The Study of the Solid Polymer Electrolyte Oxygen Concentrator with Nanostructural Catalysts Based on Hydrophobized Support.

The efficient production of gaseous oxygen used in many branches of industry to provide human life in anaerobic environments and in medicine (e.g., in the case of acute respiratory failure as one of COVID-19 complications) is challenging nowadays. The electrochemical oxygen pump (concentrator) with a solid polymer electrolyte representing an electrolyzer with air cathode depolarization is a very promising device, which provides the portable, safe, and efficient in situ production of highly pure oxygen at a twice lower energy consumption as compared to the water electrolyzer with a solid polymer electrolyte. The effect produced by the hydrophobization of a nanostructured oxygen reduction catalyst on the oxygen pump characteristics and the endurance of a cathode catalytic layer to flooding has been considered. The modification of a carbon support with polytetrafluoroethylene particles improves the removal of excessive water from the catalytic layer and increases the limiting current characterizing the appearance of transport limitations. The operational parameters (air temperature, flow rate, and pressure) also have an essential effect on the oxygen pump performance and must be optimized to improve water transport in catalytic layers, increase the operating current densities, and reduce the energy consumption in oxygen production.

Graphene and Graphene-Like Materials for Hydrogen Energy.

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.