Engineering surface segregation of perovskite oxide through wet exsolution for CO catalytic oxidation

Zhen Li; Xiyang Wang; Xinbo Li; Minli Zeng; Carl Redshaw; Rui Cao; Ritimukta Sarangi; Changmin Hou; Zuolong Chen; Wenhua Zhang; Nannan Wang; Xiaofeng Wu; Yanqiu Zhu; Yimin A Wu

doi:10.1016/j.jhazmat.2022.129110

Engineering surface segregation of perovskite oxide through wet exsolution for CO catalytic oxidation

J Hazard Mater. 2022 Aug 15:436:129110. doi: 10.1016/j.jhazmat.2022.129110. Epub 2022 May 10.

Authors

Zhen Li¹, Xiyang Wang², Xinbo Li³, Minli Zeng⁴, Carl Redshaw⁵, Rui Cao⁶, Ritimukta Sarangi⁶, Changmin Hou³, Zuolong Chen², Wenhua Zhang⁷, Nannan Wang⁸, Xiaofeng Wu⁹, Yanqiu Zhu⁴, Yimin A Wu¹⁰

Affiliations

¹ Guangxi Institute Fullerene Technology (GIFT), State Key Laboratory of Featured Metal Resources and Advanced Materials, School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China; Department of Mechanical and Mechatronics Engineering, Waterloo Institute for Nanotechnology, Materials Interface Foundry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
² Department of Mechanical and Mechatronics Engineering, Waterloo Institute for Nanotechnology, Materials Interface Foundry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
³ State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin Provincial International Cooperation Key Laboratory of Advanced Inorganic Solid Functional Materials, Jilin University, Changchun 130012, China.
⁴ Guangxi Institute Fullerene Technology (GIFT), State Key Laboratory of Featured Metal Resources and Advanced Materials, School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
⁵ Plastics Collaboratory, Department of Chemistry, University of Hull, Hull HU6 7RX, UK.
⁶ Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
⁷ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China.
⁸ Guangxi Institute Fullerene Technology (GIFT), State Key Laboratory of Featured Metal Resources and Advanced Materials, School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China. Electronic address: wangnannan@gxu.edu.cn.
⁹ State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin Provincial International Cooperation Key Laboratory of Advanced Inorganic Solid Functional Materials, Jilin University, Changchun 130012, China. Electronic address: wuxf@jlu.edu.cn.
¹⁰ Department of Mechanical and Mechatronics Engineering, Waterloo Institute for Nanotechnology, Materials Interface Foundry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. Electronic address: yimin.wu@uwaterloo.ca.

PMID: 35739693
DOI: 10.1016/j.jhazmat.2022.129110

Abstract

Cation segregation occurring near the surface or interfaces of solid catalysts plays an important role in catalytic reactions. Unfortunately, the native surface of perovskite oxides is dominated by passivated A-site segregation, which severely hampers the catalytic activity and durability of the system. To address this issue, herein, we present a wet exsolution method to reconstruct surface segregation in perovskite cobalt oxide. Under reduction etching treatment of glycol solution, inert surface Sr segregation was transformed into active Co₃O₄ segregation. By varying the reaction time, we achieved differing coverage of the active Co₃O₄ segregation on the La_0.5Sr_0.5CoO_3-δ (LSCO) perovskite oxide surface. This study reveals that CO oxidation activity exhibits a volcano-shaped dependence on the coverage of Co₃O₄ segregation at the surface of a perovskite cobalt oxide. Furthermore, we find that a suitable coverage of Co₃O₄ segregation can dramatically improve the catalytic activity of the perovskite catalyst by enhancing interface interactions. Co K-edge, Co L-edge, and O K-edge X-ray absorption spectra confirm that the synergistic effect optimizes the covalence of the metal-oxygen bond at the surface and interface. This work not only contributes to the design and development of perovskite-type catalysts, but also provides important insight into the relationship between surface segregation and catalytic activity.

Keywords: CO oxidation; Perovskite oxides; Surface segregation; Surface/interface electronic structure; Wet exsolution.