Synergistic yttrium doping accelerates surface reconstruction and optimizes d-band centers in NiFe-LDH for superior oxygen evolution catalysis

Abstract

NiFe layered double hydroxide (NiFe-LDH) is a promising electrocatalyst for the oxygen evolution reaction (OER). However, its performance still requires improvement to meet practical demands. Doping modification represents an effective strategy to modulate the electronic structure and enhance the electrocatalytic OER activity of NiFe-LDH. Yttrium-doped NiFe-LDH was synthesized via a one step hydrothermal method. X-ray photoelectronic spectroscopy (XPS) and density functional theory calculations (DFT) were employed to investigate the influence of yttrium doping on electronic modulation. The results indicate that yttrium incorporation regulates the electron distribution of the active center as well as optimizes the d-band center of Ni active sites and the adsorption energy of the oxygen intermediate species, consequently enhancing the OER activity of NiFe-LDH. Operando electrochemical Raman spectroscopy was used to monitor the dynamic evolution of its structure/composition. In comparison with NiFe-LDH, NiFeY-LDH exhibits more intensive self-reconstruction and requires a lower potential to form highly active NiFeO_xH_y sites, thereby significantly facilitating the OER behavior. The presence of yttrium reduces the Ni oxidation potential and enhances the adsorption capacity for OH⁻ to accelerate surface reconstruction. NiFeY-LDH delivered superior OER performance with overpotentials of 192 mV and 234 mV at 10 and 100 mA cm⁻², respectively. Moreover, NiFeY-LDH shows outstanding catalytic stability for 125 hours at 100 mA cm⁻². This study investigated the cause of accelerated surface reconstruction and d-band center optimization effects induced by rare earth element doping, providing valuable insights for the design of efficient OER electrocatalysts.