Increasing the service life of electrochemical devices is an important task, the solution of which will ensure their competitiveness and commercial attractiveness. One of the methods of protecting device elements from corrosion is the application of coatings of various compositions. Various methods are used, both chemical and physical. Recently, plasma methods, especially magnetron sputtering, have attracted increasing attention. Control of the plasma parameters allows the deposition of crystalline and amorphous coatings and films of different thicknesses (even very thin ones) having the required composition, structure, stoichiometry, density, and porosity. A detailed description and analysis of nanometer coatings and island films of noble metals (Pt, Au, Ir, Pd), which are traditionally used for protective coatings, is presented. We also describe promising nanostructured coatings from carbides and nitrides of transition metals of Groups IV–VI (Ti, Zr, V, Nb, Ta, Mo, W) and carbon-based nanostructured films (amorphous carbon, diamond-like, graphite). They are synthesized under various modes and conditions of magnetron sputtering using plasma- and heat-treatment methods. Tests under conditions close to real ones show their high efficiency in extending the service life of devices. The magnetron-sputtering method is a promising technology with a wide range of applications for coating electrochemical devices, which is confirmed by the references. The optimization of application modes and conditions will make it possible to achieve the greater efficiency and stability of nanostructured coatings.

Magnetron sputtering is a well-known method of obtaining various coatings and surface modifications, but nowadays it is successfully used for the synthesis of electrocatalysts. One of the main advantages of the method is the possibility to vary the parameters during the process, such as the mode (direct current sputtering, pulsed medium-frequency sputtering, high radio frequency sputtering), potential supply to the sputtered substrate or catalyst carrier, pressure in the vacuum chamber, atmosphere composition, which allows to change the composition and structure of the obtained coatings and catalysts very widely. Changing the modes of sputtering makes it possible to create both dense (porous) protective/catalytic coatings and coatings with a very developed surface, i.e. for obtaining electrode materials

The large-scale commercialization of polymer electrolyte membrane (PEM) water electrolyzers is still constrained by their high capital cost, which is largely associated with the use of noble metal-based electrocatalysts. There is an urgent need to reduce their loading in the composition of electrocatalytic layers. In the present work, an approach of the microporous sublayer made of titanium nitride (TiNx) and formed over the anode surface by magnetron sputtering is proposed. It contributes to an increase in the anode electrocatalyst utilization, opening up wide possibilities to reduce its loading.

During the operation of electrochemical devices with a proton exchange membrane, the electrode is gradually destroyed and degrades at the anode side under the influence of oxygen. Performance and service life of electrodes in electrochemical devices can be increased by applying Ti-based protective coatings to the surface of current collectors. Nanostructured coatings of Ti, TiO _x , TiN _y , TiO _x N _y compositions were obtained by magnetron sputtering using a titanium target under various conditions. The structure and composition of the samples were studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray phase analysis. The influence of various modes and conditions of magnetron sputtering on the composition and structure of titanium coatings has been established. The service life of the TiN _y coated electrode in the electrolyzer mode is two times higher than that of the uncoated anode under similar conditions with comparable performance.

In this paper, we study the effect of platinum loading on the structure, density, and uniformity of deposition of a platinum film sputtered by a magnetron, as well as on the electrochemical characteristics of the deposited electrodes, such as the electrochemically active surface area of platinum (EASA), the durability of the electrodes, and the electrochemical performance of membrane-electrode assemblies of a fuel cell generally. An increase in the mean diameter of individual platinum particles from 1.5 to 3.8 nm and particle agglomerates from 5 to 12 nm, respectively, is shown to be observed as the platinum loading in the samples increases from 0.15 to 1.65 mg/cm 2 . A decrease in the EASA of catalysts occurs due to an increase in the thickness of the sputtered film and partial overlap of the active sites of the electrocatalyst. In this case, the platinum film is a nanostructured catalytic layer with a high degree of uniformity of the deposited metal. The catalytic layers obtained by sputtering platinum using a magnetron in a pulsed mode are characterized by high values ​​of the active surface up to 112 m 2 /g and improved durability due to the strong interaction of active sites and carbon particles of the substrate, which is confirmed by the results of X-ray diffraction analysis. EASA losses of platinum in the process of stress testing for deposited electrodes were about 20%, which is twice lower than that for catalytic layers based on platinum powder electrocatalysts. The current–voltage characteristics of a fuel cell with deposited electrodes as a cathode increase with increasing the platinum film thickness. The maximal characteristics were obtained for electrodes with a platinum film thickness of about 100 and 200 nm; values ​​of 0.43 and 0.52 A/cm 2 were obtained at 0.5 V.

