Local Electronic Regulation by Oxygen Coordination with Single- Atomic Iridium on Ultrathin Cobalt Hydroxide Nanosheets for Electrocatalytic Oxygen Evolution

Rationally optimizing the atomic and electronic structure of electrocatalysts is an effective strategy to improve the activity of the electrocatalytic oxygen evolution reaction (OER), yet it remains challenging. In this work, atomic heterointerface engineering is developed to accelerate OER by decorating iridium atoms on low-crystalline cobalt hydroxide nanosheets (Ir-Co(OH)_<i>x</i>) via oxygen-coordinated bonds to modulate the local electronic structure. Leveraging detailed spectroscopic characterizations, the Ir species were proved to promote charge transfer through Ir-O-Co coordination between the Ir atom and the Co(OH)_<i>x</i> support. As a result, the optimized Ir-Co(OH)_<i>x</i> exhibits excellent electrocatalytic OER activity with a low overpotential of 251 mV to drive 10 mA cm^-2, which is 63 mV lower than that of pristine Co(OH)_<i>x</i>. The experimental results and density functional theory calculations reveal that the isolated Ir atoms can regulate the local coordination environment and electronic configuration of Co(OH)_<i>x</i>, thus accelerating the catalytic OER kinetics. This work provides an atomistic strategy for the electronic modulation of metal active sites in the design of high-performance electrocatalysts.