The Pt/C catalysts with similar morphology of active catalytic phase (platinum nanoparticles), which were deposited on the supports with different types of carbon structures (Vulkan XC-72 carbon black, Taunit carbon tubes, and Timrex HSAG-300 carbon support with graphite structure), were fabricated by the method of electrochemical dispersion. The effect of the carbon structure type on the electrocatalytic properties of Pt/C catalysts was studied in their operation in the three-electrode cell and in-service in the membrane-electrode assembly of air-hydrogen solid-polymer fuel cell. The Pt/C catalyst based on the Vulkan XC-72 carbon support showed the best performance. The anisotropic shape of Taunit carbon nanotubes and the microstructure of Timrex HSAG-300 carbon support do not allow us to form a catalytic layer with a large active platinum surface area and a structure, which provides an effective ionic transport and mass exchange near the platinum surface.