在支金颗粒上吸附气的三站式模型:支的离子性和颗粒大小对气覆盖面的影响
Michiel K Oudenhuijzen1, Jeroen A van Bokhoven, Jeffrey T Miller
1Department of Inorganic Chemistry and Catalysis, Debye Institute, Utrecht University, PO Box 80083, 3508 TB Utrecht, The Netherlands.
Journal of the American Chemical Society
|February 3, 2005
概括
在 (Pt) 纳米颗粒上的吸附取决于压力和温度. 离子支增强吸附能量,影响解和化等催化反应.
科学领域:
- 表面科学是一门学科.
- 不同质的催化剂.
- 材料科学 材料科学 材料科学
背景情况:
- 了解金属相互作用对于催化非常重要.
- (Pt) 纳米粒子是广泛使用的催化剂,但它们的表面行为很复杂.
- 支材料在修改Pt纳米粒子特性中的作用尚未完全理解.
研究的目的:
- 为了研究的化学吸附点和小型支持的Pt粒子的结合强度.
- 为了确定支电离度对吸附和Pt表面位点的影响.
- 为了将发现与Pt催化解和化反应相关联.
主要方法:
- 使用Pt L(3) 射线吸收边缘光谱来探测结合.
- 运用密度函数理论 (DFT) 计算来建模吸附能量.
- 综合光谱数据与化学吸收测量.
主要成果:
- 在低H(2) 压力/高温下,化学吸收在顶部位置.
- 在较高的H(2) 压力/较低的温度下,n-fold (2或3) 位点被占用.
- 在由离子 (基础) 材料支的 Pt 粒子上,吸附能量增加.
结论:
- 支持电离度显著影响气覆盖面和活性Pt表面的可用性.
- 在高温催化反应相关的条件下,这些效应至关重要.
- 这些发现对优化Pt催化解和化过程有意义.
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