Synthesis of graphene-carbon nanotube hybrid foam and its use as a novel three-dimensional electrode for electrochemical sensing

Three-dimensional (3D) graphene-carbon nanotube (CNT) hybrids are synthesized by two-step chemical vapor deposition (CVD) under atmospheric pressure. As revealed by scanning electron microscopy (SEM), the hybrid is a monolithic graphene foam with conformal coverage of a dense CNT mesh. We further demonstrate that the obtained graphene-CNT hybrid foams can be used as novel 3D electrochemical electrodes for sensing applications. Specifically, the 3D graphene-CNT electrodes exhibit a high sensitivity (similar to 470.7 mA M-1 cm(-2)) and low detection limit (similar to 20 nM with S/N approximate to 9.2) for dopamine detection. Modified with horseradish peroxidase and Nafion, the 3D hybrid electrodes are also used to detect H2O2 with a high sensitivity (137.9 mA M-1 cm(-2)), low detection limit (similar to 1 mu M with S/N approximate to 17.4), and wide linear detection range (10 mu M-1 mM).