Large-scale chemical vapor deposition synthesis of graphene nanoribbions/carbon nanotubes composite for enhanced membrane capacitive deionization

The composite comprised of graphene and carbon nanotubes (CNTs) exhibited significantly enhanced electrochemical performance due both to the improved dispersion and inhibition of restacking of graphene and CNTs. In this work, graphene nanoribbons (GNRs)/CNTs composite (GNRs/CNTs) was synthesized on gram-scale by chemical vapor deposition. Under optimal growth conditions, the yield of GNRs/CNTs as high as 26 g per gram catalyst could be achieved in 30 min growth time. The morphology and quality of the as-synthesized composite was verified by using SEM, TEM and Raman spectroscopy. The electrochemical properties of GNRs/CNTs was evaluated using cyclic voltammetry (CV) and galvanostatic charge-discharge techniques. GNRs/CNTs exhibited specific capacitance of 242.3 F/g at 0.5 A g-1, which was over 4 times of that of CNTs. The GNRs/CNTs based electrodes exhibited excellent cycling stability at 1 A g-1 for over 4000 cycles, which can be attributed to the excellent electrical conductivity and the unique structure. When employed as electrode for membrane capacitive desalination, the desalination capacity of 16.46 mg g-1 has been achieved under 1.2 V with 500 mg L-1 NaCl solution as feeding water.