Mechanism of O2 Production from Water Splitting: Nature of Charge Carriers in Nitrogen Doped Nanocrystalline TiO2 Films and Factors Limiting O2 Production

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• 作者：Junwang Tang ; Alexander J. Cowan ; James R. Durrant ; David R. Klug
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：February 24, 2011
• 年：2011
• 卷：115
• 期：7
• 页码：3143-3150
• 全文大小：918K
• 年卷期：v.115,no.7(February 24, 2011)
• ISSN：1932-7455

文摘

The low efficiency of the extensively investigatedvisible light photocatalyst N-TiO₂ has been widely assumed to be determined by the dynamics of the charge carriers. The nature of the photoelectrons and photoholes produced on the nanostructured (nc) N-TiO₂ film has been systematically investigated in this work by the use of time-resolved absorption spectroscopy. Here the fingerprints of the two distinct photohole populations on nc-N-TiO₂ films are reported and the reaction between these photoholes and water has been examined. The origin of the low efficiency of the visible-driven material for water oxidation was explored and rapid electron hole decay following visible excitation is believed to be a key factor. Pt deposition on nc-N-TiO₂ resulted in an 80% enhancement of the quantum yield for O₂ production under UV light. Finally, it has been summarized that the oxygen production on the nc-N-TiO₂ film requires photoholes with lifetimes of 0.4s.