Direct Observation of Active Nickel Oxide Cluster in Nickel-Borate Electrocatalyst for Water Oxidation by in Situ O K-Edge X-ray Absorption Spectroscopy

Masaaki Yoshida, Yosuke Mitsutomi, Takehiro Mineo, Masanari Nagasaka, Hayato Yuzawa, Nobuhiro Kosugi, Hiroshi Kondoh

研究成果: Article査読

60 被引用数 (Scopus)

抄録

In situ O K-edge X-ray absorption fine structure (XAFS) spectroscopy was applied to investigate the electronic and structural change in the nickel-borate (Ni-B<inf>i</inf>) electrocatalyst during the oxygen evolution reaction (OER). An absorption peak was observed around 528.7 eV at 1.0 V versus Ag/AgCl in a potassium borate aqueous solution, which relates with the formation of nanoscale order domains of edge-sharing NiO<inf>6</inf> octahedra in the Ni-B<inf>i</inf> electrocatalyst. XAFS spectra were measured with variation of the electrode potential from 0.3 up to 1.0 V. The measured absorption peaks suggest that the quantity of NiO<inf>6</inf> octahedra increased in correlation with the OER current; however, when the potential was changed downward, the XAFS absorption peak assigned to NiO<inf>6</inf> octahedra remained constant, even at the electrode potential for no OER current. This difference implies that the water oxidation catalysis proceeds at the domain edge of NiO<inf>6</inf> octahedra. The XAFS technique provides the first successful direct probing of the active species in the Ni-B<inf>i</inf> electrocatalyst during electrochemical reaction.

本文言語English
ページ(範囲)19279-19286
ページ数8
ジャーナルJournal of Physical Chemistry C
119
33
DOI
出版ステータスPublished - 2015 8 20

ASJC Scopus subject areas

  • 物理化学および理論化学
  • 電子材料、光学材料、および磁性材料
  • 表面、皮膜および薄膜
  • エネルギー(全般)

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