A facile method for preparing the CeMnO3 catalyst with high activity and stability of toluene oxidation: The critical role of small crystal size and Mn3+-Ov-Ce4+ sites

Jianshen Wang; Junming Su; Gangguo Zhao; Dan Liu; Hua Yuan; Alex T Kuvarega; Bhekie B Mamba; Hu Li; Jianzhou Gui

doi:10.1016/j.jhazmat.2024.134114

A facile method for preparing the CeMnO₃ catalyst with high activity and stability of toluene oxidation: The critical role of small crystal size and Mn³⁺-O_v-Ce⁴⁺ sites

J Hazard Mater. 2024 May 15:470:134114. doi: 10.1016/j.jhazmat.2024.134114. Epub 2024 Mar 22.

Authors

Jianshen Wang¹, Junming Su², Gangguo Zhao¹, Dan Liu³, Hua Yuan⁴, Alex T Kuvarega⁵, Bhekie B Mamba⁵, Hu Li⁶, Jianzhou Gui⁷

Affiliations

¹ State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Key Laboratory of Green Chemical Technology and Process Engineering, and School of Material Science and Engineering, Tiangong University, Tianjin 300387, China.
² School of Chemical Engineering and Technology, Tiangong University, Tianjin 300387, China.
³ School of Chemistry, Tiangong University, Tianjin 300387, China; Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida 1709, Johannesburg, South Africa. Electronic address: liudan@tiangong.edu.cn.
⁴ Ningxia Coal Industry Co. Ltd., CHN ENERGY, Yinchuan 750011, China.
⁵ Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida 1709, Johannesburg, South Africa.
⁶ Ningxia Coal Industry Co. Ltd., CHN ENERGY, Yinchuan 750011, China. Electronic address: 15010874@chnenergy.com.cn.
⁷ State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Key Laboratory of Green Chemical Technology and Process Engineering, and School of Material Science and Engineering, Tiangong University, Tianjin 300387, China; School of Chemical Engineering and Technology, Tiangong University, Tianjin 300387, China. Electronic address: guijianzhou@tiangong.edu.cn.

PMID: 38547755
DOI: 10.1016/j.jhazmat.2024.134114

Abstract

Volatile organic compounds (VOCs) cause severe environmental pollution and are potentially toxic to humans who have no defense against exposure. Catalytic oxidation of these compounds has thus become an interesting research topic. In this study, microcrystalline CeMnO₃ catalysts were prepared by a precipitant-concentration-induced strategy and evaluated for the catalytic oxidation of toluene/benzene. The effect of crystal size on catalytic performance was confirmed by XRD, TEM, N₂ adsorption-desorption, XPS, Raman, H₂-TPR, and TPSR. The CeMnO₃ catalyst with more Mn³⁺-O_v-Ce⁴⁺ active sites exhibited enhanced VOCs catalytic oxidation performance, lowest active energy, and highest turnover frequency, which was attributed to its larger surface area, lower crystal size, higher low-temperature reducibility, and presence of more oxygen defects. In-situ FTIR results suggested more oxygen vacancies can profoundly promote the conversion of benzoate to maleate species, the rate-determining step of toluene oxidation. The work provides a convenient and efficient strategy to prepare single-metal or multi-metal oxide catalysts with smaller crystal sizes for VOC oxidation or other oxidation reactions.

Keywords: CeMnO(3); Mn(3+)-O(v)-Ce(4+); Small particle; VOC oxidation.