Constructing Electron- and Surface-Structure-Controlled Crystalline/Amorphous Hierarchical NiTe/NiFeCe-LDH Nanoarrays for Efficient Overall Water Splitting

Constructing nonprecious metal-based telluride heterointerfaces provides an effective strategy for developing efficient bifunctional catalysts for overall water splitting. However, there still remain major challenges for catalysts that rely on constructing heterojunction interfaces to obtain high-active sites with optimized electronic structures to achieve an efficient oxygen evolution reaction (OER). Herein, hierarchical NiTe/NiFeCe-LDH core-shell heterojunction nanoarrays with crystalline/amorphous interfaces were synthesized based on the Ce doping and interface engineering strategy. Benefiting from the high conductivity of crystalline NiTe nanorods and abundant active sites in amorphous NiFeCe-LDHs, the NiTe/NiFeCe-LDH heterojunction nanoarrays exhibited an excellent OER performance and long-term stability of more than 120 h in an alkaline medium, achieving a low overpotential of ∼247 mV at 100 mA·cm^-2, which was ∼44% lower than commercial RuO₂ (∼443 mV). Moreover, the NiTe/NiFeCe-LDHs achieved a current density of 10 mA·cm^-2 at a low voltage of 1.45 V in overall water splitting. Density functional theory calculations revealed that Ce doping and the strong electronic interaction at the crystalline/amorphous interface of the NiTe/NiFeCe-LDHs could modulate its electronic structure by upward-shifting the d-band center of the Ni sites. This modulation optimized the binding energies of oxygen intermediates and consequently enhanced the OER performance of the NiTe/NiFeCe-LDHs. This research presents a novel approach for designing efficient overall water-splitting electrocatalysts through the synergistic doping-interface strategy.