for LFO vs ~22 m for SFO (Figure ). This indicates SFO facilitates better gas diffusion and results in a more active TPB region, where reactants, ions and electrons are simultaneously transported. This morphological analysis provides additional evidence for the poor performance of LFO as there is less gas diffusion occurring in this electrode, explaining the lower ethane conversion. Lower gas diffusivity in LFO (due to processing conditions) combined with a high oxygen vacancy formation energy (due to materials chemistry) suggests a low concentration of active TPBs (i.e., poor transport of reactant gas and oxide ions). As such LFO would be a poor candidate for ODH at these conditions.