Nanoporous Membrane Electrodes with an Ordered Array of Hollow Giant Carbon Nanotubes

Abstract This study proposes a next‐generation model membrane electrode for fundamental electrochemical research of amorphous‐based porous carbon materials. This novel electrode is fabricated by the uniform carbon coating of anodic aluminum oxide formed on an Al substrate and free from a barrier layer. The conformally carbon‐coated layer forms vertically aligned giant carbon nanotubes, and their walls comprise low‐crystalline stacked graphene sheets. The diameter and the length of the nanopores can be tuned over a broad range of between 10 to 200 nm and 2 to 90 µm, respectively. Moreover, unlike composite electrodes made from other ordered nanoporous carbons, this model electrode exhibits an absence of inter‐particle spacing and hence no contact resistance between particles. Thus, this model electrode provides representative nanopores of low‐crystalline carbon materials. An atomic‐scale structural model of the low‐crystalline carbon walls is built with the aid of an in‐house temperature‐programmed desorption system to enable theoretical simulations to be performed. Using this model electrode, the electrical conductivity of low‐crystalline carbon walls and mass transportation in an electric double‐layer system are elucidated. This representative model electrode is expected to help clarify the complex electrochemical processes in porous carbon electrodes.