Bisht et al. and Yadav et al. have demonstrated via H2 TPR studies that the substitution of Sr improves the lattice oxygen exchange properties and the reducibility of the LaCoO3. As mentioned, ring current is very pronounced even at the start of the experiment, which provide evidence of the reduction of lattice oxygen. In order to verify if this is indeed happening, we first reduced the catalyst (LSCO) to prepare R-LSCO catalyst in order to utilize the lattice oxygen present in the system (Figure ). Clearly, from Figure , it is evident that the ring current for ORR is almost negligible in the case of R-LSCO as compared to fresh LSCO catalyst. Thus, the reduced catalyst, which is deficient in the lattice oxygen show less reduction current on the ring and this proves that the ring current before OER is indeed due to the lattice oxygen from the catalyst. It is noticeable that the activity of R-LSCO is not very different from the original LSCO thus, lattice oxygen may not have any role in alerting the catalyst's activity.