Ammonia selective catalytic reduction of NO over Fe/Cu-SSZ-13

Abstract

A series of CHA-type Fe_x/Cu-SSZ-13 catalysts were prepared by liquid ion exchange method based on the one-pot synthesized Cu-SSZ-13 catalyst. The catalysts were applied to the selective catalytic reduction of NO with NH₃ and were characterized by means of XRD, N₂ adsorption–desorption, UV-Vis-DRS, H₂-TPR, XPS and in situ DRIFTS. Fe_x/Cu-SSZ-13 catalysts achieved high NH₃-SCR activity, excellent N₂ selectivity from 150 °C to 550 °C, high hydrothermal stability and were highly resistant to high space velocity. The results may be attributed to the synergistic effects between copper and iron species. The results of H₂-TPR, UV-Vis DRS and XPS indicated that more active sites and stronger redox capacity contributed to the excellent NH₃-SCR performance upon the addition of Fe species into Cu-SSZ-13. In situ DRIFTS results showed that NO⁺ and NO³⁻ generated from NO + O₂ adsorption were the key intermediates and were further reduced to N₂ by NH₃.