An iron oxide photoanode with hierarchical nanostructure for efficient water oxidation

Title
An iron oxide photoanode with hierarchical nanostructure for efficient water oxidation
Authors
박상백양태열강호영진경석이지훈심욱정희윤주영창남기태
Issue Date
2014-02
Publisher
Journal of materials chemistry. A, Materials for energy and sustainability
Citation
VOL 2, NO 7-2305
Abstract
Hematite (alpha-Fe2O3) has been attracting attention for photoelectrochemical water oxidation due to its visible light photon absorption capacity and high chemical stability, but the short-diffusion length of holes and the large overpotential are still challenging to overcome. Here, in an effort to address these challenges, we develop a hierarchically nanostructured photoanode composed of iron-oxides; Ti-doped hematite nanorods are decorated with an undoped hematite underlayer and beta-FeOOH nano-branches. The Ti-doped hematite nanorod array is prepared by hydrothermal synthesis, and this nanostructure offers enhanced separation of photogenerated charges. The underlayer not only increases the photocurrent density but also improves the onset potential. The photocurrent further increases by the epitaxially grown b-FeOOH nano-branches on the hematite, but the onset potential is positively shifted by the b-FeOOH due to increasing flat-band potential. The analyses of the photocurrent transients and electrochemical impedance spectra reveal that beta-FeOOH improves the photocurrent by decreasing the resistance to charge transfer through the anode/electrolyte. This study demonstrates a new possibility for improving the efficiency of a hematite photoanode with the interface of other iron-oxides.
URI
http://pubs.kist.re.kr/handle/201004/71230
ISSN
2050-7488
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KIST Publication > Article
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