Kinetic and mechanistic aspects of the oxygen evolution reaction at hydrous iron oxide films in base
Citation:
Michael E G Lyons, Richard L Doyle, Kinetic and mechanistic aspects of the oxygen evolution reaction at hydrous iron oxide films in base, Journal of the Electrochemical Society, 160, 2, 2013, H142 - H154Download Item:
Abstract:
The oxygen evolution reaction atmulti-cycled iron oxy-hydroxide films in aqueous alkaline solution is discussed. The factors affecting
the growth and electrocatalytic properties of the latter are described. In particular, steady-state Tafel plot analysis and electrochemical
impedance spectroscopy have been used to elucidate the kinetics and mechanism of oxygen evolution. Tafel slopes of ca. 60 mV
dec?1 and 40 mV dec?1 are found at low overpotentials depending on the oxide growth conditions, with an apparent Tafel slope of
ca. 120 mV dec?1 at high overpotentials. Reaction orders of ca. 0.5, 1.0 and 1.5 are observed at low and high overpotentials, again
depending on the oxide growth conditions. A mechanistic scheme involving the active participation of octahedrally coordinated
anionic iron oxyhydroxide surfaquo complexes, which form the porous hydrous layer, is proposed. The latter structure contains
considerable quantities of water molecules which facilitate hydroxide ion discharge at the metal site during active oxygen evolution.
This work brings together current research in both heterogeneous electrocatalysis and homogeneous molecular catalysis for water
oxidation.
Sponsor
Grant Number
Science Foundation Ireland (SFI)
SFI/10/IN.1/I2969-Lyons
Author's Homepage:
http://people.tcd.ie/melyonsDescription:
PUBLISHED
Author: LYONS, MICHAEL
Type of material:
Journal ArticleCollections
Series/Report no:
Journal of the Electrochemical Society160
2
Availability:
Full text availableSubject (TCD):
Nanoscience & Materials , Smart & Sustainable PlanetMetadata
Show full item recordLicences: