Enhancing Bi-functional electrocatalytic activity of perovskite by temperature shock: A case study of LaNiO_3-δ

Perovskite oxide offers an attractive alternative to precious metal electrocatalysts given its low cost and high oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity. The results obtained in this work suggest a correlation of crystal structure with ORR and OER activity for LaNiO_3-δ. LaNiO_3-δ perovskites with different crystal structure were obtained by heating at different temperatures, e.g., 400, 600, and 800 C followed by quenching into room temperature. Cubic structure (relative to rhombohedral) leads to higher ORR and OER activity as well as enhanced bi-functional electrocatalytic activity, e.g., lower difference in potential between the ORR at -3 mA cm^-2 and OER at 5 mA cm ^-2 (ΔE). Therefore, this work shows the possibility to adjust bi-functional activity through a simple process. This correlation may also extend to other perovskite oxide systems.