Mesoporous Spinel Ir-doped NiCo2O4 Nanostructure as an Efficient Catalyst for Oxygen Evolution Reaction

Abstract Water electrolysis (WE) is an attractive advanced technology for the production of H2. A key issue in the WE is to develop suitable catalysts for the oxygen evolution reaction (OER), where a relatively large energy loss occurs. The Ir-doped NiCo2O4 catalysts exhibit the formation of a solid solution and a porous nanostructure. The oxygen vacancies formed by Ir doping can enhance the electrocatalytic activity for the OER owing to increased electrical conductivity and tunable adsorption energies of OH- and H2O. In comparison to IrO2 as a representative OER catalyst, the Ir(10 at%) doped NiCo2O4 catalyst (10-Ir-NCO) exhibits the better OER performance (overpotential of 303 mV at 10 mA cm−2) and its stability for 20,000 s. In addition, in the overall water splitting test, the 10-Ir-NCO || Pt/C exhibits the excellent OER activity (a low overpotential of 0.5 V at 100 mA cm−2) and stability (20 h at 50 mA cm−2).