Efficient One‐Pot Preparation of Cu‐SSZ‐13 Materials using Cooperative OSDAs for their Catalytic Application in the SCR of NO<sub><i>x</i></sub>

Martínez-Franco, Raquel; Moliner, Manuel; Thøgersen, Joakim R.; Corma, Avelino

doi:10.1002/cctc.201300141

Cited by 123 publications

(92 citation statements)

References 22 publications

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“…This explains why hydrothermal aging effects have been so extensively studied [39][40][41][52][53][54]. Prior studies have suggested that Cu/SSZ-13 durability enhancement can be achieved in a number of ways: (1) composition optimization, that is, choosing optimized Si/Al and Cu/Al ratios [31]; (2) zeolite particle size optimization [55]; (3) new synthesis methods development [30,[56][57][58][59]; and (4) introduction of stability enhancement additives. Among these, some appear not to be as useful as others.…”

Section: Towards Rational Design Of Cu/ssz-13mentioning

confidence: 99%

“…From our own experience, too large of a particle size can even be detrimental due to poor heat dissipation during structure directing agent (SDA) combustion that induces rather serious thermal degradation of the SSZ-13 substrate. Also, new Cu/SSZ-13 synthesis methods, including one-pot ones, do not necessarily lead to catalysts with better stability than catalysts prepared with more traditional solution ion-exchange methods [30,[56][57][58][59].…”

Section: Towards Rational Design Of Cu/ssz-13mentioning

confidence: 99%

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Recent Progress in Atomic-Level Understanding of Cu/SSZ-13 Selective Catalytic Reduction Catalysts

2018

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Cu/SSZ-13 Selective Catalytic Reduction (SCR) catalysts have been extensively studied for the past five-plus years. New and exciting fundamental and applied science has appeared in the literature quite frequently over this time. In this short review, a few topics specifically focused on a molecular-level understanding of this catalyst are summarized: (1) The nature of the active sites and, in particular, their transformations under varying reaction conditions that include dehydration, the presence of the various SCR reactants and hydrothermal aging; (2) Discussions of standard and fast SCR reaction mechanisms. Considerable progress has been made, especially in the last couple of years, on standard SCR mechanisms. In contrast, mechanisms for fast SCR are much less understood. Possible reaction paths are hypothesized for this latter case to stimulate further investigations; (3) Discussions of rational catalyst design based on new knowledge obtained regarding catalyst stability, overall catalytic performance and mechanistic catalytic chemistry.

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Section: Towards Rational Design Of Cu/ssz-13mentioning

confidence: 99%

Section: Towards Rational Design Of Cu/ssz-13mentioning

confidence: 99%

Recent Progress in Atomic-Level Understanding of Cu/SSZ-13 Selective Catalytic Reduction Catalysts

2018

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“…Recently, it has been described the direct synthesis of Cu-SSZ-13 [13] and other related Cu-containing silicoaluminophosphate materials, such as Cu-SAPO-34 [12d, [14]] and Cu-7 SAPO-18, [15] using the combination of an organometallic Cu-complex (Cu-TEPA) and a cooperative organic molecule as OSDA. Following a similar "one-pot" synthesis procedure combining Cu-TEPA and N,N-dimethyl-3,5-dimethylpiperidinium as cooperative OSDAs, a crystalline Cu-containing SSZ-39 material has been achieved (see supporting information for experimental details and the PXRD pattern of Cu-SSZ-39 in Figure 1).…”

