低温等离子体协同制备高分散性铁基催化剂催化还原NO性能研究

Preparation of highly-dispersed iron based catalyst with low temperature plasma for NO catalytic reduction

采用浸渍法协同低温等离子体还原制备出负载在椰壳活性炭上的高分散铁基催化剂xFe/AC-φNH_(3)-(t)。采用固定床反应器探究催化剂制备中金属负载量、等离子体处理过程中NH_(3)浓度以及处理时间对催化剂分散性和催化还原NO能力的影响,利用XRD、XPS、SEM、TEM等方法表征催化剂的物化性质,并对反应机理进行推测。结果表明,随着金属负载量、等离子体处理过程中NH_(3)浓度及时间的提升,高分散铁基催化剂催化还原NO的能力逐渐增强,催化剂活性组分数目及分散性协同作用主导催化剂活性。5Fe/AC-10%NH_(3)-(1)催化剂表面Fe_(3)O_(4)均匀分散在活性炭表面,该催化剂在375℃时催化还原NO效率可达97.0%。随着催化还原NO反应的进行,Fe_(3)O_(4)逐渐被氧化成Fe2O3,导致催化剂失活。

The highly dispersed iron based catalyst x Fe/AC-φNH_(3)-(t)loaded on coconut shell activated car-bon was prepared by impregnation method and low temperature plasma reduction.The effects of metal loading amount,NH_(3) concentration and treatment time during the plasma treatment on dispersion and catalytic reduc-tion of NO were investigated in a fixed bed reactor.The physical and chemical properties of catalysts were characterized by XRD,XPS,SEM,TEM and so on.The mechanism of NO reduction was speculated.The re-sults showed that with the increase of metal load,NH_(3) concentration and time in the plasma treatment pro-cess,the catalytic reduction ability of NO was gradually enhanced.The synergistic effect of the amount of ac-tive components and the dispersion of catalysts dominated the catalyst activity.For 5Fe/AC-10%NH_(3)-(1)cata-lyst,Fe_(3)O_(4) was uniformly dispersed on the surface of activated carbon,and the catalytic NO reduction effi-ciency reached to 97.0%at 375℃.With the progress of catalytic NO reduction,Fe_(3)O_(4) is gradually oxidized to Fe2O3,resulting in catalyst deactivation.