沉淀剂对铁铈复合氧化物催化剂SCR脱硝性能的影响

Effect of precipitants on selective catalytic reduction of NO by NH_3 over iron-cerium mixed metal oxide catalyst

通过共沉淀法制备铁铈复合氧化物催化剂,考察两种典型氨基和4种典型碱金属沉淀剂对其选择性催化还原脱硝(NH3-SCR)的影响规律;借助N2吸附、X射线衍射(XRD)和红外光谱(IR),探讨不同沉淀剂影响铁铈催化剂SCR脱硝性能的原因。结果表明:与碱金属沉淀剂(NaOH,KOH,Na2CO3和K2CO3)相比,氨基沉淀剂(NH4OH和(NH4)2CO3)制备的铁铈催化剂具有良好SCR脱硝性能;氨基沉淀剂促使铁铈催化剂中形成铁铈固溶体,优化铁铈催化剂的孔隙结构,增大其表面积和孔容,细化其孔径,使铁铈催化剂具有良好的SCR脱硝性能;FeCe-NH4OH和FeCe-(NH4)2CO3的比表面积依次为107.05,108.80 m2/g,分别为FeCe-NaOH和FeCe-Na2CO3比表面积的1.36和1.83倍。

Iron-cerium mixed oxide catalysts were prepared through co-precipitation method,and two typical amino-precipitants and four base-precipitants were used to study the effect of precipitants on selective catalytic reduction of NO（SCR） over iron-cerium mixed oxide catalyst.Catalysts were characterized by N2 adsorption-desorption,X-ray diffraction（XRD） and IR to reveal the effect of precipitants on their SCR activity.The results indicate that compared with the catalysts prepared with base-precipitants（NaOH,KOH,Na2CO3 and K2CO3）,iron-cerium mixed oxide catalysts prepared with amino-precipitants（NH4OH and（NH4）2CO3） show a better SCR activity.Compared with base-precipitants,amino-precipitants can promote the formation of iron-cerium solution mixed oxide in catalyst,and optimize its pore structure.Therefore,amino-precipitants enlarge the BET surface and the pore volume of the iron-cerium mixed oxide catalyst,and refine its pore size.Hence,iron-cerium mixed oxide catalyst prepared by amino-precipitants shows a better SCR activity.The BET surface areas of FeCe-NH4OH and FeCe-（NH4）2CO3 are 107.05 and 108.80 m2/g,and are 1.36 and 1.83 times of the BET surface areas of FeCe-NaOH and FeCe-Na2CO3,respectively.