Surface reconstruction of La0.6Sr0.4Co0.8Ni0.2O3-δ perovskite nanofibers for oxygen evolution reaction

Abstract

Perovskites have become promising alternatives to precious metal-catalyzed oxygen evolution reaction (OER). Herein, we report the synthesis of several perovskite nanofibers, specifically La0.6Sr0.4CoxNi1-xO3-δ (LSCN), and investigate their electrocatalytic water oxidation activity in alkaline electrolytes. La0.6Sr0.4Co0.8Ni0.2O3-δ (LSCN-0.8) is selected and immersed in an aqueous NaBH4 solution for 1 h for surface reconstruction. The perovskite nanofibers' electrocatalytic OER activity and stability are rigorously evaluated using a standard three-electrode system. Results reveal that even a slight Co substitution for Ni content within the LSCN perovskite structure has a notable impact on electrocatalytic activity. Moreover, LSCN-0.8 exhibits an overpotential of 363 mV at 20 mA cm−2 in 1 M KOH. However, significant improvement is observed after the surface reconstruction process. The optimized LSCN-0.8 (now called LSCN-2) displays the lowest OER overpotential (320 mV) under the same conditions. Furthermore, the LSCN-2 nanostructure demonstrates exceptional electrode stability, as evidenced by only a slight decrease in electrocatalytic performance during 5000 cycles of linear sweep voltammetry.