электрокатализатор

Electrochemical activity of anodes on the basis of a nickel mesh grid for water electrolysis is investigated. Activation of anodes was made by three ways:
1) chemical covering sulfur-containing compounds of nickel and iron;
2) immersing in solution Na₂S₂O₃ + H₂SO₄ (till pH=3);
3) immersing in solution Na₂S + H₂SO₄ (till pH=3).
The water solution 6M KOH was used as the electrolyte while the electrodes testing. Current density varied in a range from 1 to 600 mAJ cm2 at temperature 20, 50 and 70°C. The greatest electrochemical activity have anodes activated by the third method. The anode potential at current density 600 mA/cm² and temperature 70°C is equal +0.57 V (concerning Hg/HgO – the comparison electrode).

Electrochemical activity of cathodes with Pt or Pt-Pd-electrocatalysts was studied by voltammetry method under galvanostatic conditions. The dependence of the overvoltage of hydrogen evolution reaction on the logarithm of current density and on the test time of the cathode with Pt-Pd-electrocatalysts are defined. It is shown that the electrochemical activity of cathode with Pt-Pd-electrocatalyst is two times higher than with Pt-electrocatalyst at the hydrogen evolution reaction in 30% KOH solution at 90°C. As the temperature increases from 15 to 90° C the current density at 40 mV overvoltage at the cathode with Pt-Pd-electrocatalyst increases by 8 times. The test results with this cathode electrocatalyst in the laboratory electrolyzer at a current density of 400 mA/cm² and 65° C temperature within 11 days of intermittent regime work confirm the overvoltage stability in time.

By cyclic voltammetry and rotating disk electrode investigated the stability of the composite catalyst Pt/C–CNT from electrochemical action through multiple changes of the electrode potential from –150 to 1000 mV vs. silver chloride reference electrode. Investigated: the dynamics of the electrochemically active surface area of platinum and electrode in whole, change of amount of quinone groups, change in density of the kinetic current reduction of air oxygen on the surface of the catalyst. With the use of the method of differential thermal analysis studied the oxidation processes and the mechanisms of change of the physicochemical properties of the material under electrochemical action.

State-of-the-art development of the reversible electrochemical systems with proton-exchange membrane for cyclic direct and reverse transformation of electric energy to the chemical ones is considered in this review. Concept of reversible cells and areas of theirs application are described. Possible schemes of organization of the reversible systems operation, and catalytic, electrode and membrane materials used in them are analyzed.