Enhanced Catalytic Efficiency and CO Tolerance of Novel Pt Nanostructures Prepared By Pulsed Electrodeposition for Methanol Oxidation

Innovative support-free platinum (Pt) nanostructures were developed in this study for enhancing the anode catalyst activities for proton exchange membrane fuel cell (PEMFC) application. The platinum nanostructures were directly grown on carbon paper by a pulsed electrodeposition technique. The morphology of Pt nanostructures were investigated by SEM, and shown as dendritic structures instead of nanoparticles. The sizes of the dendritic structures are 2-4 μm in length and 400-600 nm in diameter. A cyclic voltammetry analysis was carried out for characterizing the behavior of methanol oxidation on specimen bearing the Pt dendritic nanostructures in mixed 1 M methanol and 0.5 M sulfuric acid solutions. It was found that the peak current density of methanol oxidation obtained from the cyclic voltammogram on the new Pt dendritic nanostructures specimen was 263 mA/cm². Due to its unique morphology, the Pt dendritic nanostructures could exhibit a good carbon monoxide tolerance and high efficiency without the joined Ruthenium (Ru) catalyst. The catalytic efficiency of prepared Pt dendritic nanostructures was much better than that of a commercial Pt-black catalyst. It is noteworthy that the i_f/i_b value of the Pt dendritic nanostructures is higher than 1.4, which is very different from pure Pt nanoparticles. The outcome signified that the novel catalyst morphology of the Pt dendritic nanostructures have remarkable CO tolerance even if Ru or other metal catalyst were not joined.