Ce- and La-doped polymetallic layered double hydroxides for enhanced oxygen evolution reaction performance at high current density

Polymetallic layered double hydroxides are promising cost-effective catalysts for the oxygen evolution reaction (OER) due to their versatile anionic and cationic tunability. Nevertheless, several challenges persist, notably, issues related to low electrical conductivity, poor catalytic activity, and stability, especially at high current density. Herein, we report the design of Ce- and La-doped CoNiFe-layered double hydroxide (CeLaCoNiFe-LDH) nanosheets through a facile and scalable in situ self-assembly strategy that displays enhanced OER activity. Experimental and theoretical investigations provide insights into the impact of Ce-and La-doping by comparing CeCoNiFe-LDH, LaCoNiFe-LDH, and pristine CoNiFe-LDH, all synthesized using the same methodology. These results reveal that doping Ce³⁺ and La³⁺ into CoNiFe-LDH substantially improves its electronic structure, resulting in enhanced conductivity, more oxygen vacancies (Vo), electron interaction, and active site formation. Consequently, significantly reduced overpotentials of 175, 314, and 424 mV at 10, 100, and 500 mA cm⁻², respectively, and a highly stable current density of 120 h in 1 M KOH were achieved. Notably, these performance metrics surpass those of unmodified LDHs and are competitive with many lanthanide-doped transition metal-based LDH electrocatalysts, as well as noble metal catalysts like ruthenium catalysts. This work represents a pioneering effort in doping Ce³⁺ and La³⁺ ions into a functional CoNiFe-based electrocatalyst, offering inspiring OER performance and scalability potential.