Cubic Mn2O3 nanoparticles on carbon as bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions

Transition metal oxides are most promising non-platinum catalysts for oxygen reduction (ORR) and oxygen evolution reactions (OER) in renewable-energy technologies. Among transition metal oxides, Mn oxides are very active for both ORR and OER and can act as a bifunctional catalyst. But due to their poor electronic conductivity, carbon materials are used as supports or mixed with other metal oxides to increase their conductivity that assistances in electrochemical applications. Herein, a highly active mesoporous cubic material consisting of Mn2O3 nanoparticles grown on carbon (Vulcan XC-72 R) as a high performance bifunctional catalyst for both ORR and OER have been synthesized. The synthesized Mn2O3/C has been characterized by various structural analyses. The Mn2O3/C material exhibits much better ORR activity compared to the commercially available Pt/C and Pd/C in alkaline media. The same material is also active for OER, making it a bifunctional electrocatalyst for both the reactions. Consequently, Mn2O3/C is quite stable up to 1000 cycles displaying its better stability. The reaction mechanism follows a 4-electron pathway for ORR. The superior electrocatalytic presentation mainly arises due to the better synergistic coupling effect of carbon and Mn2O3. (C) 2017 Elsevier B.V. All rights reserved.