Anion-Environment-Controlled Synthesis of Ce-Doped NiFe LDH for Enhanced Activity and Stability in High-Current-Density Alkaline Oxygen Evolution
Paul Byaruhanga, Yu Wang, Richard Tran, Kai Shen Choong, Zhong Hong, Vidhi Joshi, Shaowei Song, Dezhi Wang, Mingchu Zou, Viktor G. Hadjiev, Hua Guo, Jiming Bao, Lars C. Grabow, Zhenxing Feng, Zhifeng Ren, Shuo Chen
Abstract
Hydrogen production in aqueous alkaline media is constrained by both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Here, we report an anion-environment-regulated synthesis strategy that enables uniform Ce incorporation into NiFe layered double hydroxides (LDHs) by replacing NH 4 F with NH 4 Cl during hydrothermal growth. The chloride precursor provides a milder coordination environment, enabling homogeneous Ce doping and improved charge transfer. The optimized NiFe 0.95 Ce 0.05 LDH requires only a 307 mV overpotential to reach 1000 mA cm –2 in 1 M KOH. Raman spectroscopy, X-ray absorption spectroscopy, and density functional theory analyses indicate that Ce doping accelerates Ni oxidation and stabilizes β-NiOOH active species. When paired with a Ni&Ni 0.2 Mo 0.8 N cathode, the resulting anion exchange membrane electrolyzer (AEMWE) delivers 1 A cm –2 at 1.616 V and 8 A cm –2 at 2.185 V in 1 M KOH at 80 °C without iR compensation for high-current-density alkaline water electrolysis.