Platinum nanowire or nanoparticle shells on different cores are selectively obtained by controlling the experimental conditions. Palladium-coated polymeric or ceramic cores are used as substrates to form shells of sub-monolayer or multilayer coatings of Pt nanoparticles or dense coatings of quasiradial Pt nanowires (see figure). Characterization of the morphology of the obtained structures confirms that the amount of iron species added during the synthesis controls the structure of the products.