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Micro/meso/macroporous (hierarchical) zeolites show remarkable catalytic performance for reactions involving bulky reactants. However, quantitative assessment of the microstructural characteristics contributing to the observed performance remains elusive. Here, structure–activity relationships are established for a set of micro/mesoporous self‐pillared pentasil (SPP) zeolites using two parallel liquid‐phase reactions (benzyl alcohol alkylation and self‐etherification) based on analysis of mass transport and reaction kinetics. A reaction–diffusion mathematical model is developed that quantitatively assigns the catalytic contributions of the external surface and micropores of SPP zeolites for these reactions. In addition, the effect of the zeolite external surface structure on the corresponding catalytic activity is quantitatively assessed by comparing SPP zeolites (with MFI structure) with MCM‐22 (with MWW structure). This work demonstrates that reaction–diffusion modeling allows quantitative description of the catalytic performance of hierarchical zeolites and provides a model reaction to assess nm‐sized characteristic diffusion lengths in MFI. © 2018 American Institute of Chemical Engineers AIChE J, 65: 1067–1075, 2019 [ABSTRACT FROM AUTHOR]

Abstract: Two‐dimensional MFI zeolite nanosheets contain Brønsted acid sites partially confined at the intercept between micro‐ and mesopores. These acid sites exhibit exceptional reactivities and stabilities for C=C bond coupling and ring‐closure reactions that transform light aldehydes to aromatics. These sites are much more effective than those confined within the micropores of MFI crystallites and those unconfined on H4SiW12O40 clusters or mesoporous aluminosilicate Al‐MCM‐41. The partially confined site environment solvates and stabilizes the transition states of the kinetically relevant steps during aromatization. [ABSTRACT FROM AUTHOR]

A comparison of activity and selectivity of external Brønsted acid sites in catalytic conversion of benzyl alcohol in mesitylene over unit-cell thick zeolite materials (MCM36 or pillared MWW, pillared MFI, and self-pillared pentasil (SPP)) showed that the external surface of MWW and MFI zeolites influences drastically the activity and selectivity of the parallel alkylation and etherification reactions. Pillared MWW, containing independent (not-interconnected) micropores and mesopores, catalyzed both of the parallel reactions only in the mesopores as evidenced by complete loss of the activity upon 2,6-di-tert-butylpyridine (DTBP) titration. Pillared MFI and SPP, consisting of highly interconnected micropores and mesopores, catalyzed both of the parallel reactions in the mesopores. Pillared MFI and SPP catalyzed only the etherification reaction in the micropores as illustrated by the complete suppression of alkylation and retention of residual etherification activity after DTBP titration. Moreover, it was found that the external surface of MWW zeolites favors the alkylation reaction, while the etherification reaction takes place with similar reaction rates on MFI and MWW external surfaces. The evidence shown here for the assessment of external acid sites in catalyzing parallel reactions extends the scope of observed catalytic performances in these materials beyond those reflecting transport effects and accessibility of acid sites and highlights the importance of external surface structure. [ABSTRACT FROM AUTHOR]

Zeolites are generally defined as three-dimensional (3D) crystalline microporous aluminosilicates in which silicon (Si4+) and aluminum (Al3+) are coordinated tetrahedrally with oxygen to form large negative lattices and consequent Brønsted acidity. Two-dimensional (2D) zeolite nanosheets with single-unit-cell or near single-unit-cell thickness (~2–3 nm) represent an emerging type of zeolite material. The extremely thin slices of crystals in 2D zeolites produce high external surface areas (up to 50% of total surface area compared to ~2% in micron-sized 3D zeolite) and expose most of their active sites on external surfaces, enabling beneficial effects for the adsorption and reaction performance for processing bulky molecules. This review summarizes the structural properties of 2D layered precursors and 2D zeolite derivatives, as well as the acidity properties of 2D zeolite derivative structures, especially in connection to their 3D conventional zeolite analogues' structural and compositional properties. The timeline of the synthesis and recognition of 2D zeolites, as well as the structure and composition properties of each 2D zeolite, are discussed initially. The qualitative and quantitative measurements on the acid site type, strength, and accessibility of 2D zeolites are then presented. Future research and development directions to advance understanding of 2D zeolite materials are also discussed. [ABSTRACT FROM AUTHOR]

