Effect of Coprecipitated Metal Ions on the Electrochemistry of Nickel Hydroxide Thin Films: Cyclic Voltammetry in 1M KOH

Binary 9:1 composite hydroxides of nickel with 13 other metals were prepared by cathodic electrocoprecipitation from metal nitrate solutions and characterized by cyclic voltammetry in . Under these conditions, coprecipitated Ce, Fe, and La strongly catalyzed the oxygen evolution reaction. Conversely, Cd, Pb, and Zn poisoned this reaction. The hydrogen evolution reaction was less affected by the coprecipitated metals; Ag and Pb had a catalytic effect on this reaction. Co and Mn shifted the nickel hydroxide redox potentials to more cathodic values. In contrast, Cd, Ce, Cr, Fe, La, Y, and Zn each shifted these redox potentials anodically. The coulombic efficiency of the oxidation‐reduction process was substantially lowered by Ce, Fe, and La.