Ce改性Mn系催化剂结构及低温催化活性影响研究

采用浸渍法制备了Ce改性负载型Mn系TiO 2催化剂,考察了Ce负载量、反应温度等因素对催化剂效率以及选择性的影响,利用扫描电镜、氮气物理吸附(N 2-TPD)等表征手段分析了Ce/TiO 2催化剂催化活性影响机理。结果表明:改性催化剂在Ce/Ti摩尔比为0.08的条件下表现出最佳的脱硝效率及NO选择性;MnCe(0.08)Ti催化剂在180℃条件下的脱硝效率超过85%,而N 2 O体积分数仅为24×10-6(47.1 mg/m 3);Ce的加入优化了催化剂表面的孔隙结构,比表面积与和孔容积分别达到121.11 m 2/g、1.71 cm 3/g;MnCe(0.08)Ti催化剂在210℃通入体积分数为300×10-6(857.1 mg/m 3)的SO 2和8%的水蒸气,连续运行180 h过程中的脱硝效率均可保持在80%以上,具有良好的抗硫性和稳定性。

Influence on structure property of Ce doped Mn-based catalysts and low-temperature catalytic activity

Ce doped Mn-based TiO 2 catalyst was prepared by impregnation method.The influences of Ce doped and reaction temperature on the efficiency and selectivity of the catalyst were studied.The Ce/TiO 2 catalyst was characterized by various techniques to study the influence mechanism of catalytic activity,including scanning election microscopy(SEM)、N 2 absorption-desorption(N 2-TPD),etc.The results showed that:the MnCe(0.08)Ti catalyst exhibits the best denitration efficiency and NO selectivity withthe optimal Ce/Ti molar ratio of 0.08 at 180℃;the denitration efficiency is higher than 85%,butthe volume fraction of N 2 O is only 24×10-6(47.1 mg/m 3);meanwhile,the addition of Ce element optimizes the pore structure at the surface of the catalyst,which increases the specific surface area and pore volume to 121.11 m 2/g and 1.71 cm 3/g,respectively;when sulfur dioxide with a volume fraction of 300×10-6(857.1 mg/m 3)and 8%watervapor are introduced,the denitration efficiency of MnCe(0.08)Ti catalyst can reach 80%during 180 h continuous operation at 210℃;in addition,MnCe(0.08)Ti catalystgood sulfur dioxide resistance andstability.