• Anchoring nature and spatial distribution of ReO x on zeolite supports were studied. • Effects of zeolite support acidity and mesoporosity on ReO x were examined. • ReO x species anchored predominantly on Brønsted acid sites enclosed in micropores. • Decrease in acidity transited the anchoring of ReO x onto silanol (Si-OH) groups. • Increase in mesoporosity migrated ReO x onto external acid sites and Si-OH groups. The anchoring nature and spatial distribution of rhenium oxide (ReO x) supported on zeolites (ReO x /zeolite) were determined as a function of the support acidity and mesoporosity. The ReO x /zeolite samples were characterized collectively using Argon isotherm, XRD, Raman, XAS, DRIFTS, and organic chemical titrations. The results show that the ReO x species formed the isolated distorted tetrahedral ReO 4 − structure. On the zeolite support, ReO x species anchored predominantly on Brønsted acid sites (Si-OH+-Al) enclosed in micropores (internal acid sites), by replacing the protons in Si-OH+-Al sites at a H+/Re ratio of ∼1.1 in zeolites with high acidity. The decrease in zeolite acidity led to the anchoring of ReO x species onto both Si-OH+-Al and silanol group (Si-OH). The increase in zeolite mesoporosity migrated the ReO x species onto both internal acid sites and those on the external surface and mesopores (external acid sites), as well as Si-OH groups. The implication of distribution of ReO x in zeolite was explored by direct non-oxidative methane conversion reaction. [ABSTRACT FROM AUTHOR]

Abstract The pillared MWW (PMWW or MCM-36) and pillared MFI (PMFI) are two prominent representatives of meso-/microporous lamellar zeolites, which are made by pillaring of layered MCM-22(P) and multilamellar MFI precursors, respectively. They both consist of a 10-membered ring sinusoidal micropore channel within each zeolitic layer and mesopore voids created by pillars between two adjacent zeolitic layers. Although catalytic activities of PMWW and PMFI have been compared, identification of mesopore differences between these two pillared lamellar zeolites has not been attempted. In this work, we report the differences in mesopore characteristics between PMWW and PMFI zeolites probed by atomic layer deposition (ALD) of titania (ALD-TiO 2) species and a combination of structural, textural, composition and catalytic property analyses of the samples before and after ALD treatment, respectively. The results suggest PMFI has cylindrical mesopores with uniform sizes from pore entrance to main body, while PMWW has ink-bottle mesopores with the neck size much smaller than pore body. The communication between micropore and mesopore in PMFI is direct, but no communication exists in PMWW zeolites. The ALD-TiO 2 process considerably modified external surface composition of PMFI and PMWW zeolites, which consequently led to a new application of the pillared lamellar zeolite materials, i.e., photo-catalytically active meso-/microporous zeolites for environmental remedy reactions. Graphical abstract Image 1 Highlights • Identification of mesopore differences between PMFI and PMWW was attempted. • Atomic layer deposition of titania was used as probe for mesopore differences. • PMFI has more uniform mesopores compared to PMWW zeolite. • Atomic layer deposition of titania enabled photocatalytic activity. [ABSTRACT FROM AUTHOR]

