Furthermore, controlled experiments under conditions (low polyoxometalate concentrations of 2.5 μM and high electrochemical potentials ≥1.3 V vs. Ag/AgCl, in pH 5.8 and 8.0 sodium phosphate electrolyte at a glass carbon working electrode) specifically chosen that are favor to [Co4(H2O)2(PW9O34)2]10− POM catalyzing water oxidation but found that Co4-POM is not stable in a thermodynamic sense to the conditions examined.