Noble-Metal-Assisted Fast Interfacial Oxygen Migration with Topotactic Phase Transition in Perovskite Oxides

TL;DR

This study demonstrates that noble metal layers can significantly accelerate oxygen migration in perovskite oxides by weakening metal-oxygen bonds, enabling low-temperature phase transitions with potential applications in catalysis and energy devices.

Contribution

The paper introduces a novel method using noble metal interfaces to reduce oxygen migration barriers and induce topotactic phase transitions at room temperature in perovskite oxides.

Findings

Noble metals weaken M-O bonds, lowering oxygen migration energy barriers.

Topotactic phase transition temperature reduced from 200 K to room temperature.

Method applicable to multiple perovskite oxides like SrCoO3 and SrFeO3.

Abstract

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.