Nanoscale limitations in metal oxide electrocatalysts for oxygen evolution

Venkatasubramanian Viswanathan, Katie L. Pickrahn, Alan C. Luntz, Stacey F. Bent, Jens K. Nørskov*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Metal oxides are attractive candidates for low cost, earth-abundant electrocatalysts. However, owing to their insulating nature, their widespread application has been limited. Nanostructuring allows the use of insulating materials by enabling tunneling as a possible charge transport mechanism. We demonstrate this using TiO2 as a model system identifying a critical thickness, based on theoretical analysis, of about ∼4 nm for tunneling at a current density of ∼1 mA/cm2. This is corroborated by electrochemical measurements on conformal thin films synthesized using atomic layer deposition (ALD) identifying a similar critical thickness. We generalize the theoretical analysis deriving a relation between the critical thickness and the location of valence band maximum relative to the limiting potential of the electrochemical surface process. The critical thickness sets the optimum size of the nanoparticle oxide electrocatalyst and this provides an important nanostructuring requirement for metal oxide electrocatalyst design.

Original languageEnglish
JournalNano Letters
Volume14
Issue number10
Pages (from-to)5853-5857
Number of pages5
ISSN1530-6984
DOIs
Publication statusPublished - 2014
Externally publishedYes

Bibliographical note

ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

Keywords

  • Atomic layer deposition
  • Charge transport
  • Nanostructuring
  • Water splitting

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