Modulating Interfacial Electronic Reconfiguration in Hollow Co 2 P@NiFe LDH Heterostructures for Accelerated Water Splitting Kinetics

ABSTRACT Developing bifunctional electrocatalysts that combine high activity with durable operation is crucial for advancing alkaline water electrolysis toward practical hydrogen production. However, simultaneously promoting hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at high current densities remains challenging due to limited interfacial charge transfer and mass transport. Herein, we demonstrate that integrating a hollow conductive phosphide scaffold with a catalytically active nickel–iron (NiFe)‐layered double hydroxide (LDH) layer effectively regulates electron redistribution and reaction transport in bifunctional electrocatalysts. Accordingly, a hollow Co 2 P@NiFe LDH heterostructure was constructed on Ni foam (NF) via phytic‐acid‐assisted phosphidization followed by electrochemical deposition. The zeolitic imidazolate framework (ZIF)‐derived triangular hollow Co 2 P framework provides conductive pathways and an open architecture that facilitates electrolyte penetration and mass transport while forming a strongly coupled heterointerface with NiFe LDH. X‐ray photoelectron and absorption spectroscopy revealed partial Co–O(H) coordination and interfacial charge redistribution without loss of phosphide character, indicating effective electronic‐structure modulation. As a result, the H‐Co 2 P@NiFe LDH/NF electrode required overpotentials of only 165 mV for HER and 300 mV for OER to achieve 100 mA cm −2 in 1.0 M KOH. The assembled symmetric electrolyzer required only 1.79 V to deliver 100 mA cm −2 and maintained durable performance for over 50 h, demonstrating the effectiveness of hollow phosphide/LDH heterointerface engineering for efficient water splitting.