Vertically Aligned Double-Walled Platinum Nanotubes Decorated with Inner Fibrils for Their Enhanced Electrocatalytic Properties

Vertically aligned double-walled platinum nanotubes (Pt DNTs) with inner fibrils have been synthesized by means of homogeneous coating of Pt onto a Pd thin-wall nanotube array template using electrochemical deposition, followed by chemical etching of the template. The resulting Pt DNTs with inner fibrils have advantageous morphological characteristics including high crystallinity of the coated Pt layers, high porosity of the inner nanotubes, the non-carbon-supported substrate, and a three-dimensional orientation, whereby the catalysts are directly and vertically connected with a conducting electrode. In addition, tube length can be controlled by tuning the total amount of charge injected during the electrochemical deposition. Electrochemical measurements have demonstrated that the resulting Pt DNTs have considerably greater electrochemically active surface area (ECSA) and higher electrocatalytic activity toward methanol oxidation and CO oxidation behavior compared to Pt single nanotube and Pt nanorod structures as well as other reported Pt-based catalysts under similar testing conditions. These results suggest that Pt DNTs are excellent nanocatalytic systems for low-temperature catalytic reactions and surface chemical processes.