Tunable Oxygen Activation for Catalytic Organic Oxidation: Schottky Junction versus Plasmonic Effects
Tunable Oxygen Activation for Catalytic Organic Oxidation: Schottky Junction versus Plasmonic Effects
复制标题
用于催化有机氧化的可调氧活化：肖特基结与等离子体效应
DOI：
10.1002/anie.201309660
复制
发表时间：
2014-03-17
影响因子：
16.6
通讯作者：
Xiong, Yujie
中科院分区：
文献类型：
--
作者：
Long, Ran;Mao, Keke;Xiong, Yujie
钯表面的电荷态是一个关键参数，它关系到钯纳米晶体激活O₂以产生一种在化学和物理性质上类似于单线态O₂的物质的能力。受这一发现的启发，我们设计了一种金属 - 半导体杂化体系，其中由{100}晶面包封的钯纳米晶体沉积在TiO₂载体上。在肖特基结的驱动下，TiO₂载体在适当光照下可为金属催化剂提供电子。通过超快光谱进一步检测发现，在强光照下，钯的等离子体效应可能迫使大量电子从钯反向迁移到TiO₂的导带，从而作为一种副作用降低了钯表面的电子密度。因此，我们能够合理地调整金属表面的电荷态，进而通过简单地改变照射在Pd - TiO₂杂化结构上的光强来调节钯纳米晶体在O₂活化和有机氧化反应中的功能。
The charge state of the Pd surface is a critical parameter in terms of the ability of Pd nanocrystals to activate O-2 to generate a species that behaves like singlet O-2 both chemically and physically. Motivated by this finding, we designed a metal-semiconductor hybrid system in which Pd nanocrystals enclosed by {100} facets are deposited on TiO2 supports. Driven by the Schottky junction, the TiO2 supports can provide electrons for metal catalysts under illumination by appropriate light. Further examination by ultrafast spectroscopy revealed that the plasmonics of Pd may force a large number of electrons to undergo reverse migration from Pd to the conduction band of TiO2 under strong illumination, thus lowering the electron density of the Pd surface as a side effect. We were therefore able to rationally tailor the charge state of the metal surface and thus modulate the function of Pd nanocrystals in O-2 activation and organic oxidation reactions by simply altering the intensity of light shed on Pd-TiO2 hybrid structures.