Rational Design of Dodecahedral MnCo2O4.5 Hollowed-Out Nanocages as Efficient Bifunctional Electrocatalysts for Oxygen Reduction and Evolution

Efficient bifunctional electrocatalysts are in demand to increase kinetics of oxygen reduction and evolution reactions (ORR and OER) for rechargeable zinc–air batteries. In this work, dodecahedral MnCo 2 O 4.5 hollowed-out nanocages are synthesized using a seed-mediated coordination chemistry of metal–organic frameworks. The hollowed-out MnCo 2 O 4.5 nanocages used as bifunctional oxygen electrocatalysts exhibit high catalytic activity and excellent stability for both ORR and OER in alkaline media, which can be attributed to both the hierarchical porosity and stable hollowed-out structure that not only facilitate fast charge transfer reaction but also prevent the agglomeration of MnCo 2 O 4.5 nanoparticles. The dodecahedral hollowed-out MnCo 2 O 4.5 nanocages as the air electrode catalyst can deliver good stability in a rechargeable zinc–air battery. Scanning electron microscopy and transmission electron microscopy images, X-ray diffraction and X-ray photoelectron spectroscopy of the electrocatalyst were measured again after durability tests. There is no significant influence on the morphologies, compositions, and structures before and after durability tests.