You Ruiyang, Ou Yang, Qi Rui, Yu Jian, Wang Fei, Jiang Ying, Zou Shihui, Han Zhong-Kang, Yuan Wentao, Yang Hangsheng, Zhang Ze, Wang Yong
State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Nano Lett. 2023 Aug 23;23(16):7260-7266. doi: 10.1021/acs.nanolett.3c00923. Epub 2023 Aug 3.
Understanding the oxidation mechanism of metal nanoparticles under ambient pressure is extremely important to make the best use of them in a variety of applications. Through ambient pressure transmission electron microscopy, we investigated the dynamic oxidation processes of Ni nanoparticles at different temperatures under atmospheric pressure, and a temperature-dependent oxidation behavior was revealed. At a relatively low temperature (e.g., 600 °C), the oxidation of Ni nanoparticles underwent a classic Kirkendall process, accompanied by the formation of oxide shells. In contrast, at a higher temperature (e.g., 800 °C), the oxidation began with a single crystal nucleus at the metal surface and then proceeded along the metal/oxide interface without voids formed during the whole process. Through our experiments and density functional theory calculations, a temperature-dependent oxidation mechanism based on Ni nanoparticles was proposed, which was derived from the discrepancy of gas adsorption and diffusion rates under different temperatures.
了解金属纳米颗粒在常压下的氧化机制对于在各种应用中充分利用它们极其重要。通过常压透射电子显微镜，我们研究了镍纳米颗粒在大气压力下不同温度下的动态氧化过程，并揭示了温度依赖性氧化行为。在相对较低的温度（例如600°C）下，镍纳米颗粒的氧化经历了经典的柯肯达尔过程，伴随着氧化壳的形成。相比之下，在较高的温度（例如800°C）下，氧化从金属表面的单个晶核开始，然后沿着金属/氧化物界面进行，整个过程中没有形成空隙。通过我们的实验和密度泛函理论计算，提出了一种基于镍纳米颗粒的温度依赖性氧化机制，该机制源于不同温度下气体吸附和扩散速率的差异。
