Catalytic activation of OKO zeolite with intersecting pores of 10- and 12-membered rings using atomic layer deposition of aluminium

Verheyen, Elke; Sree, Sreeprasanth Pulinthanathu; Thomas, Karine; Dendooven, Jolien; Prins, Michiel De; Vanbutsele, Gina; Breynaert, Eric; Gilson, Jean‐Pierre; Kirschhock, Christine; Detavernier, Christophe; Martens, Johan A.

doi:10.1039/c3cc49028a

Cited by 24 publications

(25 citation statements)

References 23 publications

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“…The mesopore gallery between two unit-cell thick zeolititic nanosheets, parallel to the width of PMWW flakes and PMFI platelets, might be big enough to allow TMA to transport through but resist TDMAS diffusion, and as a result, led to more Si-species deposited Al) on pillared zeolites bonded to distorted Al tetrahedral with links to oxygen atoms of the zeolite framework. Similar phenomena have been reported for ALD-Al of FAU[41,53] and OKO[37] zeolites in literature.Solid state27 Al MAS NMR was employed to investigate the local bonding environment in the ALD-Si and ALD-Al modified PMFI and PMWW zeolite catalysts…”

supporting

confidence: 91%

“…For Al-PMFI zeolites, the increase in N total, H + is 2.34 x 10 -4 mol H + g -1 , and N ext, H + is also enhanced by 0.25 x 10 -4 mol H + g -1 , compared to those in PMFI zeolite ( Table 1). The increase in N ext, H + reflects that more Brønsted acid sites generated on the external surface of the PMFI zeolite, similar to the inclusion of acidity into siliceous zeolites reported previously [37]. The decrease in f ext, H + in Al-PMFI hints that accessibility of acid sites to bulky molecules is also…”

Section: External Acid Sites In Pillared Zeolites After Ald Modificatsupporting

confidence: 80%

“…The non-or slight change in absorption band for Brønsted acid sites in Figure 4(A) indicates that ALD-Si did not obviously modify the properties of Brønsted acid sites in PMWW zeolite. The "inhomogeneous broadening" in the Lewis acid band indicates the formation of various types of Lewis acid sites in PMWW zeolite materials via the ALD-Si or ALD-Al process [37,53]. Figure 4(B) shows the FTIR spectra of adsorbed pyridine on PMFI zeolite before and after ALD modifications.…”

Section: External Free Acid Site Determination To Study the Spatial mentioning

confidence: 99%

“…The self-limiting character of the reactions makes it possible to achieve uniform deposits on high-surface-area porous solid materials. ALD has been used to control the porosity and surface properties of mesoporous catalytic materials [33][34][35][36], to synthesize zeolite materials [37], as well as to load metal or metal oxide onto zeolite materials [38][39][40]. Application of ALD to nanoporous zeolites is a new area and is presumably more complicated compared to above applications because of the subtle differences in diameters between the ALD reactant molecules and the zeolite pore apertures.…”

Section: Introductionmentioning

confidence: 99%

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Tuning external surface of unit-cell thick pillared MFI and MWW zeolites by atomic layer deposition and its consequences on acid-catalyzed reactions

Lü

Emdadi

et al. 2016

Journal of Catalysis

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The pillared MWW (PMWW or MCM-36) and pillared MFI (PMFI) zeolites are 2dimensional (2D) catalytically active materials made by pillaring of layered MCM-22(P) and multilamellar MFI precursors, respectively. The single-or near single-unit-cell thick 2D microporous layers in PMWW and PMFI expose comparable number of external surface acid sites (i.e., acid sites enclosed in mesopores between zeolitic layers) to those in micropores, which become important or dominant contributor to the catalytic properties. Although the acidity and catalytic activities of PMWW and PMFI have been studied, modification of their external surfaces and its implications on catalytic reactions are not available. In the present study, we report the tailoring of external surfaces of PMWW and PMFI zeolites by atomic layer deposition (ALD) of silicon (ALD-Si) and aluminum (ALD-Al), respectively. The textural, acidic and catalytic properties of the ALD modified pillared zeolites were investigated using a variety of characterization methods. ALD-Al and ALD-Si modifications kept micropore almost intact, but resulted in significant reduction in mesopore volume and considerable changes in external surface composition and acidity. The catalytic tests showed that intrinsic catalytic behavior of Brønsted acid sites in ALD modified pillared zeolites was similar to their parent counterparts. In diffusion constrained parallel reactions, ALD of Al-or Si-species altered catalyst selectivity. In addition, ALD of Si-species on PMFI zeolite deactivated surface active sites, which resulted in improved catalytic activity in direct methane aromatization reactions under optimal ALD cycles. The study exemplified for the first time that ALD is an effective tool for tuning the surface properties of 2D unit-cell thick zeolites.

