Methanol electrocatalytic oxidation on highly dispersed Pt/sulfonated-carbon nanotubes catalysts

Highly dispersed Pt nanoparticles supported on sulfonated carbon nanotubes (Pt/sulfonated-CNTs) with a high density of sulfonic acid groups were first prepared, and then a Pt/sulfonated-CNTs modified GC electrode was constructed successfully. The structure of Pt/sulfonated-CNTs was characterized with SEM, TEM and XRD; and the electrocatalytic performance of Pt/sulfonated-CNTs was evaluated by methanol oxidation. Various factors affecting the electrocatalytic activity were investigated and discussed. The peak current of methanol oxidation in the solution of 0.5 mol/L CH3OH and 0.5 mol/L H2SO4 can reach 0.12 mA with the Pt deposition amount 14.5 μg/cm2, which is twice of Pt/pristine-CNTs/GC electrode at the same condition. The electrocatalytic oxidation of methanol on Pt/sulfonated-CNTs/GC electrode is a diffusion-controlled process. With the increase of methanol concentration, the peak current increases and anodic peak potential shifts positively. The results show that the resultant Pt/sulfonated-CNTs catalysts have high electrocatalytic activity and excellent electrocatalytic performance for the direct methanol fuel cell (DMFC).