Graphene has attracted extensive research interests recently due to its outstanding physical,chemical and electronic prop-erties and numerous potential applications.In particular,the extremely high carrier mobilities in graphene with the theoretical limit of-200,000 cm2 V-I s-l ensure it the best candidate for replacing silicon in the future electronics.Unfortunately,these outstanding properties of graphene may be greatly degraded for the existence of defects in the honeycomb lattice.Thus,the synthesis of high-quality graphene is essential to its practical applications.Beyond the linear GBs,various point defects are the most potential candidates which are responsible for the downgrading of graphenes quality.Thus,understanding on the structural stability and formation of point defects during graphene CVD growth and the healing of these point defects are pressing and important to improve graphenes quality by further optimizing the experimental design.The formation and kinetics of single and double vacancies in graphene chemical vapor deposition(CVD)growth on Cu(111),Ni(111)and Co(OOOI)surfaces are investigated by the first-principles calculation.It is found that the vacancies in graphene on the metal surfaces are dramatically different from those in free-standing graphene.The interaction between the vacancies and the metal surface and the involvement of a metal atom in the vacancy structure greatly reduce their formation energies and significantly change their diffusion barriers.Furthermore,the kinetic process of forming vacancies and the potential route of their healing during graphene CVD growth on Cu(111)and Ni(111)surfaces are explored.The results indicate that Cu is a better catalyst than Ni for the synthesis of high-quality graphene because the defects in graphene on Cu are formed in a lower concentration and can be more efficiently healed at the typical experimental temperature.This study leads to a deep insight into the atomic process of graphene growth and the mechanism revealed in this study can be used for the experimental design of high-quality graphene synthesis.