Investigation of Manganese-Cobalt Oxide Nanoparticles As Electrocatalysts for the Oxygen-Evolution Reaction: Influence of Synthesis Conditions on Structure and Activity

The storage of electric energy has become one of the main challenges in infrastructure development. The development of scalable, cost-efficient and robust synthetic routes toward well-defined solid state structures is a major objective in this field. Electrocatalytic water splitting is a promising way of chemical energy storage wherein the anodic oxygen evolution reaction (OER) is the determining factor. Manganese based oxides have attracted particular attention as non-noble metal catalysts for the OER. Due to their abundance, low price and ecological harmlessness, those materials are promising candidates for a commercial application. Therefore insights into the relations between synthesis conditions, composition, structure and activity as well as stability are of fundamental interest. 1,2 Here, we present the comparison of different synthesis routes for Mixed Oxide Nanoparticles (NPs) of Manganese and Cobalt to yield Mn3-xCoxOy-NPs in a range from X=0 to 3. The well characterized (TEM, EDX, XRD) catalysts were tested with respect to the relation of crystal structure to electrocatalytic activity and stability for the OER in alkaline media using Rotating Disk Electrode (RDE) measurements. We report a significant impact of the Cobalt fraction on the morphology, while the crystal structure remains unchanged. Further we found a non-linear relation between composition and activity. References (1) Bergmann, A.; Martinez-Moreno, E.; Teschner, D.; Chernev, P.; Gliech, M.; de Araujo, J. F.; Reier, T.; Dau, H.; Strasser, P. Nat Commun 2015, 6. (2) Gliech, M.; Bergmann, A.; Spöri, C.; Strasser, P. Journal of Energy Chemistry 2016.