Efficient Direct-Methanol Fuel Cell Based on Graphene Quantum Dots/Multi-Walled Carbon Nanotubes Composite

Direct-methanol fuel cells are proton-exchange fuel cell in which methanol is used as the fuel. The important advantage of these fuel cells is the simplicity of transport and storage of methanol. In this study, methanol fuel cell electrocatalysts including graphene quantum dots (GQDs), functionalized multi-walled carbon nanotubes (f-MWCNTs) and GQDs/f-MWCNTs composite were synthesized. The structures of synthesized electrocatalysts were highlighted by scanning electron microscope (SEM), raman spectroscopy, UV-vis spectroscopy, fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and x-ray diffraction (XRD) method. After that, the effective surface areas (ESA) of GQDs, f-MWCNTs and GQDs/f-MWCNTs were calculated. Finally, GQDs/f-MWCNTs composite modified glassy carbon electrode (GQDs/f-MWCNTs/GCE) showed highest current signals for methanol oxidation than those of comparable GQDs/GCE and f-MWCNTs/GCE.