Modulation of Co d-band center by La and Zn co-doping for high efficiency oxygen evolution reaction in alkaline...

Hydrogen production through seawater electrolysis is a crucial approach to address energy and global warming issues, yet its efficiency is limited by the sluggish anodic kinetics. In this study, a series of metal-doped LaM-Co₃O₄ (M = Ni, Mn, Zn) materials were in-situ synthesized on nickel foam via a hydrothermal-calcination method for the first time. Among these materials, the LaZn-Co₃O₄ electrocatalyst exhibited excellent oxygen evolution reaction (OER) activity to achieve a current density of 10 mA cm^-2, which only required overpotentials of 267 mV and 273 mV in 1.0 M KOH solution and alkaline seawater, respectively. Particularly, the introduction of rare earth element La significantly improved the resistance to chloride ion corrosion of catalyst in seawater environments. In-situ Raman spectroscopy confirmed that after La and Zn doping, the catalyst surface underwent significant reconstruction, leading to the formation of cobalt hydroxide (CoOOH), which is a true active species in the OER process. Density functional theory (DFT) calculations further demonstrated that the co-doping of La and Zn could modulate the d-band center of Co atoms, bringing it closer to the Fermi level. This study provides valuable insights for the design of efficient and stable OER catalysts under alkaline conditions.