Selective Synthesis of Manganese Oxide Nanostructures for Electrocatalytic Oxygen Reduction

This work presents two points with respect to manganese oxide (MnOx) nanomaterials their controllable synthesis with desired phases and shapes together with their applications as catalysts for oxygen reduction and AI/air batteries. Solid MnOx with crystalline phases of MnOOH, Mn2O3 and MnO2 as well as shape of the sphere, wire rod, and particle were prepared through a simple one pot hydrothermal route. Selective preparation was achieved by adjusting the surfactant concentration that controls simultaneously the growth thermodynamic and dynamic parameters of MnOx nanocrystals. Electrochemical investigations show that the obtained Mn2O3 nanowires, which possess a large aspect ratio and preferentially exposed (222) crystal surfaces exhibit remarkable catalytic activity (comparable to Pt/C counterparts) toward the electroreduction of oxygen in alkaline media. The tailored MnOx nanostructures may find prospective applications as low cost catalysis for alkaline fuel cells and metal/air batteries.