Metallic cobalt modified MnO–C nanocrystalline composites as an efficient bifunctional oxygen electrocatalyst†
Exploring non-noble-metal-based bifunctional oxygen electrocatalysts remains a challenge for renewable clean energy applications, including metal–air batteries and dual functionality regenerative fuel cells. Herein, a facile two-step rheological phase reaction strategy was proposed to synthesize metallic cobalt modified MnO–C nanocrystalline composites (Co/MnO–C) for efficiently catalyzing oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). The resulting optimal catalyst, Co/MnO–C, exhibits comparable electrocatalytic properties and superior methanol tolerance relative to commercial platinum black catalyst towards ORR. Furthermore, the critical role of cobalt content on ORR catalytic activity was investigated. In addition, Co/MnO–C also displays remarkable OER activity with an overpotential of 385 mV. Importantly, the facile two-step rheological phase reaction strategy described in this work could provide new methodologies for the synthesis of transition-metal-based catalysts and also offers prospects in raising the ORR and OER activity for many different electrochemical energy technologies.