Postsynthesis Construction of Distorted Fe Sites in NiAl Layered Double Hydroxides for the Oxygen Evolution Reaction

Regulating the local coordination environment of active sites is an effective strategy to enhance the intrinsic activity of layered double hydroxides (LDHs) for the oxygen evolution reaction (OER). Here we report a controlled postsynthesis Fe incorporation approach that uses NiAl-LDH as a structurally robust host to construct NiAl(a)-Fe(e)-LDH with distorted local Fe coordination environments through alkali treatment and ultrasonic assistance. The resulting catalyst exhibits superior OER performance compared to counterparts with similar Fe content, highlighting the critical role of Fe coordination. Solid-state NMR and X-ray absorption fine structure reveal that ultrasonic-assisted Fe incorporation induces Fe–O lattice distortion and modifies the local electronic states of Fe. Density functional theory calculations show that these distorted environments upshift the d-band center and lower the *OOH formation energy barrier, thereby accelerating OER kinetics. This work establishes a direct correlation between local Fe coordination, electronic structure, and catalytic activity and provides a general strategy for active-site engineering in LDH-based OER electrocatalysts.