Co–Ni nanowires supported on porous alumina as an electrocatalyst for the hydrogen evolution reaction.

• A porous anodic alumina (AAO) template is prepared by DC constant voltage anodization and the step-down method. • The pore size of the AAO template is about 60 nm. • Cobalt, nickel and alloy nanowires are prepared by alternating current deposition. • AAO loaded with nanowires had a low hydrogen evolution overpotential and high stability. Water electrolysis is a promising way to produce hydrogen fuel, but many electrocatalytic systems require electrodes made of noble metals such as platinum. There is a demand for high-efficiency, low-cost materials to replace these noble metals. Herein, porous anodic alumina (AAO) templates are prepared by direct current (DC) constant voltage anodization and the step-down method. Cobalt, nickel and Co – Ni alloy nanowires are then prepared by alternating current (AC) electrodeposition. This nanoarray system can be employed in fuel cells to minimize the use of precious metals and reduce the cost of the cathodes. The pores of the AAO template are uniform with a size range from 35 to 75 nm. Using cyclic voltammetry (CV) and linear sweep voltammetry (LSV), the Co–Ni nanowire array prepared on AAO by this method is shown to have a low overpotential for hydrogen evolution and excellent stability. [ABSTRACT FROM AUTHOR]