We investigated the electrochemical properties of Pt/graphene/SiC(0001) model nanostructures prepared by thermal annealing of the SiC(0001) substrates at 1300-1600 °C in vacuum, followed by the vacuum deposition of Pt. Thermal annealing of the Si-terminated 4H-and 6H-SiC(0001) substrate surfaces generated graphene layers as a result of the sublimation of Si atoms of the substrates: the thickness of the graphene layer depended on the annealing temperatures. For example, annealing of the 4H-and 6H-SiC(0001) substrates at 1600°C generated fewer than ca. 20 monolayers and ca. 40 monolayers of graphene, respectively, as judged by cross-sectional scanning transmission electron microscopy (STEM) images. Then, Pt was deposited on the prepared graphene/SiC(0001) surfaces at room temperature by electron-beam deposition in ultra-high vacuum (~10' Pa). The electrochemical properties of the prepared nanostructures are discussed on the basis of the cyclic voltammetry and linear sweep voltammetry results.