Reversible one-electron electro-reduction of O2 to produce a stable superoxide (O2-) catalyzed by adsorbed Co(II) hexadecafluoro-phthalocyanine in aqueous alkaline solution

A reversible one-electron reduction of O2 to produce the stable superoxide ion (O2-) was observed in an aqueous solution of 1 M NaOH. This electro-reduction of O2 was catalyzed by Cobalt(II) 1,2,3,4, 8,9,10,11, 15,16,17,18, 22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine (abbreviated as CoIIHFPC) adsorbed on a graphite electrode. The OH− concentration has a very strong effect on the reduction process. Higher OH− concentration could stabilize O2- ion.