Improving the stability of Sb doped Sn oxides electrode thermally synthesized by using an acid ionic liquid as solvent

Antimony doped tin oxide electrodes were thermally synthesized over titanium substrates using three methodologies differentiated by the solvent in the preparation of the metal precursor solution, i.e.: alcoholic and sol–gel methods and a novel procedure based on the use of an acid ionic liquid. Synthesized electrodes were physically characterized and compared using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The three methods were compared in terms of activity towards dissolved organic molecule electrooxidation and electrode stability, evaluated by cyclic voltammetry, electrochemical impedance and the galvanostatic service life test. The prepared electrodes showed similar performance when working as anodes for the electrochemical oxidation of Ranitidine. However, the electrodes prepared by the proposed method, based on the use of an acid ionic liquid as solvent and structuring agent, showed the highest stability and longest service life, which regard to the properties of the ionic liquid: higher acidity and viscosity and lower volatility.

► Doped SnO2 electrodes were synthesized by alcoholic, sol–gel and ionic liquid solvent. ► Morphology, organic electrooxidation activity and electrode stability were compared. ► Anodes have similar performance for the electrooxidation of Ranitidine. ► Highest stability and longest service life was obtained with ionic liquid method. ► Results are mainly related with higher acidity and viscosity and lower volatility.