The effect of Ce-Zr on NH₃-SCR activity over MnO_x(0.6)/Ce_0.5Zr_0.5O₂ at low temperature

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• 作者：Boxiong Shen ; Yinyin Wang ; Fumei Wang ; Ting Liu
• 关键词：MnOx/CeuZr1&minus ; uO2 ; Low-temperature selective catalytic reduction ; Kinetic parameters ; Oxygen vacancy ; Activation energy
• 刊名：Chemical Engineering Journal
• 出版年：15 January, 2014
• 年：2014
• 卷：236
• 期：Complete
• 页码：171-180
• 全文大小：987 K

文摘

A series of Mn/Ce-Zr-based catalysts with various Ce/Zr ratios and Mn loadings were employed to investigate the selective catalytic reduction (SCR) of NO at low temperatures. The physicochemical properties of these catalysts were investigated by a variety of characterization methods. The experimental and kinetic model results showed that the MnO_x(0.6)/Ce_0.5Zr_0.5O₂ catalyst exhibited high NO conversion (nearly 100%) at low temperature, good resistance to H₂O and SO₂ and high N₂ selectivity. The apparent activation energy of the MnO_x(0.6)/Ce_0.5Zr_0.5O₂ catalyst was 18.08 kJ mol^鈭?, which is much lower than that of MnO_x/TiO₂ (38 kJ mol^鈭?). The presence of ZrO₂ in the catalyst introduced high total H₂ consumption, surface acidity and Brunauer-Emmett-Teller (BET) specific surface area, and the introduction of CeO₂ to the catalyst lowered the H₂ reduction temperature and enhanced the Mn⁴⁺/Mn³⁺ ratio and adsorbed oxygen species on the surface. The combination of the advantages of the ZrO₂ and CeO₂ supports contributed to the highest NO conversions for MnO_x(0.6)/Ce_0.5Zr_0.5O₂ catalyst.