Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (7): 1303-1308.doi: 10.3866/PKU.WHXB201405062

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

MnOx/CeO2/SiO2 Catalysts Prepared by Adsorption Phase Reaction Technique for Selective Catalytic Reduction of NOx at Low-Temperature

GAO Lin-Xin1, JIANG Xin1, GUO Sen2   

  1. 1. Department of Chemical & Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China;
    2. College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, P. R. China
  • Received:2014-02-27 Revised:2014-05-04 Published:2014-06-30
  • Contact: JIANG Xin E-mail:jiangx@zju.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21276223), National High-Tech Research and Development Program of China (863) (2010AA064905), and Program for Zhejiang Leading Team of Science & Technology Innovation, China (2009R50020).

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Abstract:

MnOx/CeO2/SiO2 catalysts were prepared by the adsorption phase reaction technique and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. HRTEM showed that MnOx and CeO2 particles were uniformly coated on the surface of SiO2. The XRD spectra showed that the intensity of the Mn3O4 diffraction peaks gradually decreased and then completely disappeared with the increasment of the CeO2 content, which indicated that CeO2 reduced the crystallinity of MnOx and improved the dispersibility of MnOx. Raman spectroscopy indicated that Mn ions on the surface of catalysts could enter into the lattice of CeO2, replace oxygen ions, and form oxygen vacancies. With the increasment of CeO2 content, the density of oxygen vacancies initially increased and then decreased. We used the catalysts for selective catalytic reduction (SCR) of NOx with NH3. The catalytic activity initially increased and then decreased with the increasment of CeO2 content, similar to the change in the density of oxygen vacancies. Thus, the catalytic activity of the MnOx/CeO2/SiO2 catalysts increases with increasing the density of oxygen vacancies.

Key words: MnOx/CeO2/SiO2 catalyst, Low temperature, Selective catalytic reduction, Oxygen vacancies, Adsorption phase reaction technique