Synergistic Geometric and Electronic Modulation in Ni–Ce Layered Double Hydroxides for Enhanced Oxygen Evolution Reaction

Abstract

Efficient and durable oxygen evolution catalysts are critical for the advancement of practical water electrolysis. This study demonstrates that controlled doping of cerium (Ce) in nickel-based layered double hydroxides (Ni1-xCex–LDHs) significantly enhances the activity of the oxygen evolution reaction (OER) through a synergistic effect involving both structural and electronic modifications. The optimized Ni0.75Ce0.25–LDH exhibits a distinct hexagonal nanosheet architecture, increased interlayer spacing, and a favorable ratio of Ni³⁺ to Ni²⁺ ions. These structural attributes promote the rapid formation of active nickel oxyhydroxide (NiOOH) and oxygen species at reduced potentials, as confirmed via in situ Raman spectroscopy. Electrochemical evaluations reveal that Ni0.75Ce0.25–LDH achieves an overpotential of 220 mV at a current density of 20 mA cm⁻², outperforming both unmodified Ni(OH)₂ and cerium oxide (CeO₂) controls. Furthermore, the catalyst exhibits stable performance for over 265 hours at a current density of 100 mA cm⁻². The findings suggest that the combination of geometric lattice expansion and electronic tuning through Ce doping represents a highly effective strategy for the development of next-generation OER catalysts