(190a) Two-Dimensional Co3O4-Supported Metal Atoms for Water Oxidation Catalysis

With readily available electricity from photovoltaics and wind power, large-scale electrochemical water splitting to produce hydrogen is expected to become practically competitive. Improved catalyst performance and long-term stability for the two half-reactions, hydrogen evolution reaction (HER) on cathode and oxygen evolution reaction (OER) on anode, are critical to large scale and inexpensive production of hydrogen from water. Because of their superior performance and stability, noble metal Pt and oxides (RuO₂ and IrO₂), respectively, are widely used for HER and OER. Since these noble-metal-based catalysts are expensive and are of limited supply, effective use of noble metals and/or employment of non-noble metals as stable electrodes are highly desirable. Supported metal atoms, possessing strong electronic interactions with their supports, provide a feasible platform for enhancing both the performance and long-term stability of electrodes for water oxidation catalysis. We present here an in-depth investigation of the electrochemical properties of various (noble and non-noble) metals, which are dispersed onto two-dimensional Co₃O₄ nanosheets, for OER and HER, and correlate their performance with atomic scale structural observations. The long-term stability of these atomically dispersed active species under alkaline conditions will be investigated as well. These studies are expected to spur innovative synthesis strategies with the goal of illustrating the underlying mechanisms of atomically dispersed metal species for water oxidation catalysis, leading to development of low-cost, high-efficiency electrocatalysts with long-term stability for hydrogen production via water splitting processes.