A series of metals (Co, Ce and Ni) were introduced into non-pitch coal-based activated coke (NPAC) by isometric impregnation method to elevate the low-temperature activity of NH3-SCR. The modified NPAC was characterized by N2 adsorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and NH3-temperature programmed desorption (NH3-TPD) techniques. The results show that, the low-temperature denitrification activity of both the single modified NPAC and co-modified NPAC was enhanced, and the co-modified NPAC exhibited a stronger ability of denitrification. The cobalt, cerium and nickel species incorporated the graphite crystalline structure of the NPAC, and were dispersed uniformly in the surface of the NPAC. The existing forms of Ce in the surface of the modified NPAC were Ce3+and Ce4+, with Ce4+ as the major form, the existing forms of Co were Co2+ and Co3+, and the existing forms of Ni were Ni2+ and Ni3+. The modification has improved the chemisorbed oxygen concentration and enhanced the surface acidity of the NPAC, which promoted the NO oxidation and enhanced the ammonia adsorption and activation capacity of the NPAC. The denitrification rate of the NPAC-CoCeNi-7 at 150 ℃ was as high as 71.55%.%采用等体积浸渍法制备了系列CoCeNi改性非沥青基煤质活性焦(NPAC)催化剂,并结合N2吸附、X射线衍射、X射线光电子能谱分析以及NH3程序升温脱附等表征技术,对3种金属单一负载和共负载后改性活性焦的低温NH3-SCR脱硝活性进行了研究.结果表明:单一负载和共负载都可提高非沥青基煤质活性焦的低温脱硝活性,且共负载的脱硝能力较强;CoCeNi可以较好地并入NPAC的类石墨微晶结构,Ce、Co和Ni在负载改性NPAC表面分散均匀;Ce以Ce3+和Ce4+形式存在,但以Ce4+为主,Co以Co2+和Co3+形式存在,Ni以Ni2+和Ni3+形式存在;金属负载改性使NPAC的化学吸附氧浓度增加,氧化NO能力和表面酸性增强,增加了NH3吸附和活化能力,从而提高其低温脱硝能力.共负载改性NPAC在150℃脱硝率达到71.55%.
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