Dulina O.A.

Candidate of Chemical Sciences (Ph.D.), Associate Professor, MIREA – Russian Technological University

Investigation of chemical power sources on an automated electronic load with controlled parameters

https://doi.org/10.58224/2619-0575-2024-7-4-25-36
Abstract
Hybrid installations for converting fuel energy into electricity are a promising way to provide humanity with affordable energy resources. However, the issue of obtaining reagents (hydrogen and oxygen) with high purity remains one of the most urgent. In this work, the energy characteristics of a hydrogen-oxygen fuel cell in combination with a water electrolyzer were investigated. Membrane-electrode assemblies were formed consisting of a modified membrane based on polytetrafluoroethylene with a platinum-containing component (Pt(30%)/C), as well as an anode and cathode made of carbon fabric and porous nickel doped with technical carbon and graphene. The structural characteristics of the material were studied using the scanning electron microscopy method. For the first time the investigation of hydrogen-oxygen membrane-electrode assemblies energy characteristics was carried out on an automated electronic load AKIP-1375/1E with embedded software. In the developed hydrogen-oxygen fuel cell, a more affordable commercial polytetrafluoroethylene-based membrane was used as a solid polymer elec-trolyte instead of the Nafion membrane, which significantly reduced the cost of developed MEA. As a result of the tests carried out, it was found that the maximum specific power is demonstrated by elements constructed on the basis of an anode and a cathode made of porous nickel modified with graphene.
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Energy-efficient nanocomposite membrane-electrode blocks for chemical current sources

Abstract
Electrode materials based on platinum metal nanoparticles are widely used to create alternative energy sources with high specific characteristics. Industrial carbon-containing carriers and perfluorinated proton exchange membranes of the Nafion type are used as matrices for the fuel cell electrodes formation. In this work, new effective polymer-carbon catalysts modified with platinum nanoparticles have been synthesized. Physicochemical and functional characteristics of nanocomposites have been studied by electron microscopy, X-ray phase analysis, small-angle X-ray scattering and cyclic voltammetry. Increased catalytic activity and stability of the formed electrodes in hydrogen-oxygen fuel cells had been found. The test results of hydrogen-air fuel cells in model operating conditions had been obtained. The current density maximum parameters of the membrane-electrode assemblies had been found for nanocomposites formed on multi-walled carbon nanotubes with a solubilization coefficient of ω equal to 1.5 and a platinum content of 0.35 mg/cm2. The creation of new membrane-electrode assemblies helps to reduce the cost of chemical current sources, as well as increase their energy efficiency.
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FORMATION AND RESEARCH OF BIMETALLIC ELECTRODE MATERIALS ON POLYMER-CARBON CARRIER MATRICES FOR ENERGY POWER SOURCES

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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