Gold Nanofilm Redox Catalysis for Oxygen Reduction at Soft Interfaces

Evgeny Smirnov, Pekka Peljo, Micheál D. Scanlon, Hubert H. Girault*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

29 Citations (Scopus)

Abstract

Functionalization of a soft or liquid-liquid interface by a one gold nanoparticle thick "nanofilm" provides a conductive pathway to facilitate interfacial electron transfer from a lipophilic electron donor to a hydrophilic electron acceptor in a process known as interfacial redox catalysis. The gold nanoparticles in the nanofilm are charged by Fermi level equilibration with the lipophilic electron donor and act as an interfacial reservoir of electrons. Additional thermodynamic driving force can be provided by electrochemically polarising the interface. Using these principles, the biphasic reduction of oxygen by a lipophilic electron donor, decamethylferrocene, dissolved in α,α,α-trifluorotoluene was catalysed at a gold nanoparticle nanofilm modified water-oil interface. A recently developed microinjection technique was utilised to modify the interface reproducibly with the mirror-like gold nanoparticle nanofilm, while the oxidised electron donor species and the reduction product, hydrogen peroxide, were detected by ion transfer voltammetry and UV/vis spectroscopy, respectively. Metallization of the soft interface allowed the biphasic oxygen reduction reaction to proceed via an alternative mechanism with enhanced kinetics and at a significantly lower overpotential in comparison to a bare soft interface. Weaker lipophilic reductants, such as ferrocene, were capable of charging the interfacial gold nanoparticle nanofilm but did not have sufficient thermodynamic driving force to significantly elicit biphasic oxygen reduction.

Original languageEnglish
Pages (from-to)362-373
Number of pages12
JournalElectrochimica Acta
Volume197
DOIs
Publication statusPublished - 10 Apr 2016
MoE publication typeA1 Journal article-refereed

Keywords

  • electrocatalysis
  • electron transfer
  • gold nanoparticles
  • oxygen reduction reaction
  • soft interfaces

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