organization , The University of Tokyo , Sayo, Sayo-gun, Hyogo 679-5148 , Japan
| | - Kosuke Yamazoe
- Institute for Solid State Physics , The University of Tokyo , Kashiwa , Chiba 277-8581 , Japan
- Synchrotron Radiation Research Organization , The University of Tokyo , Sayo, Sayo-gun, Hyogo 679-5148 , Japan
| | - Jun Miyawaki
- Institute for Solid State Physics , The University of Tokyo , Kashiwa , Chiba 277-8581 , Japan
- Synchrotron Radiation Research Organization , The University of Tokyo , Sayo, Sayo-gun, Hyogo 679-5148 , Japan
| | - Yoshihisa Harada
- Institute for Solid State Physics , The University of Tokyo , Kashiwa , Chiba 277-8581 , Japan
- Synchrotron Radiation Research Organization , The University of Tokyo , Sayo, Sayo-gun, Hyogo 679-5148 , Japan
| | - Olaf Rüdiger
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , Mülheim an der Ruhr 45470 , Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , Mülheim an der Ruhr 45470 , Germany
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Leedahl B, McCloskey DJ, Boukhvalov DW, Zhidkov IS, Kukharenko AI, Kurmaev EZ, Cholakh SO, Gavrilov NV, Brinzari VI, Moewes A. Fundamental crystal field excitations in magnetic semiconductor SnO 2: Mn, Fe, Co, Ni. Phys Chem Chem Phys 2019; 21:11992-11998. [PMID: 31134978 DOI: 10.1039/c9cp01516g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Directly measuring elementary electronic excitations in dopant 3d metals is essential to understanding how they function as part of their host material. Through calculated crystal field splittings of the 3d electron band it is shown how transition metals Mn, Fe, Co, and Ni are incorporated into SnO2. The crystal field splittings are compared to resonant inelastic X-ray scattering (RIXS) experiments, which measure precisely these elementary dd excitations. The origin of spectral features can be determined and identified via this comparison, leading to an increased understanding of how such dopant metals situate themselves in, and modify the host's electronic and magnetic properties; and also how each element differs when incorporated into other semiconducting materials. We found that oxygen vacancy formation must not occur at nearest neighbour sites to metal atoms, but instead must reside at least two coordination spheres beyond. The coordination of the dopants within the host can then be explicitly related to the d-electron configurations and energies. This approach facilitates an understanding of the essential link between local crystal coordination and electronic/magnetic properties.
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Affiliation(s)
- B Leedahl
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
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