LaFeO3- showed negligible oxygen storage capacity (<0.1%) in comparison to 6.28% for SrFeO3- (Figure ). The negligible oxygen capacity of LaFeO3- is likely caused by a large oxygen vacancy formation energy in lanthanum ferrite (~5eV) , formation energy which can be reduced by substituting lanthanum with strontium . This energy barrier for vacancy formation suggests less active lattice oxygen atoms leading to slower kinetics for ethane reactivity, culminating in lower rates of ethylene generation. Further, this would likely indicate increased coupling of oxide ions at the anode-electrolyte interface, due to lack of vacancies in LFO, generating gaseous oxygen resulting in greater formation of carbon oxides. This could explain the lower ethylene selectivity for LFO in comparison to SFO at the same current density values i.e. similar oxide ion transport rates (Table ). In other words, because SrFeO3- has a lower barrier for oxygen vacancy formation, the transported oxide ions are more likely to replace lattice oxygens than couple and directly oxidize ethane, resulting in greater ethylene selectivity. Furthermore, this may also explain the reasoning behind halogenic substitution in certain oxide perovskite studies as this substitution enhances oxygen vacancy formation and would provide more oxygen storage capacity and higher ethylene selectivity. Additional mechanistic studies will be required to support this hypothesis regarding the kinetics for oxide ion transport (current density) relative to the kinetics of ethane ODH to ethylene and ethane oxidation to carbon oxides.