Synthetic diamonds nanoparticles can be produced either by detonation or by chemical vapor deposition (CVD) techniques. Trinitrotoluene (TNT) detonation yields, among other carbon structures, diamonds nanoparticles with diameters in the range from 2 to 10 nm. Purification of nanoparticle diamond (NPD) is important because small amounts of graphitic impurities and other carbon structures in diamond can alter its most important properties. We carried out chemical purification of commercially available NPD by refluxing in aqueous HNO3 and characterized the samples by spectroscopic and surface techniques before and after purification. As a first step in the preparation of electrodes for electrochemistry, we have electrophoretically deposited thin, highly uniform layers of controlled thickness (1-8 μm) on silicon substrates using the purified NPD and have characterized them by scanning electron microscopy (SEM). Such structures could also be used in many other applications. © 2005 Advanced Study Center Co. Ltd.