Physical and electrochemical characterization of platinum and platinum-ruthenium treated carbon nanotubes directly grown on carbon cloth

Dense carbon nanotubes (CNTs) were grown via a thermal chemical vapor deposition process on titanium treated carbon cloths. The catalysts in the form of either platinum (Pt) or platinum-ruthenium (Pt-Ru) nano-sized particles were then deposited on the CNT surface by potentiostatic electrodeposition. After the deposition process, the surface morphology of prepared specimens was examined by scanning electron microscopy and transmission electron microscopy, and the electrochemical characteristics of the specimens were also investigated by cyclic voltammetry in nitrogen saturated sulfuric acid aqueous solutions and in mixed sulfuric acid and methanol aqueous solutions. Well dispersed catalysts, Pt alone or Pt-Ru, were observed on the surfaces of the CNTs directly grown on carbon cloths. It was found that the electrochemical behavior of the specimen with Pt-Ru deposits was distinctly different from that of those with only Pt deposits. It was also observed that a more negative electrodeposition potential led to a better performance of the catalysts in terms of methanol oxidation efficiency and the suppression of carbon monoxide poisoning.