The role of carbonate in electro-catalytic water oxidation by using Ni(1,4,8,11-tetraazacyclotetradecane)2+

NiLi2+ are good electro-catalysts for water oxidation in phosphate or carbonate buffers. The results point out that the active oxidizing agents are L(X)(NiOH4-(3-n+ 1)/(2-n+ 1))-O-IV, where X = PO4Hn(3-n)- or CO3Hn(2-n)- formed from (LNiX2)-X-IV via a mechanism involving an acid catalyzed O-P or O-C bond heterolysis. Carbonate behaves differently from phosphate as it is a non-innocent ligand and it can be oxidized.