Photochemically deposited Ir-doped NiCo oxyhydroxide nanosheets provide highly efficient and stable electrocatalysts for the oxygen evolution reaction

To achieve practical production of fuel from water, it is essential to develop efficient and durable electrocatalysts for the oxygen evolution reaction (OER). We report here that doping NiCoOOH nanosheets with 8% Ir leads to a low overpotential of only 260 mV for 50 mA/cm², far better than previous OER catalysts. We synthesized this catalyst using a novel photochemical deposition method that leads to a uniform distribution of dopant, large catalytic active area, high interfacial charge transfer efficiency, good adhesion between catalyst and matrix, and long lifetime. Moreover, these nanosheets show significant stable performance for 70 h in alkaline media. Our density functional theory calculations show that Ir and Co both play essential bifunctional roles in stabilizing the key O radical intermediate on Ir and promoting the O–O bond coupling on Co, which are optimum for the 8% Ir.