Boosting Electrochemical Water Oxidation with Metal Hydroxide Carbonate Templated Prussian Blue Analogues

The development of efficient and stable catalyst systems with low‐cost, abundant, and non‐toxic materials is the primary demand for electrochemical water oxidation. A unique method is reported for the syntheses of metal hydroxide carbonate templated Prussian blue analogues (PBAs) on carbon cloth and their outstanding water oxidation activities in alkaline medium. The best water oxidation activity is obtained with cobalt hydroxide carbonate templated t‐Co^II‐Co^III with an overpotential as low as 240 mV to reach a current density of 10 mA cm^?2. It produces constant current over 50 h in chronoamperometric measurements. Moreover, the catalysts outperform the activities of the PBAs prepared without any template and even the noble metal catalyst RuO₂. Spectroscopic and microscopic studies show that the PBAs are transformed into layered hydroxide–oxyhydroxide structures during electrochemical process and provide the active sites for the water oxidation.