Direct observation and catalytic role of mediator atom in 2D materials
Open Access
- 12 June 2020
- journal article
- research article
- Published by American Association for the Advancement of Science (AAAS) in Science Advances
- Vol. 6 (24), eaba4942
- https://doi.org/10.1126/sciadv.aba4942
Abstract
The structural transformations of graphene defects have been extensively researched through aberration-corrected transmission electron microscopy (AC-TEM) and theoretical calculations. For a long time, a core concept in understanding the structural evolution of graphene defects has been the Stone-Thrower-Wales (STW)–type bond rotation. In this study, we show that undercoordinated atoms induce bond formation and breaking, with much lower energy barriers than the STW-type bond rotation. We refer to them as mediator atoms due to their mediating role in the breaking and forming of bonds. Here, we report the direct observation of mediator atoms in graphene defect structures using AC-TEM and annular dark-field scanning TEM (ADF-STEM) and explain their catalytic role by tight-binding molecular dynamics (TBMD) simulations and image simulations based on density functional theory (DFT) calculations. The study of mediator atoms will pave a new way for understanding not only defect transformation but also the growth mechanisms in two-dimensional materials.This publication has 38 references indexed in Scilit:
- The Role of the Bridging Atom in Stabilizing Odd Numbered Graphene VacanciesNano Letters, 2014
- Stability and Dynamics of the Tetravacancy in GrapheneNano Letters, 2014
- Dislocation-Driven Deformations in GrapheneScience, 2012
- Dynamics and stability of divacancy defects in graphenePhysical Review B, 2011
- Stone-Wales-type transformations in carbon nanostructures driven by electron irradiationPhysical Review B, 2011
- From Point Defects in Graphene to Two-Dimensional Amorphous CarbonPhysical Review Letters, 2011
- Stability of dislocation defect with two pentagon-heptagon pairs in graphenePhysical Review B, 2008
- Defect energies of graphite: Density-functional calculationsPhysical Review B, 2005
- Diffusion, Coalescence, and Reconstruction of Vacancy Defects in Graphene LayersPhysical Review Letters, 2005
- Wigner defects bridge the graphite gapNature Materials, 2003