Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (02): 353-359.doi: 10.3866/PKU.WHXB20090227

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N2O Catalytic Decomposition over Mixed Oxides Derived from Zn-substituted Hydrotalcite-like Compounds

YU Jun-Jie; ZHU Ling; ZHOU Bo; SHAO Li-Nan; ZHANG Yu-Ting; HE Xu-Wen   

  1. School of Chemical and Environmental Engineering, China University of Mining and Technology(Beijing), Beijing 100083, P. R. China; Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, P. R. China
  • Received:2008-09-26 Revised:2008-10-20 Published:2009-01-16
  • Contact: HE Xu-Wen

Abstract: A series of hydrotalcite-like precursors with different Zn contents of ZnxMg3-xAl-HT (x=0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized by co-precipitation methods, and by keeping the atomic ratio of M2+/M3+ constant at 3. Mixed oxides derived from these precursors through calcination were applied to N2O catalytic decomposition. X-ray diffraction (XRD), BET surface area, thermal analysis (TG-DSC), and Fourier transform infrared (FT-IR) techniques were used to study the influence of Zn content on the composition and structure of precursors and corresponding mixed oxides. N2O catalytic decomposition behavior over ZnxMg3 -xAlO catalysts was investigated and impacts of reaction conditions, such as N2O concentration, space velocity, O2 and H2O on catalytic activity, were studied in detail. The results showed that the complete hydrotalcite layer structure was formed in all precursors. After calcination the main catalyst phase is Zn-Al spinel. The introduction of Zn promotes the formation of the spinel. Mg can improve the thermal stability of catalysts to some degree. Zn content has an important influence on the thermal stability, surface area and activity of the catalyst. As Zn content increases the surface area of the catalyst decreases. Surface area is, however, not an important factor in N2O catalytic decomposition. Zn2.0Mg1.0AlO catalyst, calcined at 650 ℃, shows relatively good activity for N2O decomposition. The N2O concentration, space velocity, and O2 have little impact on activity, while H2O obviously influences the activity of N2O catalytic decomposition.

Key words: N2O, Hydrotalcite-like component, Mixed oxide, Catalytic decomposition, Catalytic activity


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