Synergistic Effect of Defect Engineering and Crystalline/Amorphous Interfaces in NiFe Layered Double Hydroxides for Efficient Oxygen Evolution

Abstract

The development of efficient and durable oxygen evolution reaction (OER) catalysts is pivotal for sustainable hydrogen production via water electrolysis. Herein, a hybrid crystalline/amorphous NiFe-layered double hydroxides (c/a-NiFe-LDHs) catalyst with tailored defects is synthesized via rapid electrodeposition followed by plasma post-treatment. The c/a heterostructure was constructed via rapid electrodeposition, followed by introducing cationic and oxygen vacancies via Ar/H₂ plasma. Optimizing plasma power (300 W) and duration (1 min) yielded c/a-NiFe-LDHs-P@300:1 with abundant defects and preserved structural integrity. The optimal catalyst exhibited exceptional OER activity, requiring an overpotential of only 290 mV to achieve 100 mA cm^-², along with a low Tafel slope of 32.3 mV dec^-¹ and robust stability over 48 h. Density functional theory calculations revealed that plasma-induced vacancies reduced the energy barrier of the rate-determining step (*O → *OOH) by optimizing intermediate adsorption and electronic structure. This work highlights the synergistic effect of crystalline/amorphous interfaces and defect engineering in designing high-performance OER catalysts for efficient water oxidation.