Understanding the Electronic Structure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>IrO</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Using Hard-X-ray Photoelectron Spectroscopy and Density-Functional Theory

Jm, Kahk; Poll, Christopher G.; Oropeza, Freddy E.; Ablett, J. M.; Céolin, Denis; Rueff, Jean‐Pascal; Agrestini, S.; Utsumi, Yuki; Kd, Tsuei; Liao, Yen Fa; Borgatti, F.; Panaccione, G.; Regoutz, Anna; Egdell, R.G.; Morgan, Benjamin J.; Scanlon, David O.; Payne, David J.

doi:10.1103/physrevlett.112.117601

Cited by 125 publications

(76 citation statements)

References 54 publications

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“…The occupied t 2g bandwidth of 3 eV for IrO 2 is significantly broader than that of SrIrO 3 and Sr 2 IrO 4 (approximately 0.3 and 0.8 eV, respectively 14 ). Each of the major features in the measured spectrum is remarkably well reproduced by the DFT calculation, and consistent with a previous hard xray photoemission study 27 , but with a higher sensitivity to the O 2p states due to the higher relative cross section at low photon energies.…”

supporting

confidence: 88%

Evolution of electronic correlations across the rutile, perovskite, and Ruddelsden-Popper iridates with octahedral connectivity

et al. 2016

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supporting

confidence: 88%

Evolution of electronic correlations across the rutile, perovskite, and Ruddelsden-Popper iridates with octahedral connectivity

et al. 2016

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“…We do not expect a perfect agreement between theory and experiments because we did not include the matrix element effects, as was done in ref 11. However, we expect the peak positions between the XPS spectra and the DOS computed at the appropriate level of theory should be aligned, as discussed in refs 30 and 31.…”

Section: ■ Computational Detailsmentioning

confidence: 94%

Electronic Structure of IrO₂: The Role of the Metal d Orbitals

2015

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IrO 2 is one of the most active catalysts for the oxygen evolution reaction (OER) and remains the only known stable OER catalyst in acidic conditions. As a first step in understanding the mechanism for OER we carried out detailed Density Functional Theory (DFT) studies of the electronic structure of IrO 2 . We compared the electronic states and magnetic properties of IrO 2 using several density functionals. We found that DFT with hybrid functionals (B3PW and PBE0) leads to a weak ferromagnetic coupling, although IrO 2 has often been reported as nonmagnetic. We also found a magnetic ground state for RuO 2 , whose electronic structure is similar to that of IrO 2 . Ru−Ru antiferromagnetic interaction has been observed experimentally in nanoparticle RuO 2 . Further low temperature measurements are necessary to confirm whether a weak magnetism may occur below 20 K in IrO 2 . We also found that PBE leads to a better agreement with the experimental XPS spectra, compared with hybrid functionals and PBE +U.

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“…For example, the perovskites iridates Sr 2 IrO 4 262728 and CaIrO 3 29 are a Mott insulator due to a strong spin-orbital interaction (SOI) coupled with electron-electron repulsion in their IrO 6 coordination to generate a band gap. While, most of iridates are metallic oxides and on account of extensive broad d band structure makes Fermi level (E F ) easily crosses their valence band30. Therefore, there is no doubt that the different properties of iridates are completely dominated by their electronic structure, which duly has strong relationship with the IrO 6 coordination geometry in the oxides.…”

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confidence: 99%

OER activity manipulated by IrO6 coordination geometry: an insight from pyrochlore iridates

Sun

Liu

Gong

et al. 2016

Sci Rep

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The anodic reaction of oxygen evolution reaction (OER), an important point for electrolysis, however, remains the obstacle due to its complicated reaction at electrochemical interfaces. Iridium oxide (IrO2) is the only currently known 5d transition metal oxide possessing admirable OER activity. Tremendous efforts have been carried out to enhance the activity of iridium oxides. Unfortunately there lies a gap in understanding what factors responsible for the activity in doped IrO2 or the novel crystal structure. Based on two metallic pyrochlores (Bi2Ir2O7 and Pb2Ir2O6.5) and IrO2. It has been found that there exists a strong correlation between the specific OER activity and IrO6 coordination geometry. The more distortion in IrO6 geometry ascends the activity of Ir sites, and generates activity order of Pb-Ir > IrO2 > Bi-Ir. Our characterizations reveal that distorted IrO6 in Pb-Ir induces a disappearance of J = 1/2 subbands in valence band, while Bi-Ir and IrO2 resist this nature probe. The performed DFT calculations indicated the distortion in IrO6 geometry can optimize binding strength between Ir-5d and O-2p due to broader d band width. Based on this insight, enhancement in OER activity is obtained by effects that change IrO6 octahedral geometry through doping or utilizing structural manipulation with nature of distorted octahedral coordination.

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Understanding the Electronic Structure ofIrO2Using Hard-X-ray Photoelectron Spectroscopy and Density-Functional Theory

Cited by 125 publications

References 54 publications

Evolution of electronic correlations across the rutile, perovskite, and Ruddelsden-Popper iridates with octahedral connectivity

Evolution of electronic correlations across the rutile, perovskite, and Ruddelsden-Popper iridates with octahedral connectivity

Electronic Structure of IrO₂: The Role of the Metal d Orbitals

OER activity manipulated by IrO6 coordination geometry: an insight from pyrochlore iridates

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Understanding the Electronic Structure ofIrO2Using Hard-X-ray Photoelectron Spectroscopy and Density-Functional Theory

Cited by 125 publications

References 54 publications

Evolution of electronic correlations across the rutile, perovskite, and Ruddelsden-Popper iridates with octahedral connectivity

Evolution of electronic correlations across the rutile, perovskite, and Ruddelsden-Popper iridates with octahedral connectivity

Electronic Structure of IrO2: The Role of the Metal d Orbitals

OER activity manipulated by IrO6 coordination geometry: an insight from pyrochlore iridates

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Product

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Electronic Structure of IrO₂: The Role of the Metal d Orbitals