The influence of carbon monoxide on the voltammetric behaviour of nickel in acid solutions

Abstract

The voltammetric behaviour of nickel in acid solutions is considerably modified by the presence of CO. As in plain acid the voltammogram also exhibits two main anodic peaks, but in this case, the adsorption of CO on the nickel surface shifts the metal electrodissolution to more positive potentials, and increases the contribution of the second electrooxidation current peak at the expense of the first one. The latter is the main peak in CO-free acids. The presence of CO adsorbates also decreases the charge of the Ni(OH)2/NiOOH redox couple in alkaline solutions. The potential shift of the nickel electrooxidation reaction in acids follows the trend which is expected from the energy difference between CO and H2O adsorption on nickel in the gas phase.