Chao Hsin-Yun, Jiang Hua, Ospina-Acevedo Francisco, Balbuena Perla B, Kauppinen Esko I, Cumings John, Sharma Renu
Materials Science and Engineering, University of Maryland, College Park, MD, USA.
Nanoscale. 2020 Nov 5;12(42):21923-21931. doi: 10.1039/d0nr05916a.
The structure and phase transformation of a cobalt (Co) catalyst, during single walled carbon nanotube (SWCNT) growth, is elucidated for inactive, active and deactivated nanoparticles by in situ imaging using an environmental transmission electron microscope. During nanotube growth, the structure was analyzed using Miller indices to determine the types of planes that favor anchoring or liftoff of nanotubes from the Co catalyst. Density functional theory was further applied to model the catalyst interactions to compare the work of adhesion of the catalyst's faceted planes to understand the interactions of different Miller planes with the graphene structure. Through in-depth studies of multiple distinct Co nanoparticles, we established a dominant nanoparticle phase for SWCNT growth. In addition, we identified the preferred lattice planes and a threshold for work of adhesion to allow the anchoring and liftoff of SWCNTs.
通过使用环境透射电子显微镜进行原位成像，阐明了钴（Co）催化剂在单壁碳纳米管（SWCNT）生长过程中，对于无活性、活性和失活纳米颗粒的结构和相变情况。在纳米管生长过程中，利用密勒指数分析结构，以确定有利于纳米管从Co催化剂上锚定或脱离的平面类型。进一步应用密度泛函理论对催化剂相互作用进行建模，以比较催化剂刻面平面的粘附功，从而理解不同密勒平面与石墨烯结构的相互作用。通过对多个不同的Co纳米颗粒进行深入研究，我们确定了SWCNT生长的主要纳米颗粒相。此外，我们还确定了优先晶格平面和粘附功阈值，以实现SWCNT的锚定和脱离。
