The oxygen electrode bifunctionality studies: La2FeNiO6 double perovskite nanoparticles

Double perovskites oxides (DPOs)-based bi-functional catalysts (oxygen reduction reaction, ORR, and oxygen evolution reaction, OER) have gained great importance due to their low oxygen electrode overpotential (η) performance. We demonstrate a nickel-based DPO material, La2FeNiO6 (LFNO), prepared via the sol-gel polymer method and a controlled synthesis approach, and the resultant product displays a reduced nanoparticle size of ~41.5 ± 5 nm and a surface area of 27.52 m2 g−1. The LFNO sample with a well-controlled textural property influences the electrochemical characteristics in all aspects, like OER/ ORR onset and Tafel slope values under 0.1 M KOH. Moreover, the LFNO exhibits exceptional bifunctionality characteristics: an ORR η value of 518 mV at −3 mA cm−2 and an OER η value of 311 mV at 10 mA cm−2; thus, the LFNO DPOs delivered a bifunctionality index value of ~0.82 V. In addition, a long-term stability test of the best LFNO catalyst achieved high retention values of 91.4% (ORR) and 72.2% (OER) after 10 h continuous working operation.