摘要
氮氧化物(NOx)会引发严重酸雨,光化学烟雾和破坏对流层的臭氧。氨选择性催化还原(NH_3-SCR)是燃煤电厂烟气脱硝最广泛工艺,目前该工艺正在向低温低灰低毒方向发展。本文采用液相自发沉积策略制备了非晶态锰钛复合氧化物作为高效的低温NH_3-SCR催化剂(Mn@Ti),并运用XRD、Raman、BET、H_2-TPR、NH_3-TPD、(HR)TEM、XPS和In-situ FTIR等多种表征手段对Mn@Ti的织态结构、表面性质及其催化历程进行深入分析。结构表征结果表明Mn@Ti催化剂以非晶态结构存在,元素Mn、Ti高度混合且存在较强的相互作用。另外,Mn@Ti具有较高的比表面积和表面羟基数量。与共沉淀和浸渍等方法制备的锰钛氧化物催化剂相比,Mn@Ti催化剂表现出优异的低温脱硝活性和抗水蒸汽能力。催化机制研究揭示了Mn@Ti在NH_3-SCR过程的构效关系。
Amorphous Mn-Ti oxides(Mn@Ti) were fabricated by a liquid spontaneous deposition strategy, and reported as efficient catalysts for low temperature NH_3-SCR. Based on the characterizations from various techniques, including XRD, Raman, BET, H_2-TPR, NH_3-TPD,(HR)TEM, XPS, and In-situ FTIR, it was revealed that the Mn@Ti catalysts in essence are amorphous texture, and the strong interaction between Mn and Ti in atomic scale was confirmed. Furthermore, the synthesis method enabled the preparation of catalysts with high surface area and hydroxyl. Compared with Mn-Ti composite oxide catalysts prepared by traditional impregnation and co-precipitation methods, the current Mn@Ti catalysts showed higher activity at lower temperatures and excellent H_2O durability.
引文
[1]Li,P.;Xin,Y.;X.;Li,Q.;Wang,Z.P.;Zhang,Z.L.;Zheng,L.R.Environ.Sci.Technol.2012,46:9600.