Enhanced catalytic performance in low-temperature NH3-SCR process of spherical MCM-41 modified with Cu by template ion-exchange and ammonia treatment

Abstract

Spherical MCM-41 (S-MCM-41) was synthesised and used as support for deposition of copper by template ion-exchange (TIE) method using CuCl2 solutions. Another series of catalysts was prepared by modified TIE procedure, including treatment of S-MCM-41, directly after TIE, with ammonia solution (TIE-NH3). The samples were characterized with respect to chemical composition (ICP-OES), texture (N2-sorption), structure (XRD, FTIR), morphology and surface composition (SEM-EDS), aggregation of copper species (UV–vis-DRS), reducibility (H2-TPR) and surface acidity (NH3-TPD). It was shown that deposition of copper by TIE method resulted in samples containing simultaneously highly dispersed copper species as well as CuO nanorods. The TIE-NH3 procedure resulted in deposition of highly dispersed copper species located mainly inside pores without formation of CuO crystallites. The samples obtained by TIE-NH3 method were found to be very promising catalysts for the low-temperature NH3-SCR process, possibly due to the presence of large number of highly dispersed copper species, deposited on the large surface area of S-MCM-41.