Defect-assisted covalent binding of graphene to an amorphous silica surface: A theoretical prediction

We propose a mechanism for defect-assisted covalent binding of graphene to the surface of amorphous silica (a-SiO₂) based on first-principles density functional calculations. Our calculations show that a dioxasilirane group (DOSG) on a-SiO₂ may react with graphene to form two Si-O-C linkages with a moderate activation barrier (≈0.3 eV) and considerable exothermicity (≈1.0 eV). We also examine DOSG formation via the adduction of molecular O₂ to a silylene center, which is an important surface defect in a-SiO₂, and briefly discuss modifications in the electronic structure of graphene upon the DOSG-assisted chemical binding onto the a-SiO₂ surface.