POM-Intercalated NiFe-LDH as Enhanced OER Catalyst for Highly Efficient and Durable Water Electrolysis at Ampere-Scale Current Densities

Efficient and cost-effective electrocatalysts are essential for large-scale hydrogen production via electrochemical water splitting, particularly at industrial-scale current densities. In this study, a heterogeneous electrocatalyst, comprising Keggin-type polyoxometalate (POM), H₃PW₁₂O₄₀ (PTA), intercalated into nickel–iron layered double hydroxides (NiFe-LDH-PTA) was synthesized in situ using a one-step hydrothermal method. The intercalation of PTA into the NiFe-LDH layers triggers electronic interactions between the LDH host and PTA guest, modulating the electronic structure of the Ni and Fe active sites and mitigating the dissolution of active species, as confirmed by physicochemical characterizations and theoretical calculations. Leveraging these host–guest interactions, NiFe-LDH-PTA demonstrates exceptional catalytic activity for the oxygen evolution reaction (OER), even under industrial-scale conditions. Notably, the catalyst requires an overpotential of only 342 ± 9 mV to achieve a current density of 1000 mA cm^–2 and maintains stable operation at this current density for 500 h. Furthermore, the assembled anion-exchange membrane (AEM) electrolyzer achieves an industrial-scale current density of 1000 mA cm^–2 at a low cell voltage of 1.93 V at 60 °C. This work provides valuable insights into the rational design of high-performance LDH-based OER electrocatalysts tailored for industrial applications.