Pinning effect of lattice co enhances lattice oxygen regeneration in NiFe-LDH for oxygen evolution reaction

NiFe-based catalysts are widely recognized as the optimal binary-metal-based catalyst for the anodic oxygen evolution reaction (OER) in water electrolysis. However, simultaneously improving the OER activity and stability of NiFe-based catalysts remains a challenge because the rapid lattice oxygen consumption of the NiFe-based catalysts leads to irrepressible Ni and Fe leaching and structural collapse. Herein, we report that lattice Co acts as a doping source to induce a pinning effect, effectively promoting lattice oxygen regeneration in NiFe-layered double hydroxide (NiFe-LDH) and thereby simultaneously improving its activity and stability. The Co-doped NiFe-LDH (Co-NiFe-LDH) exhibits high OER performance with a low overpotential of 195 mV at 10 mA cm^-2 and maintains stable operation over 500 h at 50 mA cm^-2 in 1 M KOH. Experimental and theoretical studies show that introducing Co atoms into the NiFe-LDH catalyst reduces NiO covalency due to enhanced electron localization between Ni 3d and O 2p orbitals. This electronic modulation simultaneously decreases the adsorption energy of OH/O species and the conversion energy from *OH to *O, thereby enhancing the lattice oxygen regeneration, which dynamically improves the OO coupling processes and maintains the structural stability of NiFe-LDH.