Ta2O5 Nanotubes Obtained by Anodization: Effect of Thermal Treatment on the Photocatalytic Activity for Hydrogen Production

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• 作者：Renato V. Gon莽alves ; Pedro Migowski ; Heberton Wender ; Dario Eberhardt ; Daniel E. Weibel ; Fl谩via C. Sonaglio ; Maximiliano J. M. Zapata ; Jairton Dupont ; Adriano F. Feil ; Sergio R. Teixeira
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：July 5, 2012
• 年：2012
• 卷：116
• 期：26
• 页码：14022-14030
• 全文大小：495K
• 年卷期：v.116,no.26(July 5, 2012)
• ISSN：1932-7455

文摘

Freestanding tantalum oxide nanotubes (Ta₂O₅ NTs) were easily fabricated by controlling only the electrolyte temperature during anodization in a sulfuric acid solution. When the electrolyte temperature decreased, the adherence of NTs to the Ta substrate increased. High electrolyte temperatures facilitated formation of freestanding NTs. Thermal treatment of the freestanding Ta₂O₅ NTs below 750 掳C resulted in an amorphous structure. The orthorhombic crystalline phase appeared only at temperatures higher than 750 掳C. The effect of thermal treatment on the crystalline structure and morphology of Ta₂O₅ NTs showed that the NTs retained their tubular shape up to 800 掳C. In addition, it was shown that the crystallinity of the NTs was enhanced from 11% to 34% by increasing the treatment time for the NTs at 800 掳C from 0.5 to 1 h. High crystallinity and low surface contamination increased the photocatalytic activity of the freestanding NTs for hydrogen production by water splitting using a water/ethanol solution under UV radiation. The sample annealed at 800 掳C for 1 h showed the highest photocatalytic activity for hydrogen generation. Additionally, changes to the physicochemical properties of the surface and bulk of the photocatalyst showed decreased selectivity for minor products (C₂H₄ and C₂H₆).