ZSM-5 and ferrierite single crystals with lower Si/Al ratios: Synthesis and single-crystal synchrotron X-ray diffraction studies

Kim, Seok Han; Komarneni, Sridhar; Heo, Nam Ho

doi:10.1016/j.micromeso.2011.02.010

Cited by 9 publications

(5 citation statements)

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“…The small diffraction peak observed at 2ϑ of ca. 9.3° was attributed to the formation of the ferrierite (FER) phase in the zeolite [ 35 , 39 ]. On the other hand, both the low intensity of this maximum and other physicochemical features of the material further confirmed that the morphology and textural parameters are characteristic for the MWW zeolites.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization, and NH3-SCR Catalytic Performance of Fe-Modified MCM-36 Intercalated with Various Pillars

et al. 2023

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Two series of MCM-36 zeolites intercalated with various pillars and modified with iron were synthesized, analyzed with respect to their physicochemical properties, and tested as catalysts for the NH3-SCR process. It was found that the characteristic MWW morphology of MCM-36 can be obtained successfully using silica, alumina, and iron oxide as pillars. Additionally, one-pot synthesis of the material with iron resulted in the incorporation of monomeric Fe3+ species into the framework positions. The results of catalytic tests revealed that the one-pot synthesized sample intercalated with silica and alumina was the most efficient catalyst of NO reduction, exhibiting ca. 100% activity at 250 °C. The outstanding performance of the material was attributed to the abundance of Lewis acid sites and the beneficial influence of alumina on the distribution of iron species in the zeolite. In contrast, the active centers originating from the Fe2O3 pillars improved the NO conversion in the high-temperature range. Nevertheless, the aggregated particles of the metal oxide limited the access of the reacting molecules to the inner structure of the catalyst, which affected the overall activity and promoted the formation of N2O above 300 °C.

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Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization, and NH3-SCR Catalytic Performance of Fe-Modified MCM-36 Intercalated with Various Pillars

et al. 2023

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“…Preparation of CsÀZSM-5. Colorless crystals of ZSM-5 (30 Â 30 Â 100 μm) were synthesized as twin tabloids by Kim et al 42 The reagents used for their synthesis were Et 3 N 3 3HF (98%, Aldrich), tetrapropylammonium bromide (TPABr, 98%, Aldrich), pyridine (99%, Aldrich), propylamine (98%, Aldrich), pseudoboehmite (Al 2 O 3 3 2H 2 O, Catapal B, Vista), fumed silica (SiO 2 , Aerosil 200, Degussa), and deionized water. The molar composition of the final synthesis mixture was 2(Et 3 N 3 3HF) 3 0.5TPABr 3 16pyridine 3 2propylamine 3 0.25Al 2 O 3 3 2SiO 2 3 90H 2 O.…”

Section: Methodsmentioning

confidence: 99%

Framework Sites Preferred by Aluminum in Zeolite ZSM-5. Structure of a Fully Dehydrated, Fully Cs⁺-Exchanged ZSM-5 Crystal (MFI, Si/Al = 24)

2011

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ARTICLEdetermined by powder diffraction methods. 30À34 Only one to five cation positions were found, suggesting that Al 3+ was not distributed randomly over the 12 T sites. Chao et al. found only one Cs + position in both hydrated and dehydrated CsÀZSM-5 (Cs 3.56 Si 92.44 Al 3.56 O 192 , Si/Al = 26) and reported that it was near a 4-ring (near T9), near the intersection of the two (straight and sinusoidal) channels. 30 However, Olson et al. later reported three crystallographically distinct Cs + positions in dehydrated CsÀZSM-5 (Cs 5.8 Si 90.2 Al 5.8 O 192 , Si/Al = 15.6), all different from that reported by Chao, close to the T12, T7, and T10 tetrahedra. 31 Finally in more recent work, Mentzen et al. 32À35 reported the temperature dependence of the Cs + positions in hydrated and dehydrated MFI; two of Mentzen's five Cs + positions were essentially the same as those of Olson, two others amounted to a resolution of Olson's third position into two, and the fifth was new. These results indicated that Al atoms prefer sites T12, T7, T10, and T5.To maximize the signal, the crystallographic determination of the extraframework cation positions is best done using cations with high scattering power to charge ratios. To maximize their number, a ZSM-5 material with a relatively high Al content is desirable. Finally, single-crystal crystallography generally provides more detailed results than power diffraction. However, suitably large single crystals with relatively high framework Al contents have been difficult to obtain, possibly because of increased nucleation rates due to Al 3+ -containing species in the synthesis solution. 36 It has recently been reported that the framework sites that are preferred by Al ions in high silica aluminosilicates are a sensitive function of the method of synthesis. 37À40 Accordingly, the results presented here are unlikely to be correct for ZSM-5 crystals that were synthesized differently, even if only somewhat differently.This work was done before with Tl + and with a ZSM-5 single crystal that had been synthesized differently. 41 From the occupancies and TlÀO bond lengths of the 18 low occupancy Tl + positions found, a reliable preference order for Al among the 12 T positions was inferred. Cs + may be better than Tl + for this because covalent bonding considerations to framework oxygen atoms are much less, allowing the Cs + ions to more reliably indicate the Al 3+ positions. Although Cs + does not scatter X-rays as strongly as Tl + (atomic numbers 55 and 81, respectively), more Cs + cations are present here because Si/Al = 24; it was 29 in the TlÀZSM-5 work. 41 Here we attempted to fully Cs + -exchange a single crystal of ZSM-5 and to determine crystallographically the exchangeable cation positions in its fully dehydrated structure. Available to us were moderate-sized modestly twinned single crystals of ZSM-5 with moderate Al contents, Si/Al = 24, and synchrotron X-radiation. With anticipated high quality data, we hoped to accurately determine the positions of the low occupancy extra...

