Abstract
Composite electrocatalysts have exhibited high activities toward water electrolysis, but the catalytically active sites really in charge of the reaction are still debatable while the conventional in situ X-ray spectroscopies are not capable of conclusively identifying the interaction of these materials with the electrolyte because of the complexity of catalysis. In this work, by utilization of operando K β1,3 high-energy resolution fluorescence-detected X-ray absorption spectroscopy (HERFD-XAS) with a small incident angle, the operando quadrupole transition obviously showed that oxygen directly interacted with 3d orbitals of Co ions rather than that of Fe ions. Most importantly, Fe ions can promote the stabilization of the Co ions under a higher valent state during water oxidation, which may lead to a stable intermediate of reactant and its superior intrinsic activity. Accompanied by the first-principle calculations, the intermediates between 3d orbitals for surface Co ions and O 2p orbitals for the attaching hydroxide ions were ascribed to this orbital hybridization. Because of the unvaried structural features in conventional in situ techniques, operando HERFD-XAS revealed the remarkable change of chemical status to correlate with the orbital interaction rather than with the structural variation. This operando HERFD-XAS approach corresponding to the local orbital interaction in reactant/catalyst interface can potentially offer synergetic strategies toward realizing the chemical reactions or reaction pathways in various fields.
| Original language | English |
|---|---|
| Pages (from-to) | 17263-17270 |
| Number of pages | 8 |
| Journal | Journal of the American Chemical Society |
| Volume | 140 |
| Issue number | 49 |
| DOIs | |
| Publication status | Published - 2018 Dec 12 |
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ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Identification of Stabilizing High-Valent Active Sites by Operando High-Energy Resolution Fluorescence-Detected X-ray Absorption Spectroscopy for High-Efficiency Water Oxidation. / Hung, Sung Fu; Chan, Yu Te; Chang, Chun Chih; Tsai, Ming-Kang; Liao, Yen Fa; Hiraoka, Nozomu; Hsu, Chia Shuo; Chen, Hao Ming.
In: Journal of the American Chemical Society, Vol. 140, No. 49, 12.12.2018, p. 17263-17270.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Identification of Stabilizing High-Valent Active Sites by Operando High-Energy Resolution Fluorescence-Detected X-ray Absorption Spectroscopy for High-Efficiency Water Oxidation
AU - Hung, Sung Fu
AU - Chan, Yu Te
AU - Chang, Chun Chih
AU - Tsai, Ming-Kang
AU - Liao, Yen Fa
AU - Hiraoka, Nozomu
AU - Hsu, Chia Shuo
AU - Chen, Hao Ming
PY - 2018/12/12
Y1 - 2018/12/12
N2 - Composite electrocatalysts have exhibited high activities toward water electrolysis, but the catalytically active sites really in charge of the reaction are still debatable while the conventional in situ X-ray spectroscopies are not capable of conclusively identifying the interaction of these materials with the electrolyte because of the complexity of catalysis. In this work, by utilization of operando K β1,3 high-energy resolution fluorescence-detected X-ray absorption spectroscopy (HERFD-XAS) with a small incident angle, the operando quadrupole transition obviously showed that oxygen directly interacted with 3d orbitals of Co ions rather than that of Fe ions. Most importantly, Fe ions can promote the stabilization of the Co ions under a higher valent state during water oxidation, which may lead to a stable intermediate of reactant and its superior intrinsic activity. Accompanied by the first-principle calculations, the intermediates between 3d orbitals for surface Co ions and O 2p orbitals for the attaching hydroxide ions were ascribed to this orbital hybridization. Because of the unvaried structural features in conventional in situ techniques, operando HERFD-XAS revealed the remarkable change of chemical status to correlate with the orbital interaction rather than with the structural variation. This operando HERFD-XAS approach corresponding to the local orbital interaction in reactant/catalyst interface can potentially offer synergetic strategies toward realizing the chemical reactions or reaction pathways in various fields.
AB - Composite electrocatalysts have exhibited high activities toward water electrolysis, but the catalytically active sites really in charge of the reaction are still debatable while the conventional in situ X-ray spectroscopies are not capable of conclusively identifying the interaction of these materials with the electrolyte because of the complexity of catalysis. In this work, by utilization of operando K β1,3 high-energy resolution fluorescence-detected X-ray absorption spectroscopy (HERFD-XAS) with a small incident angle, the operando quadrupole transition obviously showed that oxygen directly interacted with 3d orbitals of Co ions rather than that of Fe ions. Most importantly, Fe ions can promote the stabilization of the Co ions under a higher valent state during water oxidation, which may lead to a stable intermediate of reactant and its superior intrinsic activity. Accompanied by the first-principle calculations, the intermediates between 3d orbitals for surface Co ions and O 2p orbitals for the attaching hydroxide ions were ascribed to this orbital hybridization. Because of the unvaried structural features in conventional in situ techniques, operando HERFD-XAS revealed the remarkable change of chemical status to correlate with the orbital interaction rather than with the structural variation. This operando HERFD-XAS approach corresponding to the local orbital interaction in reactant/catalyst interface can potentially offer synergetic strategies toward realizing the chemical reactions or reaction pathways in various fields.
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U2 - 10.1021/jacs.8b10722
DO - 10.1021/jacs.8b10722
M3 - Article
VL - 140
SP - 17263
EP - 17270
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 49
ER -