Selective catalytic reduction of NOx with NH3 and tolerance to H2O & SO2 at high temperature over zeolite supported indium-copper bimetallic catalysts for gas turbine

An indium and copper-doped mordenite catalyst (InCu/MOR) was prepared and tested as a potential catalyst for high temperature NH 3 selective catalytic reduction (NH 3 -SCR) of NO x in the gas turbine . The InCu/MOR catalyst exhibited excellent catalytic activity (over 83 % NO x conversion) in the presence of 5 % H 2 O and 100 ppm SO 2 above 550 °C. A series of characterization (XRD, Py-TR, XPS, NH 3 -TPD, H 2 -TPR and in-situ DRIFTS) were applied to analyze the catalyst. The obtained results showed that the addition of indium promoted the formation of isolated Cu 2+ and more Brønsted acid sites, which could improve the tolerance to sulfur dioxide and inhibit the occurrence of high temperature ammonia oxidation side reactions. Meanwhile, the ammonia on InO + /In 2 O 3 sites was activated and reacted with the nitrate/nitrite species on the catalyst surface to form nitroammonium (NH 4 NO 3 /NH 4 NO 2 ), which was a short lived intermediate for NH 3 -SCR. The superior catalytic performance of InCu/MOR could attribute to these comprehensive effects.