High Reactivity of Dimethyl Ether Activated by Zeolite Ferrierite within a Fer Cage: A Prediction Study.

The zeolite-catalyzed conversion of DME into chemicals is considered environmentally friendly in industry. The periodic density functional theory, statistical thermodynamics, and the transition state theory are used to study some possible parallel reactions about the hydrogen-bonded DME over zeolite ferrierite. The following are the key findings: (1) the charge separation probably leads to the conversion of a hydrogen-bonded DME into a dimethyl oxonium ion (i.e., DMO+ or (CH3)2OH+) with a positive charge of about 0.804 e; (2) the methylation of DME, CH3OH, H2O, and CO by DMO+ at the T2O6 site of zeolite ferrierite shows the different activated internal energy (∆E≠) ranging from 18.47 to 30.06 kcal/mol, implying the strong methylation ability of DMO+; (3) H-abstraction by DMO+ is about 3.94-15.53 or 6.57-18.16 kcal/mol higher than DMO+ methylation in the activation internal energy; (4) six DMO+-mediated reactions are more likely to occur due to the lower barriers, compared to the experimental barrier (i.e., 39.87 kcal/mol) for methyl acetate synthesis; (5) active intermediates, such as (CH3)3O+, (CH3)2OH+, CH3CO+, CH3OH2+, and CH2=OH+, are expected to appear; (6) DMO+ is slightly weaker than the well-known surface methoxy species (ZO-CH3) in methylation; and (7) the methylated activity declines in the order of DME, CH3OH, H2O, and CO, with corresponding rate constants at 463.15 K of about 3.4 × 104, 1.1 × 102, 0.18, and 8.2 × 10-2 s-1, respectively.

Unlocking Enhanced Butadiene Selectivity: The Crucial Role of Zeolite Channel Confinement in the Selective Decarbonylation of γ-Valerolactone.

Herein, we report a highly selective production route for butadiene from γ-valerolactone over zeolite catalysts. The catalytic performance of eight zeolites with different framework topologies were compared, revealing that zeolites with narrower 10-membered ring channels exhibit enhanced selectivity of butadiene. Specifically, ZSM-35 and ZSM-22, featuring the narrowest 10-membered ring channels, demonstrate the highest butadiene selectivity to 61 % and 59 %, respectively. Notably, surface passivation of ZSM-35 leads to a remarkable increase in butadiene selectivity to 82 %, maintaining a 99 % conversion. Additionally, we propose a reaction network and identify cyclopentenone as a key intermediate in the transformation of γ-valerolactone to butadiene. Both experimental and theoretical results conclude that confinement effect of 10-membered ring channels improves the selectivity of butadiene.

Transcriptomic and functional analyzes reveal that the brassinosteroid insensitive 1 receptor (OsBRI1) regulates cold tolerance in rice.

Brassinosteroids (BR) play crucial roles in plant development and abiotic stresses in plants. Exogenous application of BR can significantly enhance cold tolerance in rice. However, the regulatory relationship between cold tolerance and the BR signaling pathway in rice remains largely unknown. Here, we characterized functions of the BR receptor OsBRI1 in response to cold tolerance in rice using its loss-of-function mutant (d61-1). Our results showed that mutant d61-1 was less tolerant to cold stress than wild-type (WT). Besides, d61-1 had lower levels than WT for some physiological parameters, including catalase activity (CAT), superoxide dismutase activity (SOD), peroxidase activity (POD), peroxidase activity (PRO), soluble protein, and soluble sugar content, while malondialdehyde content (MDA) and relative electrical conductivity (REC) levels in d61-1 were higher than those in WT plants. These results indicated that the loss of OsBRI1 function resulted in decreased cold tolerance in rice. In addition, we performed RNA sequencing (RNA-seq) of WT and d61-1 mutant under cold stress. Numerous common and unique differentially expressed genes (DEGs) with up- and down-regulation were observed in WT and d61-1 mutant. Some DEGs were expressed to various degrees, even opposite, between CK1 vs. T1 (WT) and CK2 vs. T2 (d61-1). Among these specific DEGs, some typical genes are involved in plant tolerance to cold stress. Through weighted correlation network analysis (WGCNA), 50 hub genes were screened in the turquoise and blue module. Many genes were involved in cold stress and plant hormone, such as Os01g0279800 (BRI1-associated receptor kinase 1 precursor), Os10g0513200 (Dwarf and tiller-enhancing 1, DTE1), Os02g0706400 (MYB-related transcription factor, OsRL3), etc. Differential expression levels of some genes were verified in WT and d61-1 under cold stress using qRT-PCR. These valuable findings and gene resources will be critical for understanding the regulatory relationships between cold stress tolerance and the BR signaling pathways in rice.

