Metal-Organic Frameworks as Porous Templates for Enhanced Cobalt Oxide Electrocatalyst Performance

Water oxidation to dioxygen is an essential energy capture process in biological systems, and is a part of the oxygen-evolving complex. It continues to attract interest as a half-reaction portion in the electrochemical water-splitting to hydrogen and dioxygen in abiotic systems. There is a corresponding interest in improving the activity of non-precious metal electrocatalysts for this reaction. One of the most well-known water oxidation catalysts is amorphous cobalt oxide. This catalyst can operate in water at neutral pH with low overpotentials, and is known to continually re-form under catalytic conditions, a type of self-healing. The active sites for the electrocatalytic reaction are thought to be adjacent octahedral cobalt sites in the bulk material, meaning that only the surface of the material is active. Thus, catalytic activity can be improved by increasing the surface area to volume ratio of the active material. To this effect, microporous materials such as metal organic frameworks (MOFs) can be us...