TITLE:
Enhancement of Oxygen Evolution Activity of Ruddlesden-Popper-Type Strontium Ferrite by Stabilizing Fe4+
AUTHORS:
Toshihiro Takashima, Koki Ishikawa, Hiroshi Irie
KEYWORDS:
Oxygen Evolution, Charge Disproportionation, Water-Splitting, Sr3Fe2O7
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.5 No.4,
April
30,
2017
ABSTRACT: Development of active iron based water oxidation for designing an ideal artificial photosynthesis devices operating under benign neutral pH is highly demanded. We investigated the electrocatalytic activity of Ruddlesden-Pop-per-type strontium ferrite (Sr3Fe2O7) toward the oxygen evolution reaction (OER). Owing to the temperature-dependent efficiency of the charge disproportionation of Fe4+, the OER activity of Sr3Fe2O7 varied with the temperature, and the onset potential for the OER at a neutral pH underwent a negative shift of approximately 200 mV by increasing the temperature for the stabilization of Fe4+. When metal substitution was made to Sr3Fe2O7 for stabilizing Fe4+ at room temperature, the temperature dependence of the OER activity disappeared and the OER was driven at a small overpotential without increasing the temperature, indicating that the stabilization of Fe4+ is substantially important for achieving high OER activity.