Electrochemistry (Jan 2021)

Operando X-ray Absorption Spectroscopic Study on the Effect of Ionic Liquid Coverage upon the Oxygen Reduction Reaction Activity of Pd-core Pt-shell Catalysts

  • Chen LIU,
  • Tomoki UCHIYAMA,
  • Jyunichi ISHIHARA,
  • Kentaro YAMAMOTO,
  • Toshiki WATANABE,
  • Hideto IMAI,
  • Koichiro OSHIMA,
  • Shigeki SAKURAI,
  • Minoru INABA,
  • Yoshiharu UCHIMOTO

DOI
https://doi.org/10.5796/electrochemistry.20-00122
Journal volume & issue
Vol. 89, no. 1
pp. 31 – 35

Abstract

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This study provides evidence of the enhancement of the oxygen reduction reaction (ORR) activity of Pt/C and Pd-core Pt-shell catalysts upon ionic liquid modification. Under high potential at 1.15 V (vs. reversible hydrogen electrode), the lower coverage of the oxide species on the Pt surface modified with [7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD)][bis(trifluoromethylsulfonyl)imide (NTf2)] ionic liquid (IL) was confirmed by electrochemical analysis. Operando X-ray absorption spectra (XAS) of the ionic liquid-modified Pd-core Pt-shell catalyst displayed smaller 5d orbital vacancies than the naked catalyst. Shrinkage of Pt-Pt bond length was also displayed, indicating the suppression of oxidation. Thus, we conclude that the IL-modified systems are effective in avoiding the adsorption of oxide species on the Pt surface and improving the oxygen reduction activity.

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