Detection of high-valent iron species in alloyed oxidic cobaltates for catalysing the oxygen evolution reaction

Abstract Iron alloying of oxidic cobaltate catalysts results in catalytic activity for oxygen evolution on par with Ni-Fe oxides base but at much higher compositions. Zero-field 57 Fe Mössbauer spectroscopy and X-ray absorption (XAS) are able to clearly identify 4+ mixed-metal Co-Fe oxides. The highest population is obtained the 40–60% range, XAS identifies ion residing an octahedral oxide ligand field. reaction (OER) activity, as reflected Tafel analysis CoFeO x films 1 M KOH, tracks absolute concentration . reported herein suggest important role formation redox state activating OER high iron loadings.