A study on the optimization of the method of application of the Ni catalyst for the growth of carbon nanotubes (CNTs) onto the gas diffusion layers (GDLs) (predominantly carbon cloths) by magnetron sputtering is presented. The mode of magnetron sputtering of the Ni catalyst which makes it possible to obtain a uniform metal coating on the GDLs which is required for the successful synthesis of CNTs is selected for the first time. It is shown that the sputtering of Ni in the direct current mode with the supply of pulsed bias voltage to the substrate with a frequency of 100 kHz and time of supply of the negative pulse of 7 µs makes it possible to obtain the optimum nanostructured coating of the metal with a low specific surface and a high degree of uniformity of application onto the entire area of the substrate. The applied Ni coating acts as the catalyst for the growth of CNTs. CNT arrays with the average diameters of 40 and 80 nm for the hydrophobic and hydrophilic GDLs, respectively, are grown on the GDLs with the applied Ni catalyst by pyrolytic gas-phase deposition. The CNT arrays are directly obtained on the entire surface of the carbon substrates with a high degree of uniformity. It is found that the diameter of the nanotubes is mainly determined by the structure of the GDL being used.

Carbon nanomaterials doped with heteroatoms, in particular, nitrogen atoms, are of great interest for electrochemical power engineering as nonmetallic catalysts or carriers of catalytically active metal nanoparticles. A nanostructured, reduced graphene oxide modified with nitrogen in a gas discharge plasma in a vacuum chamber of a magnetron-ion sputtering facility is considered. It is shown that plasma treatment of reduced graphene oxide does not cause undesirable morphological changes in the structure of carbon nanomaterial, but it leads to the incorporation of nitrogen atoms into the structure of reduced graphene oxide with the formation of pyridine-, pyrrole-, and graphite-like configurations. The application of pulsed negative bias voltages of various magnitudes to the substrate with the sample increases the concentration of nitrogen atoms to 2.6 at % and also promotes an increase in the proportion of nitrogen atoms in the pyridine form and a slight decrease in the proportion of atoms in the pyrrole form. The results allow for considering the obtained carbon nanomaterials for use as components of electrochemical devices, for example, fuel cells, in the future.

The review is devoted to current and promising areas of application of graphene and materials based on it for generating environmentally friendly hydrogen energy. Analysis of the results of theoretical and experimental studies of hydrogen accumulation in graphene materials confirms the possibility of creating on their basis systems for reversible hydrogen storage, which combine high capacity, stability, and the possibility of rapid hydrogen evolution under conditions acceptable for practical use. Recent advances in the development of chemically and heat-resistant graphene-based membrane materials make it possible to create new gas separation membranes that provide high permeability and selectivity and are promising for hydrogen purification in processes of its production from natural gas. The characteristics of polymer membranes that are currently used in industry for the most part can be significantly improved with small additions of graphene materials. The use of graphene-like materials as a support of nanoparticles or as functional additives in the composition of the electrocatalytic layer in polymer electrolyte membrane fuel cells makes it possible to improve their characteristics and to increase the activity and stability of the electrocatalyst in the reaction of oxygen evolution.

The comparative study of electrocatalysts synthesized by chemical reduction and pulsed magnetron-ion sputtering for polymer electrolyte membrane electrochemical systems are presented.Various carbon nanomaterials were used as supports of Pt nanoparticles: carbon black, nanotubes, nanofibers and reduced graphene oxide.The electrochemical studies of the obtained electrocatalysts as well as their testing in the fuel cell membrane-electrode assembly were carried out.The influence of supports morphology and the deposition approach of Pt nanoparticles on the electrochemically active surface area and activity of electrocatalysts, as well as the prospects of the magnetron-ion sputtering approach for electrocatalysts synthesis were studied and discussed.

НИЦ «Курчатовский институт» д. 1, пл. Курчатова, Москва, 123182, Россия тел.: +7 (499) 196-92-41, e-mail: fateev_vn@nrcki.ru Институт прикладной механики (ИПРИМ РАН) д. 7, Ленинградский проспект, Москва, 125040, Россия тел.: +7(495)946-18-06; e-mail: iam@iam.ras.ru Научно-исследовательский институт ядерной физики имени Д.В. Скобельцына (НИИЯФ МГУ) стр. 2, д. 1, Ленинские горы, Москва, ГСП-1, 119234, Россия тел.: +7(495)939-18-18, факс: +7(495)939-08-96, e-mail: info@sinp.msu.ru