Nanosized CHA zeolites with high thermal and hydrothermal stability derived from the hydrothermal conversion of FAU zeolite

Takata, Tomoka; Tsunoji, Nao; Takamitsu, Yasuyuki; Sadakane, Masahiro; Sano, Tsuneji

doi:10.1016/j.micromeso.2016.01.045

Cited by 96 publications

(82 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…100 nm), particularly when the Si/Al ratios of the initial FAUw ere fixed between 35-60. [65] Recently,C orma and co-workers reported the efficient synthesis of the high-silica CHA zeolite using tetraethylammonium (TEA, see Figure 11), al ess-expensive OSDAt han those previously employed, and precrystallized FAUzeolites as the sole silicon and aluminum source ( Figure 13). [65] Recently,C orma and co-workers reported the efficient synthesis of the high-silica CHA zeolite using tetraethylammonium (TEA, see Figure 11), al ess-expensive OSDAt han those previously employed, and precrystallized FAUzeolites as the sole silicon and aluminum source ( Figure 13).…”

Section: Angewandte Chemiementioning

confidence: 99%

“…[65] The nanosized CHA zeolite showed ahigh catalytic activity in the ethanol to propylene conversion. [65] Recently,C orma and co-workers reported the efficient synthesis of the high-silica CHA zeolite using tetraethylammonium (TEA, see Figure 11), al ess-expensive OSDAt han those previously employed, and precrystallized FAUzeolites as the sole silicon and aluminum source ( Figure 13). [13c] The authors proposed that the presence of common d6r SBUsi n the former FAUz eolite was the main driving force for the formation of the CHA zeolite when TEA was used as the OSDA, since the use of other amorphous or crystalline zeolites as initial silicon and aluminum sources mostly results in the crystallization of Beta zeolite.…”

Section: Angewandte Chemiementioning

confidence: 99%

See 1 more Smart Citation

Building Zeolites from Precrystallized Units: Nanoscale Architecture

2018

View full text Add to dashboard Cite

Since the early reports by Barrer in the 1940s on converting natural minerals into synthetic zeolites, the use of precrystallized zeolites as crucial inorganic directing agents to synthesize other crystalline zeolites with improved physicochemical properties has become a very important research field, allowing the design, particularly in recent years, of new industrial catalysts. This Review highlights how the presence of some crystalline fragments in the synthesis media, such as small secondary building units (SBUs) or layered substructures, not only favors the crystallization of other zeolites with similar SBUs or layers, but also permits control over important parameters affecting their catalytic activity (chemical composition, crystal size, or porosity, etc.). Recent advances in the preparation of 3D and 2D zeolites through seeding and zeolite-to-zeolite transformation processes will be discussed extensively in this Review, including their preparation in the presence or absence of organic structure-directing agents (OSDAs). The aim is to introduce general guidelines for more efficient approaches for target zeolites.

show abstract

Section: Angewandte Chemiementioning

confidence: 99%

Section: Angewandte Chemiementioning

confidence: 99%

Building Zeolites from Precrystallized Units: Nanoscale Architecture

2018

View full text Add to dashboard Cite

show abstract

“…More recent efforts in zeolite transformation utilize various organic templates for synthesizing targeted zeolites, either in the presence or absence of targeted zeolite seeds . New advances in the seed‐directed OSDA‐free synthesis of zeolites stimulated more research activities on interzeolite transformation with the goal of providing unique strategies to synthesize zeolites without OSDAs.…”

Section: Organotemplate‐free Interzeolite Transformationmentioning

confidence: 99%

Understanding Commonalities and Interplay Between Organotemplate‐Free Zeolite Synthesis, Hierarchical Structure Creation, and Interzeolite Transformation

2018

View full text Add to dashboard Cite

are crystalline microporous materials that have been widely used in many applications related to industrial catalysis, ion-exchange, and adsorption. In recent years, there has been a growing emphasis on the development of green chemistry toward more sustainable zeolite synthesis routes. Considerable efforts have been devoted to identifying alternative approaches in order to reduce the negative impacts of organic templates. This review will focus on the significant progress achieved during the past decade on the development of novel organotemplate-free strategies through three distinctive topics, i. e. zeolite synthesis, hierarchical zeolite synthesis, and interzeolite transformation. The progress of each topic will be documented, followed by a summary of the intriguing commonalities and interplay among these approaches. The insights into the mechanism and interplay leading to different zeolite materials will enable us to understand the requirements for designing novel zeolite catalysts and catalyst supports in an organotemplate-free environment that are likely to further enhance the industrial impact of these materials in the future. We conclude this article with a perspective and outlook focusing on current trends and future directions in this area.[a] Dr.

show abstract

“…Although the crystallite size of zeolite was found to influence limitedly the intrinsic NH3-SCR activities of metal-exchanged zeolite catalysts (e.g., Cu-SSZ-13, Cu-SAPO-34, Fe-ZSM-5) [56][57][58], a decrease of crystal size from several micrometers to 50-100 nm can improve the hydrothermal stability of zeolite catalysts [56,57]. For proton transport in zeolites, the influence of crystallite size (or grain boundary) is negligible with crystallite size at micrometer level, and is noted only with crystallite sizes below 200 nm [59].…”

Section: Zeolite Crystallite Sizementioning

confidence: 99%

In Situ Spectroscopic Studies of Proton Transport in Zeolite Catalysts for NH3-SCR

Chen

Simon

2016

Catalysts

View full text Add to dashboard Cite

Proton transport is an elementary process in the selective catalytic reduction of nitrogen oxides by ammonia (DeNO x by NH 3 -SCR) using metal-exchanged zeolites as catalysts. This review summarizes recent advancements in the study of proton transport in zeolite catalysts using in situ electrical impedance spectroscopy (IS) under NH 3 -SCR reaction conditions. Different factors, such as the metal cation type, metal exchange level, zeolite framework type, or formation of intermediates, were found to influence the proton transport properties of zeolite NH 3 -SCR catalysts. A combination of IS with diffuse reflection infrared Fourier transformation spectroscopy in situ (in situ IS-DRIFTS) allowed to achieve a molecular understanding of the proton transport processes. Several mechanistic aspects, such as the NH 3 -zeolite interaction, NO-zeolite interaction in the presence of adsorbed NH 3 , or formation of NH 4 + intermediates, have been revealed. These achievements indicate that IS-based in situ methods as complementary tools for conventional techniques (e.g., in situ X-ray absorption spectroscopy) are able to provide new perspectives for the understanding of NH 3 -SCR on zeolite catalysts.

show abstract

Nanosized CHA zeolites with high thermal and hydrothermal stability derived from the hydrothermal conversion of FAU zeolite

Cited by 96 publications

References 57 publications

Building Zeolites from Precrystallized Units: Nanoscale Architecture

Building Zeolites from Precrystallized Units: Nanoscale Architecture

Understanding Commonalities and Interplay Between Organotemplate‐Free Zeolite Synthesis, Hierarchical Structure Creation, and Interzeolite Transformation

In Situ Spectroscopic Studies of Proton Transport in Zeolite Catalysts for NH3-SCR

Contact Info

Product

Resources

About