(Invited) Ionic Self-Assembly of Iron(III) Porphyrin into Nanoflowers As Highly Efficient Oxygen Reduction Reaction Electrocatalysts after Pyrolysis

Abstract

Non-noble metal electrocatalysts (NNMEs) with a high performance are urgently needed to rival Pt-based electrocatalysts for fuel cells and metal-air batteries. Exploration of unique synthetic approaches is the key to the creation of highly efficient NNMEs yet remains a challenge. Herein, we report an unprecedented synthetic route that combines ionic self-assembly (ISA) technology of iron (III) porphyrins (FePs) with traditional pyrolysis to prepare unique NNMEs with tunable structures. Remarkably, the original morphology of nanostructures of self-assembled FePs was nearly retained after carbonization, enabling highly desired manipulation over the size and shape closely related to the performance of NNMEs. Molecular Dynamics (MD) simulations turned out that pi-pi interaction of neighbouring FePs primarily contributes to the morphology maintenance after pyrolysis. The as-prepared NNMEs exhibited superb oxygen reduction reaction (ORR) activities, excellent durability and methanol tolerance in both alkaline and acidic solution. This approach opens up an innovative avenue to produce high performance NNMEs with controllable structural features that are difficult to be achieved prior to this study.