Water Splitting by Nanocrystalline TiO2 in a Complete Photoelectrochemical Cell Exhibits Efficiencies Limited by Charge Recombination

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• 作者：Alexander J. Cowan ; Junwang Tang ; Wenhua Leng ; James R. Durrant ; David R. Klug
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：March 11, 2010
• 年：2010
• 卷：114
• 期：9
• 页码：4208-4214
• 全文大小：252K
• 年卷期：v.114,no.9(March 11, 2010)
• ISSN：1932-7455

文摘

We report on the mechanism of water splitting by TiO₂ in the absence of chemical scavengers in a fully functional photoelectrochemical (PEC) cell. The application of a positive potential to a nanocrystalline-TiO₂ film is shown to lead to the formation of long-lived holes which oxidize water on the milliseconds time scale. These first time-resolved studies of a nanocrystalline-TiO₂ (nc-TiO₂) film in a complete PEC cell also showed that all of the long-lived photoholes go on to generate O₂, and that there are no major branching inefficiencies in the catalysis itself, which appears to be operating at efficiencies close to 100%. The overall quantum yield of oxygen production under pulsed illumination (355 nm) was found to be 8% at excitation densities of 4.4 photons per particle. Under all conditions examined, electron−hole recombination was found to be the dominant loss pathway.