The Role of Photon Energy and Semiconductor Substrate in the Plasmon-Mediated Photooxidation of Citrate by Silver Nanoparticles

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• 作者：Elizabeth S. Thrall ; Asher Preska Steinberg ; Xiaomu Wu ; Louis E. Brus
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：December 12, 2013
• 年：2013
• 卷：117
• 期：49
• 页码：26238-26247
• 全文大小：477K
• 年卷期：v.117,no.49(December 12, 2013)
• ISSN：1932-7455

文摘

The plasmon-mediated photooxidation of citrate ions adsorbed on silver (Ag) nanoparticle鈥搒emiconductor electrodes is studied in a photoelectrochemical cell. Consistent with previous reports, a negative photovoltage and an anodic photocurrent arise from citrate photooxidation under weak visible light illumination. We measure the wavelength dependence of this reaction for three different types of Ag nanoparticles and find that both the photovoltage and photocurrent increase with photon energy over the visible spectral range. The electrode photoresponse does not closely track the localized surface plasmon resonance of the Ag nanoparticles. We also explore the role of the semiconductor substrate in this reaction, and we find a similar electrode photoresponse for several different substrates. The strong dependence of reaction rate on photon energy is consistent with a hot-carrier photochemical process where photoexcited hot holes generated in the Ag nanoparticles are responsible for the oxidation of adsorbed citrate.