Kinetics of the electrochemical evolution of isotopically enriched gases. Part 2.—18O16O evolution on NiCo2O4 and LixCo3–xO4 in alkaline solution

The kinetics of the electrochemical evolution of 18O16O from NiCo2O4 and LixCo3–xO4(0 < x < 1.5) electrodes enriched with 18O have been studied. The number of sites responsible for oxygen evolution is related to the lithium content of LixCo3–xO4, showing the importance of tetrahedrally coordinated Co3+. NiCo2O4 has different Tafel parameters and a greater number of sites. In this case some participation of Ni2+ and Co2+ is indicated. The data are consistent with a multistep reaction on a single site, or reaction via a bridged structure.