Platinum: A key element in electrode composition for reversible chloralkaline electrochemical cells

Abstract In this work, the performance of a reversible electrochemical cell using three different electrodes (Ti/Ru0.5Ir0.5O2, Ti/Ru0.3Ti0.7O2, and Ti/Ru0.3Ti0.6O2Pt0.1) is evaluated and compared for the oxidation of chlorides and reduction of chlorine. Results indicate that this technology is successful and that its efficiency depends significantly on the composition of the electrode in charge of the chlorine electrochemistry. Operating at 0.5 V allows us to obtain near 7 mA cm−2 and power efficiencies around 120 Wh mmol−1 hydrogen supplied. In electrolytic mode, efficiencies around 4 mol Cl2 mWh−1 can be obtained. The best performance is shown by the Ti/Ru0.3Ti0.6O2Pt0.1 electrode resulting from its roughest morphology and the presence of Pt. In shifting from electrolyzer to fuel cell mode, the current produced is rapidly stabilized for Ti/Ru0.3Ti0.6O2Pt0.1 and Ti/Ru0.5Ir0.5O2 electrodes. However, the electrode Ti/Ru0.5Ir0.5O2 showed a progressive change, which suggests a change in its composition that negatively affects the system.