Abstract Hierarchical lamellar zeolites, comprised of both micro- and mesoporosity, afford high active site accessibility and mass transport in processing of bulky molecules. Here, we report the synthesis of hierarchical lamellar MFI zeolites with sequential intergrowth that is induced by composition variation in the standard recipe of 100SiO 2 /0.5Al 2 O 3 /3C 22-6-6 /18.5Na 2 O/4000H 2 O, where C 22-6-6 stands for the diquaternary ammonium surfactant ([C 22 H 45 N+(CH 3) 2 C 6 H 12 N+(CH 3) 2 C 6 H 13 ]Br− 2) template. The influences of C 22-6-6 concentration, alkalinity, and aluminum amount on the intergrowth of hierarchical lamellar MFI zeolites were investigated. The consequences of intergrowth on mesoporosity were analyzed. In all studied synthesis conditions except for very low alkalinity, hierarchical lamellar MFI zeolites were successfully crystallized. The increasing template concentration in the synthesis gel resulted in an increase in intergrowth and thus mesoporsotiy in the hierarchical MFI products. The increasing alkalinity led to an increase and then a decrease in mesoporosity in the hierarchical MFI products, which reflects the same trend in intergrowth in the hydrothermal synthesis process. The aluminum concentration, however, did not significantly affect the intergrowth and mesoporosity of the resultant hierarchical MFI zeolites. The sequential intergrowth achieved by simple variation in the synthesis composition for lamellar MFI zeolites resulted in higher structure hierarchy, mesoporosity, and acid site accessibility in one-step. Graphical abstract Image 1 Highlights • Hierarchical lamellar MFI zeolites were synthesized in one-step. • Intergrowth enhanced mesoporosity in hierarchical lamellar MFI zeolites. • Intergrowth increased with increasing surfactant template content in synthetic gel. • Intergrowth increased and then decreased with alkalinity in synthetic gel. • Aluminum content in synthetic gel did not influence intergrowth noticeably. [ABSTRACT FROM AUTHOR]

Producing value-added light aromatics (BTEX) from solid waste streams holds excellent promise for resource recovery. Here we present a thermochemical conversion approach that enhanced BTEX production by coupling CO 2 atmosphere and Fe-modified HZSM-5 zeolite to facilitate the Diels-Alder reactions in catalytic pyrolysis of sawdust and polypropylene. The Diels-Alder reactions between sawdust-derived furans and polypropylene-derived olefins could be controlled by tuning CO 2 concentration and Fe loading amount. Sufficient CO 2 (≥50%) with moderate Fe loading (10 wt%) were observed to produce more BTEX and fewer heavy fractions (C 9 +aromatics). To deepen the mechanistic understanding, quantification of polycyclic aromatic hydrocarbons (PAHs) and catalyst coke was further conducted. The co-use of CO 2 atmosphere and Fe modification suppressed the appearance of low-, medium-, and high-membered ring PAHs by over 40%, decreased pyrolysis oil toxicity from 42.1 to 12.8 μg/g oil TEQ, and transformed coke from "hard" to "soft". Based on the characterization of CO 2 adsorption behavior, it was deduced that the introduced CO 2 was activated by loaded Fe and reacted in situ with H 2 generated during aromatization to expedite H-transfer. Meanwhile, BTEX recondensation was prevented through the Boudouard reactions of CO 2 and water-gas reactions between the resulting water and carbon deposits. These synergistically enhanced the production of BTEX and suppressed the formation of heavy species, including PAHs and catalyst coke. [Display omitted] • Coupling of CO 2 atmosphere and Fe/HZSM-5 increased BTEX yield to 74.8% while suppressing C 9 +aromatics. • Diels-Alder reactions for aromatics production was controlled by tuning CO 2 concentration and Fe loading amount. • Co-using CO 2 and Fe/HZSM-5 decreased LPAHs, MPAHs, and HPAHs by > 40%. • Coupling of CO 2 and Fe/HZSM-5 transformed coke from "hard" to "soft". • Fe activated CO 2 can expedite H-transfer through RWGS and hinder BTEX recondensation via Boudouard and water-gas reactions. [ABSTRACT FROM AUTHOR]

