Plasmon-Driven Reaction Mechanisms: Hot Electron Transfer versus Plasmon-Pumped Adsorbate Excitation
Plasmon-Driven Reaction Mechanisms: Hot Electron Transfer versus Plasmon-Pumped Adsorbate Excitation
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DOI：
10.1021/acs.jpcc.8b12054
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发表时间：
2019-04-11
影响因子：
3.7
通讯作者：
Habteyes, Terefe G.
中科院分区：
文献类型：
--
作者：
Tesema, Tefera E.;Kafle, Bijesh;Habteyes, Terefe G.
由于对结合联合收割机表面反应和原位光谱的基本需求以及等离子体激元驱动的反应可以提供将太阳能有效转化为燃料的途径的机会，可以在光激发的等离子体纳米颗粒上以低入射光子通量驱动的光化学正吸引越来越多的研究兴趣。在等离子体激元驱动反应的机理研究中，迄今为止，大量的重点是热电子转移。这篇专题文章中总结的结果表明，等离子体纳米颗粒上的光化学可以通过从纳米颗粒到吸附物的未占据轨道的热电子转移和/或通过等离子体激元泵浦的电子从吸附物的占据分子轨道到未占据分子轨道的跃迁来诱导。对氨基苯硫酚在等离子体金表面上的分支光化学反应取决于影响热电子浓度的十六烷基三甲基溴化铵表面配体的存在，用于突出热载流子驱动的反应。基于亚甲基蓝（MB）在金纳米结构上的N-去甲基化作用，证明了等离子体激发的吸附物电子激发在引发表面光化学反应中的重要性。在与MB和金纳米颗粒的共振重叠的激发波长处，在大气中的氧和表面分子复合物中的水的存在下观察到MB向噻吩的转化。考虑到MB是一种众所周知的光敏剂，该观察结果表明，光化学N-脱甲基反应涉及单线态氧，其可以通过从MB三重激发态到O-2三重基态的能量转移产生。
Photochemistry that can be driven at low incident photon flux on optically excited plasmonic nanoparticles is attracting increasing research interest because of the fundamental need to combine surface reaction and in situ spectroscopy as well as the opportunity that plasmon-driven reactions may offer a pathway for efficient conversion of solar energy into fuel. In mechanistic studies of plasmon-driven reactions to date, a great deal of emphasis is given to hot electron transfer. The results summarized in this Feature Article indicate that photochemistry on plasmonic nano particles can be induced by hot electron transfer from the nano particle to an unoccupied orbital of the adsorbate and/or by plasmon-pumped electron transition from an occupied molecular orbital to an unoccupied molecular orbital of the adsorbate. The branching photochemical reaction of para-aminothiophenol on the plasmonic gold surface depending on the presence of a cetyltrimethylammonium bromide surface ligand that influences the hot electron concentration is used to highlight reactions driven by hot carriers. The importance of plasmon-pumped electronic excitation of adsorbates in initiating surface photochemistry is demonstrated based on the N-demethylation of methylene blue (MB) on gold nanostructures depending on excitation wavelengths. At excitation wavelength that overlaps with the resonances of MB and the gold nanoparticles, conversion of MB to thionine is observed in the presence of oxygen in the atmosphere and water in the surface-molecule complex. Considering that MB is a well-known photosensitizer, this observation suggests that the photochemical N-demethylation reaction involves singlet oxygen that can be generated via energy transfer from the MB triplet excited state to the O-2 triplet ground state.