An approach for in situ preparation of bimetallic Pd-Cu catalysts active in nitrate electroreduction is described. The catalysts are prepared by modification of the surface of Pd carbon- supported nanoparticles by monolayer of Cu. The morphology of Pd/C nanoparticles is characterized by HR-TEM and by their electrochemical properties in the adsorption of hydrogen and Cu adatoms. Modification of Pd surface by Cu adlayer results in significant increase of the activity in nitrate electroreduction. Dependencies of the reaction rate for Cu/Pd/C catalysts on the electrode potential, nitrate concentration and anion of supporting electrolyte are discussed. (c) 2006 Elsevier B.V. All rights reserved.