A catalytic gas diffusion layer for improving the efficiency of a direct methanol fuel cell

The efficiency of a single direct methanol fuel cell (DMFC) with Pt–Ru decorated carbon nanotubes directly grown on carbon cloth (Pt–Ru/CNTs/CC) as a catalytic gas diffusion layer (GDL) at the anode was evaluated by polarization analysis. Pt–Ru nanoparticles were electrodeposited on dense carbon nanotubes directly grown on carbon cloth in ethylene glycol containing sulfuric acid solutions. The presence of relatively well dispersed Pt–Ru nanoparticles (4–6 nm) on the surfaces of CNTs was confirmed by transmission electron microscopy. Two more GDLs, one with dense CNTs but without the presence of Pt–Ru nanoparticles and the other with neither CNTs nor catalysts, were also prepared for comparison purpose. For quantitatively evaluating the performance of the catalytic GDL, three identical membrane–electrode-assemblies were prepared and laminated with different GDLs before they were used to construct DMFCs for performance test. It was found via polarization analyses the catalytic GDL was able to promote the peak specific power density of the DMFC by 27% at ambient temperature.