Mercury-coated platinum microelectrodes for steady-state voltammetry in aqueous solutions at high temperature

Sphere-cap mercury microelectrodes fabricated on a platinum disk substrate were tested in aqueous solutions over the temperature range 295¯353 K. The performance of these electrodes was assessed in solutions containing Ru(NH3)6Cl3 and LiClO4 as supporting electrolyte. From the steady-state limiting current obtained at three different mercury microelectrodes, the diffusion coefficient of the electroactive species at different temperatures was determined. It was found that the diffusion coefficient values were consistent with the Stokes¯Einstein and activation energy models. The results obtained also allowed us to conclude that sphere-cap mercury microelectrodes can be useful for elevated temperature electroanalysis in aqueous solutions.