▎ 摘　　要

Graphene is known for its high surface-area-to-mass ratio. However, for using graphene in engineering processes such as catalytic reactors or heat exchangers, a high surface-area-to-volume ratio is essential. Currently, graphene is only prepared in sheet form, which limits its surface-area-to-volume ratio to around 200 m(2) m(-3). Herein, a technique based on chemical vapor deposition (CVD) to realize graphene on a micro-tubular substrate to not only substantially increase its surface-area-to-volume ratio to a value over 2000 m(2) m(-3) but also to eliminate the maldistribution of flows commonly unavoidable in flat-sheet configurations is proposed and demonstrated. This approach uses a dual-layer micro-tubular substrate fabricated by a phase-inversion technique. In the substrate, a thin copper outer layer is used to enable the CVD growth of graphene, and an inner Cu-Fe layer is adopted to provide a strong mechanical support. This approach is feasible to produce graphene with a very high surface-area-to-volume ratio for possible applications in catalytic reactors or heat exchangers, although problems such as inter-diffusion between the two metal layers and defects in graphene need to be addressed. To the best of our knowledge, this study is the first attempt to prepare graphene with high surface-area-to-volume ratios by a CVD route.