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 (∼470.7 mA M ^-1 cm ^-2) and low detection limit (∼20 nM with S/N ≈ 9.2) for dopamine detection. Modified with horseradish peroxidase and Nafion, the 3D hybrid electrodes are also used to detect H ₂O ₂ with a high sensitivity (137.9 mA M ^-1 cm ^-2), low detection limit (∼1 μM with S/N ≈ 17.4), and wide linear detection range (10 μM-1 mM).