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.

分形石墨烯由于其独特的形态，可以为电催化反应提供更多的活性位点。大面积分形石墨烯的制备及其形态演变的理解对于提高催化性能至关重要。化学气相沉积（CVD）技术是获得高质量分形石墨烯的独特方法。本研究采用低压CVD法在Cu衬底上制备分形石墨烯。通过冷却过程中氢的刻蚀作用，实现了石墨烯从致密物到枝晶的演化过程，并计算了不同形貌的石墨烯的分形维数。发现石墨烯的氢蚀刻反应从边缘开始并且逐渐向成核点移动，直到蚀刻进度完成。