Controllable growth of high-quality hybrid nanostructures is highly desirable for the fabrication of hierarchical, complex and multifunctional devices. Here, PdAg alloys have been controllably grown at different locations on gold nanorods, producing dumbbell-like nanostructures with PdAg at the ends of the gold nanorods or branched nanostructures with PdAg grown almost perpendicular to the gold nanorods. The nucleation sites of PdAg alloys on the gold nanorods can be effectively tuned by varying the concentrations of H2PdC14, AgNO3 and cetyltrimethylammonium bromide （CTAB）. The dumbbell-like and branched nanostructures were characterized by transmission electron microscopy （TEM）, high-resolution TEM （HRTEM）, line-scanning energy-dispersive X-ray spectros-copy （EDS）, X-ray photoelectron spectroscopy （XPS） and UV-Vis absorption spectroscopy. Their electrocatalytic performance was evaluated using ethanol oxidation as a probe reaction. The dumbbelMike nanostructures show a better anti-poisoning performance, but a worse electrochemical activity than the branched ones. The results provide guidelines for the controlled growth of complicated nanostructures for either fundamental studies or potential applications.
