Electronic Activation during Nanoparticle Exsolution for Enhanced Activity at Elevated Temperature

作者：Chen, Huijun; Lim, Chaesung; Tan, Ting; Zhou, Mengzhen; Zhang, Lei; Sun, Xiang; He, Zuyun; Ye, Yongjian; Li, Xiaobao; Zhang, Hui; Han, Jeong Woo^*; Yang, Chenghao^*; Chen, Yan^*

来源：ACS Nano, 2023, 17(11): 10677-10688.

DOI：10.1021/acsnano.3c01841

• perovskite oxide
• exsolution
• electronic structure
• oxygen vacancy
• thin film

Nanoparticle (NP) exsolution from perovskite-based oxidesmatrixupon reduction has emerged as an ideal platform for designing highlyactive catalysts for energy and environmental applications. However,the mechanism of how the material characteristics impacts the activityis still ambiguous. In this work, taking Pr0.4Sr0.6Co0.2Fe0.7Nb0.1O3 thinfilm as the model system, we demonstrate the critical impact of theexsolution process on the local surface electronic structure. Combiningadvanced microscopic and spectroscopic techniques, particularly scanningtunneling microscopy/spectroscopy and synchrotron-based near ambientX-ray photoelectron spectroscopy, we find that the band gaps of boththe oxide matrix and exsolved NP decrease during exsolution. Suchchanges are attributed to the defect state within the forbidden bandintroduced by oxygen vacancies and the charge transfer across theNP/matrix interface. Both the electronic activations of oxide matrixand the exsolved NP phase lead to good electrocatalytic activity towardthe fuel oxidation reaction at elevated temperature.

• 单位
  中国科学院; y