Etching-controlled preparation of large-area fractal graphene by low-pressure CVD on polycrystalline Cu substrate

Abstract Fractal graphene can provide more active sites for electrocatalytic reactions due to its unique morphology. The preparation of large-area fractal graphene and the understanding of its morphology evolution are crucial to the improvement of catalytic performance. Chemical vapour deposition (CVD) technology is a unique method to obtain high quality fractal graphene. In this study, low-pressure CVD method was used to prepare fractal graphene on Cu substrate. Through the etching effect of hydrogen in the cooling process, the evolution process of graphene from compact to dentritic was realized and the fractal dimensions of graphene with different morphologies were calculated. It was found that the hydrogen etching reaction of graphene begins at the edges and moves towards the nucleation point gradually until the etching progress is completed. And continuous large-area fractal graphene films were obtained for the first time, which would find potential application in electrocatalysis and other fields.