Abstract: SbO_x+SnO₂ were prepared by thermal decomposition as intermediate layer of Ti based MnO₂ anode. Service lives of the anodes with or without SbOx +SnO₂ intermediate layer in 0.5 mol·L ^-1 H₂SO₄ solution were investigated by using accelerated electrolysis. Polarization curves and cyclic voltammetric curves (CVs) were utilized to analyze Cl₂ evolution reaction (CER) of the oxide electrodes. Cyclic voltammetric curves and electrochemical impedance spectroscopy (EIS) were utilized with the aim of obtaining detailed information related to the changes of the inner structure during the electrolysis. The results indicated that the main reason for the deactivation of MnO₂ anodes was the passivation derived from the increase of the thickness of the insulating TiO₂ layer. With the introduction of intermediate layer, the resistance between Ti base and active coating was lowered and the increase of resistance during the electrolysis was postponed dramatically, so the service lives were improved remarkably.

Key words: Intermediate layer, Manganese dioxide, Accelerated life, EIS