Hot-Electron-Induced Highly Efficient O2 Activation by Pt Nanoparticles Supported on Ta2O5 Driven by Visible Light

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• 作者：Hirokatsu Sakamoto ; Tomoyuki Ohara ; Naoki Yasumoto ; Yasuhiro Shiraishi ; Satoshi Ichikawa ; Shunsuke Tanaka ; Takayuki Hirai
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：July 29, 2015
• 年：2015
• 卷：137
• 期：29
• 页码：9324-9332
• 全文大小：612K
• ISSN：1520-5126

文摘

Aerobic oxidation on a heterogeneous catalyst driven by visible light (位 >400 nm) at ambient temperature is a very important reaction for green organic synthesis. A metal particles/semiconductor system, driven by charge separation via an injection of 鈥渉ot electrons (e_hot^{鈥?/sup>)鈥?from photoactivated metal particles to semiconductor, is one of the promising systems. These systems, however, suffer from low quantum yields for the reaction (<5% at 550 nm) because the Schottky barrier created at the metal/semiconductor interface suppresses the e_hot鈥?/sup> injection. Some metal particle systems promote aerobic oxidation via a non-e_hot鈥?/sup>-injection mechanism, but require high reaction temperatures (>373 K). Here we report that Pt nanoparticles (鈭? nm diameter), when supported on semiconductor Ta₂O₅, promote the reaction without e_hot鈥?/sup> injection at room temperature with significantly high quantum yields (鈭?5%). Strong Pt鈥揟a₂O₅ interaction increases the electron density of the Pt particles and enhances interband transition of Pt electrons by absorbing visible light. A large number of photogenerated e_hot鈥?/sup> directly activate O₂ on the Pt surface and produce active oxygen species, thus promoting highly efficient aerobic oxidation at room temperature.}