The combination of two compositionally and/or structurally different zeolites into one single zeolite composite particle is a potential approach to integrate advantages of different zeolite structures for desirable properties and applications. In the present study, we report the overgrowth of lamellar mesoporous silicalite-1 on the commercial microporous MFI and BEA zeolites, respectively, to render hierarchical meso-/microporous lamellar silicalite-1/MFI (L-Si/MFI) and lamellar silicalite-1/BEA (L-Si/BEA) zeolite composites via hydrothermal crystallization of lamellar silicalite-1 with the assistance of a diquaternary ammonium template. Epitaxial growth of lamellar silicalite-1 on commercial bulk MFI was observed, resulting in the L-Si/MFI zeolite composite as porcupine sensory message ball with nerve-stimulating silicalite-1 bumps extended from the MFI particle. In the L-Si/BEA zeolite composite, the lamellar silicalite-1 was laid over the surface of or partially interdigitated into the commercial bulk BEA particle, forming a BEA nanosponge structure connected to lamellar silicalite-1 nanosheets. The resultant interconnected micro- and mesoporosity in the L-Si/MFI and L-Si/BEA composite zeolites allowed facile mass transport of bulky molecules. The acid sites sitting on the external surface of commercial MFI and BEA zeolites were partially passivated by the lamellar silicalite-1. The consequences of improved mass transport and passivation of external acid sites on the catalytic performance of these zeolite composites were tested in 2 wt% molybdenum (Mo) loaded L-Si/MFI and L-Si/BEA for direct non-oxidative methane aromatization reaction, which showed higher methane conversion and hydrocarbon product formation as well as higher selectivity to naphthalene and coke in comparison with 2 wt% Mo-loaded commercial MFI and BEA catalysts. [ABSTRACT FROM AUTHOR]

The pillared MWW (PMWW or MCM-36) and pillared MFI (PMFI) zeolites consist of a single- or near single-unit-cell thick two-dimensional (2D) zeolitic layer structure. The concentrations of external surface and pore mouth Brønsted acid sites in these zeolites were quantified by a combined dimethyl ether (DME) titration and methanol dehydration in the presence of 2,6-di-tert-butylpyridine (DTBP) or triphenylphosphine (TPP), respectively. DME can access to all Brønsted acid sites in PMFI and PMWW zeolites and thus determine the total number of acid sites. DTBP cannot access to acid sites in micropores, but on the external surface and at the pore mouth regions. In contrast, TPP can only access to acid sites on external surface. The degree of decrease in methanol dehydration rate in the presence of DTBP or TPP indicates the fraction of the sum of external surface and pore mouth acid sites and the sole fraction of external surface acid sites, respectively. The study shows that PMFI contains ∼32% external surface and ∼6% pore mouth acid sites, while PMWW consists of ∼33% external surface and ∼31% pore mouth acid sites. The individual external surface or pore mouth acid site performed distinctively in alkylation of mesitylene by benzyl alcohol reactions. [ABSTRACT FROM AUTHOR]

The synthesis of hierarchical meso-/microporous zeolite materials with spatially controlled morphology, meso-/microporosity, and acidity is an expanding area of research interest for a wide range of applications. Here, we report a one-step dual template synthesis method for integration of 3-dimensional (3D) BEA nanosponge and ultra-thin 2D lamellar MFI into a new type of hierarchical meso-/microporous zeolite composite structures. Specifically, the 2D layered MFI nanosheets were laid over the surface of or interdigitated into the 3D BEA particles in the bulk BEA nanosponge-lamellar MFI (BBLM) zeolite structure, which generated a unique morphology of interconnected micropores and mesopores underneath the ‘skinning’ shell (∼3–10 nm) of MFI nanosheets. The BBLM zeolites have higher mesoporosity than either bare BEA or lamellar MFI zeolites. The micropore size decreases with increasing lamellar MFI component in the composite. The fraction of external acid sites of BBLM zeolite composite, represented by the percentage of active sites accessible to bulky organic base molecules, decreases with increasing MFI component. Additionally, the types of acid sites are diversified in the BBLM composites compared to either bare BEA or lamellar MFI zeolites. The catalysis tests using conversion of benzyl alcohol in mesitylene showed that BBLM zeolites had significant higher activity and durability than single zeolites or their physical mixture. The BBLM zeolite composite provides a good model catalyst with integrated 2D-3D structures and meso-/microporosity for studying a series of important catalytic reactions in hierarchical zeolites. The one-step dual template synthesis method described herein is versatile and facile, which may prove to be a general platform for hierarchical zeolite composite design at the unit-cell scales of zeolites and with potentially broader applicability to other porous materials. [ABSTRACT FROM AUTHOR]

