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A facile method was established using composition-gradient pattern on zeolite surface to guide the deposition and formation of chemical and biomolecular patterns with features as small as five microns.

A zeolite-based microengineered reactor was fabricated and tested for 1-pentene epoxidation over titanium silicalite-1 (TS-1) catalyst, which has been selectively incorporated within the microreactor channel using a new synthesis procedure.

Pd membranes of excellent stability and flux were prepared with multi-legged anchors by electroless plating of Pd on a porous support modified by a zeolite barrier layer containing Pd seeds; these membranes provide stable phenol production by direct hydroxylation of benzene. [ABSTRACT FROM AUTHOR]

Abstract: Zeolites are increasingly used in fuel cell, from fuel conversion and conditioning to membrane additives as well as support for electrocatalysts. Zeolites’ ionic conductivity and capacity for water adsorption and retention were exploited to create zeolite and zeolite-PFSA proton conducting membranes for PEMFC. HZSM-5 micromembranes of different Si/Al ratios (from ∞ for Sil-1 to 30) were fabricated in a regular array on silicon followed by assembly and test for fuel cell performance. HZSM-5 with high aluminum content exhibits good proton conductivity and better PEMFC performance that approaches that of Nafion MEA. A rational approach in the design of structured HZSM-5-PFSA composite membrane was demonstrated. The PFSA was confined in subnanoliter volumes within zeolite sleeves to obtain self-humidifying membrane and enhanced PEMFC performance (i.e., up to nine-fold in MPD) at elevated temperatures (i.e., up to 100°C) and dry conditions. Higher water retention and improved membrane thermomechanical properties are believed to be responsible. [Copyright &y& Elsevier]

Zeolite powders and films were prepared from six published synthesis recipes claimed to produce zeolite film coatings and membranes with (2 0 0), (0 2 0), (0 0 2) and (1 0 1) orientations. The morphology and orientation of the zeolite films prepared from each synthesis recipe were characterized and compared to determine the influence of synthesis composition and crystallization conditions. The zeolite growth environment was manipulated by changing the seed concentration on the substrate. The experimental results indicate that the synthesis chemistry and crystallization conditions affect the crystal grain morphology, whereas the growth environment influences the crystal habit. A simple method for predicting the orientation of the zeolite film based on the morphology of the zeolite crystal and the growth environment is also presented. [Copyright &y& Elsevier]

Abstract: Synthesis of Sn-Beta zeolites was studied by using a steam-assisted conversion (SAC) method. The effects of the amount of water in the bottom of autoclave, the crystallization time, the crystallization temperature and the gel drying temperature on the formation of the Sn-Beta zeolite frameworks, which have not been addressed before, were investigated in detail. An improved SAC autoclave was used for investigating the role of water in the formation of Sn-Beta zeolites. The characterization results of XRD, SEM, FT-IR, and UV–Vis for the as-synthesized samples show that the SAC method can rapidly produce pure and highly crystalline Sn-Beta zeolites. For the first time, we found that the interior construction of the conventional SAC autoclave can affect the formation of Sn-Beta zeolites. In the synthesis process, the condensed water over the gel changed synthesis composition. This issue was solved successfully by our improved autoclave. The optimized synthesis conditions of high quality Sn-Beta zeolites are the gel drying temperature of 333–373 K and the crystallization temperature of 433–473 K. [Copyright &y& Elsevier]

Abstract: Sn-Beta zeolites were prepared by a rapid and clean steam-assisted conversion (SAC) method from dry stannosilicate gel. The amorphous gel was converted to highly crystalline Sn-Beta within 5h at mild reaction temperature of 453K. The properties of the as-prepared samples were characterized by XRD, SEM, FT-IR, UV–Vis, UV-Raman, ICP and N2 adsorption. A high gel conversion to BEA can be obtained with Sn4+ inserted in the zeolite framework. The SAC method was successfully used to produce pure silica Beta zeolite (Si/Sn=∞) to Sn-Beta zeolite with 3.8wt.% SnO2 (i.e., Si/Sn=83). The Sn-Beta prepared by SAC method is an efficient catalyst for Baeyer–Villiger (B–V) reaction of cyclohexanone to ε-caprolactone. [Copyright &y& Elsevier]

