Platinum nanotubes are created by galvanic deposition inside porous templates.
The effects of the electrolyte's ion concentration and pH, of the applied
potential and of the deposition duration on the morphology of the tubes are
investigated systematically. The system provides a model electrode platform
with accurately tunable geometry for the fundamental investigation of
electrochemical transformations. For slow electrochemical reactions, we
observe a linear increase of the galvanic current with the length of the
nanotubes, and therefore with the specific surface area of the electrode. In
contrast to this, inherently fast electrochemical transformations are
diffusion-limited and give rise to the same current density independently of
the geometry. These results delineate a strategy for optimizing the
performance of electrochemical energy conversion devices systematically via
nanostructuring the electrode surfaces.