Doping of Pt into Anodic TiO2 Nanotubes for Water Oxidation: Underpotential Shock Method in Cl鈥?/sup> Solution

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• 作者：Sunkyu Kim ; Hyeonseok Yoo ; Oonhee Rhee ; Jinsub Choi
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：September 17, 2015
• 年：2015
• 卷：119
• 期：37
• 页码：21497-21503
• 全文大小：546K
• ISSN：1932-7455

文摘

For the preparation of a highly stable and active electrode for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), Pt was doped into TiO₂ nanotubes by means of an underpotential shock method, in which positively biased voltage lower than the anodizing voltage was applied to anodic TiO₂ for short seconds immediately after anodization, to reduce the overpotential of the catalyzed hydrogen and oxygen evolution reactions of water splitting. Because aqueous acidic H₂PtCl₆ solution was used as a doping precursor, Cl^{鈥?/sup> ions were generated during imposing high positive voltage (so-called potential shock), which would aggressively damage the anodic oxide if a normal potential shock were applied. Instead, the novel underpotential shock method allowed Pt to be homogeneously doped into TiO₂ films without destroying the structures. Pt could not thoroughly penetrate the barrier oxide into the interface between the oxide and Ti metal because the voltage of the potential shock was lower than the anodizing voltage, which determines the thickness of barrier oxide. Thus, a high amount of Pt was doped in the outer region of the barrier oxide. In the water splitting application, both the HER and OER were greatly enhanced when catalyzed by TiO₂ that was doped with Pt at 10 V in 2 mM H₂PtCl₆ for 10 s.}