Abstract: A catalytic layer of CsNaX zeolite film was deposited on quartz capillary tube by flow synthesis method under hydrothermal conditions. The procedure involved seeding of the capillary tube with zeolite nanocrystals followed by controlled zeolite regrowth and crystallization under flow conditions. The CsNaX capillary microreactor was employed in Knoevenagel condensation reaction of benzaldehyde and ethyl cyanoacetate. The sensitivity of the catalyst to water produced by the condensation reaction was remedied with the use of solvents. Ninety nine percent benzaldehyde conversions were obtained using a traditional solvent DMSO, but decreased with time as water accumulates and poisons the catalyst. Replacing the solvent with an ionic liquid (IL-BMIC) improves water absorption and the catalyst displayed better (i.e., >99%) and stable conversions. [Copyright &y& Elsevier]

Abstract: A new proton conducting membrane was prepared by confining sub-nanoliter volumes of perfluorosulfonic acid (PFSA) polymer within rigid pores cladded with zeolite layers. Tests showed membrane-electrode assembly (MEA) made of confined Nafion PFSA-HZSM-5/Sil-1 structured composite membrane delivered an order of magnitude higher MPD (maximum power density) compared to a standard Nafion 117 MEA in a hydrogen PEMFC at high temperature operation under dry feed conditions. Similarly, 900% higher MPD was obtained from direct methanol fuel cell (DMFC) made of the new membrane. The zeolites are believed to play an active role in the water and methanol managements through adsorption and transport, and the confinement of the PFSA within zeolite environment changes its microstructure resulting in the improved thermal stability. [Copyright &y& Elsevier]

Abstract: A monolayer of zeolite nanoparticles was deposited uniformly on SiO2 beads’ surface by a new seeding method based on the combined use of organic linker and dip-coating procedure. The seeds were transformed into a well-intergrown TS-1 zeolite film and characterizations by SEM and XRD indicated that the film has a preferred (011) orientation. EDXS, XPS and UV–vis spectroscopies confirmed the successful preparation of egg-shell TS-1/SiO2 catalysts. Thin shell catalysts (i.e., <11μm) were more active for styrene oxidation. Conversion reaction rate of 8.9mmolg−1 h−1 and turnover frequency of 28h−1 were obtained with aromatic aldehydes (i.e., benzaldehyde and phenyl acetaldehyde) being the main products. Greater mass transfer resistance made thick shell catalysts less efficient with lower specific conversion rate of 6.9mmolg−1 h−1 and turnover frequency of 25h−1. Also, the extra-framework titanium resulting from the longer synthesis led to poorer selectivity. Egg-shell TS-1/SiO2 catalyst beads were shown to be resistant to attrition and were easier to separate and recover from reaction. [Copyright &y& Elsevier]

Abstract: Pd membrane with excellent stability was prepared on macroporous α-Al2O3 tubes using a nanoporous Sil-1 zeolite as an intermediate support and diffusion barrier layer. The detailed microstructure of the composite membrane was examined by scanning electron microscopy and mapped by EDXS and EPMA to reveal a palladium membrane anchored by multi-legs Pd protrutions that penetrates through the interstices of the zeolite grains into the seed layer. This membrane architecture allowed the membrane to tolerate rapid and repeated cycling of gases, temperature and pressure over 300h without lost of permeance and selectivity. The zeolite layer contributed up to 25% of the transport resistance across the Pd–Sil-1 composite membrane and has a significant effect on the hydrogen permeance. [ABSTRACT FROM AUTHOR]

