Insight into the effects of oxygen vacancy on the toluene oxidation over α-MnO2 catalyst

Jia Zeng; Hongmei Xie; Hanyi Zhang; Min Huang; Xuecheng Liu; Guilin Zhou; Yi Jiang

doi:10.1016/j.chemosphere.2021.132890

Insight into the effects of oxygen vacancy on the toluene oxidation over α-MnO₂ catalyst

Chemosphere. 2022 Mar;291(Pt 3):132890. doi: 10.1016/j.chemosphere.2021.132890. Epub 2021 Nov 18.

Authors

Jia Zeng¹, Hongmei Xie², Hanyi Zhang², Min Huang¹, Xuecheng Liu², Guilin Zhou³, Yi Jiang⁴

Affiliations

¹ National Engineering Laboratory for VOCs Pollution Control Material & Technology, Chengdu Institute of Organic Chemistry, Chinese Academy of Science, Chengdu, 610041, China; University of Chinese Academy of Science, Beijing, 100049, China.
² Key Laboratory of Catalysis Science and Technology of Chongqing Education Commission, Department of Chemical Engineering, Chongqing Technology and Business University, Chongqing, 400067, China.
³ Key Laboratory of Catalysis Science and Technology of Chongqing Education Commission, Department of Chemical Engineering, Chongqing Technology and Business University, Chongqing, 400067, China. Electronic address: dicpglzhou@ctbu.edu.cn.
⁴ National Engineering Laboratory for VOCs Pollution Control Material & Technology, Chengdu Institute of Organic Chemistry, Chinese Academy of Science, Chengdu, 610041, China. Electronic address: yjiang@cioc.ac.cn.

PMID: 34801567
DOI: 10.1016/j.chemosphere.2021.132890

Abstract

In order to clarify the role of oxygen vacancy (OV), five α-MnO₂ catalysts with abundant OVs are fabricated via a novel and facile redox-precipitation approach and employed to the toluene oxidation in air. The concentration of OVs in α-MnO₂ catalysts is regulated via the alkyl chain length of alcohols, and its correlation with catalytic performances is scientifically investigated based on various characterization technologies and density functional theory (DFT) calculation. The α-MnO₂-C2 catalyst exhibits excellent catalytic activity (T₉₀ = 217 °C), stability, and water resistance for toluene oxidation in air. The OVs can induce the new bandgap states (BGS), which upshift the antibonding orbitals relative to the Fermi level (E_f), eventually favoring the formation of adsorbed active oxygen species. Furthermore, the OVs cause an increase in the amount of Mn³⁺, resulting in the elongated Mn-O bonds due to the strong Jahn-Teller effect of Mn³⁺. Therefore, the synergistic effects of OVs benefit toluene oxidation through L-H and MvK mechanisms over the prepared α-MnO₂-Cx catalysts. This work reveals the important role of OVs in the promotion of toluene catalytic oxidation activity and also may provide new insights for the design of high-performance VOCs oxidation elimination catalyst.

Keywords: Catalytic oxidation; DFT calculation; Oxygen vacancy; Toluene; α-MnO(2).

MeSH terms

Catalysis
Manganese Compounds*
Oxides*
Oxygen
Toluene

Substances

Manganese Compounds
Oxides
Toluene
Oxygen