The review paper accumulates the latest information on the analysis of catalyst synthesis for the electrolysis of water in alkaline and partially in acidic media. Literature data on the production of electro-catalysts based on noble, refractory, transition and pure metals, as well as metals doped with molybdenum, phosphorus, and other elements, are presented. Given the different methods of synthesis of electro-catalyst, the advantage of the electrochemical method is emphasized as easy, accessible method enabling to regulate the composition of synthesized electrodes by changing the content of an electrolyte and the conditions of electrolysis, controlling the properties of synthesized materials.

The influence of various factors current density, concentration of electrolyte components of stirring, and temperature on the composition and quality of Ni-Mo thin films, obtained by electrochemical deposition has been studied. It is established that the composition of deposited compounds strongly depends on the concentration of electrolyte components and electrolysis conditions. Increasing the current density increases the molybdenum content, and increasing the temperature increases the nickel content in the sediments. Stirring affects the electrodeposition process slightly. For obtaining high quality deposits, optimal conditions and electrolyte composition have been determined.

The process of co-deposition of Ni with Mo from alkaline electrolytes was studied by taking linear and cyclic polarization curves of Pt electrode at various concentrations of initial components and potential scan rates. Solutions of Na2MoO4∙2H2O and NiSO4∙7H2O were used as sources of ions of the main components in NH4OH electrolyte. It was found that co-deposition of nickel with molybdenum goes through the oxide formation stage, and a solid solution of these two metals is deposited on the cathode surface. The film obtained at constant current on Ni electrode under optimal conditions was found amorphous, but additional thermal treatment at 500 °C for one hour made it polycrystalline. This was confirmed by peaks in X-ray diffraction patterns, corresponding to NiMoO4, Ni, and MoO3. The proposed electrolyte and electrolysis conditions allow to obtain thin films with molybdenum content ranging from 17.1 to 50.9 at.%. The co-deposition of Ni with Mo is limited by diffusion of these ions to the cathode surface. The knowledge of the mechanism of co-deposition of Ni and Mo will make possible a selection of optimal conditions for deposition of alloys of the required composition with satisfactory electrocatalytic properties.

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The essay is about studies of the electrochemical reduction of nickel ions from a glycine electrolyte by the method of recording cyclic and linear potentiodynamic polarization curves. The effect of the concentration of the main components, potential sweep and temperature on the electrodeposition process of nickel has been studied. It has been found that at the beginning of the process the electrodeposition of the nickel ions from glycine electrolyte is controlled by electrochemical polarization, which turns into concentration polarization