Fluoride-Modulated Cobalt Catalysts for Electrochemical Oxidation of Water under Non-Alkaline Conditions



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The acid test: Electrochemical oxidation of CoII salts in aqueous solution in the presence of fluoride (pH 3.5) results in formation of an heterogeneous cobalt oxide deposit on the electrode that serves as an electrocatalyst for water oxidation under mildly acidic conditions. Further studies reveal that fluoride is an effective proton acceptor for the oxygen-evolving reaction and lacks the inhibitory properties evident with other buffering electrolytes, such as inorganic phosphate.