Electronically Coupled Metastable Rh-Engineered NiCo-LDH Fibers for Efficient Alkaline and Seawater Electrolysis

Abstract

Accelerating charge transfer across heterogeneous interfaces is a key strategy for enhancing water-splitting electrocatalysis. In this study, we design a fibrous NiCo-LDH framework decorated with metastable Rh sites, which forms highly conductive junctions and provides numerous active centers. DFT studies indicate that Rh/NiCo-LDH greatly enhances the electronic density near the Fermi energy (Ef), while Bader charge analysis reveals substantial charge redistribution (ΔQ = –1.463e). Work function measurements further reveal the presence of a Mott–Schottky junction that facilitates electron flow from NiCo-LDH to Rh₂O₃, thereby ensuring efficient carrier flow. This interfacial restructuring also shifts the d-band center toward favorable values (–2.614 to –1.590 eV), thereby accelerating reaction kinetics. As a result, the catalyst achieves an ultra-low overpotential of 250 mV (OER) and 144 mV (HER) in alkaline media, and 307 mV (OER) and 167 mV (HER) in artificial seawater, demonstrating outstanding durability for up to 50 hours.