Facile Solution Synthesis of 伪-FeF3路3H2O Nanowires and Their Conversion to 伪-Fe2O3 Nanowires for Photoelectrochemical Application

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• 作者：Linsen Li ; Yanghai Yu ; Fei Meng ; Yizheng Tan ; Robert J. Hamers ; Song Jin
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：February 8, 2012
• 年：2012
• 卷：12
• 期：2
• 页码：724-731
• 全文大小：529K
• 年卷期：v.12,no.2(February 8, 2012)
• ISSN：1530-6992

文摘

We report for the first time the facile solution growth of 伪-FeF₃路3H₂O nanowires (NWs) in large quantity at a low supersaturation level and their scalable conversion to porous semiconducting 伪-Fe₂O₃ (hematite) NWs of high aspect ratio via a simple thermal treatment in air. The structural characterization by transmission electron microscopy shows that thin 伪-FeF₃路3H₂O NWs (typically <100 nm in diameter) are converted to single-crystal 伪-Fe₂O₃ NWs with internal pores, while thick ones (typically >100 nm in diameter) become polycrystalline porous 伪-Fe₂O₃ NWs. We further demonstrated the photoelectrochemical (PEC) application of the nanostructured photoelectrodes prepared from these converted hematite NWs. The optimized photoelectrode with a 400 nm thick hematite NW film yielded a photocurrent density of 0.54 mA/cm² at 1.23 V vs reversible hydrogen electrode potential after modification with cobalt catalyst under standard conditions (AM 1.5 G, 100 mW/cm², pH = 13.6, 1 M NaOH). The low cost, large quantity, and high aspect ratio of the converted hematite NWs, together with the resulting simpler photoelectrode preparation, can be of great benefit for hematite-based PEC water splitting. Furthermore, the ease and scalability of the conversion from hydrated fluoride NWs to oxide NWs suggest a potentially versatile and low-cost strategy to make NWs of other useful iron-based compounds that may enable their large-scale renewable energy applications.

Keywords:

Nanowire; 伪-FeF₃路3H₂O; 伪-Fe₂O₃; conversion; photoelectrochemical water splitting; nanostructured hematite photoelectrodes