Stabilization of bare divalent Fe(II) cations in Al-rich beta zeolites for superior NO adsorption

Ogura, Masaru; Itabashi, Keiji; Dědeček, Jiřı́; Onkawa, Tatsuki; Shimada, Yuichiro; Kawakami, Kazuto; Onodera, Kenzo; Nakamura, Shinnosuke; Okubo, Tatsuya

doi:10.1016/j.jcat.2014.04.001

Cited by 29 publications

(24 citation statements)

References 41 publications

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“…Previous reports of varying zeolite framework topologies [8,9,13,17,18] adopting as eed-assisted, OSDA-free approach also showed products in the absence or ar elatively small amount of extra-framework Al. In ar elated matter,r ecent works [47][48][49] showedt hat zeolite beta obtained from seed-assisted, OSDAfree synthesis exhibitedadifferent Al distribution compared to that of conventional OSDA-directed beta. [42][43][44][45][46] According to Kennedy et al, [42,43] the 27 Al DD-MASN MR peak attributed to four-coordinated framework Al can be resolved into three overlapped signals around d Al = 61, 56 and 50 ppm, assigned to the T 2 , T 1 + T 3 + T 4 + T 5 + T 8 ,a nd T 6 + T 7 sites, respectively (see Figure S8 in the Supporting Information for as chematic representation).…”

Section: Resultsmentioning

confidence: 99%

“…Althought he detailed mechanism for Al siting is still unclear, the above resultsb y 27 Al DD-MASN MR spectroscopy suggest that the local distribution of T-sites such as Al atoms within the MWW framework could be different depending on the syntheticm ethodology adopted (OSDA-directed or seed-assisted with OSDA-free gel). In ar elated matter,r ecent works [47][48][49] showedt hat zeolite beta obtained from seed-assisted, OSDAfree synthesis exhibitedadifferent Al distribution compared to that of conventional OSDA-directed beta.…”

Section: Resultsmentioning

confidence: 99%

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Seed‐Assisted Synthesis of MWW‐Type Zeolite with Organic Structure‐Directing Agent‐Free Na‐Aluminosilicate Gel System

Kamimura

Itabashi

Kon

et al. 2017

Chemistry An Asian Journal

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The seed-assisted synthesis of zeolites without using organic structure-directing agents (OSDAs) has enabled alternative routes to the simple, environmentally friendly and low-cost production of industrially important zeolites. In this study, the successful seed-assisted synthesis of MCM-22 (MWW-type) zeolite with an OSDA-free gel is reported for the first time. MWW-type zeolites are obtained by the addition of as-synthesized MCM-22 seeds prepared with hexamethyleneimine (HMI) into OSDA-free Na-aluminosilicate gels. Based on the results of XRD, ICP-AES, NMR, N physisorption and NH -TPD, the product exhibited different features compared to those of the seeds. The H-form product can serve as a catalyst in Friedel-Crafts alkylation reaction of anisole with 1-phenylethanol, and its catalytic activity is comparable to the seeds. Furthermore, XRD, FE-SEM, TG-DTA, CHN, FT-IR and NMR analyses of products and intermediates provide insights into the role of seeds and occluded HMI, the crystallization process, and key factors for achieving seed-assisted synthesis of MWW-type zeolites with an OSDA-free gel system. The present results provide a new perspective for the economical and environmentally friendly production of MWW-type zeolites.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Seed‐Assisted Synthesis of MWW‐Type Zeolite with Organic Structure‐Directing Agent‐Free Na‐Aluminosilicate Gel System

Kamimura

Itabashi

Kon

et al. 2017

Chemistry An Asian Journal

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“…Moreover, they have discovered that OSDA-free beta possessed high Al content in the *BEA framework (Si/Al <7) with a greater degree of well-defined microstructural features (crystallinity, micropore volume and morphology) as compared with conventional beta synthesized using OSDAs [12,13,31]. Since the reporting of OSDA-free synthesis, several important results have been published, in which OSDA-free beta showed enhanced performance in antibacterial [32], N 2 O decomposition [33], benzene alkylation [34], hexane cracking [23], selective catalytic reduction (SCR) of NO x [35] and NO sorption [36] applications when compared with conventional beta and other common zeolites.…”

Section: Introductionmentioning

confidence: 99%

CO 2 adsorption–desorption properties of zeolite beta prepared from OSDA-free synthesis

Kamimura

Shimomura

Endo

2016

Microporous and Mesoporous Materials

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“…[25][26][27][28][29][30] Taking advantage of the large cation-exchange capacity, Fe-exchanged Beta(OF) was applied in NOx decomposition. 25,26 Beta(OF) with a large number of Brønsted acid sites showed the high catalytic activities in cracking of cumene and Friedel-Crafts reactions. 27,28 In contrast, it has been reported that the high Al content resulted in fast deactivation and that the appropriate dealumination providing Beta(OF) with the high-silica compositions delayed the deactivation.…”

Section: Introductionmentioning

confidence: 99%

Development of a post-synthetic method for tuning the Al content of OSDA-free Beta as a catalyst for conversion of methanol to olefins

Otomo

Müller

Feyen

et al. 2016

Catal. Sci. Technol.

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Zeolites synthesized without any organic structure-directing agent (OSDA) have several advantages over conventional zeolites synthesized with OSDAs. Their Al-rich compositions, however, are sometimes not suitable for applications as catalyst. In the present study, post-synthetic modification was performed upon an Al-rich Beta zeolite synthesized without any OSDAs (designated as "Beta(OF)") to obtain high-silica Beta zeolites. We have successfully developed a facile postsynthetic method for tuning the Al content of Beta(OF) with the * BEA-type structure retained by calcination at >750 °C, followed by acid treatment. Solid-state 29 Si and 27 Al MAS NMR analyses revealed that during the calcination, framework Al atoms were isomorphously substituted with Si atoms to form high-silica frameworks and concomitant extra-framework Al species. Stability of the obtained frameworks against the acid treatment was evaluated in terms of the framework Al content, finding that the framework with the Si/Al ratio over 12 is well stabilized enough for the acid treatment. Thus dealuminated Beta(OF) zeolites with high-silica compositions were found to be effective catalysts for the methanol-toolefins (MTO) reaction; particularly, Beta zeolite with the Si/Al ratio of 112 kept the conversion of methanol over 90% with the selectivity to C2 -C4 olefins over 70% even at 40 hours on stream at WHSV = 3.2 h -1 .

show abstract

Stabilization of bare divalent Fe(II) cations in Al-rich beta zeolites for superior NO adsorption

Cited by 29 publications

References 41 publications

Seed‐Assisted Synthesis of MWW‐Type Zeolite with Organic Structure‐Directing Agent‐Free Na‐Aluminosilicate Gel System

Seed‐Assisted Synthesis of MWW‐Type Zeolite with Organic Structure‐Directing Agent‐Free Na‐Aluminosilicate Gel System

CO 2 adsorption–desorption properties of zeolite beta prepared from OSDA-free synthesis

Development of a post-synthetic method for tuning the Al content of OSDA-free Beta as a catalyst for conversion of methanol to olefins

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