Fe doping regulates the surface reconstruction and activates lattice oxygen of NiCr LDH for water oxidation

Deep profiling of the structural evolution during dynamic surface reconstruction of lattice oxygen mechanism (LOM)-based metal double hydroxide catalysts is challenging. Herein, we propose that the doping of Fe in nickel chromium layered double hydroxide (Fex-NiCr LDH) can optimize the surface reconstruction behavior in the oxygen evolution reaction (OER) by modulating Cr leaching. Operando Raman results indicate that the Fe0.5-NiCr LDH is dynamically reconstructed into metal oxyhydroxide as the active center, and Fe doping reduces the oxidation potential of Ni2+. Density functional theory (DFT) results reveal that Fe doping shifts the O 2p band upward and increases the covalency of the metal–oxygen bond, thereby promoting lattice oxygen oxidation. The optimal Act100-Fe0.5-NiCr LDH exhibits a low overpotential of 208.4 mV at 100 mA cm−2. Moreover, Act100-Fe0.5-NiCr LDH displays low voltage and high stability (1.47 V and 100 h at 10 mA cm−2) for overall water splitting. This work offers an important basis for understanding the reconstruction mechanism of LOM-based catalysts and provides new insights for identifying the activity origins.