Evolution of hydrogen on the surface of the nanostructured nickel with additional deposited bismuth from acid solutions

Method voltammetry with linear potential sweep in an acidic environment was used to investigate the process of hydrogen evolution at nanostructured nickel surface with additional deposited bismuth. Intensity of hydrogen evolution at these electrodes in comparison with a smooth surface of bismuth increases in 5.7 times. The working solutions we used the sulfuric acid with a pH of 1-3. On the basis of analysis of the potentiodynamic curves is showed that at pH = 1, hydrogen begins to stand out at the potential of the working electrode -0.1 V relative to the Argentum-chloride electrode (exclusively due to the discharge of hydroxonium ions). Upon reaching the potential of the working electrode -0.47V discharge occurs due to both hydroxonium ions and water molecules. Changing the rate of application of the potential does not affect the intensity of the hydrogen evolution. The influence of alkali metal ions Li+ , Na+ , Cs+ on the overvoltage of hydrogen evolution was studied. Introduction into the solution of sodium chloride increases the overvoltage of hydrogen evolution for both mechanisms. And such behavior is observed only for sufficiently acidic solutions with a pH of 1-2. Lithium ions reduce overvoltage of hydrogen evolution, and cesium ions opposite – increases it. The lithium ions have a small radius and are subjected to a strong solvation, this leads to a decrease in the degree of solvation of hydroxonium ions, which generally facilitates the delivery of the hydroxonium ions to the electrode surface. This will be a decisive factor, which reduces the hydrogen overvoltage. Cesium ions, which have a much larger radius, have the opposite effect on the hydrogen overvoltage.