Modulating Spatial Distributions of Single Atoms on Supports for Enhanced Oxygen Evolution

Single-atom catalysts (SACs) hold great promise in oxygen evolution reactions due to their ultrahigh atomic utilization rates and uniform active sites. The performance of SACs is closely related to the spatial distributions of single atoms on the supports. However, modulating the spatial distributions of single atoms on the supports is extremely challenging. Herein, we precisely anchored Ir single atoms onto the face sites (Ir₁/F-CoOOH) and the edge sites (Ir₁/E-CoOOH) of CoOOH. Ir single atoms with distinct spatial distributions on CoOOH exhibited different electronic structures but nearly identical coordination environments. Nevertheless, Ir₁/E-CoOOH required an overpotential of only 220 mV to reach a current density of 10 mA cm^-2, which was 80 mV lower than that of Ir₁/F-CoOOH. Mechanistic studies demonstrated that Ir single atoms with distinct spatial distributions activated the supports through different mechanisms.