Ligand and Strain Synergistic Effect in NiFeP_0.32 LDH for Triggering Efficient Oxygen Evolution Reaction

Developing efficient water-splitting electrocatalysts to accelerate the slow oxygen evolution reaction (OER) kinetics is urgently desired for hydrogen production. Herein, ultralow phosphorus (P)-doped NiFe LDH (NiFeP_x LDH) with mild compressive strain is synthesized as an efficient OER electrocatalyst. Remarkably, NiFeP_x LDH with the phosphorus mass ratio of 0.32 wt.% and compressive strain ratio of 2.53% (denoted as NiFeP_0.32 LDH) exhibits extraordinary OER activity with an overpotential as low as 210 mV, which is superior to that of commercial IrO₂ and other reported P-based OER electrocatalysts. Both experimental performance and density function theory (DFT) calculation demonstrate that the doping of P atoms can generate covalent Fe─P coordination bonds and lattice distortion, thus resulting in the consequent depletion of electrons around the Fe active center and the downward shift of the d-band center, which can lead to a weaker adsorption ability of ^*O intermediate to improve the catalytic performance of NiFeP_0.32 LDH for OER. This work provides novel insights into the distinctive coordinated configuration of P in NiFeP_x LDH, which can result in superior catalytic performance for OER.