Impact of Copper Loading on NH3-Selective Catalytic Reduction, Oxidation Reactions and N2O Formation over Cu/SAPO-34

G, Prabhakaran K, Joseph K, Salih A. Selective catalytic reduction of NO over hierarchical Cu ZSM-5 coated on an alumina foam support

Hydrothermal coating of hierarchical Cu ZSM-5 catalyst on alumina foam.

Revisiting NH3–catalyst interactions in Cu-SSZ-13 SCR catalysts: an in situ spectro-kinetics study

At low surface coverages, NH3 consumption was found to occur during adsorption at 120 °C over both Cu-SSZ-13, and H-SSZ-13; albeit much faster on Cu-SSZ-13.

Regeneration of water-deactivated Cu/SAPO-34(MO) with acids

Deactivation and acid regeneration of Cu/SAPO-34 used for NH₃ SCR.

Why does there have to be a residual Na ion as a co-cation on Cu/SSZ-13?

Only the residual Na⁺ ion as co-cation improves the hydrothermal stability and NH₃-SCR activity of Cu/SSZ-13.

Cu/SAPO-34 prepared by a facile ball milling method for enhanced catalytic performance in the selective catalytic reduction of NOx with NH3

Cu/SAPO-34 catalysts were prepared by different solid-state ion exchange methods, i.e., mechanical mixing (Cu/SAPO-34-M) and ball milling (Cu/SAPO-34-B), and were used for selective catalytic reduction of NOx with NH3 (NH3-SCR) reaction. Compared with Cu/SAPO-34-M, Cu/SAPO-34-B exhibited more excellent NH3-SCR catalytic activity. Various characterization methods, including XRD, SEM, N2 adsorption-desorption, UV-vis, H2-TPR, EPR, NO + O2-TPD, NH3-TPD, and in situ DRIFTS, were used to elucidate their different catalytic performances. The characterization results suggested that ball milling could be beneficial for increasing the amount of isolated Cu2+ ions in the Cu/SAPO-34 catalyst. In comparison with Cu/SAPO-34-M, Cu/SAPO-34-B had more isolated Cu2+ ions, which mainly contributed to the NOx adsorption and Lewis acid sites. Furthermore, ball milling could improve the redox property of the Cu/SAPO-34 catalyst. The in situ DRIFTS results verified that NH3 adsorbed on Lewis acid sites were more active than those adsorbed on Brønsted acid sites. Therefore, it was believed that ball milling was a suitable method to prepare more efficient Cu/SAPO-34 catalysts for NOx removal from diesel exhaust.

Suppression of N2O formation by H2O and SO2 in the selective catalytic reduction of NO with NH3 over a Mn/Ti–Si catalyst

Proposed mechanism of NO reduction and N₂O formation as well as H₂O/SO₂ suppression effects with participation of (a) Lewis acid sites and (b) Brønsted acid sites over a Mn/Ti–Si catalyst.

Understanding the mechanism of low temperature deactivation of Cu/SAPO-34 exposed to various amounts of water vapor in the NH3-SCR reaction

Water-exposure at 70 °C deteriorates Cu/SAPO-34, the extent of which depends on water exposure time, reaction temperature, and choice of SDAs.

Effect of various structure directing agents (SDAs) on low-temperature deactivation of Cu/SAPO-34 during NH3-SCR reaction

Cu/SAPO-34(TEA) only exhibited minor deactivation and mostly recovered its original activities, while Cu/SAPO-34(MO) showed major deactivation and was not fully regenerated during low temperature NH₃-SCR reaction.