Chinese Journal of Catalysis ›› 2014, Vol. 35 ›› Issue (9): 1465-1474.DOI: 10.1016/S1872-2067(14)60070-X

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Ozone catalytic oxidation of benzene over AgMn/HZSM-5 catalysts at room temperature:Effects of Mn loading and water content

Yang Liu, Xiaosong Li, Jinglin Liu, Chuan Shi, Aimin Zhu   

  1. Laboratory of Plasma Physical Chemistry, Dalian University of Technology, Dalian 116024, Liaoning, China
  • Received:2014-01-22 Revised:2014-03-03 Online:2014-08-19 Published:2014-08-22
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (U1201231, 11175036).

Abstract:

The effects of Mn loading and water content on AgMn/HZSM-5 (AgMn/HZ) catalysts were investigated in the ozone catalytic oxidation (OZCO) of benzene in a continuous air flow at room temperature. The catalytic activity is closely related to the Mn loading, and the AgMn/HZ catalyst with 2.4 wt% Mn (AgMn/HZ(2.4)) had the highest activity and stability in benzene oxidation as a result of its large surface area and high MnOx dispersion. Temperature-programmed desorption of the used catalysts demonstrated that 2.4 wt% was also the optimal Mn loading for suppressing the accumulation of benzene and HCOOH over the catalyst surface after benzene oxidation. For AgMn/HZ catalysts with Mn loadings ≤ 2.4 wt%, O3 decomposition to active oxygen species (O*) plays the most important role in benzene oxidation; however, benzene activation is the crucial step for benzene oxidation by O3 over AgMn/HZ catalysts with Mn loadings > 2.4 wt%. The AgMn/HZ(2.4) catalyst was then used to perform OZCO of benzene in a humid stream. Compared with dry gas, water vapor greatly enhanced the activity and stability of the AgMn/HZ(2.4) catalyst, and 0.1-0.2 vol% was the optimal water content for benzene oxidation.

Key words: Catalytic oxidation of benzene, Ozone, AgMn/HZSM-5 catalyst, Mn loading, Water vapor