Abstract: Titanium silicalite-1 (TS-1) films were prepared on porous α-Al2O3 tubes using nanosized silicalite-1 (Sil-1) particles as seeds by hydrothermal treatment and a TS-1 catalytic membrane reactors (CMR) was reasonably designed and evaluated by phenol hydroxylation with hydrogen peroxide as oxidant. Some factors on influencing TS-1 film formation and catalytic properties were investigated and the TS-1 films were characterized by scanning electron microscope (SEM), transmission electron micrograph (TEM), X-ray diffractometer (XRD), FTIR, UV–vis and X-ray fluorescence (XRF). It was indicated that TS-1 films prepared from Sil-1 and TS-1 seeds were comparable in structure, morphology and reaction behavior. The crystallization time and times of TS-1 film had a strong effect on its morphology, thickness and orientation. However, the film thickness could be easily controlled by crystallization time and times. The Ti/Si ratio in synthesis solution intensely influenced the content of the titanium atoms incorporated as framework Ti that was correlated well with the activity. The maximum Ti (IV) incorporated corresponds to a Ti/Si ratio of approximately 0.02–0.03. A constant conversion for phenol hydroxylation was obtained with the film thickness of over 7.5μm. It is demonstrated that most of the reaction occurred in a shallow layer near the film due to the mass transfer effects in the TS-1 films. [Copyright &y& Elsevier]

Abstract: Titanium silicalite-1 (TS-1) zeolites and films supported on porous α-Al2O3 tubes were prepared using TS-1 and silicalite-1 (Sil-1) seeds by hydrothermal synthesis. The structure and catalytic properties of the TS-1 powders and films were characterized by SEM, XRD, FT-IR, UV–vis and styrene partial oxidation by hydrogen peroxide. The results showed that TS-1 prepared from Sil-1 seeds were as active as TS-1 from nucleated and TS-1 seeded syntheses, in spite of the concerns about nonuniformity and dilution caused by the use of pure silica Sil-1 seeds. The Ti atoms were successfully incorporated as tetra-coordinated titanium in the zeolite framework and the phenylacetaldehyde selectivity correlates well with the infrared band for Ti–O–Si of the TS-1. Reaction over TS-1 film indicates that reactions occurred at the topmost layer of the film due to the slow diffusion in the zeolite pores. [Copyright &y& Elsevier]

Abstract: A novel method for the modification of carbon membranes was developed by zeolite growth on the surface of porous carbon tubes using a hydrothermal synthesis method and carbon–zeolite composite membranes were successfully obtained. Zeolite seeds for the zeolite growth were introduced to the inner surface of the tubes by using a slip-casting technique in 1wt.% seed ethanol solution and continuous and highly intergrown zeolite layers on the seeded tubes were formed by subsequent hydrothermal synthesis. Different types of zeolite layers can be grown on porous carbon tubes by using different types of zeolite seeds. Without zeolite seeds, a zeolite layer could not be formed on the carbon surface. SEM, XRD and pure gas permeation characterization indicates that the carbon–zeolite membranes are continuous and defect-free. [Copyright &y& Elsevier]

New basic zeolite catalysts obtained by grafting amino groups onto NaX and CsNaX zeolites exhibit excellent catalytic activities for Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate (ECA), ethyl acetoacetate (EAA) and diethyl malonate (DEM). The CsNaX-NH2 catalyst also displays higher conversion compared to aminopropylated MCM-41. Knoevenagel condensation reaction in a CsNaX zeolite microreactor performed better than the traditional packed bed reactor (PBR) with an order of magnitude higher productivity (i.e. moles ethyl 2-cyano-3 phenylacrylate produced per hour for each gram catalyst). A nearly fourfold increase in reaction conversion was obtained for the microreactor when CsNaX-NH2 catalyst was used. A membrane microreactor was obtained by incorporating a water-selective, NaA membrane to the multi-channel microreactor. The selective removal of water byproduct during the reaction led to a 25% improvement in reaction conversion for both catalysts. [Copyright &y& Elsevier]

Using a new fabrication method based on microelectronic fabrication and zeolite thin film technologies, MFI-type zeolites with engineered structures were incorporated as catalyst, membrane and structural material within the design architecture of a microreactor, membrane microseparator and microeletrochemical cell. Complex microchannel geometry and network (<5 μm), as well as zeolite arrays (<10 μm) were successfully fabricated onto highly orientated supported zeolite films. The zeolite micropatterns were stable even after repeated thermal cycling between 303 and 873 K for prolonged period of time. Blueprints for zeolite-based microchemical systems were presented, and test units were fabricated and the structural details of the microdevices’ architecture were analysed. [Copyright &y& Elsevier]