Platinum-Modified Mixed Metal Oxide Electrodes for Efficient Chloralkaline-Based Energy Storage

In this work, a series of novel mixed metal oxide (MMO) electrodes with the composition Ti/RuO2Sb2O4Ptx (0 <= x <= 10.0) were developed, envisaging their application in a reversible electrochemical cell based on the chloralkaline process as an energy storage system. These electrodes were synthesized via the ionic liquid method. Comprehensive physical, chemical, and electrochemical characterizations were conducted to evaluate their performance. The feasibility of employing these electrodes within reversible processes was explored, using the products generated during the electrolytic operation of the system for fuel cell operation. During the electrolyzer operation, higher current densities resulted in enhanced current efficiencies for the production of oxidized chlorine species. Notably, the presence of platinum in the catalyst exhibited a negligible impact on the coulombic efficiency at low current densities where water oxidation predominates. However, at higher current densities, the presence of platinum significantly improved coulombic efficiency, approaching values of approximately 60%. Transitioning to a fuel cell operation, despite the improved kinetic performance associated with a higher platinum content, the process efficiency was predominantly governed by ohmic losses. Curiously, the MMO electrode made without platinum (Ti/(RuO2)70-(Sb2O4)30) displayed the lowest ohmic losses. This study establishes optimal conditions for future investigations into this promising possibility, which holds great potential for energy storage via chloralkaline-based reversible reactions.