Improved kinetics of methanol oxidation on Pt/hollow carbon sphere catalysts

Hollow carbon spheres (HCSs) have been prepared by combining the hydrothermal method and intermittent microwave heating (IMH) technique. The preparation factors affecting the performance of the HCSs are studied. The results show that Pt nanoparticles supported on HCSs (Pt/HCS), which were heated for 3 min in a microwave oven, give the best performance for methanol oxidation. The higher electrochemical active surface area of the Pt/HCS catalysts results in higher catalytic activity for methanol oxidation compared to that of the commercial Pt/C catalyst at the same Pt loadings. Higher exchange current density and lower reaction activation free energy are observed on Pt/HCS catalysts, indicating improved kinetics. It is recognized that the hollow structure of the Pt/HCS with open microspores and nanochannels is responsible for this higher catalytic activity for methanol oxidation.