Effect of Small Nb‐doping Amount on the Performance of BaCoO 3‐δ ‐based Perovskite as Bifunctional Oxygen Catalysts

Abstract Perovskite oxides are of great interest as cost‐effective replacements for noble metals and oxides employed in bifunctional electrocatalysts including the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this work, a series of Bi/Nb co‐doped BaCoO 3‐δ ‐based perovskite oxides BaBi 0.05 Co 0.95‐x Nb x O 3‐δ (BBC 0.95‐x N x , x=0.1, 0.15, 0.2) were synthesized and evaluated as oxygen electrocatalysts for ORR and OER. It is interesting to note that Nb‐doping amount is related to the contents of surface oxygen vacancies and oxidation states of cobalt, subsequently inducing performance differences among BBC 0.95‐x N x . Results show that BBC 0.95‐x N x have bifunctional electrocatalytic activities toward both ORR and OER in alkaline media. Compared with the BBC 0.85 N 0.1 and BBC 0.8 N 0.15 , BBC 0.75 N 0.2 with the highest Nb‐doping rate delivered a lowest total overpotential between the ORR and the OER. Moreover, the BBC 0.95‐x N x catalysts deliver outstanding durability and methanol tolerance for ORR, better than Pt/C. BBC 0.95‐x N x holding promising application as nonprecious bifunctional catalysts.