Abstract
The activation energies of the reversible electrochemical reduction of oxygen on 
and lithiated nickel oxide were shown to correlate with those of the gas phase exchange reaction between 
and 
on these catalysts. This result suggests that the rate‐determining step of the reversible oxygen reduction is the dissociative chemisorption of an oxygen molecule, in agreement with the "joint pseudosplitting/dissociative chemisorption" mechanism. The electrochemical reduction and isotopic exchange reaction on high and low surface area lithiated nickel oxide showed that only above the Neel temperature could oxygen be chemisorbed as 2 O−. The effect of particle size distribution, leading to a mixed potential, may account for the fact that high surface area lithiated nickel oxide is reversible only above 150°C.