Formation of Stone–Wales edge: Multistep reconstruction and growth mechanisms of zigzag nanographene

5 years ago

Formation of Stone–Wales edge: Multistep reconstruction and growth mechanisms of zigzag nanographene

Shigeru Nagase, Jing-Shuang Dang, Xiang Zhao, Wei-Wei Wang, Jia-Jia Zheng

Although the existence of Stone–Wales (5-7) defect at graphene edge has been clarified experimentally, theoretical study on the formation mechanism is still imperfect. In particular, the regioselectivity of multistep reactions at edge (self-reconstruction and growth with foreign carbon feedstock) is essential to understand the kinetic behavior of reactive boundaries but investigations are still lacking. Herein, by using finite-sized models, multistep reconstructions and carbon dimer additions of a bared zigzag edge are introduced using density functional theory calculations. The zigzag to 5-7 transformation is proved as a site-selective process to generate alternating 5-7 pairs sequentially and the first step with largest barrier is suggested as the rate-determining step. Conversely, successive C2 insertions on the active edge are calculated to elucidate the formation of 5-7 edge during graphene growth. A metastable intermediate with a triple sequentially fused pentagon fragment is proved as the key structure for 5-7 edge formation. © 2017 Wiley Periodicals, Inc. To uncover the formation mechanism of Stone–Wales (5-7) defect on graphene edge, multistep reconstructions and carbon dimer additions of a bared zigzag edge are investigated using density functional theory calculations. The site reactivity and energy variation during multistep reactions are taken into account to get insight about the regioselectivity and determinants for 5-7 edge formation.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/jcc.24871