Au-, Pt- and glassy carbon (GC) surfaces were treated with OH center dot radicals before performing the metal electrodeposition. The number of active sites at electrodes diminished, since after the treatment smaller numbers of nuclei were formed. Electrodeposition of Ag, as a model system, was selected for this examination. The drop in surface activity towards nucleation was found to be a function of treatment time. The biggest changes, including a change in nucleation mechanism, were noticed for the glassy carbon surface. The use of OH. radicals gives a chance of controlling the density of silver nuclei on all examined surfaces. (C) 2012 Elsevier B.V. All rights reserved.