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

Abstract Cobalt metaphosphate Co(PO 3 ) 2 nanoparticles are prepared via the thermolytic molecular precursor (TMP) method. A Ni form electrode decorated with Co(PO 3 ) 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 Co 3 O 4 nanoparticles, with a comparable surface area under identical conditions. A per‐metal turnover frequency (TOF) of 0.10–0.21 s −1 is observed at an overpotential, η , 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.