Generalities: The formation of gaseous O2 at the anode of an electrolytic cell containing an aqueous electrolyte solution is the most frequent electrode reaction. It has immense practical implication because it always accompanies the electrolytic production of H2 in water electrolyzers, the cathodic deposition of metals in metal electrowinning processes, and the application of a cathodic current in cathodic protection operations, and it takes place at the negative pole of metal–air power sources upon recharging. .
