Revealing Bismuth Oxide Hollow Nanoparticle Formation by the Kirkendall Effect

We study the formation of bismuth
oxide hollow nanoparticles by
the Kirkendall effect using liquid cell transmission electron microscopy
(TEM). Rich dynamics of bismuth diffusion through the bismuth oxide
shell have been captured in situ. The diffusion coefficient of bismuth
through bismuth oxide shell is 3–4 orders of magnitude higher
than that of bulk. Observation reveals that defects, temperature,
sizes of the particles, and so forth can affect the diffusion of reactive
species and modify the kinetics of the hollowing process.

本研究借助液相池透射电子显微镜（TEM），基于柯肯达尔效应（Kirkendall effect）探究了氧化铋空心纳米颗粒的形成机制。实验原位捕捉到铋原子经由氧化铋壳层扩散的丰富动力学过程。铋穿过氧化铋壳层的扩散系数较块体材料高出3~4个数量级。观测结果表明，缺陷、温度、颗粒尺寸等因素均可影响反应物种的扩散行为，并改变空心化过程的动力学特征。