Impact of Ir-Valence Control and Surface Nanostructure on Oxygen Evolution Reaction over a Highly Efficient Ir-TiO2 Nanorod Catalyst

Junfang Cheng, Jun Yang, Sho Kitano, Gergely Juhasz, Manabu Higashi, Masaaki Sadakiyo, Kenichi Kato, Satoru Yoshioka, Takeharu Sugiyama, Miho Yamauchi, Naotoshi Nakashima

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Iridium oxide (IrOx)-based materials are the most suitable oxygen evolution reaction (OER) catalysts for water electrolysis in acidic media. There is a strong demand from industry for improved performance and reduction of the Ir amount. Here, we report a composite catalyst, IrOx-TiO2-Ti (ITOT), with a high concentration of active OH species and mixed valence IrOx on its surface. We have discovered that the obtained ITOT catalyst shows an outstanding OER activity (1.43 V vs RHE at 10 mA cm-2) in acidic media. Moreover, no apparent potential increase was observed even after a chronopotentiometry test at 10 mA cm-2 for 100 h and cyclic voltammetry for 700 cycles. We proposed a detailed OER mechanism on the basis of the analysis of the in situ electrochemical X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements as well as density functional theory (DFT) calculations. All together, we have concluded that controllable Ir-valence and the high OH concentration in the catalyst is crucial for the obtained high OER activity.

Original languageEnglish
Pages (from-to)6974-6986
Number of pages13
JournalACS Catalysis
Volume9
Issue number8
DOIs
Publication statusPublished - Aug 2 2019

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Nanorods
Nanostructures
Iridium
Oxygen
Catalysts
X ray absorption
Oxides
Electrolysis
Cyclic voltammetry
Density functional theory
Water
Composite materials
iridium oxide
Industry

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

Cite this

Impact of Ir-Valence Control and Surface Nanostructure on Oxygen Evolution Reaction over a Highly Efficient Ir-TiO2 Nanorod Catalyst. / Cheng, Junfang; Yang, Jun; Kitano, Sho; Juhasz, Gergely; Higashi, Manabu; Sadakiyo, Masaaki; Kato, Kenichi; Yoshioka, Satoru; Sugiyama, Takeharu; Yamauchi, Miho; Nakashima, Naotoshi.

In: ACS Catalysis, Vol. 9, No. 8, 02.08.2019, p. 6974-6986.

Research output: Contribution to journalArticle

Cheng, J, Yang, J, Kitano, S, Juhasz, G, Higashi, M, Sadakiyo, M, Kato, K, Yoshioka, S, Sugiyama, T, Yamauchi, M & Nakashima, N 2019, 'Impact of Ir-Valence Control and Surface Nanostructure on Oxygen Evolution Reaction over a Highly Efficient Ir-TiO2 Nanorod Catalyst', ACS Catalysis, vol. 9, no. 8, pp. 6974-6986. https://doi.org/10.1021/acscatal.9b01438
Cheng, Junfang ; Yang, Jun ; Kitano, Sho ; Juhasz, Gergely ; Higashi, Manabu ; Sadakiyo, Masaaki ; Kato, Kenichi ; Yoshioka, Satoru ; Sugiyama, Takeharu ; Yamauchi, Miho ; Nakashima, Naotoshi. / Impact of Ir-Valence Control and Surface Nanostructure on Oxygen Evolution Reaction over a Highly Efficient Ir-TiO2 Nanorod Catalyst. In: ACS Catalysis. 2019 ; Vol. 9, No. 8. pp. 6974-6986.
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