Effective catalysts for the low-temperature NH3-SCR process based on MCM-41 modified with copper by template ion-exchange (TIE) method

Abstract

Effective catalysts for the low-temperature process of selective catalytic reduction of NO with ammonia (NH3-SCR) were obtained by deposition of copper species on MCM-41 using template ion-exchange method (TIE). It was shown that the form and aggregation of deposited copper species depend on concentration of copper salt (CuCl2) solution and solvent composition used for TIE procedure. In the case of methanol solution of CuCl2 copper in the highly dispersed form, mainly monomeric species, was deposited on the silica support, while in the case of water containing solutions of CuCl2 more aggregated CuO species were formed. The efficiency in deposition of highly dispersed copper species was significantly improved by treatment of the MCM-41 samples with ammonia directly after TIE procedure. In this case nearly 13 wt.% of copper was deposited on MCM-41 nearly exclusively in the form of monomeric cations. The catalysts obtained by this method presented high activity, selectivity to N2 and stability in the low-temperature (200–300 °C) NH3-SCR process.