Strontium-doped lanthanum iron nickelate oxide as highly efficient electrocatalysts for oxygen evolution reaction

Pursuing efficient and low-cost catalysts for the sluggish oxygen evolution reaction (OER) is imperative for the large-scale deployment of promising electrochemical technologies such as water splitting and CO₂ electrochemical reduction. The earth-abundant perovskite catalysts based on LaNiO_3-δ show promise in OER catalysis because of their relatively low cost and their optimal electronic structure but suffer from low electrode-area normalized activity. In this work, we partially substituted La with Sr and Ni with Fe to enable a remarkably high OER activity with an ultra-low overpotential of 374 ± 3 mV vs RHE at a current density of 10 mA cm^-2 normalized by electrode geometric area. This performance even surpasses the performance of benchmark RuO₂. Our results show that Sr could promote OER-active sites including Ni(III), O^2-₂/O^-, and optimal Ni/Fe ratios, which significantly improve the surface intrinsic activity at the perovskite surface. Therefore, this work not only developed a highly efficient earth-abundant catalyst towards OER, but also demonstrated the effective modulation of catalyst surface interactions through A-site doping for perovskite oxides for key applications such as water splitting, CO₂ electrochemical reduction and N₂ electrochemical fixations.