Two methods were used for the deposition of Pt particles on synthetic B-doped diamond (BDD) surfaces: chem. deposition and electrodeposition under potentiostatic conditions. However, electrodeposition leads much higher Pt dispersion than chem. deposition. The mechanism of nucleation and growing of the electrodeposited Pt was studied by chronoamperometric studies in acid medium. The electrodeposition on diamond surfaces shows a mechanism of progressive nucleation as deduced from the chronoamperometric studies in acid medium. The stability of the deposited Pt is very low and the Pt particle are dissolved/detached by cycling. The modified BDD electrodes by deposition of Pt were tested for the oxidn. of MeOH, showing that multi-step deposition results in higher values of surface and mass activities for MeOH oxidn. than 1-step deposition process. [on SciFinder (R)]