Generating Nanoporous Graphene from Point and Stone-Wales Defects: A Study with Dimensionally Restricted Molecular Dynamics (DR-MD)

Abstract

Defects in graphene are both a boon and a bane for applications - they can induce uncontrollable effects but can also provide novel ways to manipulate the properties of pristine graphene. Nanoporous Graphene, which contains nanoscopic holes, has found impactful applications in sustainability domains, e.g. gas separation, water filtration membranes and battery technologies. For this report, we investigate pore formation in graphene with no defect, one and two mono-vacancies, and two di-vacancies using bespoke Dimensionally Restricted Molecular Dynamics (DR-MD) designed for the purpose. We show DR-MD to be superior to free-standing or substrate suspended configurations for simulating stable defected structures. Applying DR-MD, stable pore configurations are identified, and their formation mechanisms elucidated. We also investigated formation mechanisms due to two Stone-Wales 55-77 defects, and the formation energies of their linearly extended structures, along the zigzag and armchair directions, and when they are placed in different relative orientations. This study offers a way to identify stable porous defect structures in graphene and insights into atomistic pore formation mechanisms for an environmentally important material.