ISSN 1063-7842, Technical Physics, 2010, Vol. 55, No. 2, pp. 296–302. © Pleiades Publishing, Ltd., 2010. Original Russian Text © V.V. Poplavskii, T.S. Mishchenko, V.G. Matys, 2010, published in Zhurnal Tekhnicheskoі Fiziki, 2010, Vol. 80, No. 2, pp. 138–145. 296 INTRODUCTION Ion-beam-assisted surface modification of engi- neering and functional materials provides the intro- duction of a controlled amount of any alloying impu- rity into their near-surface layers on the atomic scale under nonequilibrium conditions. Ion-beam modifica- tion of the materials whose service properties are mainly controlled by the surface composition is of particular interest. These materials include catalysts for chemical reactions, in particular, electrocatalysts, namely, elec- trodes in electrochemical devices (electrolyzers and fuel cells) [1]. A catalytic reaction is based on an electronic mechanism: the electron exchange between reacting molecules occurs through a catalyst with the partici- pation of catalyst electrons. The properties of depos- ited heterogeneous catalysts are controlled by the electronic structure of active centers on the surface that form during preparation. The active centers can be represented by structural heterogeneities on the surface. However, the active centers of electron exchange are most often related to catalytic-metal particles. Therefore, the nature of the deposited cata- lytic metal is very important [2, 3]. The catalytic prop- erties of the surface irradiated by an ion beam can also be changed due to both a radiation-assisted change in the structure of the near-surface layer and specific ion alloying effects induced by the nature of the implanted impurity and the target material [4]. To predict the catalytic effect and the formation of catalysts, researchers still use empirical approaches, which are explained by the complexity of the catalysis problem. First, a catalytic reaction is a complex mul- tistage process. Second, strong metal–carrier electron interaction effects manifest themselves when a metal- lic catalyst is prepared because of the small size of metallic catalyst particles. As a result, a deposited cat- alytic metal can have properties other than those of the bulk metal [2–5]. The substrate material can also sub- stantially affect the catalyst activity due to its effect on the particle size and electronic structure of a deposited catalytic metal. During ion-beam introduction of a catalytic metal into a matrix, these effects can become specific on a nanoscale [6]. The purpose of this work is to form coatings by ion- beam-assisted deposition of a catalytic metal onto alu- minum and to study their composition and electrocat- alytic activity during the electrochemical oxidation of methanol and ethanol. The study of the electrocatalysts intended for the electrochemical oxidation of methanol and ethanol is now of great importance due to the development of fuel cells for direct oxidation of organic fuel, which is a promising chemical source of an electric current. Platinum is known to be the most effective catalytic metal accelerating chemical processes, including the electrochemical oxidation of organic substances [7]. The cost of platinum-containing catalysts can be decreased by a decrease in the metal content in the active layer at high retained catalytic activity. Ion- beam-assisted deposition of a catalytic metal can be one of the methods for achieving this aim. As the basis for modified electrodes, we chose alu- minum, which belongs to film-forming valve metals [8]. Such metals cannot serve as anodes, since the Composition and Electrocatalytic Properties of the Coatings Formed by the Ion-Beam-Assisted Deposition of Platinum from a Pulsed Arc-Discharge Plasma onto Aluminum V. V. Poplavskii, T. S. Mishchenko, and V. G. Matys Belarussian State Technological University, Minsk, 220006 Belarus e-mail: vasily.poplav@tut.by Received April 27, 2009 Abstract—The structure, composition, and electrocatalytic properties of the coatings formed on aluminum by ion-beam-assisted deposition of platinum from the plasma of a pulsed arc discharge under conditions where deposited-metal ions are used as deposition-assisting ions are studied. The coating thickness reaches ~30 nm, and the near-surface content of platinum atoms in the coatings is ~2.6 × 10 16 cm –2 . The electrocat- alytic activities of aluminum-based electrodes with the coatings in the reactions of electrochemical oxidation of methanol and ethanol, which form the basis for the principle of operation of low-temperature fuel cells (considered as promising chemical sources of an electric current), are significantly higher than the activity of a platinum electrode. DOI: 10.1134/S1063784210020222 SURFACE, ELECTRON AND ION EMISSION