CO and NO adsorption for the IR characterization of Fe2+ cations in ferrierite: An efficient catalyst for NOx SCR with NH3 as studied by operando IR spectroscopy

• DOI: 10.1016/j.cattod.2009.09.015
• Publication Date: 2009-10-31T04:56:09Z
• Authors: I. Malpartida; E. Ivanova; M. Mihaylov; K. Hadjiivanov; V. Blasin-Aubé; O. Marie; M. Daturi
• Keywords: SCR-NH3; Ferrierite; CO and NO adsorption; [CHIM]Chemical Sciences; 02 engineering and technology; In situ IR; 540; Operando IR; 0210 nano-technology

Abstract Iron was introduced by ionic exchange inside the FER structure in order to yield a Fe-FER series with increasing metal loading. Characterization of the Fe 2+ cations by adsorption of CO at liquid nitrogen temperature followed by infrared spectroscopy allowed to identify three distinct sites for iron. The most abundant iron species are located on easily accessible sites of the FER structure, whereas high metal loading is required to observe more confined Fe 2+ species. According to the CO adsorption results, the main iron species appears to be coordinatively unsaturated whereas isotopic labelling upon NO adsorption indicates that two distinct iron sites almost give rise to the same mononitrosyl infrared signature. Studying the catalyst upon interaction with NO and O 2 in operando conditions leads to the observation of these mononitrosyl species who behave as reaction intermediates for the NO oxidation into NO 2 . All our Fe-FER samples presenting these mononitrosyl complexes are active not only in NO-to-NO 2 reaction but also in the NOx selective catalytic reduction with ammonia. The effects of both NH 3 and SO 2 as adsorption competitor during the low temperature NH 3 -SCR are also discussed.