在MgO表面的能量转移,由UV诱导的H2化学吸收监控
Martin Sterrer1, Thomas Berger, Oliver Diwald
1Institut für Materialchemie, Technische Universität Wien, c/o Veterinärplatz 1/GA, A-1210 Vienna, Austria.
Journal of the American Chemical Society
|January 8, 2003
概括
在MgO纳米颗粒上的表面离子在紫外线激发后与反应. 紫外线诱导的刺激子或电子孔迁移到角位,形成基团.
科学领域:
- 材料科学 材料科学 材料科学
- 表面化学 表面化学
- 纳米技术纳米技术
背景情况:
- 立方MgO纳米粒子在边缘 (4-coordinated,4C) 和角落 (3-coordinated,3C) 具有明显的表面离子.
- 这些表面离子表现出特有的紫外线共振吸收.
研究的目的:
- 研究MgO纳米颗粒的紫外线诱导的表面反应的性质.
- 阐明与激发的表面离子相互作用的机制.
主要方法:
- 紫外线-紫外线光谱法用于监测吸收变化.
- 电子偏磁共振 (EPR) 光谱检测激进物种.
- 红外 (IR) 光谱法用于识别化学键形成.
- 在探测器反应路径中添加气 (H2) 气体.
主要成果:
- 4C和3C位点的紫外线激发导致了3协调O-激素 (O- 3C) 的EPR信号.
- 添加气会使O-(3C) EPR信号变白,并减少3C紫外线的吸收.
- 在OH伸展区域出现了一个新的IR波段,表明基组形成.
- 发现激发和反应部位不同,这表明激发子的移动性.
结论:
- 紫外线刺激在MgO纳米粒子边缘产生移动激子或电子孔 (O-(4C)).
- 这些移动物种迁移到角位 (3C),在那里与发生反应,形成基组 (O- 3C) H).
- 这项研究揭示了金属氧化物纳米粒子表面功能化的新机制.
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