Electrolyte-Dependent Electrosynthesis and Activity of Cobalt-Based Water Oxidation Catalysts

Electrolysis of Co2+ in phosphate, methylphosphonate, and borate electrolytes effects the electrodeposition of an amorphous highly active water oxidation catalyst as a thin film on an inert anode. Electrodeposition of a catalytically competent species immediately follows oxidation of Co2+ to Co3+ in solution. Methylphosphonate and borate electrolytes support catalyst activity comparable to that observed for phosphate. Catalytic activity for O2 generation in aqueous solutions containing 0.5 M NaCl is retained for catalysts grown from phosphate electrolyte.