Adsorption of Thiol-Protected Gold Nanoparticles on TiO2 and Their Behavior under UV Light Irradiation

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• 作者：Igor Dolamic ; Cyrille Gautier ; Julien Boudon ; Natallia Shalkevich ; Thomas B&uuml ; rgi
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：April 17, 2008
• 年：2008
• 卷：112
• 期：15
• 页码：5816 - 5824
• 全文大小：422K
• 年卷期：v.112,no.15(April 17, 2008)
• ISSN：1932-7455

文摘

A combination of in situ attenuated total reflection infrared (ATR-IR) spectroscopy, UV-vis spectroscopyand transmission electron microscopy was used to study the adsorption of thiol-protected gold nanoparticleson TiO₂ films and the behavior of the resulting composite films upon UV irradiation. The gold nanoparticleswere covered by charged thiols N-acetyl-L-cysteine and L-glutathione and had a mean core diameter of about1 nm. The TiO₂ film was prepared by deposition of a slurry of TiO₂ nanoparticles with a particles size of 21nm. The combination of the two spectroscopic techniques showed that the adsorption of the gold nanoparticlesonto the TiO₂ films is significantly limited by intrafilm diffusion. Upon illumination the IR spectra revealedthe removal of the adsorbed thiolates and the appearance of sulfates. These species were also observed whenN-acetyl-L-cysteine adsorbed on TiO₂ was illuminated, i.e., in the absence of gold. In the latter case oxalatewas observed in large quantity on the TiO₂ surface, in contrast to the illumination of the N-acetyl-L-cysteine-protected gold particles. This indicates a different pathway for the decomposition of the adsorbed thiol whenadsorbed on the gold or directly on the TiO₂ surface. In situ UV-vis spectroscopy also shows the formationof larger particles upon illumination, which is confirmed by transmission electron microscopy.