Ostroverkh A. Scientific and technological bases for the creation of multilayer composites for fuel and electrolysis cells with polymer electrolyte and low content of noble metals

The dissertation is devoted to the development of scientific and technological bases for the creation of materials for hydrogen energy and the determination of technological aspects of structural optimization of the electrodes of the fuel and electrolysis cell with a reduced content of noble metals. To achieve this goal, relevant studies and structural optimization of fuel-cell and electrolysis systems were carried out. For the first time, the use of platinum materials with high catalytic activity for a proton exchange membrane fuel cell with a power density up to 1.1 W cm-2 was systematized and optimized. The platinum content is in the range of 1 – 50 µg cm-2 instead of standard values of 400 – 2000 µg cm-2. It was found that the stability and efficiency of the platinum catalyst is provided by the multilayer structure of CeOx and CNx. For the first time, based on the results of structural studies of the fuel cell cathode, a highly efficient porous material of high catalytic activity based on Pt and C, which is characterized by a low platinum content, has been developed. This composite is stable to corrosion processes in the voltage range up to 2.5 V, and has a high mass activity value of 1967 mA mgPt-1, which is confirmed in real conditions of a fuel cell and durability tests. Method for creating a catalytic layer of fuel cell electrodes for industrial deposition has been optimized. According to the results of mass spectrometry studies of corrosion process of the anode and cathode of the fuel cell, was determined the resistance of Pt–CNx material to the cell potential of 1.7 V. For the first time, it was also determined that amorphous carbon in the structure of the anode electrode of the fuel cell is prone to corrosion even in the operating voltage range of the fuel cell 0.5 – 1.0 V. For the first time, the structure of a catalytic layer with a low Ir content was developed for a highly efficient proton-conducting cell using an additional TiC layer. The inefficiency of using the catalyst in the membrane region, which can be used in the development of the catalytic layer of the anode to reduce the cost of iridium in the technology of creating proton-conductor electrolyzers, has been determined. Keywords: porous material, fuel cell electrode structure, catalyst, microporous layer, catalytic layer, oxidation and reduction reactions, mass spectrometry, magnetron sputtering, fuel cell, reverse fuel cell, electrolyzer