  Co(II) dissolved in acetate buffer at pH 7 is found to be a good water
oxidation catalyst (WOC) showing electrocatalytic water oxidation current
significantly greater than Co(II) in phosphate buffer under the same conditions
owing to the higher solubility of the former. When electrodeposited on ITO/FTO
electrodes it forms acetate bound cobalt(II)oxide based material (Co-Ac-WOC)
showing catalytic water oxidation current density of 0.1 mA/cm$^{2}$ at 830 mV
and 1 mA/cm$^{2}$ at 1 V in a pH 7 buffer solution. The morphology of Co-Ac-OEC
is investigated with AFM, HR-TEM and SEM (at different times and
electrodeposition potentials). The chemical composition of Co-Ac-OEC is
investigated using XPS, EDX, combustion analysis and ATR-FTIR which indicates
that this material has a CoO core with chloride and acetate anions bound to the
Co center. Sodium is found to be integrated in the Co-Ac-WOC. The presence of
the sodium ions and the chloride ions lowers the onset potential for oxygen
evolution reaction (OER) by 240 mV relative to the classic Co-Pi at pH 7. The
lower onset potential and higher OER current lowers the exchange current
density to 10$^{-6.7}$ in Co-Ac-WOC relative to 10$^{-8}$-10$^{-10}$ in Co-Pi
and its derivatives.
