Bi0.15Sr0.85Co0.8Fe0.2O3- perovskite: A novel bifunctional oxygen electrocatalyst with superior durability in alkaline media

Abstract

• A novel perovskite oxygen electrocatalyst, Bi 0.15 Sr 0.85 Co 0.8 Fe 0.2 O 3-δ (BiSCF), was prepared by the conventional solid-state reaction method. • BiSCF shows excellent electrocatalytic activities towards both OER and ORR in 0.1 M KOH, as well as superior durability, and the best bifunctional property among the reported perovskites. • With high activities, excellent stability, and easy fabrication, BiSCF is expected to be a promising bifunctional oxygen electrocatalyst for large-scale production. Perovskite-type oxides are considered as promising alternatives to the scarce and expensive precious metal-based electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Here, we report a Bi 0.15 Sr 0.85 Co 0.8 Fe 0.2 O 3- δ (BiSCF) perovskite prepared by the conventional solid-state reaction method as a novel bifunctional oxygen electrocatalyst in alkaline media. BiSCF shows excellent electrocatalytic activities towards both OER and ORR with a low OER overpotential ( η OER @ 10 mA c m − 2 = 354 mV), good chemical reaction kinetics (Tafel slope = 94.21 mV dec −1 and 72.8 mV dec −1 for OER and ORR, respectively), and excellent durability (i.e., η OER @ 10 mA c m − 2 increases from 354 mV to 404 mV within 24 h; better durability than the commercial 30 wt.% Pt/C at 0.4 V vs RHE regarding ORR). It also presents the best bifunctional property among the reported perovskites. The excellent electrocatalytic properties of BiSCF can be attributed to its abundant oxygen vacancies and rich oxidation states of Co and Fe. With high activities, excellent stability and easy fabrication, BiSCF is expected to be a promising bifunctional oxygen electrocatalyst for renewable energy conversion and storage devices.