In Situ DRIFTs Investigation of the Low-Temperature Reaction Mechanism over Mn-Doped Co3O4 for the Selective Catalytic Reduction of NOx with NH3

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• 作者：Hang Hu ; Sixiang Cai ; Hongrui Li ; Lei Huang ; Liyi Shi ; Dengsong Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：October 8, 2015
• 年：2015
• 卷：119
• 期：40
• 页码：22924-22933
• 全文大小：687K
• ISSN：1932-7455

文摘

The Co₃O₄ and Mn-doped Co₃O₄ nanoparticle were synthesized by a co-precipitation method and used as selective catalytic reduction of NO with NH₃ (NH₃-SCR) catalysts. After the doping of manganese oxides, the NH₃-SCR activity of Mn_0.05Co_0.95O_x catalyst is greatly enhanced. The NO oxidation ability of two catalysts is compared, and the X-ray diffraction results demonstrate that Mn has been successfully doped into the lattice of Co₃O₄. The X-ray photoelectron spectroscopy and temperature-programmed reduction with H₂ results confirmed that there is a strong interaction between Mn and Co in the Mn_0.05Co_0.95O_x catalyst. Their adsorption and desorption properties were characterized by temperature-programmed desorption with NH₃ or NO + O₂ and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTs). These results indicated that the doping of manganese could provide more acid sites on the catalysts, and bidentate nitrates species originated from NO_x adsorption are obviously activated on the Mn_0.05Co_0.95O_x catalyst surface. Moreover, the transient reaction studied by in situ DRIFTs found that the 鈥渇ast SCR鈥?reaction participated by gaseous NO₂ and the standard SCR reaction participated by bidentate nitrates contribute to the low-temperature SCR activity.