Al-PILC负载铜铁复合氧化物在NH3选择性催化还原NO中的协同作用

摘要

以铝柱撑黏土（ Al-PILC）为载体采用旋蒸-浸渍法制备了铜、铁单组分催化剂（ Cu/Al-PILC、Fe/Al-PILC）和铜铁复合氧化物催化剂（ CuFe/Al-PILC），并测试其对NH3选择性催化还原NO反应（ NH3-SCR）的催化性能。相比Cu/Al-PILC和Fe/Al-PILC，CuFe/Al-PILC活性组分之间有较强的协同效应，显著提高了催化剂的脱硝性能。 CuFe/Al-PILC在290～450℃的宽温区NO脱除效率保持90％以上，最高可达97％。此外，CuFe/Al-PILC有很好的抗水抗硫性能，催化活性不受反应气氛中水蒸气和SO2的影响。 XRD、UV-vis、XPS和N2吸附脱附表征结果表明，CuFe/Al-PILC中活性组分相互作用生成CuFe2 O4，有利于活性组分在载体表面分散，提高催化剂的比表面积和孔容；H2-TPR表征结果表明，CuFe/Al-PILC活性组分在载体表面生成的CuFe2 O4改善了催化剂氧化还原性能，有利于NH3对NO选择性的还原；NH3-TPD表征结果表明，CuFe/Al-PILC在较宽温区范围内对NH3都有很好的吸附，这有利于提高催化剂表面还原物种的浓度，从而保证催化剂在较宽温区范围内具有较好的NO脱除效率。%Cu/Al-PILC, Fe/Al-PILC and CuFe/Al-PILC were prepared by rotary evaporation-impregnation method using Al-PILC as support.Selected catalytic reduction of NO with NH3( NH3-SCR) was carried out in a fixed bed er actor to evaluate their catalytic performance.Compared to Cu/Al-PILC and FeA/l-PILC, CuFe/Al-PILC showed better NO removal efficiency ( 97%) and a wider temperature range ( 290 ~450℃) of 90%DeNO because of the strong synergetic effect of Cu-Fe com pso tie oxides.Moreover, CuFe/Al-PILC showed good resistance to water vapor and SO2 .XRD, UV-vis, XPS and N2 adsorption were used to characterize the structure of the catalysts.A new phase CuFe2 O4 formed in CuF e/Al-PILC, which changed the surface properties of CuFe/Al-PILC, improved the dispersion of Cu and Fe on the Al-PILC surface and increased ABET and vp of CuFe/Al-PILC.H2-TPR confirmed the existence of CuFe2 O4 , which improved the re-dox property of CuFe/Al-PILC.The result of NH3-TPD implied that the surface acidity of CuFe/Al-PILC made it possible to adsorb and desorb NH3 in a wide temperature range.The concentration of reducible species on the surface of CuFe/Al-PILC increased, which resulted in high NO removal efficiency.