The durability dependence of Pt/CNT electrocatalysts on the nanostructures of carbon nanotubes: hollow- and bamboo-CNTs.

The electrochemical durability of Pt/CNT with hollow- and bamboo-structured carbon nanotubes (H-CNT and B-CNT) as the support for PEM fuel cells was investigated. Both Pt/CNT electrocatalysts were degraded under cyclic voltammetry (CV, 0.6-1.1 V) accelerated degradation test method. Pt/CNT electrocatalysts were characterized with cyclic voltammograms, rotating disk electrodes, and TEM images. The changes in the electrochemical surface area of Pt and the activity toward oxygen reduction reaction (ORR) before and after the degradation indicate that Pt/B-CNT catalyst exhibited much higher durability than Pt/H-CNT. TEM images indicate that the sintering of Pt nanoparticles was much less for Pt/B-CNT. Pt/B-CNT also exhibited a little higher activity toward ORR than Pt/ H-CNT. These are attributed to the specific bamboo-like nanostructures which provide more "bamboo-knot" defects and edge plane-like defects. Pt-support interaction was therefore enhanced and the durability and activity were improved.