Boron-doped diamond (BDD) was prepared in nanosize particles and they were used as a support for noble metal-based nanoparticles. Nanosize platinum oxide was deposited on diamond nanoparticles as well as on boron-doped diamond nanoparticles by the sol-gel method. Cyclic voltammetric results showed an improvement in conductivity as well as in surface capacitance when diamond nanoparticles were doped with boron. The X-ray photoelectron spectroscopy boron binding energy peak showed B-0, which is consistent with the electrochemical characterization. Platinum oxide deposition was studied by cyclic voltammetry with an improvement when BDD nanoparticles were used as a support. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3532943] All rights reserved.