WO_3对MnO_x-CeO_2/ZrO_2-TiO_2整体式催化剂NH_3选择性催化还原NO_x性能的影响

Influence of Tungsten Oxide on Selective Catalytic Reduction of NO_x with NH_3 over MnO_x-CeO_2/ZrO_2-TiO_2 Monolith Catalyst

以ZrO2-TiO2为载体,MnOx-CeO2为活性组分,WO3为助剂制备了MnOx-CeO2/WO3/ZrO2-TiO2整体式催化剂,考察了添加不同质量分数的WO3对低温氨选择性催化还原(NH3-SCR)氮氧化物反应性能的影响.通过低温N2吸附-脱附,X射线衍射(XRD),X射线光电子能谱(XPS),NH3程序升温脱附(NH3-TPD)等手段对催化剂进行表征.实验结果表明,与未添加WO3的催化剂相比,含有10.0%(w)WO3的催化剂具有较好的织构性能,且具有较多的中强酸位,较好的氧化性能,表现出良好的NH3-SCR活性和较宽的活性温度窗口(空速为10000h-1时,在144-374℃之间,NOx转化率为90%以上),该催化剂在低温净化氮氧化物中具有潜在的应用前景.

MnOx-CeO2/WO3/ZrO2-TiO2monolithic catalyst was prepared by ZrO2-TiO2 as support,MnOx-CeO2 as active components and WO3 as the promoter.The influence of the different mass fractions（w） of WO3 on the NH3-selective catalytic reduction（NH3-SCR） of NOx performance at low temperature was studied.The catalysts were characterized by N2 adsorption-desorption at low temperature,X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,and NH3 temperature-programmed desorption（NH3-TPD）.The experimental results showed that,compared with the catalyst without WO3,the catalyst with 10.0%（w） WO3 had good texture properties,middle strong acid sites,and higher oxidation performance.The results of activity test showed that the monolith catalyst had not only good catalytic activity at low temperature but also a wide activity temperature window.The NOx conversion is more than 90% in the temperature range of 144-374℃ at the space velocity of 10000 h-1.It shows potential application in de-NOx at low-temperature.