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

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)19279-19286
Number of pages8
JournalJournal of Physical Chemistry C
Volume119
Issue number33
DOIs
Publication statusPublished - 2015 Aug 20

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Fingerprint Dive into the research topics of 'Direct Observation of Active Nickel Oxide Cluster in Nickel-Borate Electrocatalyst for Water Oxidation by in Situ O K-Edge X-ray Absorption Spectroscopy'. Together they form a unique fingerprint.

Cite this