Electrochemical activation construction of LaCo1-x-yNixFeyO3 promoted by optimized lattice Ni doping toward water oxidation.

Iron sites with high intrinsic activity for oxygen evolution reaction (OER) can effectively enhanced the performance of perovskite oxide as electrocatalyst for water electrolysis. However, doping of iron in perovskite LaCoO 3 remains a challenge owing the strong Co–O bond and robust structure of LaCoO 3. Herein, the lattice doping of Ni in LaCoO 3 has been adopted to promote the interaction between iron ions and Co site in LaCoO 3. Firstly, molten salt of Ni(NO 3) 2 provides free-moving Ni ions to substitute Co sites in the lattice of LaCoO 3 forming LaCo 1-x Ni x O 3 at the optimized Ni doping condition. Then, iron ions can easily be absorbed to LaCo 1-x Ni x O 3 due to the strong interaction between Ni and Fe by electrochemical activation at room temperature. The prepared LaCo 1-x-y Ni x Fe y O 3 nanoparticles keep the coarse surface for maximizing the exposure of active sites. The high-valence Co and oxygen vacancy from LaCo 1-x-y Ni x Fe y O 3 contribute to the better intrinsic activity for OER, demonstrating the overpotential of ƞ 10 of approximately 315 mV and good stability. The strategy of by introducing the lattice doping of other metal ion can realize the facile and effective construction of iron doped perovskite oxide for water oxidation. [Display omitted] • Molten salt of Ni(NO 3) 2 provides Ni ions to substitute Co sites in the lattice of LaCoO 3. • Iron ions are absorbed to LaCo 1-x Ni x O 3 with the strong interaction Ni–Fe by electrochemical activation. • Ni/Fe doping can expose more active site sites and adjust the electronic structure of Co sites. • LaCo 1-x-y Ni x Fe y O 3 exhibits the motivated OER activity and stability. [ABSTRACT FROM AUTHOR]