耐氧化黄金-55个集群
1Abteilung Festkörperphysik, Abteilung Organische Chemie III, Universität Ulm, D-89069 Ulm, Germany. hans-gerd.boyen@physik.uni-ulm.de
Science (New York, N.Y.)
|August 31, 2002
概括
黄金纳米粒子的氧化阻力根据大小而有所不同. 拥有55个原子的魔数金团表现出最大的惰性,这是由于它们的封闭外结构,而不是电子效应.
科学领域:
- 纳米材料科学 科学 纳米材料科学
- 表面化学 表面化学
- 催化剂是一种催化剂.
背景情况:
- 金纳米粒子 (AuNPs) 在催化和材料科学中至关重要.
- 了解纳米粒子氧化是控制它们的特性和应用的关键.
- 暴露于原子氧气对纳米材料的稳定性构成重大挑战.
研究的目的:
- 为了研究金纳米颗粒的大小依赖的氧化行为.
- 确定影响黄金集群氧化阻力的关键因素.
- 探索特定金大小的潜在催化活性.
主要方法:
- 在晶片上制备直径为1至8纳米的金纳米颗粒.
- 暴露金纳米颗粒的原子氧.
- 使用X射线光电谱 (XPS) 分析氧化状态和表面组成.
主要成果:
- 在含有55个原子的金中观察到最大的氧化阻力 ("魔法数").
- 这种惰性归因于魔法集群的封闭外电子结构.
- 电子封闭和金属到绝缘体过渡被排除为惰性的原因.
- 金-55集群显示出作为有效的氧化催化剂的潜力.
结论:
- 黄金纳米颗粒的氧化阻力强烈依赖于集群大小和电子结构.
- 魔数金 (Au55) 拥有独特的稳定性,因为它们的封闭外配置.
- 黄金-55集群显示为氧化反应的高效催化剂,包括一氧化碳氧化.
相关概念视频
03:14Oxidation Numbers
In redox reactions, the transfer of electrons occurs between reacting species. Electron transfer is described by a hypothetical number called the oxidation number (or oxidation state). It represents the effective charge of an atom or element, which is assigned using a set of rules.
03:01Halogens
Group 17 elements, known as halogens, are nonmetals. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine a solid. Astatine is a highly unstable radioactive element, so currently, most of its properties are unknown due to its short half-life. Tennessine is a synthetic element also predicted to be in this group.
02:54Noble Gases
The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name “noble” because they were assumed to be nonreactive since they have filled valence shells. In 1962, Dr. Neil Bartlett at the University of British Columbia proved this assumption to be false.
02:58Properties of Transition Metals
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.