Synthesis and enhanced electrocatalytic mechanism of mesoporous La0.8Sr0.2MnO3 nanowires as high-active electrocatalysts for Zn-air batteries

Abstract The one-dimensional mesoporous La0.8Sr0.2MnO3 catalysts with excellent electronic conduction were successfully prepared by molten salt template method to accelerate the kinetics of ORR for metal-air batteries. The as-synthesized mesoporous La0.8Sr0.2MnO3 nanowires with relatively high oxygen vacancy concentration and ratio of Mn4+/Mn3+ show high specific surface area of 31.03 m2 g-1, higher than the most of reported perovskite oxides. More importantly, more catalytic active sites can be exposed at the three-phase interface of ORR due to high specific surface area. The mesoporous La0.8Sr0.2MnO3 nanowires exhibit high half-wave potential and catalyze near 4 e- ORR process. Besides, the one-dimensional mesoporous La0.8Sr0.2MnO3-based Zn-air batteries show high peak power density of 113.86 mW cm-2. Simultaneously, density functional theory (DFT) calculation reveals that strengthened electrocatalytic mechanism of La1-xSrxMnO3 catalysts originates from lower formation energy of oxygen vacancy and more positive O 2p band center because of Sr dopants, which is consistent with the experimental results. Consequently, this investigation not only provide a new idea for developing mesoporous perovskite oxides nanowires but also reveals enhanced electrocatalytic mechanism of La1-xSrxMnO3 catalysts.