Quinary Defect-Rich Ultrathin Bimetal Hydroxide Nanosheets for Water Oxidation

The electronic structure of layered double hydroxides (LDHs) can be modulated by heteroatom doping and creating vacancies. The number of exposed active sites can be enriched by exfoliating the bulk structure into fewer layers. Herein, we successfully achieved multielement doping and exfoliation for Co₃Fe LDHs by one SF₆-plasma etching step at room temperature (named as Co₃Fe LDHs-SF₆). The obtained Co₃Fe LDHs-SF₆ ultrathin nanosheets display outstanding oxygen evolution reaction (OER) activity, which only needs 268 mV overpotential to reach 10 mA cm^-2. Tafel slope and charge transfer resistance are dramatically decreased indicating a faster reaction kinetic rate. The excellent OER activity can be attributed to an increased number of active sites and an optimized electronic structure modulated by the incorporation of electron-withdrawing F, electron-donating S, and abundant vacancies resulting in proper adsorption energy to oxygen species.