Stability of zeolite supported (promoted-) Pd catalysts in the reduction of NOx in gas engines using methane

Synergy of FexCe1−xO2 mixed oxides for N2O decomposition

“…For this reaction, the best catalyst is prepared by exchanging Fe III /Fe II salts (solid and gas) within a zeolite matrix, giving rise to high turnover rates even for low Fe loadings (ca. 0.5 wt% Fe) [11][12][13][14][15]. In this paper we show that Fe-Ce mixed oxides yield improved N 2 O decomposition, much greater than those of the individual phases.…”

Potential synergic effect between MOR and BEA zeolites in NOx SCR with methane: A dual bed design approach

“…For instance, Pieterse, et al [14] reported a NO x conversion of ca. 60%, at 375 ºC, with However, results show that the NO x conversion achieved by dual bed is higher than Pd(0.3)Ce(2)-HMOR and, also, CH 4 conversion to CO 2 is lower.…”

“…Pd-zeolites are known to be active for NO x SCR using methane, under lean conditions, as a reductant [6][7][8]. The catalytic performance of these catalysts can be improved by considering bimetallic formulations, such as PdCo-zeolites [9,10] and PdCe-zeolites [11,12].Despite being active and selective catalysts, it has been reported in literature that PdCo-zeolites [13] suffer from deactivation over time, but the same seems not to happen with PdCe-zeolites, which activity has been reported to be constant over the time [14].Hence, the further understanding of the role of Ce in these catalysts might be important to move forward towards a commercial application of this type of aftertreatment system.…”

Active Sites, Deactivation and Stabilization of Fe-ZSM-5 for the Selective Catalytic Reduction (SCR) of NO with NH3

“…They are characterized by a high activity over a broad temperature range, they are nontoxic and produce little N 2 O. [7][8][9] Iron zeolites have been on the market for quite some time and especially Fe-ZSM-5 and Fe-BEA are used as raw materials for the production of SCR catalysts. Metalexchanged zeolites are usually manufactured according to the following methods: i) in liquid ion exchange (W), which is the most common technology, metal salts are stirred with the zeolite base material in an aqueous slurry.…”

“…Metalexchanged zeolites are usually manufactured according to the following methods: i) in liquid ion exchange (W), which is the most common technology, metal salts are stirred with the zeolite base material in an aqueous slurry. [9,10] Multiple charged ions, such as Cu 2+ , Fe 2+ or Fe 3+ , are more difficult to stabilize inside the zeolite than single charged ions, because their charge must be compensated by several negatively charged aluminum atoms and due to their larger hydration sphere, what makes the exchange more difficult. ii) Chemical vapor ion deposition (CVD) is a process which is particularly suitable for the production of zeolites with a high exchange degree.…”