Coral-Like LaNi x Fe 1−x O 3 Perovskite Catalyst for High-Performance Oxygen Evolution Reaction

With the rare earth element La was selected as the A site and transition metal ions (Ni, Fe) as the B site of perovskite-type oxides with general formula ABO 3 , a series of LaNi x Fe 1−x O 3 (x = 0, 0.3, 0.5, 0.7, 0.8, 1.0) perovskite catalysts were prepared by sol-gel method to investigate their catalytic performance for oxygen evolution reaction (OER). The catalyst activity was screened by linear scanning cyclic voltammetry (LSV), Tafel curves, and electrochemical impedance spectroscopy (EIS). A group of electrochemical tests for LaNi x Fe 1−x O 3 with various Ni/Fe ratios indicate that LaNi 0.8 Fe 0.2 O 3 catalyst exhibits excellent electrochemical activity, with a resistance to charge-transfer reaction ( R ct ) of 5.942 Ω cm −2 , overpotential of 391 mV, a Tafel slope of 102.8 mV dec −1 , and electrochemical double-layer capacitance ( C dl ) of 12.31 mF cm −1 . The stability test after 15000 s proves that the optimized LaNi 0.8 Fe 0.2 O 3 has better stability compared to pristine LaFeO 3 and LaNiO 3 . In addition, LaNi 0.8 Fe 0.2 O 3 also exhibits the largest electrochemical active area (ECSA = 307.75 cm 2 ) and exchange current density ( j o = 1.08 mA cm −2 ). This work provides reference for perovskite in improving oxygen evolution performance.