TiO_2-SnO_2基钨催化剂的表面性质和NH_3吸附特性及脱硝机理  

Surface properties,NH_3 adsorption characteristic and NO_x removal mechanism of TiO_2-SnO_2 supported WO_3 catalysts

作　　者：李娟[1] 张亚平[1] 王文选 王龙飞[1] 郭婉秋[1] 杨林军[1] 沈凯[1] 

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,南京210096 [2]江苏万德环保科技有限公司,扬州225131

出　　处：《东南大学学报（自然科学版）》2016年第1期92-99,共8页Journal of Southeast University：Natural Science Edition

基　　金：国家重点基础研究发展计划(973计划)资助项目(2013CB228505);国家自然科学基金资助项目(51306034);江苏省自然科学基金资助项目(BK2012347)

摘　　要：采用共沉淀法制备了TiO2-SnO2固溶体载体,浸渍WO3得到系列x%WO3/Ti O2-Sn O2脱硝催化剂,采用比表面积测定（BET）、X射线衍射（XRD）、高分辨率透射电子显微镜（HRTEM）、程序升温还原（H2-TPR）、原位漫反射傅里叶红外光谱（in situ DRIFTS）等表征研究脱硝催化剂的微观结构、表面性质和NH3吸附特性,并推测该催化剂表面的SCR脱硝反应机理.结果表明：负载WO3之后,随着负载量的增加,催化剂的比表面积有所减小;WO3以无定形态存在于催化剂表面;催化剂还原特性和表面Brnsted酸量显著增强;催化剂的脱硝效率增加,其中12%WO3/TiO2-SnO2催化剂在280~380℃的温度窗口具有90%的NOx转换效率.原位漫反射红外研究结果表明,对于x%WO3/TiO2-SnO2系列的催化剂来说,Brnsted酸中心是催化过程中的活性酸位,该催化剂脱硝反应遵循E-R反应机理.TiO2-SnO2 solid solution was prepared by the co-precipitation method and x% WO3/ TiO2-SnO2 catalysts were prepared by the impregnation method. The microstructure,surface properties and NH3 adsorption of catalysts were studied by using BET specific surface area measurement,X-ray diffraction（ XRD）,high-resolution transmission electron microscopy（ HRTEM）,H2temperature-programmed reduction（ H2-TPR） and in situ diffuse reflectance infrared spectroscopy（ in situ DRIFTS）.Furthermore,the SCR（ selective catalytic reduction） denitration mechanism of catalysts was speculated. The results showthat after the addition of WO3,the specific surface area decreases with the increase of WO3 loadings of catalysts. WO3 is in a well-dispersed state. The reducible properties of catalysts and the amount of Brnsted acidity are significantly increased. Catalytic activity increases,and the NOxconversions of 12% WO3/ TiO2-SnO2 catalysts reaches 90% when the temperature is 280 to380 ℃. The results of in situ DRIFTS indicate that the center of catalytic activity is Brnsted acid site,and the denitration mechanism of the catalysts accords with the reaction mechanism of E-R.

关 键 词：TiO2-SnO2固溶体 原位漫反射红外 NH3吸附 脱硝机理 

分 类 号：O643.36[理学—物理化学]