Samarium-Doped La₂NiO₄ Perovskite as a High-Performance Electrocatalyst for Oxygen Evolution Reaction in Alkaline Media

The design and development of highly efficient and affordable oxygen evolution reaction (OER) electrocatalysts are crucial for linking water splitting to clean, renewable energy storage. In this study, nanostructured samarium-doped lanthanum nickelate (La₂NiO₄) perovskite oxides were synthesized via the citric acid-based combustion method and evaluated for their OER performance in alkaline media. Among the prepared samples, La₁.₈Sm₀.₂NiO₄ (LS0.2NO) exhibited distinct structural features and intrinsic catalytic properties that led to remarkable OER activity. More importantly, LS0.2NO demonstrated exceptional stability and achieved a current density of 10 mA·cm⁻² at a low overpotential of 350 mV in alkaline water electrolysis. The optimized catalyst showed a high electrochemical surface area (86.2 cm²), a Tafel slope of 75 mV/dec, and a turnover frequency (TOF) of 0.05 s⁻¹ at 10 mA·cm⁻². This performance highlights the potential of Sm-doped La₂NiO₄ as a cost-effective alternative to noble metal-based OER electrocatalysts.