Electrocatalytic Water Oxidation at Neutral pH by a Nanostructured Co(PO3)2 Anode

Cobalt metaphosphate Co(PO3)2 nanoparticles are prepared via the thermolytic molecular precursor (TMP) method. A Ni form electrode decorated with Co(PO3)2 nanoparticles is evaluated as an anode for water oxidation electrocatalysis in pH 6.4 phosphate-buffered water. Catalytic onset occurs at an overpotential of ca. 310 mV, which is 100 mV lower than that observed for Co3O4 nanoparticles, with a comparable surface area under identical conditions. A per-metal turnover frequency (TOF) of 0.100.21 s-1 is observed at an overpotential, ?, of 440 mV, which is comparable to the highest rate reported for a first-row metal heterogeneous catalyst. Post-catalytic characterization of the catalyst resting state by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy reveals that surface rearrangement occurs, resulting in an oxide-like surface overlayer.