Lamellar MFI zeolite and lamellar MFI zeolite supported nickel were synthesized and examined for ex-situ catalytic upgrading of the vapors (without using any fluidized gases such as N 2 and H 2) resulted from fast pyrolysis of wood chips in comparison to its commercial MFI zeolite and its supported nickel counterparts. Pyrolysis tests were carried out using a catalytic augur reactor at atmospheric pressure, while pyrolysis unit was operating at 450 °C and upgrading unit at 420 °C, respectively. The introduction of nickel with a high dispersion over the zeolitic supports caused a significant increase in the products of aromatic compounds. Moreover, the addition of nickel to zeolite supports changed their acidity and decreased the total number of acid sites and the ratio of Brønsted to Lewis acid sites as determined by pyridine-FTIR spectroscopy. The use of lamellar zeolite catalysts increased the efficiency of catalytic cracking of pyrolysis vapors and their modification with nickel helped tuning the Lewis acidity to further increase catalytic cracking which resulted in a higher yield of the low molecular weight aromatics present in the bio-oil. • Lamellar catalysts are synthesized and extensively characterized. • Ex-situ catalytic fast pyrolysis without fluidizing gas can lead to a low bio-oil deoxygenation. • Lamellar catalysts are found to enhance catalytic cracking of pyrolysis oil vapors. • Lamellar catalysts show no loss in activity after multiple uses. [ABSTRACT FROM AUTHOR]

A comparison of selectivity in catalytic conversion of benzyl alcohol in mesitylene on hybrid lamellar-bulk MFI (HLBM) zeolite materials containing dual meso-/microporosity showed that the external Brønsted acidity in meso-/microporous MFI zeolites effectively impacts on selectivity of the parallel alkylation and etherification reactions. HLBM zeolites, consisting of crystalline bulk microporous core and lamellar mesoporous shell, not only catalyzed the parallel reactions on the external environments (external surface and mesopore) but also catalyzed the etherification reaction in the internal environment (micropore) as illustrated by the completely suppressed alkylation and retained residual etherification reactions after 2,6-di-tert-butylpyridine (DTBP) poisoning. A systematic study of HLBM zeolites with tunable meso-/microporous domain sizes achieved by a dual template assisted synthesis revealed that parallel alkylation and etherification reactions are tailored by the tunable external surface area and external acidity of the HLBM zeolites. The external alkylation and etherification reaction rates as a function of cumulative DTBP addition suggested the presence of Brønsted acid sites with different strengths on external environments of the HLBM zeolites, which influenced the external etherification reaction, but not as significantly as the alkylation reaction. The evidence shown here for the involvement of external acidity in catalyzing parallel reactions and for the role of external acidity with variable strengths in HLBM zeolite materials extends the scope of observed catalytic behaviors of meso-/microporous zeolite materials beyond those reflecting transport effects and accessibility of acid sites. [ABSTRACT FROM AUTHOR]

The lamellar MFI zeolite with tunable meso-/microporosity was prepared by a dual template synthesis method. Implications of the tunable meso-/microporosity on the spatial distribution and catalytic performance of metal–acid sites in Mo/lamellar MFI catalysts were studied. The number of free Brønsted acid sites increases linearly, accompanied by a linear decrease in Mo dispersion, with decreasing external surface areas in catalysts. The Mo–acid active sites coexisted on the external surface or mesopores of the catalysts linearly depends on the hierarchy factor, being the product of relative micropore volume and relative external surface area. The reaction rate and product selectivity of Mo/lamellar MFI in direct methane aromatization reactions are consistent with the trends of changes in zeolite porosities. These results imply that a balance between the meso- and microporosity in zeolite and the resultant active site distribution can be realized for desirable catalysis by simple one-step dual template synthesis of zeolites. [ABSTRACT FROM AUTHOR]