Section: +mentioning

confidence: 99%

Efficient synthesis of the Cu-SSZ-39 catalyst for DeNOx applications

et al. 2015

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The use of small pore zeolites with large cavities has been reported for relevant applications in catalysis or gas separation.[1] One of the most important applications of these materials as catalysts is the selective catalytic reduction (SCR) of nitrogen oxides (NO x ), where copper-containing zeolites with small pore sizes show excellent activities to remove these hazardous compounds produced during combustion in diesel engines. [1,2] Interestingly, these small-pore zeolites show higher hydrothermal stability compared to other zeolitic materials presenting larger pore sizes, such as Cu-ZSM-5 or Cu-Beta. [3] The particular stabilization of the Cu 2+ cations within the double 6-rings (D6Rs) present in some structures of these small pore zeolites, i.e. chabazite (CHA structure), has been claimed as a plausible reason for their higher hydrothermal stability.[4]Another zeolite with related structural properties to chabazite is SSZ-39 (AEI structure), which is an aluminosilicate with large cages connected by a three-directional small 8-ring (8-R) pore system, and also with D6R as secondary building units in its structure.[5]Recently, we have reported that Cu-exchanged SSZ-39 zeolite is an active and hydrothermally stable catalyst for the SCR of NO x with ammonia, showing even better catalytic performance than Cu-exchanged CHA.[6]The preferred synthesis procedure of SSZ-39 requires the use of simple alkylsubstituted cyclic quaternary ammonium cations as organic structure directing agents (OSDAs) in alkaline conditions. [7] These organic cations could be easily prepared from commercially-available pyridine precursors, [8] making attractive the use of these OSDAs for the synthesis of the SSZ-39 from an economic point of view. Unfortunately, this methodology can afford the preparation of the SSZ-39 in low solid yields (lower than 50%), since the final crystalline solids show much lower Si/Al ratios than the Si/Al ratios initially introduced in the synthesis gels, [6,7,8] indicating that most of the Si species remain in solution after the crystallization procedure. This fact limits the potential use of SSZ-39 in commercial applications.Recently, the synthesis of the high silica AEI zeolite with high solid yields (above 80%) has been reported using USY zeolite as silicon source and tetraethylphosphonium (TEP)cations as OSDA. [9] Although this achievement is highly relevant in terms of the optimization of the SSZ-39 synthesis, the use of P-based OSDAs still presents some 3 important drawbacks. On one hand, phosphine-derived organic molecules show important environmental and health hazards, and, on the other hand, the complete removal of the phosphorous-species entrapped within the zeolitic cavities is very difficult, especially within small pore zeolites, and their calcination process requires high temperatures and hydrogen atmospheres for the complete decomposition/elimination of these compounds.[9]It is worth mentioning that in the last years the use of pre-formed crystalline zeolitic precursors to synthesize different...

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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Abstract:We show that functionalization of SSZ-13 (CHA) and Fe-beta (*BEA) with copper using a recently reported solid-state ion-exchange method, facilitated by NH 3 and nitrogen oxides (NO), is a viable route to prepare Cu-SSZ-13 and (Cu + Fe)-beta catalysts, starting from H-SSZ-13 and Fe-beta, respectively. The physicochemical properties of the prepared catalysts are characterized by XRD, UV-Vis-spectroscopy and STEM-EDS, confirming that copper originally present in the physical mixture of CuO and H-SSZ-13, and CuO and Fe-beta, is inserted into the micropores of SSZ-13 and Fe-beta, respectively. Activity measurements in gas-flow reactor show that the samples are active for NO reduction by NH 3 -SCR over a broad temperature range, i.e., 150-500 • C. For the Cu-SSZ-13 catalysts, which have a copper loading range of 0.5-4 wt. %, the sample prepared from the physical mixture with a CuO/SSZ-13 ratio corresponding to 2 wt. % Cu is the most active catalyst for NH 3 -SCR under the present reaction conditions. Furthermore, the (Cu + Fe)-beta catalyst shows higher NH 3 -SCR activity over a broader temperature range and especially at low temperature as compared to the Fe-beta and Cu-beta counterparts. The results encourage further elaboration on sequential ion-exchange procedures for bimetallic functionalization of zeolites.

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Efficient One‐Pot Preparation of Cu‐SSZ‐13 Materials using Cooperative OSDAs for their Catalytic Application in the SCR of NO_x

Cited by 123 publications

References 22 publications

Recent Progress in Atomic-Level Understanding of Cu/SSZ-13 Selective Catalytic Reduction Catalysts

Recent Progress in Atomic-Level Understanding of Cu/SSZ-13 Selective Catalytic Reduction Catalysts

Efficient synthesis of the Cu-SSZ-39 catalyst for DeNOx applications

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

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Efficient One‐Pot Preparation of Cu‐SSZ‐13 Materials using Cooperative OSDAs for their Catalytic Application in the SCR of NOx

Cited by 123 publications

References 22 publications

Recent Progress in Atomic-Level Understanding of Cu/SSZ-13 Selective Catalytic Reduction Catalysts

Recent Progress in Atomic-Level Understanding of Cu/SSZ-13 Selective Catalytic Reduction Catalysts

Efficient synthesis of the Cu-SSZ-39 catalyst for DeNOx applications

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

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Efficient One‐Pot Preparation of Cu‐SSZ‐13 Materials using Cooperative OSDAs for their Catalytic Application in the SCR of NO_x