Surface Passivation of TiO2 Nanowires Using a Facile Precursor-Treatment Approach for Photoelectrochemical Water Oxidation

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• 作者：Ying-Chih Pu ; Yichuan Ling ; Kao-Der Chang ; Chia-Ming Liu ; Jin Z. Zhang ; Yung-Jung Hsu ; Yat Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：July 10, 2014
• 年：2014
• 卷：118
• 期：27
• 页码：15086-15094
• 全文大小：582K
• ISSN：1932-7455

文摘

We developed a facile precursor-treatment approach for effective surface passivation of rutile TiO₂ nanowire photoanode to improve its performance in photoelectrochemical (PEC) water oxidation. The approach was demonstrated by treating rutile TiO₂ nanowires with titanium precursor solutions (TiCl₄, Ti(OBu)₄, or Ti(OiP)₄) followed by a postannealing process, which resulted in the additional deposition of anatase TiO₂ layer on the nanowire surface. Compared to pristine TiO₂, all the precursor-treated TiO₂ nanowire electrodes exhibited a significantly enhanced photocurrent density under white light illumination. Among the three precursor-treated samples, Ti(OBu)₄-treated TiO₂ nanowires achieved the largest enhancement of photocurrent generation, which is approximately a 3-fold increase over pristine TiO₂. Monochromatic incident photon-to-electron conversion efficiency (IPCE) measurements showed that the improvement of PEC performance was dominated by the enhanced photoactivity of TiO₂ in the UV region. The photovoltage and electrochemical impedance spectroscopy (EIS) measurements showed that the enhanced photoactivity can be attributed to the improved charge transfer as a result of effective surface state passivation. This work demonstrates a facile, low-cost, and efficient method for preparing highly photoactive TiO₂ nanowire electrodes for PEC water oxidation. This approach could also potentially be used for other photoconversion applications, such as TiO₂ based dye-sensitized solar cells, as well as photocatalytic systems.