A dualtemplate synthesis strategy was employed to achieve one-stepdesign of meso- and microporous MFI nanosheet assemblies with tailoredmorphology, mesoporosity, and catalytic activity. A molecular template(tetrapropylammonium hydroxide, TPAOH) and a polyquaternary ammoniumsurfactant ([C22H45–N+(CH3)2–C6H12–N+(CH3)2–C6H13]Br2, C22–6–6) were used as cotemplatesin the synthesis with a composition of 30Na2O/1Al2O3/100SiO2/10C22–6–6/xTPAOH/4000H2O/18H2SO4. By tuning the concentration of TPAOH (x) from 0 to 20, the morphology of the as-obtained MFI nanosheet assemblieschanged from intertwined, to house-of-cards-like, and to dense packingplates. The N2isotherms showed the hysteresis loop atthe range of P/P0= 0.45–1.0increases, reaches a maximum, and then decreases with increasing xvalues, indicating a systematic tailoring of the mesoporositywith TPAOH concentrations. Under strict kinetic control, the ratesand apparent activation energies of the ethanol activation in zeolitenanosheet assemblies were comparable. The catalytic conversion ofbenzyl alcohol in mesitylene showed that the activity of as-obtainedMFI zeolites increases, reaching a maximum, and then decreases withincreasing xvalues. The consistency in the variationof morphology, mesoporosity, and catalytic activity with varying xvalues in the synthesis indicates TPAOH can be used asa secondary template to tailor the textural and catalytic propertiesof MFI nanosheet assemblies primarily guided by C22–6–6. [ABSTRACT FROM AUTHOR]

Highlights: [•] Textural/catalytic properties of Mo/mesoporous lamellar zeolites were investigated. [•] Mesopore facilitates dispersion of Mo species in zeolite catalysts. [•] Higher aromatic and coke formation was observed in the initial reaction stage. [•] Mo-acid species in mesopores account for fast reaction and deactivation rates. [•] Mo-acid species in micropores are responsible for the long term catalyst activity. [Copyright &y& Elsevier]

Fruit waste collected from a juice factory was pyrolyzed over zeolite catalysts with different pore topologies. The production of aromatic compounds was directly influenced by zeolite topology type (i.e. pore opening size and pore channel dimensionality). Zeolites with three-dimensional (3D) pore topologies (e.g. MFI, BEA and FAU) favored aromatization reactions, which yielded up to 80% aromatic compounds, compared to <20% yield in the pyrolysis over FER and MOR zeolites with two- and one-dimensional pore channels, respectively. The catalytic performance of the 3D zeolites, MFI, BEA and FAU were more vulnerable to operating conditions such as catalyst to biomass ratio and pyrolysis temperature, compared to 2D FER and 1D MOR zeolites. The results were possibly explained by the interplays of diffusion limitations and space constrains, imposed by the pore topologies. By correlation analysis, applying FAU zeolite at catalyst to biomass ratio of 2:1 under 450, 550, or 650 °C was found to be optimal for aromatics formation, affording more mono aromatic hydrocarbons (45%) and less polycyclic aromatic hydrocarbons (30%). Moreover, the zeolites employed in the reactions with larger pore size tended to coke. This work potentially provides a guideline for efficient conversion of fruit waste to aromatic compounds enriched biofuels. [Display omitted] • 3D zeolites favored aromatics formation yielding up to 80%. • Catalytic performances of 3D zeolites were more susceptible to pyrolysis conditions. • Pore channel dimensionality interplayed with opening size in pyrolysis process. • FAU zeolite with high addition was optimal for mono aromatics production. [ABSTRACT FROM AUTHOR]

