Impact of the alkali cation on the electrocatalytic oxidation of urea and benzyl alcohol on nickel electrode

• Electro-oxidation of urea and benzyl alcohol on NiOOH catalyst is investigated.
• The catalytic activity increases in the sequence Li+ < Na+ < K+.
• Two factors are proposed to explain the activities difference.

The effect of electrolyte alkali metal cations (Li+, Na+, or K+) on the electro-oxidation of urea and benzyl alcohol on NiOOH catalyst has been investigated by means of cyclic voltammetry and chronoamperometry in the presence of an electrolyte containing LiOH, NaOH, or KOH. The catalytic activity toward the electro-oxidation of urea and benzyl alcohol was found to increase in the sequence Li+ < Na+ < K+. This activity's difference is partly caused by different surface blockage abilities by OH–M+(H2O)x (M: Li, Na, K) clusters, which is similar to many electrocatalytic reactions on Pt reported previously, additionally, incorporation of various cations to the catalyst may induce the activities difference as well.