The interplay between selective etching induced cation defects and active oxygen species for volatile organic compounds degradation

Zhen Li; Xiyang Wang; Minli Zeng; Kunyu Chen; Dehua Cao; Yiwei Huang; Yanqiu Zhu; Wenhua Zhang; Nannan Wang; Yimin A Wu

doi:10.1016/j.jcis.2022.06.037

The interplay between selective etching induced cation defects and active oxygen species for volatile organic compounds degradation

J Colloid Interface Sci. 2022 Nov:625:363-372. doi: 10.1016/j.jcis.2022.06.037. Epub 2022 Jun 9.

Authors

Zhen Li¹, Xiyang Wang², Minli Zeng³, Kunyu Chen³, Dehua Cao³, Yiwei Huang³, Yanqiu Zhu³, Wenhua Zhang⁴, Nannan Wang⁵, Yimin A Wu⁶

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, PR 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 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, PR China.
⁴ National Synchrotron Radiation Laboratory, University of Science and Technology of China, 230029 Hefei, Anhui, China.
⁵ 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, PR China. Electronic address: wangnannan@gxu.edu.cn.
⁶ 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: 35717850
DOI: 10.1016/j.jcis.2022.06.037

Abstract

Surface electronic structure of transition metal oxides plays a vital role in determining the catalytic performance. Herein, we present a selective etching strategy to tune the surface cation defect of the CuWO₄ (CW) catalyst for improving the catalytic activity of volatile organic compounds (VOCs). HRTEM, SEM-EDS, EPR, and XPS show that the chelation of metal ions in acetic acid and ammonium hydroxide can help to remove a small number of surface cations in CW to form suitable W defects. Cu L-edge and O K-edge XAS, Raman, and O 1s XPS spectrum illustrate that cation defects can improve the hybrid orbits of metal-oxygen bonds, which increases the activity of surface lattice oxygen and metal sites. In-situ DRIFTS spectra reveal that CW with cation defects can easily adsorb toluene, cleave and oxidize benzene ring, and desorb CO₂ because of more surface dangling bonds and active oxygen species. Therefore, the toluene conversion rates of CW-Aci and CW-Alk are much higher than CW in VOCs degradation and the catalytic performance improved 33 times and 22 times at 200 °C, respectively. This study offers a new pathway in engineering surface electronic structure and highlights the interplay between cation defects and active oxygen species.

Keywords: Active oxygen species; Cation defects; Surface electronic structure; Toluene oxidation; Transition metal oxides.