Bioinspired synthesis of CVD graphene flakes and graphene-supported molybdenum sulfide catalysts for hydrogen evolution reaction

Chemical vapor deposition has been the most-promising approach for growing large-area high-quality graphene films on planar substrates. Beyond the lateral growth, the synthesis of three-dimensional (3D) graphene has also been demonstrated recently on metal foams and insulating nanoparticles for exploring their applications in electrochemical electrodes. However, the existing approaches need either to prefabricate abundant starting substrates, or to construct porous frameworks for graphene growth. Herein, we report a straightforward, bioinspired strategy for growing large-quantity graphene flakes on cuttlebone substrates using the chemical vapor deposition (CVD) method. The separated graphene flakes from growth substrates are highly crystalline and layer-thickness controllable, outperforming the traditional chemically exfoliated graphene with few surface groups. Due to their inheriting the biomineral-derived morphology, the 3D graphene microstructures show a highly exposed and curved surface, which can load more MoS_x (x ≥ 2) catalysts than other planar supports for highly efficient hydrogen generation. Briefly, the bioinspired approach is expected to achieve a reasonable balance between quality and quantity for graphene production, thus propelling its wide applications in energy storage and conversion devices.