Surface morphological structures and electrochemical activity properties of iridium-niobium binary alloy electrodes

Toru Matsumoto, Naoaki Sata, Kiyoshi Kobayashi, Yoko Yamabe-Mitarai

Research output: Contribution to journalArticlepeer-review


The electrochemical activities of Ir-Nb binary alloys were investigated as functions of the alloy compositions, crystal structures, and surface morphologies for a hydrogen peroxide and ascorbic acid redox reaction. High activities for the redox reaction of hydrogen peroxide were observed when pure Ir and an alloy with a composition of 77 at% Ir-23 at% Nb (Ir-23Nb) were used. Tests on eight electrodes - Ir, Ir-13Nb, Ir-17Nb, Ir-23Nb, Ir-30Nb, Ir-43Nb, Ir-62Nb, and Nb - showed that at a constant potential difference of 0.7 V vs. Ag/AgCl, the Ir-23Nb electrode had the best hydrogen peroxide oxidation capability: 9.2 μA/mm2 for 2 mM hydrogen peroxide. Apart from Nb, Ir-23Nb gave the best performance in terms of preferential hydrogen peroxide oxidation against ascorbic acid. Subsequently, the Ir and Ir-23Nb electrodes were used for the fabrication of amperometric glucose sensors. We first coated the two electrodes with a γ-aminopropyltriethoxysilane membrane and then with a glucose oxidase membrane. Tests on the Ir and Ir-23Nb electrode glucose sensors showed that the latter had better glucose detection capability than the former: 0.226 μA/(mm2 mM) for the Ir-23Nb sensor with 1.67 mM glucose. We investigated the relationship between the electrode responses to both hydrogen peroxide and ascorbic acid and the electrode surface structures.

Original languageEnglish
Pages (from-to)1104-1109
Number of pages6
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Issue number17
Publication statusPublished - 2013 Aug 20
Externally publishedYes


  • Binary alloy
  • Glucose biosensor
  • Ir + IrNb
  • Ir-Nb
  • Two-phase structure

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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