Platinum nanoparticle clusters immobilized on multiwalled carbon nanotubes: Electrodeposition and enhanced electrocatalytic activity for methanol oxidation

3D flowerlike Pt nanoparticle clusters are electrodeposited onto multiwalled carbon nanotubes (MWCNTs) by using a three-step protocol, which is all-electrochemical and involves a key, second step of a potential pulse sequence. This 3D fractal morphology is in marked contrast to the 2D uniform nanoparticle dispersion of MWCNTs, which is achieved when the second step adopts cyclic voltammetry instead of a potential-step method. The former is found to exhibit significantly higher electrocatalytic activity and better stability than the latter for oxidation of methanol. These attractive features are attributable to the unique 3D flowerlike structure of Pt nanoparticle clusters on MWCNTs with much higher electrochemically active surface areas. Our work points to a new path for the preparation of 3D Pt/MWCNT nanocomposites, which are promising as electrocatalysts in direct methanol fuel cells.