Construction of diverse hollow MFI zeolites through regulating the micropore filling agents.

Constructing hollow structure into microporous zeolites can improve the accessibility of acid sites located at the inner part and the diffusion property. Hence, the development of an efficient synthesis strategy to acquire zeolites with tunable hollow structures and acidity has attracted much attention. In this work, an innovative tandem synthesis route was proposed to prepare MFI zeolites with diverse hollow structure while maintaining solid yields exceeding 90 %. The substitution of ethanol molecules, which previously occupied the micropores, with tetrapropylammonium cations was proved to be the key factor to construct hollow structure. And a crystallization-driven particle dissolution mechanism was proposed. The dimension of the hollow cavity, particle size, and Si/Al ratio can be flexibly regulated. Interestingly, hollow MFI samples featuring the common cavity structure, "eye-like" cavity structure, or double-cavity structure can be directly synthesized by controlling the dissolution of core parts. In the 1-butene catalytic cracking reactions, a much higher conversion of 67.2 % was acquired over hollow ZSM-5 compared with that over conventional ZSM-5 (35.8 %) after 64 h of reaction. This improvement can be attributed to the eightfold increase of diffusivity in hollow ZSM-5. This facile and efficient synthesis method endows accurate regulation of the hollow structure, which is meaningful for both fundamental research and industrial applications of hollow zeolites.

Current progress in research focused on salt tolerance in Vitis vinifera L.

Soil salinization represents an increasingly serious threat to agronomic productivity throughout the world, as rising ion concentrations can interfere with the growth and development of plants, ultimately reducing crop yields and quality. A combination of factors is driving this progressive soil salinization, including natural causes, global climate change, and irrigation practices that are increasing the global saline-alkali land footprint. Salt stress damages plants both by imposing osmotic stress that reduces water availability while also inducing direct sodium- and chlorine-mediated toxicity that harms plant cells. Vitis vinifera L. exhibits relatively high levels of resistance to soil salinization. However, as with other crops, grapevine growth, development, fruit yields, and fruit quality can all be adversely affected by salt stress. Many salt-tolerant grape germplasm resources have been screened in recent years, leading to the identification of many genes associated to salt stress and the characterization of the mechanistic basis for grapevine salt tolerance. These results have also been leveraged to improve grape yields through the growth of more tolerant cultivars and other appropriate cultivation measures. The present review was formulated to provide an overview of recent achievements in the field of research focused on grapevine salt tolerance from the perspectives of germplasm resource identification, the mining of functional genes, the cultivation of salt-tolerant grape varieties, and the selection of appropriate cultivation measures. Together, we hope that this systematic review will offer insight into promising approaches to enhancing grape salt tolerance in the future.

Effects of Physical Exercise Interventions for Individuals With Gynecologic Cancer: A Systematic Review and Meta-Analysis.

PROBLEM IDENTIFICATION: Data on the efficacy of physical exercise interventions for individuals with gynecologic cancer are limited and discordant. The purpose of this review was to determine the benefits of exercise interventions in this population. LITERATURE SEARCH: The PubMed®, Web of Science, Embase® (Ovid), and Cochrane Central Register of Controlled Trials databases were searched for studies published from January 1, 2010, to November 9, 2022. DATA EVALUATION: 12 randomized controlled trials were included. A quantitative synthesis method was used to investigate the effects of exercise interventions on individuals with gynecologic cancer. SYNTHESIS: The findings indicate that physical exercise interventions may have beneficial effects on the fatigue, depression, and health-related quality of life of this patient population. However, because of the small group of studies available, the evidence must be regarded as preliminary. IMPLICATIONS FOR PRACTICE: Clinicians and oncology nurses should recommend and refer individuals with gynecologic cancer to clinic- or community-based physical exercise programs.

