Electronic Activation during Nanoparticle Exsolution for Enhanced Activity at Elevated Temperature

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

doi:10.1021/acsnano.3c01841

Electronic Activation during Nanoparticle Exsolution for Enhanced Activity at Elevated Temperature

ACS Nano. 2023 Jun 13;17(11):10677-10688. doi: 10.1021/acsnano.3c01841. Epub 2023 May 30.

Authors

Huijun Chen^{1

2}, Chaesung Lim³, Ting Tan¹, Mengzhen Zhou¹, Lei Zhang⁴, Xiang Sun¹, Zuyun He¹, Yongjian Ye¹, Xiaobao Li⁵, Hui Zhang⁵, Jeong Woo Han³, Chenghao Yang¹, Yan Chen¹

Affiliations

¹ School of Environment and Energy, National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, South China University of Technology, Guangzhou, Guangdong 510006, China.
² Guangdong Institute of Laser Plasma Accelerator Technology, Guangzhou, Guangdong 510415, China.
³ Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Republic of Korea.
⁴ Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
⁵ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China.

PMID: 37253163
DOI: 10.1021/acsnano.3c01841

Abstract

Nanoparticle (NP) exsolution from perovskite-based oxides matrix upon reduction has emerged as an ideal platform for designing highly active catalysts for energy and environmental applications. However, the mechanism of how the material characteristics impacts the activity is still ambiguous. In this work, taking Pr_0.4Sr_0.6Co_0.2Fe_0.7Nb_0.1O₃ thin film as the model system, we demonstrate the critical impact of the exsolution process on the local surface electronic structure. Combining advanced microscopic and spectroscopic techniques, particularly scanning tunneling microscopy/spectroscopy and synchrotron-based near ambient X-ray photoelectron spectroscopy, we find that the band gaps of both the oxide matrix and exsolved NP decrease during exsolution. Such changes are attributed to the defect state within the forbidden band introduced by oxygen vacancies and the charge transfer across the NP/matrix interface. Both the electronic activations of oxide matrix and the exsolved NP phase lead to good electrocatalytic activity toward the fuel oxidation reaction at elevated temperature.

Keywords: electronic structure; exsolution; oxygen vacancy; perovskite oxide; thin film.