Template Synthesis of Aligned Carbon Nanotube Arrays using Glucose as a Carbon Source: Pt Decoration of Inner and Outer Nanotube Surfaces for Fuel-Cell Catalysts

A facile method is developed to synthesize aligned arrays of open‐ended carbon nanotubes (CNTs) via in situ glucose polymerization in the inner pores of anodic aluminum oxide templates under hydrothermal conditions, followed by carbonization at high temperature. Pt nanoparticles are decorated on the surfaces of the as‐prepared CNTs using the incipient wet method based on the use of NaBH4 as a reductant. Characterization of the resulting structures by transmission electron microscopy and field‐emission scanning electron microscopy demonstrates that the Pt nanoparticles are anchored on both the inner and outer walls of CNTs, thus giving rise to a shell–core–shell‐like nanotube composite. The electrocatalytic properties of the Pt–CNT–Pt electrodes are investigated for methanol oxidation by cyclic voltammetry and chronoamperometric measurements. It is found that the hybrid electrodes show superior catalytic performance compared to commercial carbon‐black‐supported Pt. The increased catalytic efficiency of Pt might be a result of the unique morphology of these structures. Aligned carbon nanotube arrays with open ends are prepared by the in situ polymerization of glucose within anodic aluminum oxide templates under hydrothermal conditions followed by high‐temperature carbonization, as schematically illustrated in the figure. Pt nanoparticles are decorated on the outer and inner surfaces of the nanotubes, and the resulting hybrid materials serve as excellent electrocatalysts for methanol oxidation.