Effect of preparation method on NH3-SCR activity of Cu-LTA catalysts

• Preparation method effect on the NH 3 -SCR activity of Cu-LTA is investigated. • Copper nitrate and ion exchange are the best Cu source and loading method, respectively. • The [2Z-Cu] species is responsible for the superior hydrothermal stability of Cu-LTA. The preparation method effect on the catalytic properties and hydrothermal stability of copper-loaded LTA (Cu-LTA) zeolites for the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) has been investigated. Copper nitrate and liquid-state ion exchange (IE) was found to be the best for maximizing the SCR performance of Cu-LTA among the Cu sources and loading methods studied here. When fresh, the low-temperature (≤ 400 °C) activity of Cu-LTA prepared in this way, denoted Cu-LTA( n )IE, is lower than that of the catalyst prepared using copper acetate via ion exchange. After hydrothermal aging at 900 °C for 24 h, however, Cu-LTA( n )IE shows a higher deNO x activity in the studied temperature range than any other catalysts. The overall characterization results show that the excellent hydrothermal durability of Cu-LTA( n )IE resulted from the stability of [2Z-Cu] species generated by locating Cu 2+ ions onto Al pairs in the LTA framework.