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在高温下反应性氧气下支持的超小合金纳米粒子的原子扩散和收缩
Han-Wen Cheng1,2, Shan Wang2, Guanyu Chen1
1Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Department of Materials Science, Academy for Engineering & Technology, Fudan University, Shanghai 200438, China.
Journal of the American Chemical Society
|June 10, 2025
概括
在活性氧下控制超小的合金纳米粒子是很困难的. 这项研究揭示了氧气诱导的扩散和收缩现象对于纳米合金稳定性至关重要,为催化剂设计提供了新的见解.
科学领域:
- 材料科学
- 纳米技术
- 表面化学
背景情况:
- 控制超小 (5 nm) 支合金纳米粒子的形态是具有挑战性的,特别是在高温的反应性氧气下.
- 现有的研究通常集中在更大的纳米粒子的晶体相上,限制了对纳米尺度界面相互作用的理解.
- 控制超小合金系统中纳米级表面主导相互作用和反应性的因素仍然难以捉摸.
研究的目的:
- 在高温下暴露在氧气下,研究在上支的超小三元合金纳米粒子的时空动力学.
- 阐明氧气诱导的纳米合金形态变化的现象.
- 了解这些动态在维持超小支纳米合金稳定性的作用.
主要方法:
- 在现场跟踪支持的超小三元合金纳米粒子的时空动力学.
- 在不同温度下接触氧气.
- 使用一氧化碳作为探针反应来评估催化剂的稳定性.
主要成果:
- 在氧气下观察到超小支持合金纳米粒子的反直觉扩散和收缩现象.
- 这种现象表现出一种动态的无形晶体相二元性,被称为"ebb-and-flow"行为.
- 观察到的动态与高容量的氧气呼吸行为相关,对纳米合金的稳定性至关重要.
- 证明了这种现象在探针反应 (CO氧化) 期间保持稳定性的作用.
结论:
- 氧气诱导的扩散和收缩现象是稳定反应条件下的超小支合金纳米粒子的关键.
- 这种动态无形晶相二元性为纳米合金行为提供了新的视角.
- 通过利用动态和可逆相变特性设计催化剂的潜力.
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