  Transition-metal perovskite oxides constitute a series of functional material
systems for electronics, catalysis and energy-conversion processes, in which
oxygen migration and evolution play a key role. However, the stable
metal-oxygen (M-O) bond forms large energy barrier inhibiting ion diffusion.
Therefore, seeking efficient and facile approaches to accelerate oxygen
kinetics has become a significant issue. Here, the interaction (interfacial
charge transfer and cooperative bonding) between noble metal (Pt, Ag) and
perovskites oxide (SrCoO3-delta) is employed to weaken (M-O) bond and decrease
the energy barrier of oxygen migration. Noble metal layers serving as oxygen
pumps can continuously extract oxygen from oxide films to atmosphere. The
temperature of topotactic phase transition from perovskite (SrCoO3) to
brownmillerite (SrCoO2.5) is remarkably lowered from 200 K to room temperature.
Furthermore, this approach can also be applied to SrFeO3 for similar topotactic
phase reduction by moderate thermal activation. Our finding paves a promising
and general pathway to achieve fast oxygen migration in perovskite oxides, with
important application prospect in low-temperature electrodes and high-activity
catalysis interface.
