Pelz Philipp M, Groschner Catherine, Bruefach Alexandra, Satariano Adam, Ophus Colin, Scott Mary C
Department of Materials Science and Engineering, University of California Berkeley, Berkeley, California 94720, United States.
The National Center for Electron Microscopy, Molecular Foundry, 1 Cyclotron Road, Berkeley, California 94720, United States.
ACS Nano. 2022 Jan 25;16(1):588-596. doi: 10.1021/acsnano.1c07772. Epub 2021 Nov 16.
Shape-controlled synthesis of multiply twinned nanostructures is heavily emphasized in nanoscience, in large part due to the desire to control the size, shape, and terminating facets of metal nanoparticles for applications in catalysis. Direct control of the size and shape of solution-grown nanoparticles relies on an understanding of how synthetic parameters alter nanoparticle structures during synthesis. However, while outcome populations can be effectively studied with standard electron microscopy methods, transient structures that appear during some synthetic routes are difficult to study using conventional high resolution imaging methods due to the high complexity of the 3D nanostructures. Here, we have studied the prevalence of transient structures during growth of multiply twinned particles and employed atomic electron tomography to reveal the atomic-scale three-dimensional structure of a Pd nanoparticle undergoing a shape transition. By identifying over 20 000 atoms within the structure and classifying them according to their local crystallographic environment, we observe a multiply twinned structure consistent with a simultaneous successive twinning from a decahedral to icosahedral structure.
在纳米科学中，多重孪晶纳米结构的形状控制合成受到高度重视，很大程度上是因为希望控制金属纳米颗粒的尺寸、形状和终止面，以用于催化应用。溶液生长纳米颗粒尺寸和形状的直接控制依赖于对合成参数在合成过程中如何改变纳米颗粒结构的理解。然而，虽然可以用标准电子显微镜方法有效地研究最终产物群体，但由于三维纳米结构的高度复杂性，在某些合成路线中出现的瞬态结构很难用传统的高分辨率成像方法进行研究。在这里，我们研究了多重孪晶颗粒生长过程中瞬态结构的普遍性，并采用原子电子断层扫描技术来揭示正在经历形状转变的钯纳米颗粒的原子尺度三维结构。通过识别结构内超过20000个原子，并根据它们的局部晶体学环境对其进行分类，我们观察到一种多重孪晶结构，它与从十面体到二十面体结构的同时连续孪晶一致。
