1. Bimetallic Mn-Cu oxide catalysts for toluene oxidation: Synergistic effect and catalytic mechanism.
- Author
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Jiang, Ye, Cheng, Siyuan, Su, Congcong, Jiang, Yinsheng, Sun, Xin, Zhang, Guomeng, Liu, Yanan, Dou, Xiao, and Yang, Zhengda
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TOLUENE , *CATALYSIS , *MALEIC anhydride , *PRECIPITATION (Chemistry) , *COPPER , *CATALYSTS , *OXIDATION - Abstract
[Display omitted] • Mn 5 Cu 1 possessed a unique three-phase coexisting structure. • The strong synergistic effect between Mn and Cu contributed to the excellent catalytic activity. • Appropriate loading of Cu facilitated the adsorption and activation of toluene. • The reaction pathway of toluene oxidation over Mn 5 Cu 1 was investigated. • The oxidation of maleic anhydride to CO 2 was a crucial step of toluene oxidation. A series of Mn-Cu composite oxides with different Mn/Cu molar ratios were synthesized via a facile ethanol-redox precipitation method and investigated for the oxidation of toluene. Among as-synthesized Mn x Cu y catalysts, Mn 5 Cu 1 showed the most excellent toluene catalytic activity at a weight hourly space velocity (WHSV) of 30000 mL∙g−1∙h−1, with 90 % conversion achieved at 212 °C. Furthermore, the Mn 5 Cu 1 catalyst exhibited exceptional thermal stability over a 12-hour period at 215 °C, along with outstanding resistance to H 2 O in the range of 5 vol% to 40 vol%. As characterized by XRD, BET, XPS, EPR, H 2 -TPR, and O 2 -TPD, it was found that Mn 5 Cu 1 possessed a unique three-phase coexisting structure, large specific surface area (57 m2·g−1), plentiful oxygen vacancies, excellent redox capacity, and strong mobility of oxygen, which were attributable to the synergistic effect between Mn and Cu. This strong synergy between Mn and Cu is the underlying reason for the strong catalytic activity of Mn 5 Cu 1. Moreover, toluene-TPD and TPSR results indicated that appropriate Cu loading was favorable for the adsorption and activation of toluene. The potential reaction pathway for toluene oxidation was presented based on in situ DRIFTS characterization. Maleic anhydride was the critical reaction intermediate species. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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