In this paper, nitrogen-doped carbon spheres (NCSs) were prepared as a new catalyst support for ethanol electro-oxidation through carbonization of poly(o-phenylenediamine) spheres. The NCS-supported palladium nanocatalyst exhibited higher current density and better stable life for ethanol electro-oxidation in alkaline media than palladium catalysts supported on activated carbon and nitrogen-doped carbon nanotubes. The catalytic current of the palladium/NCS composite was even comparable to commercial platinum catalyst (40 wt% Pt loading). (C) 2014 Elsevier B.V. All rights reserved.