Nanoparticles of LaCoO3 Doped with Ce, Sr, Ca, Ba on A-Site as Catalysts for the Alkaline Oxygen Evolution Reaction

Cobalt-based perovskite oxide catalysts are considered to be a promising catalyst for oxygen evolution reaction (OER) due to their structural tunability and low cost. However, the high free energy of adsorption of reactive intermediates and low conductivity limit further improvement of their OER performance. Here, we show that LaCoO₃ nanoparticles doped with different A-site elements (Ce, Sr, Ca, Ba) all have significantly enhanced catalytic activity. In particular, in 1 M KOH, the 0.1Ce–LaCoO₃ catalyst exhibited superior OER activity to the other catalysts. At a current density of 10 mA cm^–2, the overpotential of the material is as low as 343 mV with a good stability. The comprehensive experimental results show that the introduction of A-site elements into LaCoO₃ can change the geometrical configuration of the CoO₆ octahedron and modulate the electronic states around Co, which, in turn, affects the adsorption of the reaction intermediates on the catalyst surface during the OER process and accelerates the OER reaction process. In this article, we provide a promising strategy for the design and preparation of efficient and low-cost catalysts for the oxygen precipitation reaction by systematically investigating the effects of different A-site element substitutions on the performance of LaCoO₃ OER.