Unraveling the Synergistic Role of Sm3+ Doped NiFe-LDH as High-Performance Electrocatalysts for Improved Anion Exchange Membrane and Water Splitting Applications

Abstract

Effective first-row transition metal-based electrocatalysts are crucial for large-scale hydrogen energy generation and anion exchange membrane (AEM) devices in water splitting. The present work describes that SmNi_0.02Fe-LDH nanosheets on nickel foam are used as a bifunctional electrocatalyst for water splitting and AEM water electrolyzer study. Tuning the Ni-to-Fe ratios in NiFe-LDH and doping with Sm ions improves the electrical structure and intrinsic activity. SmNi_0.02Fe-LDH has higher oxygen evolution reaction (OER), HER, and TWS activity, achieving 10 mA cm⁻² current density at lower overpotentials (230 mV, 95 mV, and 1.62 V, respectively). In AEMWE cells, SmNi_0.02Fe-LDH as a cathode and anode pair exhibits outstanding activity (0.9 A cm⁻² at 2 V) and stability over 120 h. Density Functional Theory (DFT) investigations reveal that the Sm doping in NiFe-LDH surface enhances its bifunctional activity toward OER and HER. These findings emphasize the potential of non-noble composites for long-term water electrolysis in total water splitting and AEMWE applications.