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单个碳纳米颗粒的高温氧化:依赖表面结构并通过动力学探测实时结构演变

Daniel J Rodriguez¹, Chris Y Lau¹, Abigail M Friese¹

¹Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112, United States.

Journal of the American Chemical Society

|March 9, 2022

概括

这项研究揭示了碳纳米颗粒 (NP) 的氧气 (O2) 蚀刻对表面结构非常敏感,与升华不同. 这种灵敏度使得O2蚀刻可以作为实时探测器,用于跟踪高温实验中的NP结构变化.

科学领域:

材料科学
纳米技术
物理化学

背景情况:

了解碳纳米粒子在极端条件下的行为对于它们在各种领域的应用至关重要.
个体NP的氧化和升华动力学是复杂的,取决于温度和表面结构等因素.

研究的目的:

在高温下研究不同原料中的单个碳NP的氧化和升华动力学.
探索使用氧蚀作为NP表面结构演变的实时探测器.

主要方法:

用单纳米粒子质谱测量氧化和升华速率.
在5种不同的碳原料 (石墨,石墨烯氧化物,碳黑,钻石,纳米洋) 中对30多个单独的NP进行了实验.
温度在1100K到2900K之间,氧化特别研究在1200K到1600K之间.

主要成果:

氧化率对NP表面结构具有很高的敏感性,蚀刻效率 (EEo) 多达四个数量级.
在1700K以上显著的升华率显示出更低的可变性 (系数为3).
所有NP最初显示了类似的EEo值 (~10^-3 Da/O2碰撞),但演变为惰性 (EEo <10^-6 Da/O2碰撞),具有明显的时间依赖行为.

结论:

氧蚀作为一个有效的实时探测器来监测NP表面结构的演变.
不同的碳NP原料表现出独特的氧化路径和速度,钻石NP单调地演变为惰性,石墨NP显示复杂的非单调蚀刻模式.
这项研究提出了解释观察到的复杂蚀刻行为的机制,强调了NP反应性中的表面结构的重要性.

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