In recent years,reversible fuel cells (RFCs) have attracted much attention due to their high efficiency and environmental friendliness. However,the further development of RFCs is severely hindered by bifunctional oxygen catalysts. As a promising bifunctional oxygen catalyst,cobalt-based perovskites become a research hotspot in this field. However,its oxygen catalytic activity and stability still need to be further improved. In this paper,a series of Sr 1- x Sm x CoO 3 (SSC,x =0-0.6) oxygen catalysts were prepared by a modified sol-gel method and their oxygen catalytic activity and stability were studied. The results showed that samarium ion doping could effectively improve the bifunctional oxygen catalytic activities of SrCoO 3 perovskite. Among them,Sr 0.7 Sm 0.3 CoO 3 (SSC-30) had the highest oxygen reduction reaction (ORR) catalytic activity,and its onset potential and half-wave potential could reach 0.798 V and 0.638 V(vs RHE). Sr 0.8 Sm 0.2 CoO 3 (SSC-20) had the highest oxygen evolution reaction (OER) catalytic activity and its potential and corresponding overpotential η could respectively reach 1.692 V and 462 mV at a current density of 10 mA/cm ^2. Based on the results of ORR and OER catalytic activities,SSC-30 had the best bifunctional oxygen catalytic activity and the potential difference Δ E between OER and ORR was only 1.071 V. In addition,Sm-doping could further improve the oxygen catalytic stability of SrCoO 3,and its catalytic stability toward ORR and OER of SSC-30 was much higher than that of SrCoO 3. The results of this paper can give guidance for the development and application of bifunctional cobalt-based perovskites.
Journal of Functional Materials
reversible fuel cells
oxygen reduction/evolution catalyst