Tailor-Designed Platinum Nanoparticles Electrodeposited onto Gold Electrode: Catalytic Activity for Oxygen Reduction

Abstract

This work examines the electrocatalytic reduction of molecular oxygen at Pt nanoparticles (nano-Pt) electrodeposited onto polycrystalline gold (poly-Au) electrode in -saturated . Cyclic and hydrodynamic voltammetry techniques were used for the evaluation of the electrocatalytic activity of the nano-Pt modified poly-Au electrodes. The nano-Pt was electrodeposited onto unmodified poly-Au electrode and poly-Au electrode modified with a submonolayer of a thiol compound (typically cysteine) . In the latter case, Pt nanoparticles were electrodeposited, preferentially, at the bare fraction of the poly-Au electrode free from cysteine [i.e., the domains of the poly-Au] while the other facets (i.e., and ) were under the protection of cysteine. The nano-Pt electrodeposited onto the is characterized by small average particle size (ca. ) compared to that electrodeposited onto the unmodified Au electrode (ca. ). The nano- electrode offers a high electrocatalytic activity toward the oxygen reduction reaction (ORR) as compared with the nano- and bare polycrystalline Pt electrodes. A positive shift of the onset potential of the ORR was obtained at the nano- electrode as compared to the bare Pt electrode. A proper design of the nano- binary catalyst is the key point which controls the catalytic activity of the proposed electrocatalyst.