Remarkable Catalytic Activities of Hydrothermally Synthesized Bilayered HZSM-5 Coatings with Additional Nonzeolite Pores

Wang, Li; Zhao, Dandan; Pu, Sijing; Liu, Guozhu

doi:10.1021/acs.iecr.5b00574

Cited by 11 publications

(7 citation statements)

References 39 publications

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“…One effective approach to improve reactants diffusion inner films is to introduce additional nonzeolite (or intercrystal) pores by adding ethanol into the synthetic solutions, which gives an activity improvement by ca. 150% in catalytic cracking of n ‐dodecane . Another innovation idea is to prepare highly b ‐oriented ZSM‐5 films and thus to selectively use the straight and larger pores (0.53 × 0.56 nm 2 ) along b axis.…”

Section: Methodsmentioning

confidence: 99%

Controllable fabrication and catalytic performance of nanosheet HZSM‐5 films by vertical secondary growth

et al. 2018

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Significance Nanosheet HZSM-5 film vertically grown on the substrate with the tailorable macro-and meso-pores between the layers of nanosheets is hydrothermally synthesized by seed-assisted secondary growth method. The asprepared nanosheet HZSM-5 film exhibits reaction rate enhancement up to 312% in catalytic cracking of n-dodecane as well as twice light olefins selectivity, ascribed to the better mass transfer of reactants in the hierarchical porous structure and the ultra-thin b-axis pores of nanosheets. a Si/Al ratio measured by ICP. b d c : thickness of the zeolite films counted from cross-view SEM images. c m c : zeolite loadings (mg) per surface area (cm 2 ). d m l : zeolite film mass loss after ultrasonic vibration (200W) for 30min. e r d 5 (X 0 -X t )/X 0 3 100%, X 0 and X t are the n-dodecane conversion at time of 10 and 60 min. f X5 Dw/w 0 3 100%, where w 0 and Dw are the mass of n-dodecane fed and consumed at time of 10 min. g r i 5 (w 0 -w t510 )/(m c 3 t) 3 100% (%), w 0 is the mass of n-dodecane fed, w t 5 10 is the mass of n-dodecane in the products at reaction time of 10 min, m c is the mass of catalyst in the coating, t is the reaction time (10 min).

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Section: Methodsmentioning

confidence: 99%

Controllable fabrication and catalytic performance of nanosheet HZSM‐5 films by vertical secondary growth

et al. 2018

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“…Figure 1 displays the XRD patterns of the HZSM-5 membranes. For all samples, there were several typical diffraction peaks corresponding to the characteristic peaks of the MFI topology, indicating a successful crystallization of the HZSM-5 phase on the stainless steel tubes (SST) [18]. With the TPOAC/TEOS ratios in the synthesis gel growing from 0 to 0.15, the relative crystallinities of the HZSM-5 membranes decreased gradually (as shown in Table 1), which was in line with the observation of Peng et al [24] and Cho et al [31].…”

Section: Structures Characterizationmentioning

confidence: 99%

“…N 2 permeance through the zeolite membranes was selected to reflect the diffusivity of the membrane; it has been reported that the high permeance value implies a high diffusivity [18,33]. As seen in Table 1, the values of the N 2 permeance increased, monotonously, with both the TPOAC/TEOS and TMB/TPOAC ratios.…”

Section: Gas Permeation Propertiesmentioning

confidence: 99%

“…N 2 gas permeation was measured at an ambient temperature, using the HZSM-5 membranes grown on the PSSS, according to Wang et al [18]. The upstream pressure was controlled by a backpressure regulator, whereas, the downstream gas was vented to air.…”

Section: N 2 Gas Permeation Testmentioning

confidence: 99%

“…Hydrothermal growth, with stronger adhesions of zeolite membranes, to support a controllable growth rate without binders, was used for preparing the hierarchical zeolite membrane, alternatively. Richter et al [17] and Wang et al [18] created additional non-zeolite pores in the inter-crystalline, grain boundaries of the ZSM-5 membrane, using alcohol in the synthesis gel, and got a remarkable enhancement of gas permeances. However, it should be noted that the diameters of the crystalline grains were above 2 µm, in their studies, thus, the intracrystal diffusion limitation was still a problem that needed to be improved.…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of the Hierarchical HZSM-5 Membrane with Tunable Mesoporosity for Catalytic Cracking of n-Dodecane

et al. 2019

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Hierarchical HZSM-5 membranes were prepared on the inner wall of stainless steel tubes, using amphiphilic organosilane (TPOAC) and mesitylene (TMB) as a meso-porogen and a swelling agent, respectively. The mesoporosity of the HZSM-5 membranes were tailored via formulating the TPOAC/Tetraethylorthosilicate (TPOAC/TEOS) ratio and TMB/TPOAC ratio, in synthesis gel, and the prepared membranes were systematically characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), N2 adsorption–desorption, N2 permeation, inductively coupled plasma (ICP), in situ fourier transform infrared (FT-IR), ammonia temperature-programmed desorption (NH3-TPD), etc. It was found that the increase of the TPOAC/TEOS ratio promoted a specific surface area and diffusivity of the HZSM-5 membranes, as well as decreased acidity; the increase of the TMB/TPOAC ratios led to an enlargement of the mesopore size and diffusivity of the membranes, but with constant acid properties. The catalytic performance of the prepared HZSM-5 membranes was tested using the catalytic cracking of supercritical n-dodecane (500 °C, 4 MPa) as a model reaction. The hierarchical membrane with the TPOAC/TEOS ratio of 0.1 and TMB/TPOAC ratio of 2, exhibited superior catalytic performances with the highest activity of up to 13% improvement and the lowest deactivation rate (nearly a half), compared with the microporous HZSM-5 membrane, due to the benefits of suitable acidity, together with enhanced diffusivity of n-dodecane and cracking products.

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Hydrothermal synthesis of highly cross‐linked PtZn@Silicalite‐1 structured catalysts for propane dehydrogenation

Xia,

Zhang,

Hou

et al. 2024

AIChE Journal

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Structured catalysts coatings exhibit excellent performance on non‐adiabatic gas–solid process, deriving from their enhanced heat and mass transfer properties. However, the coating catalysts prepared by traditional hydrothermal method of zeolite encapsulating noble metal are prone to spalling, especially under conditions of large flow rate and high temperature. Herein, we prepared PtZn clusters encapsulated in silicalite‐1 zeolite coating on stainless steel with high bonding strength by an improved in situ growth method. The optimized catalyst exhibited ultra‐thin, uniform, continuous, and high degree of crosslinking, thereby enhancing mass transfer and thermal stability. In propane dehydrogenation reaction, the optimized PtZn@S‐1‐R showed a high specific activity of 14.7 molPt−1 s−1 and a propylene selectivity above 99% at 600°C with a high weight hourly space velocity of 120 h−1. The metal‐encapsulated zeolite coating catalysts broaden the application avenue for heterogeneous catalysis with great application prospects.

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Remarkable Catalytic Activities of Hydrothermally Synthesized Bilayered HZSM-5 Coatings with Additional Nonzeolite Pores

Cited by 11 publications

References 39 publications

Controllable fabrication and catalytic performance of nanosheet HZSM‐5 films by vertical secondary growth

Controllable fabrication and catalytic performance of nanosheet HZSM‐5 films by vertical secondary growth

Fabrication of the Hierarchical HZSM-5 Membrane with Tunable Mesoporosity for Catalytic Cracking of n-Dodecane

Hydrothermal synthesis of highly cross‐linked PtZn@Silicalite‐1 structured catalysts for propane dehydrogenation

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