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

Abstract

The kinetics of the electrochemical evolution of ¹⁸O¹⁶O from NiCo₂O₄ and Li_xCo_3–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 Li_xCo_3–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.