在现场QXAFS研究CO和H2在Pt上的吸附在[PtAu8]-H[PMo12O40]固体中
Tomoki Matsuyama1, Taishi Suzuki1, Yuto Oba1
1Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji-shi, Tokyo 192-0397, Japan. yamazoe@tmu.ac.jp.
Nanoscale
|November 29, 2024
概括
(H2) 在PtAu8-PMo12固体中迅速吸附到 (Pt) 原子上,与一氧化碳 (CO) 不同. 这种H2吸附是可逆的,而CO会触发材料的结构变化.
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:
- 在新型固体材料上研究气体分子吸附对于催化和气体储存至关重要.
- 了解 (H2) 和一氧化碳 (CO) 与含集群的相互作用动态,可以了解它们的反应性.
研究的目的:
- 为了研究H2和CO分子在冠状基因[PtAu8(PPh3)8]-H[PMo12O40] (PtAu8-PMo12) 固体上的吸附行为.
- 用先进的光谱技术阐明由H2和CO吸附引起的电子和结构变化.
主要方法:
- 在现场快速扫描X射线吸收细结构 (QXAFS) 测量,具有高时间分辨率 (0.1秒).
- 密度函数理论 (DFT) 计算来补充实验发现.
主要成果:
- 在PtAu8-PMo12中,H2在Pt上的吸附是快速的 (<0.5秒) 和可逆的,这是由于H2的动力直径较小,允许更快的扩散.
- 碳化合物吸附速度较慢 (∼2.5秒) 并不可逆转,导致PtAu8集群的结构异构化,从"冠状动图"变成稳定的"杯状动图".
- 由于Pt-H2/Pt-CO相互作用,Pt的电子状态在H2和CO吸附时发生显著变化.
结论:
- 吸附动态和由此产生的结构变化高度依赖于吸附物的特性 (例如动力直径).
- PtAu8-PMo12对H2和CO表现出明显的反应,突出显示其具有选择性气体相互作用的潜力.
- 这项研究证明了时间解析的QXAFS在观测原子水平的动态表面过程中的实用性.
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