Photoelectrochemical Activity of As-Grown, a-Fe2O3 Nanowire Array Electrodes for Water Splitting

Boris D. Chernomordik, Harry B. Russell, Uros Cvelbar, Jacek B. Jasinski, Vivekanand Kumar, Todd Deutsch, Mahendra K. Sunkara

Research output: Contribution to journalArticlepeer-review

95 Scopus Citations

Abstract

Undoped hematite nanowire arrays grown using plasma oxidation of iron foils show significant photoactivity (∼0.38 mA cm 2 at 1.5 V versus reversible hydrogen electrode in 1M KOH). In contrast, thermally oxidized nanowire arrays grown on iron exhibit no photoactivity due to the formation of a thick (>7 μm Fe 1xO) interfacial layer. An atmospheric plasma oxidation process required only a few minutes to synthesize hematite nanowire arrays with a 1-5 μm interfacial layer of magnetite between the nanowire arrays and the iron substrate. An amorphous oxide surface layer on hematite nanowires, if present, is shown to decrease the resulting photoactivity of as-synthesized, plasma grown nanowire arrays. The photocurrent onset potential is improved after removing the amorphous surface on the nanowires using an acid etch. A two-step method involving high temperature nucleation followed by growth at low temperature is shown to produce a highly dense and uniform coverage of nanowire arrays.

Original languageAmerican English
Article number194009
Number of pages9
JournalNanotechnology
Volume23
Issue number19
DOIs
StatePublished - 17 May 2012

NREL Publication Number

  • NREL/JA-5600-55504

Fingerprint

Dive into the research topics of 'Photoelectrochemical Activity of As-Grown, a-Fe2O3 Nanowire Array Electrodes for Water Splitting'. Together they form a unique fingerprint.

Cite this