V. N. Fateev

Electrolysis of Water in a System with a Solid Polymer Electrolyte at Elevated Pressure

Electrolysis of water in a system with a solid polymer electrolyte (SPE) at pressures elevated up to 3.0 MPa is studied. A mechanism of the effect of elevated pressure on the electrolysis electrochemistry is proposed. A mathematical model and relevant software, which allow one to model current–voltage curves of an SPE-based electrolyzing cell on the basis of reference and experimental data, are designed.

Catalytic layers in a reversible system comprising an electrolyzing cell and a fuel cell based on solid polymer electrolyte

Electrocatalytic layers of a fuel cell-electrolyzing cell reversible system with solid polymer electrolyte are studied. The system may be used as both a dc generator and a water electrolyzing cell. It is shown that the way the polytetrafluoroethylene (PTFE) additive is introduced into the cathode’s catalytic layer affects the cathode performance. The PTFE introduction in the form of suspension in an alcohol solution of MF-4SK polymer enhanced performance. Characteristics of platinum, iridium, and platinum-iridium anode catalysts are compared. The best characteristics are obtained using a composition based on platinum black and iridium black, applied layer-by-layer, with an iridium-black layer facing the surface of a solid-polymer membrane.

Synthesis and test of palladium-based nanostructured anodic electrocatalysts for hydrogen fuel cells with solid polymer electrolyte

Palladium-based nanostructured electrocatalysts on the Vulcan XC-72 carbon support for fuel cells with solid polymer electrolyte are synthesized and studied. In particular, electrochemical studies of the synthesized catalysts are carried out and membrane-electrode assemblies are assembled on their basis and tested. The test results indicate that platinum can be replaced with palladium in the hydrogen electrode of the fuel cells.

Combined heat and power (cogeneration) plant based on renewable energy sources and electrochemical hydrogen systems

The layout of a combined heat and power (cogeneration) plant based on renewable energy sources (RESs) and hydrogen electrochemical systems for the accumulation of energy via the direct and inverse conversion of the electrical energy from RESs into the chemical energy of hydrogen with the storage of the latter is described. Some efficient technical solutions on the use of electrochemical hydrogen systems in power engineering for the storage of energy with a cyclic energy conversion efficiency of more than 40% are proposed. It is shown that the storage of energy in the form of hydrogen is environmentally safe and considerably surpasses traditional accumulator batteries by its capacitance characteristics, being especially topical in the prolonged absence of energy supply from RESs, e.g., under the conditions of polar night and breathless weather. To provide the required heat consumption of an object during the peak period, it is proposed to burn some hydrogen in a boiler house.

Synthesis of nanostructured electrocatalysts based on magnetron ion sputtering

Nanostructured platinum catalysts for electrochemical systems with proton-exchange membranes (PEMs) have been synthesized by magnetron ion sputtering on a carbon support. The design of the powder support stirrer has been optimized to ensure uniform surface coverage with platinum metal nanoparticles. The deposition parameters (discharge power, deposition time, and bias voltage) that make it possible to obtain electrocatalysts with a large specific surface area (up to 44 m2/g) have been determined. The resulting catalysts have been studied by transmission electron microscopy and X-ray diffraction. The samples with platinum particles 3 to 4 nm in size uniformly distributed over the carbon surface and forming a single phase exhibit the greatest efficiency. The electrodes based on the synthesized electrocatalysts have been tested in a liquid electrolyte and as a component of a fuel cell and PEM water electrolyzer. The voltage across the fuel cell with the synthesized Pt/C electrocatalyst (44 m2/g) at a current density of 1 A/cm2 is as high as 0.55 V, which corresponds to a specific power of 550 mW/cm2. Qualitative correlations between the parameters of the synthesized catalysts and the deposition conditions have been established.

Mass transfer in porous systems, flooded in part with water, of gas diffusion and catalytic layers of the cathode of a fuel cell with a solid polymer electrolyte

Mass transfer in porous gas diffusion and catalytic layers of the cathode of a hydrogen-air fuel cell with a solid polymer electrolyte is considered. The transport processes are considered with allowance made for the partial flooding of porous systems of these layers with water, which forms during the fuel cell operation. The consideration also allows for the influence of the diluent gas present when air oxygen is used as the oxidant. The fraction of water-flooded pores is calculated within percolation theory as a function of structural parameters of the porous system. Conditions leading to the beginning of the gas diffusion layer flooding are presented.

Study of nanostructured electrocatalysts synthesized by the platinum magnetron–ion-beam sputtering onto metallized nanostructured carbonaceous support

Nanostructured electrocatalysts for hydrogen electrochemical systems with solid polymer electrolyte were synthesized by the platinum magnetron–ion-beam sputtering onto nanostructured carbonaceous support Vulcan XC-72 premetallized by the impregnation–reduction method. To be able to perform comparative analysis, a number of mono- and bimetallic catalyst samples was synthesized using impregnation–reduction, a traditional method. Thus prepared catalysts were examined by thermogravimetric method, transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and cyclic voltammetry. The electrodes prepared with the synthesized catalysts were tested in fuel cell and water electrolyzer with solid polymer electrolyte. This study confirmed the possibility of preparation of multicomponent catalysts with complicated structures (such as the core–shell structure) over nanostructured carbon support by magnetron sputtering and demonstrated the effectiveness of their performance as parts of electrochemical systems with solid polymer electrolyte. The effect of additional ionbeam processing of the Pt/C electrocatalysts on their efficiency is also studied.

Optimization of Mass Transfer Processes in the Zone of the Air Electrode of a Fuel Cell with a Solid Polymer Electrolyte

A two-dimensional mathematical model for the transport of reactants in a fuel cell with a solid polymer electrolyte is developed. The model is used for analyzing spatial distributions of the concentration of reactants and current density over the cell. The effect of the catalytic-layer activity, reactant speed, bipolar-plate geometry, thickness and porosity of current collector and/or gas-diffusion sublayer, and the reaction mixture composition on the fuel cell efficiency is estimated theoretically and experimentally.

Study of the Electrochemical Oxygen Pump Based on Solid Polymer Electrolyte

Electrochemical process of atmospheric oxygen concentration in a modified electrolytic cell with a solid polymeric electrolyte and cathode depolarized by atmospheric oxygen was experimentally studied. The influence exerted by various factors (catalyst hydrophobicity, temperature, pressure, and air supply rate) on the process efficiency was examined. It was shown that the energy consumption for obtaining high-purity oxygen in this process can be reduced by 50–75% as compared with obtaining oxygen by electrolysis of water. The highest activity was observed for Pt40V catalyst (40 wt % Pt on Vulcan XC-72 carbon black) containing 10 wt % fluoroplastic.

Mathematical Model of PEM-Fuel Cell Catalytic Layer

The electrochemical behavior of fuel cell catalytic layers is rather complicated and influenced by many parameters and components of the cell. That is why that optimization of the fuel cell catalytic layer is a very important but complicated problem.