WO_3对MnO_x/TiO_2低温脱硝SCR催化剂的改性研究  

WO_3 modification on MnO_x/TiO_2 low-temperature De-NO_x SCR catalyst

作　　者：张亚平[1] 汪小蕾[1] 孙克勤[1] 沈凯[1] 徐海涛[1] 周长城[1] 

机构地区：[1]东南大学能源与环境学院,江苏南京210096

出　　处：《燃料化学学报》2011年第10期782-786,共5页Journal of Fuel Chemistry and Technology

基　　金：国家高技术研究发展计划(863计划;2007AA061802);江苏省自然科学基金(BK2008001)

摘　　要：以醋酸锰为前驱物通过浸渍法制备了MnOx/TiO2催化剂,用WO3对载体进行改性制得一系列MnOx-WO3/TiO2催化剂,采用X射线衍射(XRD)、比表面积测定(BET)、拉曼光谱(LRS)、原位红外(FT-IR)光谱等表征技术进行相关的微观表征分析,同时在模拟氨气选择性催化还原NOx(NH3-SCR)的反应条件下对催化剂的脱硝反应活性进行了考察。研究表明,添加5%的WO3拓展了载体的比表面积,提高了催化剂的抗热性,增加了催化剂表面的Brnsted酸位,拓宽其选择性催化还原脱硝活性温度窗口,对MnOx/TiO2催化剂有很好的改性作用;先钨后锰的负载顺序优于先锰后钨;随着温度的升高,化学催化反应速率提高,催化剂表面NH3吸附峰呈减弱或消失趋势,故催化剂脱硝活性温度曲线呈中间高、两头低。A series of TiO2 supported manganese oxide catalysts,MnOx/TiO2,were prepared by wet-impregnation method for the low temperature selective catalytic reduction（SCR） of NO with ammonia.WO3 with different loadings was added to MnOx /TiO2 samples to investigate its possible influence on the catalytic activity of MnOx /TiO2 by using several characterization techniques including BET surface area,laser Raman spectroscopy（LRS）,Fourier transform infrared spectroscopy（FT-IR）,X-ray diffraction（XRD）.The research shows that minute addition of 5% WO3 raises the catalytic performance of MnOx /TiO2 catalyst effectively by expanding the carrier＇s surface area,improving its thermal resistance,increasing surface Brnsted acids and NH3 adsorption capacity,and broadening the temperature window of SCR reaction.The MnOx-WO3/TiO2 shows better SCR activity than WO3-MnOx /TiO2 in terms of impregnation sequence.The adsorption peaks of NH3 on surface of catalysts will be weakened or lost with temperature increasing,and the denitration reactivity curve of catalysts shows a maximum with the increase of temperature.

关 键 词：WO3 MnOx/TiO2催化剂 低温SCR 负载顺序 

分 类 号：X51[环境科学与工程—环境工程]