Hierarchical two-dimensional (2D) lamellar zeolites represent a young emerging field and a novel expression of the zeolite frameworks. Accompanied with synthesis and catalytic performance investigation, assessment on the local environment and catalytic behavior of acid sites in 2D zeolites are needed. Here, we described the local environment of Lewis acid sites and evaluated catalytic activities of external acid sites (i.e. sites on external surface and in mesopores) in 2D lamellar titanium silicalite-1 (TS-1) zeolites. For comparison purpose, four TS-1 zeolites, including 3D TS-1, multilamellar 2D TS-1 without pillarization and with pillarization by silica and silica/titania, respectively, were prepared. The local environment of Ti-sites, including coordination status of Ti-atom, speciation of hydroxyl (-OH) group that hints degree of confinement, acid site strength and accessibility, was collectively assessed by spectroscopic and organic base titration measurements. Kinetic studies of cyclooctene (C 8 H 14) epoxidation with hydrogen peroxide (H 2 O 2) discerned catalytic activity of external Ti-sites that decreased with increasing mesoporosity due to decrease in site confinement. Image 1 • External Lewis acid sites in 2D TS-1 zeolites were quantified. • 2D TS-1 zeolites have high density of isolated surface silanol and titanol groups. • Reactivity of external sites decreases with increasing mesoporosity in 2D TS-1. • Decrease in reactivity of external sites is caused by loss of partial confinement. • Kinetic decoupling of epoxidation pathways enabled catalytic behavior assessment. [ABSTRACT FROM AUTHOR]

• Characteristics of the coke deposits on lamellar metal (Ga or Zn)-modified zeolites were studied. • Mesoporous lamellar structure decreases the coke formation by facilitating the external coke deposition. • Metal modification decreases the coke formation by changing the acidity of zeolite. • Highest fraction of light coke is obtained for Zn-modified lamellar zeolite. • Both zeolite structure and metal-modified acidity affect the coke formation. The effects of meso-/microporous structure and metal-additive (Ga or Zn) of lamellar MFI catalysts on the characteristics of coke deposits during ethylene-to-aromatic liquids conversion were investigated. The nature, composition, and location of coke deposits in spent lamellar catalysts were analyzed and compared to those on the microporous MFI counterparts, using FTIR, UV–Vis, GC–MS, and argon adsorption-desorption. The total amount of coke and the changes in coke nature during catalyst regeneration were studied by MS/FTIR combined with temperature programmed oxidation. The lamellar meso-/microporous structure of MFI reduces the coke quantity and the heavy coke fractions. The coke preferentially deposites on external surface of lamellar zeolite due to the lower diffusion limitation for bulky coke precursors. Metal-additive changes the catalyst acidity and decreases the coke formation rate, especially when zinc is used. Therefore, the coke formation on zeolite can be tuned by modulating the textural and acidity properties of the metal-modified catalyst. [ABSTRACT FROM AUTHOR]

• Catalytic performance of metal (Ga or Zn)-loaded mesoporous lamellar zeolites was evaluated. • Mesoporous lamellar structure is pivotal in determining metal dispersion in zeolite catalyst. • Metal loading changes the acidity of the zeolite catalyst and effect of Zn is more pronounced compared to Ga. • Higher liquid aromatics yield and selectivity for mono-benzene alkylated aromatics was observed while less coke was formed. • Both zeolite structure (mesoporosity) and type of metal dopant affect the catalytic performance of catalyst. The effects of meso-/microporous structure and metal-modification with gallium or zinc on catalytic performances of lamellar MFI zeolites in ethylene conversion reaction to liquid aromatics were investigated. TEM, XRD, Ar adsorption-desorption, UV-Visible spectroscopy, and H 2 -TPR measurements showed that the zeolite structure is a pivotal factor for controlling the type of metal dopant species forming on zeolite, their size, and their distribution. Adding metal dopants to zeolite structure decreased the Brønsted to Lewis (B/L) acid site ratio in the zeolites and improved their catalytic performance. As a result, metal-modified lamellar MFI zeolites showed higher liquid aromatics yield and selectivity for mono-benzene alkylated aromatics and lower coke formation rate compared to their microporous commercial MFI analogies. Zinc-loaded lamellar MFI had the most efficient catalytic performance among all studied catalysts. This phenomenon can be explained by higher accessibility of reactants to active sites and facilitated transport of products from lamellar structure of this zeolite and the low B/L acid site ratio of this catalyst provided by metal-modification, which is more suitable for ethylene aromatization. A bifunctional reaction mechanism has been proposed based on the analysis results of reaction product distributions that demonstrates the effect of both zeolite acid sites and metal sites in conversion of ethylene to liquid aromatics over MFI zeolite catalysts. [ABSTRACT FROM AUTHOR]