High activity and wide temperature window of Fe‐Cu‐SSZ‐13 in the selective catalytic reduction of NO with ammonia

Abstract

Fe‐Cu‐SSZ‐13 catalysts were prepared by aqueous solution ion‐exchange method based on the one‐pot synthesized Cu‐SSZ‐13. The catalysts were applied to the selective catalytic reduction (SCR) of NO with NH3 and characterized by the means of XRD, UV‐Vis, EPR, XPS, NH3‐TPD, and so on. The selected Fe‐Cu‐SSZ‐13‐1 catalyst exhibited the high NO conversion (>90%) in the wide temperature range (225–625°C), which also showed good N2 selectivity and excellent hydrothermal stability. The results of XPS showed that the Cu and Fe species were in the internal and outer parts of the SSZ‐13 crystals, respectively. The results of UV‐Vis and EPR indicated that the monomeric Cu2+ ions coordinated to three oxygen atoms on the six‐ring sites and Fe monomers are the real active species in the NH3‐SCR reaction. Furthermore, the influence of intracrystalline mass‐transfer limitations on the Fe‐Cu‐SSZ‐13 catalysts is related to the location of active species in the SSZ‐13 crystals. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3825–3837, 2015

Fe‐Beta@CeO2 core‐shell catalyst with tunable shell thickness for selective catalytic reduction of NOx with NH3

“…Thus, the combined impacts of H 2 O and SO 2 on the SCR activity were also explored over Fe-Beta@CeO 2 -1 catalyst. NO x conversion decreases from initial 100 to about 83.4% after 2 h, and maintains at this conversion for 24 h. But NO x conversion could recover to 88.5% with increasing reaction time after cutting off the supply of H 2 O and SO 2 . The above results demonstrate that Fe-Beta@CeO 2 -1 catalyst exhibits an excellent H 2 O and SO 2 durability.…”

“…For example, Cargnello et al 22 developed Pd@CeO 2 /Al 2 O 3 CSCs for catalytic methane combustion, which exhibited better catalytic activity than either Pd/CeO 2 or Pd/CeO 2 /Al 2 O 3 due to the presence of interface effect between Pd and CeO 2 during the catalytic process. Zhang et al 23 synthesized Pd@CeO 2 CSCs by a combination of sol-gel and hydrothermal reaction, which showed high activity toward the reduction of aromatic nitro compounds attributed to CeO 2 shell preventing the migration and aggregation of Pd nanoparticles (NPs) in the catalytic reaction. Zhang et al 24 presented TiO 2 @MnCe/carbon-nanotubes (CNTs) CSCs to be employed in NH 3 -SCR reaction.…”

“…1,2 Selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) is considered as an effictive and economic method for abating NO x emmisions. The widely used catalyst for this SCR process is V 2 O 5 -WO 3 (MoO 3 )/TiO 2 .…”

Functionalization of SSZ-13 and Fe-Beta with Copper by NH3 and NO Facilitated Solid-State Ion-Exchange

“…Recently, several examples of one-pot synthesis methods to functionalize zeolite structures with Fe and/or Cu have been reported, e.g., [18][19][20][21]. As an example, one can use a one-pot synthesis of Cu-or Fe-zeolite, where either copper or iron occupies T-atom positions in the zeolite framework structure, followed by ion-exchange using AIE or wet impregnation (WI) of the other metal.…”

“…As an example, one can use a one-pot synthesis of Cu-or Fe-zeolite, where either copper or iron occupies T-atom positions in the zeolite framework structure, followed by ion-exchange using AIE or wet impregnation (WI) of the other metal. For instance, Zhang et al synthesized Cu-SSZ-13 in a direct route and ion-exchanged it with Fe [18]. Although the authors claimed an improvement of the NH 3 -SCR activity and a broadening of the active temperature window, the improvement was eventually observed only at high temperatures while the low-temperature activity of the (Fe + Cu)-SSZ-13 was considerably lower compared to the corresponding SSZ-13 ion-exchanged only with copper.…”