Role of CTAB in the improved H2O resistance for selective catalytic reduction of NO with NH3 over iron titanium catalyst

Abstract Uniform mesoporous iron titanium (CT-FeTi) catalysts were synthesized by a CTAB-assisted process and exhibited good catalytic activity and H 2 O resistance when tested in the selective catalytic reduction (SCR) of NO with NH 3 at low temperature. BET, TPD, TPSR and in situ DRIFTS were carried out to reveal the inhibition mechanism of H 2 O on SCR reaction and determine the role of CTAB in the improved H 2 O resistance during low-temperature SCR processes. Results showed that H 2 O inhibited the adsorption of NO on the surface of CT-FeTi catalysts, as well as the formation of the intermediate species (–NH 2 ), which was produced by the reaction Fe 3+ + NH 3 → Fe 2+ - NH 2 + H + . CTAB acted as a “structural” and “chemical” promoter, not only optimizing the pore size to avoid being excessively enlarged in the presence of H 2 O, but also enhancing the adsorption of bridging nitrate and NH 3 species on Lewis acid sites, thus improving the catalytic activity and H 2 O resistance.