Synthesis of AuNi/NiO nanocables by porous AAO template assisted galvanic deposition and subsequent oxidation

A facile and economic approach has been developed for the synthesis of coaxial nanocables with AuNi alloy nanowires as inner solid cores and NiO as outer shells by infiltrating a gold-coated anodic aluminum oxide (AAO) template, with ring-shaped Al foil on its outer edge, with a mixed aqueous solution of NiCl2 and HAuCl4 to form AuNi/Ni nanocables, and subsequent immersion in an aqueous NaOH solution to oxidize the Ni sheath during template removal. The formation of the AuNi/Ni nanocables in the channels of the AAO template could be ascribed to the reduction of the Ni2+ ion complexes adhering on the AAO channel walls and the redox reactions of two galvanic cells in which the surrounding Al foil acts as the anode. The approach enables excellent control over the shell thickness and the chemical composition of the AuNi/NiO nanocable by tuning the composition of the mixed solution. The AuNi/NiO nanocables have potentials in nanodevices and nanosystems.