A yolk–shell structured metal–organic framework with encapsulated iron-porphyrin and its derived bimetallic nitrogen-doped porous carbon for an efficient oxygen reduction reaction

A yolk–shell structured metal–organic framework (MOF) with encapsulated 5,10,15,20-tetraphenylporphyrinatoiron (FeTPP) in a zeolitic imidazolate framework (ZIF)-L-ZIF-8 is reported.