Promoting the bifunctional oxygen catalytic activity of the perovskite and Co3O4 heterostructure by introducing oxygen vacancies

Abstract

The Co-based perovskite of SrNb 0.1 Co 0.7 Fe 0.2 O 3-δ (SNCF) stands out for its high intrinsic catalytic activity toward the oxygen evolution reaction (OER) in the alkaline solution. However, the low catalytic activity of SNCF toward the oxygen reduction reaction (ORR) restricts its application in the zinc-air batteries (ZABs). To address this issue, we develop the oxygen vacancy enriched heterostructure (SNCF–NF–Co 3 O 4 @N 2 ) including the SNCF nanofibers with the diameter of 80 nm and Co 3 O 4 nanoparticles anchored on the SNCF surface by electrospinning and sintering in N 2 . Due to the high charge/reactant transfer rate, Co 3+ /Co 2+ ratio and oxygen vacancy concentration, SNCF-NF-Co 3 O 4 @N 2 demonstrates the superior bifunctional oxygen catalytic activity. Specially, the ORR half-wave potential can reach 0.69 V, and the OER potential at 10 mA cm −2 is as low as 1.57 V. Remarkably, the aqueous and solid-state ZABs with SNCF-NF-Co 3 O 4 @N 2 exhibit the high peak power densities of 181.2 and 73.3 mW cm −2 , respectively. Furthermore, SNCF-NF-Co 3 O 4 @N 2 based ZAB demonstrates an impressive energy efficiency of 79.6%. This study introduces an innovative strategy for enhancing the bifunctional oxygen catalytic performances of Co-based perovskites.