Chemical etching with fluoride ions is a new approach for secondary porosity engineering of aluminosilicate zeolite frameworks. We show that diluted HF solutions extract preferentially aluminum from The Brønsted acidity ZSM-5 treated in such way decreases, while its structure unaffected after an treatment. With higher concentrations, the number undissociated molecules and concentration HF2– ions, extracting indiscriminately Al Si, increase. addition NH4F shifts chemical equilibria to produce...

This study reports the seeded synthesis of MFI‐type (ZSM‐5) zeolite in fluoride medium at pH = 8.5. Crystal growth kinetics resulting (ZSM‐5‐F) as a function seed content and crystallization temperature is studied. The time reduced to 1.5 h crystals with sizes below 200 nm Si/Al ratio 23.6 are obtained. A similar characteristics but synthesized hydroxyl (ZSM‐5‐OH) used evaluate ZSM‐5s different media. Their physicochemical properties compared particular attention paid nature, number,...

ZEO-1 is the first stable extra-large pore zeolite with a substantial amount of aluminum in framework achieved directly upon synthesis, and here we present comprehensive analysis its physicochemical properties. Our findings show that varying different synthesis parameters allows for controlling crystallization kinetics, crystal size, morphology. Investigating acidic properties using 27Al 1H solid-state nuclear magnetic resonance shows exhibits potentially three populations. The nature...

Abstract We outline two methodologies to selectively characterize the Brønsted acidity of external surface FAU‐type zeolites by IR and NMR spectroscopy adsorbed basic probe molecules. The challenge goal are develop reliable quantitative investigate accessibility acidic sites in large pore zeolite Y its mesoporous derivatives often referred as ultra‐stable (USY). their acid molecules (n‐alkylamines, n‐alkylpyridines, n‐alkylphosphine‐ phenylphosphine‐oxides) different molecular sizes is...

Sorption-based atmospheric water harvesting (AWH) is regarded as an efficient and sustainable strategy to alleviate the current crisis. However, advancement of AWH continues be limited by sorbents' low efficiency, scalability challenges, poor cycling stability. This study reports optimization a relevant adsorbent, AlPO-18, with successful scale-up trials. The optimized process facilitates sing-batch production over hundred grams AlPO-18 in 1 L reactor, resulting lower costs, reduced energy...

The toxicity of two types ultra-small zeolites (8–18 nm) with LTL- and EMT-type structures is reported. Both the belong to same group molecular sieves; they have large pores (7.1–7.5 Å) low silica content (Si/Al = 1.2–2.3). are prepared by an environmentally friendly synthetic approach from precursor suspensions without using any organic template. Cellular interactions zeolite nanocrystals evaluated cell viability, reactive oxygen species life cycle assays. It found that various...

Lubricants play a significant part in current environmental considerations since they are an integral and indispensable component of modern technology. The production, application disposal the lubricants have to follow increasingly strict requirements for protecting environment living organisms. In this respect, molecular sieve (LTL type zeolite) is investigated as potential environmentally friendly alternative traditional antioxidant additives lubricant oils. Accelerated oxidation...

A novel one-step post-synthesis method for structural stabilization of germanium (Ge) silicate molecular sieves is presented. The modification includes low-temperature SiCl4 and TiCl4 plasma treatment as-synthesized Ge-silicates. During reaction template removal, partial extraction Ge from the framework incorporation Si Ti in micropore space takes place. modified material further subjected to high-temperature calcination, which completes replacing cations zeolite framework. feasibility this...

TiO2/Luffa composites have been successfully prepared via a sol–gel method from the hydrolysis of precursor TiO2. The possibility to use Luffa fibers as biotemplate self-support hierarchical TiO2 macrostructures has also tested with success. photocatalysts and were characterized by X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, FT-IR, UV-visible spectroscopy. photocatalytic activities investigated in photodegradation methanol, chosen model molecules for VOCs...

Sub-nanometer silver clusters that exhibit discrete electronic structure with molecular-like properties are highly desirable in various technologies. However, the methods for their preparation suffer from limitations related reproducibility and particles uniformity and/or possibility of scale-up. Another critical drawback is free sub-nanometer tend to aggregate into larger particles. In this work, a new approach successfully overcomes above developed. It allows, first time, an ultrafast high...

Zeolite Y and its ultra-stabilized hierarchical derivative (USY) are the most widely used zeolite-based heterogeneous catalysts in oil refining, petrochemisty, other chemicals manufacturing. After almost 60 years of academic industrial research, their resilience is unique as no catalyst displaced them from key processes such FCC hydrocracking. The present study highlights difference leading to exceptional catalytic performance USY versus parent zeolite a multi-technique combining advanced...

The interzeolite transformation of a micronsized FAU zeolite to nanosized CHA via alkali treatment is presented. impact the selection starting material on properties produced was analyzed by XRD, ICP, SEM, TEM, N2 and CO2 adsorption, in situ FT-IR. analysis showed that choice had large chemical composition, size, morphology, porosity zeolite. as prepared samples show high capacity toward (4.26 mmol g-1) it demonstrated chemisorbed vs. physisorbed controlled varying amount cations

Platinum clusters are prepared by γ radiolysis of beta zeolite suspensions (Pt-Beta) in the presence a templating agent (tetraethylammonium hydroxide, TEAOH). Further, Pt-Beta were stabilized with methyl cellulose and deposited thin films thickness 200 nm on silicon wafers. Elucidation size, distribution, stability Pt colloidal is provided high-resolution transmission electron microscopy (HRTEM) combined grazing incident X-ray diffraction (GI-XRD) measurements. The lateral length immobilized...

A new post-synthetic approach, involving cold plasma treatment, was employed for the preparation of TiO2-Beta zeolite. Zeolite Beta nanoparticles were first subjected to induced deposition TiCly (with y≤ 3), which further converted into TiOx x≤ 2) upon O2-plasma treatment. Different steps elaborated approach monitored using in situ FTIR spectroscopy. D2O isotopic exchange used order shed light on formation Si-O-Ti bonds by TiCl4-plasma followed treatments. The obtained materials studied a...

Cold VCl3-plasma is employed for the preparation of highly dispersed vanadium oxide clusters on nanosized zeolite. Different types zeolites, such as EMT, FAU (z.X), and Beta, are used. The activity prepared catalysts studied in selective photooxidation methanol under polychromatic visible UV irradiations. physicochemical properties catalytic performance plasma-treated zeolite Beta (P-V2O5@Beta) catalyst compared with (V2O5@Beta) amorphous silica (V2O5@SiO2) impregnated catalysts. Pure V2O5...

The crystallization kinetics of template free ultra-small FAU-type zeolite (X) in highly alkaline viscous precursor suspensions is investigated.

In situ IR detection of carbon monoxide in the presence hydrocarbons (methanol and pentane) using Pd-containing zeolite thin films is reported. The are prepared by spin coating deposition nanosized LTL BEA type zeolites suspensions; palladium clusters introduced ion exchange followed γ radiolysis suspensions. with a thickness 200 nm exposed to single gas (either CO or hydrocarbons) mixtures water (100 ppm), spectra collected continuously at 25, 75, 100 °C. fast recognition very low...

In the present work, we report first example of one-step selective methanol photooxidation to dimethoxymethane (DMM) at room temperature over TiO2/zeolite bifunctional catalysts. The effects porosity and basicity/acidity zeolites on selectivity reaction are discussed. role TiO2 active sites zeolitic Brønsted acid DMM production is reported. As photocatalytic occurs temperature, influence also investigated extrapolate results thermal catalysis. This study demonstrates a clear synergetic...