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supporting

confidence: 91%

Section: External Acid Sites In Pillared Zeolites After Ald Modificatsupporting

confidence: 80%

Section: External Free Acid Site Determination To Study the Spatial mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tuning external surface of unit-cell thick pillared MFI and MWW zeolites by atomic layer deposition and its consequences on acid-catalyzed reactions

Lü

Emdadi

et al. 2016

Journal of Catalysis

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“…Reprinted with permission from [369]. 19% pentacoordinated or distorted tetrahedral Al, and 60% octahedral extra-framework Al [372]. Interestingly, this modification causes a permanent conversion of the originally interrupted framework of -COK-14 to a fully connected OKO type framework, and generates new acid sites which are catalytically active for hydrocracking of n-decane.…”

Section: Wo X Ald On Sba-15mentioning

confidence: 99%

Atomic layer deposition—Sequential self-limiting surface reactions for advanced catalyst “bottom-up” synthesis

Elam

Stair

2016

Surface Science Reports

270

215

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Catalyst synthesis with precise control over the structure of catalytic active sites at the atomic level is of essential importance for the scientific understanding of reaction mechanisms and for rational design of advanced catalysts with high performance. Such precise control is achievable using atomic layer deposition (ALD). ALD is similar to chemical vapor deposition (CVD), except that the deposition is split into a sequence of two self-limiting surface reactions between gaseous precursor molecules and a substrate. The unique self-limiting feature of ALD allows conformal deposition of catalytic materials on a high surface area catalyst support at the atomic level. The deposited catalytic materials can be precisely constructed on the support by varying the number and type of ALD cycles. As an alternative to the wet-chemistry based conventional methods, ALD provides a cycle-by-cycle "bottom-up" approach for nanostructuring supported catalysts with near atomic precision. In this review, we summarize recent attempts to synthesize supported catalysts with ALD. Nucleation and growth of metals by ALD on oxides and carbon materials for precise synthesis of supported monometallic catalyst are reviewed. The capability of achieving precise control over the particle size of monometallic nanoparticles by ALD is emphasized. The resulting metal catalysts with high dispersions and uniformity often show comparable or remarkably higher activity than those prepared by conventional methods. For supported bimetallic catalyst synthesis, we summarize the strategies for controlling the deposition of the secondary metal selectively on the primary metal nanoparticle but not on the support to exclude monometallic formation. As a review of the surface chemistry and growth behavior of metal ALD on metal surfaces, we demonstrate the ways to precisely tune size, composition and structure of bimetallic metal nanoparticles. The cycle-by-cycle "bottom up" construction of bimetallic (or multiple components) nanoparticles with near atomic precision on supports by ALD is illustrated. Applying metal oxide ALD over metal nanoparticles can be used to precisely synthesize nanostructured metal catalysts. In this part, the surface chemistry of Al 2 O 3 ALD on metals is specifically reviewed. Next, we discuss the methods of tailoring the catalytic performance of metal catalysts including activity, selectivity and stability, through selective blocking of the low-coordination sites of metal nanoparticles, the confinement effect, and the formation of new metal-oxide interfaces. Synthesis of supported metal oxide catalysts with high dispersions and "bottom up" nanostructured photocatalytic architectures are also included. Therein, the surface chemistry and morphology of oxide ALD on oxides and carbon materials as well as their catalytic performance are summarized.

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Atomic Layer Deposition for Catalysis

Ramachandran

Detavernier

Dendooven

2017

Nanotechnology in Catalysis

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Catalytic activation of OKO zeolite with intersecting pores of 10- and 12-membered rings using atomic layer deposition of aluminium

Cited by 24 publications

References 23 publications

Tuning external surface of unit-cell thick pillared MFI and MWW zeolites by atomic layer deposition and its consequences on acid-catalyzed reactions

Tuning external surface of unit-cell thick pillared MFI and MWW zeolites by atomic layer deposition and its consequences on acid-catalyzed reactions

Atomic layer deposition—Sequential self-limiting surface reactions for advanced catalyst “bottom-up” synthesis

Atomic Layer Deposition for Catalysis

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