Bifunctional P-Containing RuO2 Catalysts Prepared from Surplus Ru Co-Ordination Complexes and Applied to Zn/Air Batteries.

An innovative synthetic route that involves the thermal treatment of selected Ru co-ordination complexes was used to prepare RuO2-based materials with catalytic activity for oxygen reduction (ORR) and oxygen evolution (OER) reactions. Extensive characterization confirmed the presence of Ru metal and RuP3O9 in the materials, with an improved electrocatalytic performance obtained from calcinated [(RuCl2(PPh3)3]. A mechanistic approach for the obtention of such singular blends and for the synergetic contribution of these three species to electrocatalysis is suggested. Catalysts added to carbon-based electrodes were also tested in all-solid and flooded alkaline Zn/air batteries. The former displayed a specific discharge capacity of 10.5 A h g-1 at 250 mA g-1 and a power density of 4.4 kW kg-1 cm-2. Besides, more than 800 discharge/charge cycles were reached in the flooded alkaline Zn/air battery.