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 language | English |
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Pages (from-to) | 19279-19286 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry C |
Volume | 119 |
Issue number | 33 |
DOIs | |
Publication status | Published - 2015 Aug 20 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Energy(all)