Aroma profiling of Shine Muscat grape provides detailed insights into the regulatory effect of gibberellic acid and N-(2-chloro-4-pyridinyl)-N-phenylurea applications on aroma quality.

As plant growth regulators, gibberellic acid (GA3) and CPPU [forchlorfenuron, N-(2-chloro-4-pyridinyl)-N-phenylurea] are widely used in the production of table grapes. However, how these compounds regulate the aroma quality remains unclear. By measuring free and bound aroma compounds in Shine Muscat grapes from eight groups during whole growth period, GA3 and CPPU were both found to significantly promote the synthesis of acyclic monoterpenes and (E)-2-hexenal, and double applications were found to further increase the aroma compound contents. On the other hand, GA3 and CPPU obviously promoted the expansion of berries, and the effect of promoting the synthesis of aroma compounds was largely diminished. In conclusion, free compound concentrations in berry were almost unaffected by GA3 and CPPU. From the perspective of aroma compounds, a highly concerted interplay was observed for terpenes, and bound compounds exhibited higher correlations than those of free compounds. In addition, 17 compounds could be used as markers that indicated the developmental timing of berries.

Construction of a One-Dimensional Al-Rich ZSM-48 Zeolite with a Hollow Structure.

Diffusion limitation and acid deficiency are two main challenges that the ZSM-48 zeolite faces in practical application. To date, there have been few effective strategies to solve both problems, simultaneously. Also, it is also a challenge to construct a hollow structure in a one-dimensional (1D) zeolite. Herein, an Al-rich ZSM-48 zeolite with a hollow structure is constructed through an alumination-recrystallization strategy, thereby solving the problems related to diffusion and acidity simultaneously. The hollowness and enrichment of aluminum can be controlled by judiciously matching the desilication and recrystallization. The silica to alumina ratio (SAR) of the ZSM-48 zeolite can be tuned from 130 to 45, which breaks the SAR limitation of conventional synthesis. On the basis of the different characterization results, the whole crystallization can be divided into two stages: rapid desilication-alumination and time-consuming recrystallization. In the selective desilication-recrystallization process, the preferential special distribution of the organic template leads to the formation of a hollow structure and the healing of mesopores at the outer shell, as evidenced by structured illumination microscopy images. Due to the enhancement in diffusion ability and acid density, the obtained hollow Al-rich ZSM-48 zeolite exhibits excellent catalytic stability and high p-xylene yield (∼26%) in the m-xylene isomerization reaction (WHSV = 18 h-1), indicating its strong industrial application potential.

An R2R3-MYB transcription factor VyMYB24, isolated from wild grape Vitis yanshanesis J. X. Chen., regulates the plant development and confers the tolerance to drought.

In grapevines, the MYB transcription factors play an important regulatory role in the phenylpropanoid pathway including proanthocyanidin, anthocyanin, and flavonoid biosynthesis. However, the role of MYB in abiotic stresses is not clear. In this study, an R2R3-MYB transcription factor, VyMYB24, was isolated from a high drought-tolerant Chinese wild Vitis species V. yanshanesis. Our findings demonstrated that it was involved in plant development and drought tolerance. VyMYB24 is a nuclear protein and is significantly induced by drought stress. When over-expressed in tobacco, VyMYB24 caused plant dwarfing including plant height, leaf area, flower size, and seed weight. The GA1+3 content in transgenic plants was reduced significantly, and spraying exogenous gibberellin could recover the dwarf phenotype of VyMYB24 transgenic plants, suggesting that VyMYB24 might inhibit plant development by the regulation of gibberellin (GA) metabolism. Under drought stress, the VyMYB24 transgenic plants improved their tolerance to drought with a lower wilting rate, lower relative electrical conductivity, and stronger roots. Compared to wild-type tobacco plants, VyMYB24 transgenic plants accumulated less reactive oxygen, accompanied by increased antioxidant enzyme activity and upregulated gene expression levels of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) genes. In addition, transgenic plants accumulated more proline, and their related synthetic genes NtP5CR and NtP5CS genes were significantly upregulated when exposed to drought. Besides, abiotic stress-responsive genes, NtDREB, NtERD10C, NtERD10D, and NtLEA5, were upregulated significantly in VyMYB24 transgenic plants. These results indicate that VyMYB24 plays a positive regulatory role in response to drought stress and also regulates plant development, which provides new evidence to further explore the molecular mechanism of drought stress of the MYB gene family.

