Lotus-root-like multichannel nanotubes of IrO2–ZnO for electrocatalysis of pH-universal oxygen evolution reaction: A simple strategy to control the structure and crystallinity

Yoonhee Nam, Dasol Jin, Subin Choi, Doo Hwan Hong, Hoi Ri Moon, Youngmi Lee

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

A series of IrO2-ZnO composite oxide nanomaterials (IrO2-ZnO-x) were synthesized by electrospinning and subsequent calcination process using an electrospinning solution composed of Ir/Zn metal precursors and blended polymers of PVP/PVDF at different mixing ratios (PVDF wt% out of total polymer is denoted as x = 0, 17, 33, 50, 100). The fine structure and crystallinity of the produced IrO2-ZnO-x materials were tuned simply depending on the polymer mixing ratio: As PVDF content increased in a polymer blend, IrO2-ZnO-x (x = 0, 17, 33, 50) changed the structure from wire-in-tubes to nanofibers and then to lotus-root-like multichannel nanotubes with a greater degree of amorphization via better alloying between Ir and Zn elements. IrO2-ZnO-33, exhibiting a lotus-root-like multichannel nanotubular structure with very porous surface morphology and low crystallinity, showed the best OER activity and long-term durable stability for 24 h in a wide range of pH solutions among a series of IrO2-ZnO-x, outperforming commercial Ir/C and a counterpart containing only Ir element. IrO2-ZnO-33 synthesized with an optimal polymer-blending ratio boosted up the electrocatalytic activity toward OER, which was ascribed to (1) enlarged surface area from its unique structure, (2) increased defects along with the greater amount of oxygen vacancies in the amorphous phase, and (3) the synergistic effect between Ir and Zn. This study presents a straightforward strategy to control the structure and crystallinity of nanocatalysts using a blend of properly selected two different polymers.

Original languageEnglish
Article number158741
JournalApplied Surface Science
Volume644
DOIs
StatePublished - 30 Jan 2024

Bibliographical note

Publisher Copyright:
© 2023 Elsevier B.V.

Keywords

  • Electrospinning
  • Iridium-zinc composite oxide
  • Lotus-root-like multichannel nanotube
  • Oxygen evolution reaction
  • Polymer blend
  • pH-universal electrocatalyst

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