Synergetic effect of Cu-Fe composite oxides supported on Al-PILC for SCR of NO with NH₃

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 reactor to evaluate their catalytic performance. Compared to Cu/Al-PILC and Fe/Al-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 composite 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 CuFe₂O₄ formed in CuFe/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 A_BET and v_p of CuFe/Al-PILC. H₂-TPR confirmed the existence of CuFe₂O₄, 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.