Underpotential surface reduction of mesoporous CeO 2 nanoparticle films

Charles Y. Cummings, Susan J. Stott, Michael J. Bonné, Karen J. Edler, Pauline M. King, Roger J. Mortimer, Frank Marken

Research output: Contribution to journalArticle

9 Citations (Scopus)
33 Downloads (Pure)

Abstract

The formation of variable-thickness CeO 2 nanoparticle mesoporous films from a colloidal nanoparticle solution (approximately 1-3-nm-diameter CeO 2) is demonstrated using a layer-by-layer deposition process with small organic binder molecules such as cyclohexanehexacarboxylate and phytate. Film growth is characterised by scanning and transmission electron microscopies, X-ray scattering and quartz crystal microbalance techniques. The surface electrochemistry of CeO 2 films before and after calcination at 500 °C in air is investigated. A well-defined Ce(IV/III) redox process confined to the oxide surface is observed. Beyond a threshold potential, a new phosphate phase, presumably CePO 4, is formed during electrochemical reduction of CeO 2 in aqueous phosphate buffer solution. The voltammetric signal is sensitive to (1) thermal pre-treatment, (2) film thickness, (3) phosphate concentration and (4) pH. The reversible 'underpotential reduction' of CeO 2 is demonstrated at potentials positive of the threshold. A transition occurs from the reversible 'underpotential region' in which no phosphate phase is formed to the irreversible 'overpotential region' in which the formation of the cerium(III) phosphate phase is observed. The experimental results are rationalised based on surface reactivity and nucleation effects.

Original languageEnglish
Pages (from-to)1541-1548
Number of pages8
JournalJournal of Solid State Electrochemistry
Volume12
Issue number12
Early online date25 Jan 2008
DOIs
Publication statusPublished - 1 Dec 2008

Keywords

  • Assembly
  • CeO
  • Cyclic voltammetry
  • Electroanalysis
  • Electrocatalysis
  • ITO
  • Nanoparticle
  • Sensor
  • Underpotential reduction

ASJC Scopus subject areas

  • Electrochemistry
  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • Materials Science(all)

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