Identifying the crystal and electronic structure evolution in tri-component transition metal oxide nanosheets for efficient electrocatalytic oxygen evolution

Transition metal oxides (TMOs) nanosheets comprised of earth abundant Fe, Co, and Ni elements have been designed. Remarkably, the tri-component NiCoFeO_x/Ni foam (NF) electrode delivers a high current density of 100 mA cm⁻² at an overpotential of only ≈383 mV for oxygen evolution reaction (OER), with prolonged electrochemical stability. The improved OER activity of NiCoFeO_x/NF can be ascribed to the simultaneous incorporation of Ni and Co into FeO_x/NF, boosting the intrinsic catalytic activities by altering the crystal and electronic structures. With electron redistribution happening in the tri-component NiCoFeO_x/NF, the electron transfer from Co to Ni through the Fe acting as the electron transfer bridge renders Co more acidic (Lewis acid) to activate H₂O (Lewis base) molecules through Lewis acid-base interaction. By identifying the interactions of Fe, Co, and Ni and electron redistribution in the tri-component TMOs, this study provides new insights into the crystal and electronic structure evolution of tri-component NiCoFeO_x catalysts for active electrocatalysis. Abstract: (Figure presented.).