Bifunctional P-Containing RuO 2 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 RuO 2 -based materials with catalytic activity for oxygen reduction (ORR) and oxygen evolution (OER) reactions. Extensive characterization confirmed the presence of Ru metal and RuP 3 O 9 in the materials, with an improved electrocatalytic performance obtained from calcinated [(RuCl 2 (PPh 3 ) 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.