The origin of the excellent electrocatalytic performance of PtRu alloy catalysts supported on newly synthesized carbon nanocoil supports was investigated. Among three commercially available carbon materials-Vulcan XC-72, multiwall carbon nanotube, and activated carbon, the Vulcan XC-72-supported catalyst exhibited the best catalytic performance. Carbon nanocoils with variable surface areas and crystallinity were employed as the supports for 60 wt % Pt/Ru (1:1) catalysts. The catalysts supported on all these three carbon nanocoils exhibited better electrocatalytic performance compared to the catalyst supported on Vulcan XC-72 carbon. In particular, the PtRu alloy catalyst supported on CNC-2, which has both good crystallinity and a large surface area, showed a superior electrocatalytic performance, compared to the catalysts supported on CNC-1 and CNC-3 carbons.