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“…Following this synthesis strategy, aluminosilicate FER zeolites with the Si/Al ratio in the range of 10-16 were successfully prepared, although the crystallization time was relatively long (at least 10 days) [66]. In 2011, Komarneni et al prepared the large single crystals of aluminosilicate FER zeolite using the mixed organic molecules (triethylamine (Et 3 N), TPABr, Py, and propylamine (PA)), while the structure-directing effect of these organic molecules was not mentioned [67]. Meanwhile, Davis et al reported the synthesis of aluminosilicate FER zeolites using a combination of organic templates including TMA and one of the cyclic amines (THP, hexamethyleneimine (HMI), and 1,4-diazabicyclo [2.2.2] octane (DAB)).…”

Section: Synthesis Of Aluminosilicate Fer Zeolite With the Use Of Thementioning

confidence: 99%

“…In the zeolite synthesis, the application of organic templates has many advantages such as reducing the crystallization temperature and time, increasing the Si/Al ratio of the products, adjusting the properties of the products and so on. So far, a variety of organic templates, including alkylamines, cyclic amines, and alcohols have been reported to be used in the synthesis of aluminosilicate FER zeolites [ 6 , 18 , 20 , 26 , 27 , 29 , 32 , 36 , 37 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ]. The detailed information of organic templates for synthesizing FER zeolite is shown in Table 2 .…”

Section: Synthesis Of Aluminosilicate Fer Zeolite With the Use Of mentioning

confidence: 99%

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Advances in the Synthesis of Ferrierite Zeolite

Zhu

et al. 2020

Molecules

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As one of the most important porous materials, zeolites with intricate micropores have been widely employed as catalysts for decades due to their large pore volume, high surface area, and good thermal and hydrothermal stabilities. Among them, ferrierite (FER) zeolite with a two-dimensional micropore structure is an excellent heterogeneous catalyst for isomerization, carbonylation, cracking, and so on. In the past years, considering the important industrial application of FER zeolite, great efforts have been made to improve the synthesis of FER zeolite and thus decrease the synthesis cost and enhance catalytic performance. In this review, we briefly summarize the advances in the synthesis of FER zeolite including the development of synthesis routes, the use of organic templates, organotemplate-free synthesis, the strategies of morphology control, and the creation of intra-crystalline mesopores. Furthermore, the synthesis of hetero-atomic FER zeolites such as Fe-FER and Ti-FER has been discussed.

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ZSM-5 and ferrierite single crystals with lower Si/Al ratios: Synthesis and single-crystal synchrotron X-ray diffraction studies

Cited by 9 publications

References 24 publications

Synthesis, Characterization, and NH3-SCR Catalytic Performance of Fe-Modified MCM-36 Intercalated with Various Pillars

Synthesis, Characterization, and NH3-SCR Catalytic Performance of Fe-Modified MCM-36 Intercalated with Various Pillars

Framework Sites Preferred by Aluminum in Zeolite ZSM-5. Structure of a Fully Dehydrated, Fully Cs⁺-Exchanged ZSM-5 Crystal (MFI, Si/Al = 24)

Advances in the Synthesis of Ferrierite Zeolite

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ZSM-5 and ferrierite single crystals with lower Si/Al ratios: Synthesis and single-crystal synchrotron X-ray diffraction studies

Cited by 9 publications

References 24 publications

Synthesis, Characterization, and NH3-SCR Catalytic Performance of Fe-Modified MCM-36 Intercalated with Various Pillars

Synthesis, Characterization, and NH3-SCR Catalytic Performance of Fe-Modified MCM-36 Intercalated with Various Pillars

Framework Sites Preferred by Aluminum in Zeolite ZSM-5. Structure of a Fully Dehydrated, Fully Cs+-Exchanged ZSM-5 Crystal (MFI, Si/Al = 24)

Advances in the Synthesis of Ferrierite Zeolite

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Framework Sites Preferred by Aluminum in Zeolite ZSM-5. Structure of a Fully Dehydrated, Fully Cs⁺-Exchanged ZSM-5 Crystal (MFI, Si/Al = 24)