In this work, dendritic silver–copper (Ag–Cu) nanostructures were synthesised on a copper foil by electrodeposition and subsequently galvanic displacement reaction without any surfactant. The crystalline nature of the nanostructures was examined by X-ray diffraction, and the morphology of the material was investigated by field-emission scanning electron microscopy. The applied potential, displacement reaction time, and silver nitrate solution concentration exerted different effects on the nanoparticle shape. And a possible growth mechanism of the Ag–Cu dendrites was proposed based on the experimental results. The electrochemical properties of the Ag–Cu dendrite-modified electrode were characterised by linear sweep voltammetry. The reduction peak potential of hydrogen peroxide (H2O2) was about −0.25 V (vs. a saturated calomel electrode), which indicated that the as-synthesised Ag–Cu dendrites had favourable electroreduction activity towards hydrogen peroxide. At the same time, we found that the solution pH also affected the electrocatalytic ability of the dendrites for H2O2 reduction, which was important for the design of a NaBH4–H2O2 battery.
