NH3-SCR PROPERTIES OF CeMn/ZSM-5 CATALYST MODIFIED BY ALKALI-TREATMENT
Nitrogen oxides,as one of the atmospheric pollutants,have caused serious environmental problems,endangering the ecological environment and human health.Selective catalytic reduction of NOx with ammonia(NH3-SCR)has become an important application technology for denitrification.Different from the supported ZSM-5 catalyst synthesized by traditional methods,Ce and Mn bimetallic modified ZSM-5 catalyst was synthesized by one-pot method,and the ZSM-5 molecular sieve was pretreated by alkali.The CeMn/ZSM-5-OH catalyst with improved surface area and pore structure was successfully synthesized.In the performance test,the NOx conversion rate was beyond 90％in the temperature range of 175 to 350 ℃,and the activity was increased by nearly 40％,compared with that of CeMn/ZSM-5 samples in low temperature section.After alkali-treatment,the CeMn/ZSM-5-OH catalyst generated more Ce3+and Mn4+,which increased the adsorption performance of NO and NH3.The results of XPS showed that lattice oxygen participated in the electron transfer between Ce3+and Mn4+,which was conducive to the activation of NO and NH3.Thus,the NH3-SCR reaction was promoted.
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