Template-Assisted Electrodeposition of Porous Fe-Ni-Co Nanowires with Vigorous Hydrogen Evolution.

A novel method to fabricate porous Fe-Ni-Co nanowires directly by electrodepositing into polycarbonate membranes is reported when the electrolyte pH < 0.5. Hydrogen bubbles are used as a dynamic porous template created by operating in electrolytes with very low pH to drive the proton reduction reaction. The electrolyte pH was adjusted with sulfuric acid, and the added sulfate ions are thought to help reduce bubble coalescence, but not detachment at the electrode surface, to facilitate metal deposition within the nanopores. Porous nanowires were obtained when the electrolyte pH was less than 1.0. The average alloy composition was found to be pH sensitive, which shifted from an Fe-rich porous alloy to a Ni-rich porous alloy as the electrolyte pH decreased.