Chem. J. Chinese Universities ›› 2023, Vol. 44 ›› Issue (4): 20220690.doi: 10.7503/cjcu20220690

• Physical Chemistry • Previous Articles     Next Articles

Catalytic Performance and Reaction Mechanism of Chlorobenzene Oxidation over MnO x -CeO2 Catalyst

GAO Fengyu1, CHEN Du1, LUO Ning1, YAO Xiaolong2, DUAN Erhong3, YI Honghong1, ZHAO Shunzheng1, TANG Xiaolong1()   

  1. 1.Beijing Key Laboratory of Resource?oriented Treatment of Industrial Pollutants,School of Energy and Environmental Engineering,University of Science and Technology Beijing,Beijing 100083,China
    2.Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry,Beijing Technology and Business University,Beijing 100048,China
    3.School of Environmental Science and Engineering,Hebei University of Science and Technology,Shijiazhuang 050018,China
  • Received:2022-11-03 Online:2023-04-10 Published:2022-12-12
  • Contact: TANG Xiaolong E-mail:txiaolong@126.com
  • Supported by:
    the Open Research Fund Program of Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry(CP2021YB02);the National Natural Science Foundation of China(U20A20130);the Fundamental Research Funds for the Central Universities, China(06500152)

Abstract:

The influence factors(Mn/Ce molar ratio, reaction temperature, oxygen, water), physicochemical properties, interaction process and reaction mechanism are analyzed and proposed on MnO x -CeO2 catalysts for chlorobenzene oxidation performances(activity, selectivity and stability). With 5%(volume fraction) H2Ogas and 5%(volume fraction) O2, the optimum Mn2Ce1O x catalyst obtains the chlorobenzene conversion rate of 80.6%, 86.8% and 97.5% at 100, 200 and 300 ℃, respectively. High reaction temperature, high oxygen content and also the presence of water are beneficial to the improvement of catalytic conversion and reaction stability. The doping procedure of MnO x and CeO2 multi-oxides increases specific surface area to 128.61 m2/g, decreases pore size to 6.17 nm, and strengthens surface acidity(especially at middle & strong acid sites) and also redox performance. The electron interaction(Ce4+/Ce3+Mn4+/Mn3+/Mn2+) and oxygen cycle(surface adsorbed oxygenlattice oxygen) are the essential driving processes to promote the catalytic oxidation. Chlorobenzene molecules are adsorbed on the surface of Mn2Ce1O x catalyst to de-chlorinate and form phenol, in turn, the ring-opening of aromatic ring is occurred and then oxidated into the formation of most critical acetate intermediates that result in as finial as possible CO2, HCl or Cl2, H2O. Under the activation actions of water and oxygen molecules to hydroxyl groups and active-oxygen species, the adsorption-activation of chlorobenzene and deep oxidation of intermediates are enhanced and more beneficial to reduce the generation of by-products(chloroethoxyl, phenol and aldehydes, etc.) and also Cl-containing species, thus improving the catalytic activity and reaction stability.

Key words: MnO x -CeO2, Chlorobenzene oxidation, Catalytic performance, Stability, Reaction mechanism

CLC Number: 

TrendMD: