Exsolution manipulated local surface cobalt/iron alloying and dealloying conversion in La0.95Fe0.8Co0.2O3 perovskite for oxygen evolution reaction

作者：Ma, Jiaojiao; Geng, Zhibin; Jiang, Yilan; Hou, Xiangyan; Ge, Xin; Wang, Zizhun; Huang, Keke^*; Zhang, Wei^*; Feng, Shouhua

来源：Journal of Alloys and Compounds, 2021, 854: 157154.

DOI：10.1016/j.jallcom.2020.157154

• Exsolution
• Single metal
• Exsolution temperature
• Cation exchange
• OER catalyst

The preparation of metal/perovskite oxide composite by exsolution is an effective way to synthesize highly efficient electrocatalysts. For transition metal doped Fe-based perovskite oxides, the exsolved metal nanoparticles are usually Fe-based alloys. Herein, we in-situ exsolved single Co metal from A-site defective La0.95Fe0.8Co0.2O3 (LFCO) via a thermal reduction method above 600 degrees C. At lower temperature (500 degrees C), the species exsolved from LFCO is CoFe alloy, while the temperature rises above 600 degrees C, the composition of metal nanoparticles changes to single Co metal by cation exchange between Fe in metal nanoparticles and Co in perovskite oxide, forming Co/LFCO composite. This phenomenon could be owing to the higher co-segregation energy of Co than Fe cations, and LaFeO3 is thermodynamically more stable at high temperatures. As a result, Co/LFCO shows largely improved conductivity than CoFe/LFCO counterpart, and thereof enhanced activity for oxygen evolution reaction (OER). Our work has positive implication for designing a wide range of efficient electrocatalysts by in-situ tuning the composition of surface nanoparticles.

• 单位
  吉林大学