制备方法对低温NH3-SCR催化剂Mn-La结构与性能的影响

• 作 者: 吴彦霞 梁海龙 陈鑫 王献忠 陈玉峰
• 机 构: 中国建筑材料科学研究总院陶瓷科学研究院,北京100024;萍乡学院江西省工业陶瓷重点实验室,江西萍乡337055
• 出 处: 稀有金属材料与工程
• 发表日期: 2021年12期
• 关键词: catalyst Mn-La preparation method denitration efficiency

采用固相反应法、共沉淀法制备了Mn-La复合氧化物催化剂,考察了制备方法对催化剂脱硝性能及抗SO2/H2O性能的影响.并通过XRD、BET、H2-TPR、NH3-TPD、XPS等手段对催化剂的结构和物理化学特性进行了表征.结果 表明,La掺杂降低了MnOx的结晶度,增大了催化剂的比表面积和孔体积.Mn-O-La键合作用促进了锰在催化剂表面的分散,而高分散的锰更容易被还原,催化剂的还原温度向低温方向迁移,氧化还原能力得到提高.掺杂La之后,催化剂表面Brφnsted酸和总酸量增加,同时Mn4+和表面化学吸附氧的浓度也得到提高.因此,La掺杂有利于促进催化剂的脱硝活性.反应评价结果表明,共沉淀法制备的MnLa-CPM催化剂表现出最佳的脱硝效率,在80℃时脱硝效率接近100％.在H2O和SO2存在的条件下,MnLa-CPM催化剂的脱硝效率仍能达到80％,表现出了较好的抗硫水性能.“,”Mn-La catalysts were prepared by solid-state reaction (SSR) and co-precipitation methods (CPM).The effects of preparation methods on denitration and SO2/H2O resistance of the catalysts were investigated.The structure and physicochemical properties of the catalysts were characterized by XRD,BET,H2-TPR,NH3-TPD and XPS.The results show that La doping decreases the crystallinity of MnOx and increases the specific surface area and pore volume of MnOx.The bond cooperation of Mn-O-La promotes the dispersion of Mn on the catalyst surface,while the highly dispersed Mn are easier to be reduced.The reduction temperature of the catalyst moves to lower temperature,and the redox ability is improved.After La doping,the amount of Brφnsted acid and total acid increase on the catalyst surface,and the concentration of Mn4+ and the surface chemisorption oxygen also increase.Therefore,La doping is beneficial to the denitration activity of the catalyst.The results of reaction evaluation show that MnLa-CPM catalyst exhibits the best denitration efficiency,which is close to 100％ at 80 ℃.In the presence of H2O and SO2,the denitration efficiency of MnLa-CPM catalyst can still reach 80％,showing good SO2/H2O resistance performance.