Chronoamperometry is an alternative technique to evaluate the electrocatalytic ability of redox mediator modified onto the electrode.Chronoamperograms in 1 mol L−1 KOH, NaOH, and LiOH solution with 80mmol L−1 urea or benzyl alcohol are recorded in Fig. 3. The current density response increases significantly with the order of LiOH,NaOH, and KOH for both substrates, and current densities of electrooxidation to urea (Fig. 3a) are smaller than those to benzyl alcohol (Fig. 3b) in these three strong alkaline solutions.