Effects of additives on morphology and hydrogen evolution activities of nickel films prepared by electrodepositing

摘要

Nickel thin films with different morphologies were prepared by electrodeposition from solutions withdifferent additives. It is found by observing the nickel film morphology with SEM that the compactnickel films were prepared from solutions containing H3BO3 or C6H5Na3O7. And when the solutionscontained (NH4)2SO4, porous nickel film was prepared. It is shown by investigating the effects ofdifferent additives on the nickel deposition process that (NH4)2SO4 could significantly reduce thecathode potential in the process of nickel electrodeposition. Meanwhile, (NH4)2SO4 could reducecurrent efficiencies for hydrogen evolution electrode. Cyclic voltammetry for nickel films showed that(NH4)2SO4 could significantly increase the roughness factor of nickel films. And the polarizationcurves of different nickel films for hydrogen evolution in the electrolyte of 1M NaOH show that(NH4)2SO4 could significantly increase the activity of hydrogen evolution. Chronoamperometricresponses recorded on different nickel films for hydrogen evolution at constant applied potential of - 1.6 V show that all the nickel films prepared by electrodeposition have good stability of hydrogenevolution.