Methanol oxidation efficiencies on carbon-nanotube-supported platinum and platinum–ruthenium nanoparticles prepared by pulsed electrodeposition

Dense carbon nanotubes (CNTs, 30–50 nm in diameter, 6–8 μm in length) were grown via a thermal chemical vapor deposition process on titanium treated carbon cloths. Catalysts in the form of either nano-scale platinum (Pt) or platinum-ruthenium (Pt–Ru) particles were then deposited on the CNT surfaces by pulse-mode potentiostatic electrodeposition. Surface morphologies of the prepared electrodes were examined by scanning electron microscopy and transmission electron microscopy. Well dispersed catalysts, Pt alone (particle sizes of 7–8 nm) or Pt–Ru (particle sizes of 3–4 nm) nanoparticles, were successfully electrodeposited on the CNT surfaces in citric acid aqueous solutions. In addition, electrochemical characteristics of the specimens were investigated by cyclic voltammetry in argon saturated sulfuric acid aqueous solutions and in mixed sulfuric acid and methanol aqueous solutions. The catalytic activity of the Pt–Ru/CNTs electrode for methanol oxidation was 1038.25 A g−1Pt in a mixed solution containing 0.5 M sulfuric acid and 1.0 M methanol.

► Dense carbon nanotubes (CNTs) were directly grown on carbon cloths via a thermal chemical vapor deposition process. ► Well dispersed Pt (7–8 nm) or Pt–Ru (3–4 nm) as catalysts were electrodeposited on the CNT surfaces. ► Catalyst activities of electrodes were investigated by cyclic voltammetry in aqueous solution of sulfuric acid with methanol. ► Catalytic activity of Pt–Ru/CNTs for methanol oxidation was 1038.25 A g−1Pt.