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Keywords: functional nanocomposites

DEVELOPMENT OF ELECTRODE MATERIALS BASED ON PLATINUM- RUTHENIUM NANOPARTICLES FOR METHANOL FUEL CELLS

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 7-15 p.
Abstract
The creation of effective materials for the functioning of new chemical power sources is currently an urgent task. Fuel cells can use environmentally friendly and energy resources, such as hydrogen and carbon biofuels (methanol and ethanol), which have a wide range of potential applications from portable devices to power plants. The researcher’s attention is attracted by the development of methanol fuel cells, due to their compact design, liquid fuel, low operating temperature and high specific power. However, commercialization of such energy sources is still a difficult task due to the high platinum content on the electrodes, the high cost of precious metals, low durability and delayed kinetics of both anode and cathode reactions. Increasing the activity and reducing the Pt load are two main tasks in the development of methanol fuel cell technology. In the work, bimetallic Pt-Ru nanoparticles were synthesized by chemical reduction in reversed microemulsions to evaluate the parameters of methanol fuel cells. A porous nickel was used as a carrier matrix, which was formed by template synthesis in a dimensional mask of metallic aluminum. As a result of experimental studies of methanol membrane-electrode assemblies of fuel cells based on porous nickel with Pt and Pt-Ru nanoparticles, it was concluded that the maximum voltage and current density are achieved when using electrodes based on platinum-ruthenium nanoparticles with a particle size of no more than 3 nm, a catalyst content of 0.2 mg/cm2 and a process temperature of 60oC.
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FORMATION AND RESEARCH OF BIMETALLIC ELECTRODE MATERIALS ON POLYMER-CARBON CARRIER MATRICES FOR ENERGY POWER SOURCES

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 74-82 p.
Abstract
Fuel cells are promising devices for direct conversion of chemical energy into electrical energy from the point of view of efficiency and low emission of pollutants. The main component of fuel cells is a solid polymer electrolyte. Membranes made of perfluorinated sulfonated copolymers of the Nafion type with different content of sulfogroups satisfy most of the application conditions, because they have a sufficiently high degree of proton conductivity, stability in electrolyte solutions and high mechanical strength. The principal disadvantage of such membranes is their relatively low ion selectivity and a decrease in mechanical strength at temperatures above 100oC. To improve the characteristics of the membrane, various modification methods are used, including various additives and metal nanoparticles. The main obstacle to the widespread large-scale use of fuel cells is their cost, in which the main part is the cost of electrocatalysts based on platinum metals. Therefore, the development of effective electrode materials with a reduced content of platinum metals is an urgent task. In this work, bimetallic platinum-ruthenium nanoparticles were synthesized on combined carrier matrices consisting of a Nafion polymer membrane and carbon nanotubes. The sizes of Pt-Ru nanoparticles were compared with varying the molar ratio of wa-ter:surfactant from 1.5 to 8. It was found that the minimum size is characteristic of nanoparticles obtained with a maximum platinum content in nanoparticles (7:1) and the degree of solubilization ω = 1.5. It was found that in the methanol oxidation reaction, electrode materials based on bimetallic Pt-Ru nanoparticles (7:1) demonstrate the greatest catalytic activity when the catalyst is loaded 0.2 mg/cm2 on polymer substrates with the addition of multi-walled carbon nanotubes at a temperature of 60oC.
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FORMATION OF NANOCOMPOSITE CARBON MATERIALS WITH BIMETALLIC NANOPARTICLES FOR AUTONOMOUS ENERGY SOURCES

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 5-12 p.
Abstract
The development of highly efficient autonomous energy sources allows for stable and uninterrupted power supply of physical and chemical processes and industries under various operating modes. Modern technological methods and approaches to the production of nanostructured electrode materials, as well as the elucidation of the features of the mechanisms of electrochemical reactions based on platinum metal nanoparticles make it possible to design control sensors, fuel cells and electrolyzers with increased energy characteristics. Carbon nanotubes used to create nanostructured electrodes in chemical energy converters have high functional properties compared to other matrices and, modified with nanoparticles with a reduced metal content, can increase the electrocatalytically active electrode surface area and achieve maximum fuel cell power parameters. In this work, the formation of bimetallic nanostructured composites with a variable composition on carbon carrier matrices for the construction of electrodes of autonomous current sources was carried out. Single- and multi-wall carbon nanotubes were chosen as substrates. To obtain composites, bimetallic platinum-palladium nanoparticles with different metal ratios were synthesized. The materials were studied by electron microscopy and X-ray phase analysis. As a result, an optimal algorithm, a synthesis method and conditions for creating nanocomposites with minimal particle sizes are established. The molar ratio water:surfactant changing, as well as the ratio of precursor metals, it is possible to obtain bimetallic platinum-palladium nanoparticles up to 12 nm. The data on the influence of the formation metal nanoparticles conditions on their size, shape and distribution over the matrix surface had been obtained. A series of prototypes has been formed for practical use in the design of current sources.
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