Unveiling the active sites of ultrathin Co-Fe layered double hydroxides for the oxygen evolution reaction

Two-dimensional layered double hydroxides (LDHs) have been identified as promising electrocatalysts for the oxygen evolution reaction (OER); however, simple and effective synthesis of high-quality LDHs remains extremely challenging active sites not clarified. Herein, we report a facile solution-reaction method preparing an ultrathin (thickness < 2 nm) nonprecious CoFe-based LDH. Co1Fe0.2 LDH delivers current density 10 mA cm−2 high turnover frequency 0.082 s−1 per total 3d metal atoms at low overpotential 256 mV. Its mass activity is 277.9 A g−1 300 mV OER. Kinetic studies reveal Co site main center The doped Fe lowers barrier by accelerating charge-transfer process. Theoretical calculations that surface adjacent to are centers OER subsurface dopants excessively weaken OH* adsorption, thus increasing energy rate-determining step. This study can guide rational design high-performance water splitting.