Adjunctive interleukin-2 for the treatment of drug-susceptible tuberculosis: a randomized control trial in China.

PURPOSE: Evaluation of the efficacy and safety of IL-2 in the treatment of drug-susceptible tuberculosis. METHODS: First, the cases of diagnosed drug-susceptible tuberculosis were randomized into two groups-the control group that received the background regimen of isoniazid, rifampin, pyrazinamide, and ethambutol, and the experimental group that received the background regimen plus IL-2. The efficacy and safety evaluations were performed throughout the therapy process as well as 12 months after the treatment completion. RESULTS: A total of 1151 patients underwent the randomization, among which 539 (96.2%) of the 560 in the experimental group achieved the sputum culture conversion to negative, compared to the 551 (93.2%) of the 591 in the control group, after 2 months of treatment, with significant difference observed between the groups (P = 0.025). Cavity closure after 2 months in the IL-2 (experimental) group was 60/211 (28.4%) compared to 46/248 (18.5%) in the control group, with a significant difference between the groups (P = 0.001). After treatment completion, the proportion of favorable outcomes was 559/560 (99.8%) in the experimental group and 587/591 (99.3%) in the control group, with no significant difference between the groups. Twelve months after treatment completion, relapse occurred in 15/560 (2.6%) in the IL-2 group and 19/591 (3.2%) in the control group, with no significant difference. CONCLUSION: IL-2 may enhance culture conversion and the cavity closure rate in the early treatment phase, although the enhancement may not be significant after treatment completion.

Enhanced Selectivity and Stability of Finned Ferrierite Catalysts in Butene Isomerization.

Designing zeolite catalysts with improved mass transport properties is crucial for restrictive networks of either one- or two-dimensional pore topologies. Here, we demonstrate the synthesis of finned ferrierite (FER), a commercial zeolite with two-dimensional pores, where protrusions on crystal surfaces behave as pseudo nanoparticles. Catalytic tests of 1-butene isomerization reveal a 3-fold enhancement of catalyst lifetime and an increase of 12 % selectivity to isobutene for finned samples compared to corresponding seeds. Electron tomography was used to confirm the identical crystallographic registry of fins and seeds. Time-resolved titration of Brønsted acid sites confirmed the improved mass transport properties of finned ferrierite compared to conventional analogues. These findings highlight the advantages of introducing fins through facile and tunable post-synthesis modification to impart material properties that are otherwise unattainable by conventional synthesis methods.

Corrigendum: Blockade of IL-6/IL-6R Signaling Attenuates Acute Antibody-Mediated Rejection in a Mouse Cardiac Transplantation Model.

[This corrects the article DOI: 10.3389/fimmu.2021.778359.].

Blockade of IL-6/IL-6R Signaling Attenuates Acute Antibody-Mediated Rejection in a Mouse Cardiac Transplantation Model.

Acute antibody-mediated rejection (AAMR) is an important cause of cardiac allograft dysfunction, and more effective strategies need to be explored to improve allograft prognosis. Interleukin (IL)-6/IL-6R signaling plays a key role in the activation of immune cells including B cells, T cells and macrophages, which participate in the progression of AAMR. In this study, we investigated the effect of IL-6/IL-6R signaling blockade on the prevention of AAMR in a mouse model. We established a mouse model of AAMR for cardiac transplantation via presensitization of skin grafts and addition of cyclosporin A, and sequentially analyzed its features. Tocilizumab, anti-IL-6R antibody, and recipient IL-6 knockout were used to block IL-6/IL-6R signaling. We demonstrated that blockade of IL-6/IL-6R signaling significantly attenuated allograft injury and improved survival. Further mechanistic research revealed that signaling blockade decreased B cells in circulation, spleens, and allografts, thus inhibiting donor-specific antibody production and complement activation. Moreover, macrophage, T cell, and pro-inflammatory cytokine infiltration in allografts was also reduced. Collectively, we provided a highly practical mouse model of AAMR and demonstrated that blockade of IL-6/IL-6R signaling markedly alleviated AAMR, which is expected to provide a superior option for the treatment of AAMR in clinic.

Restoration of dental services after COVID-19: The fallow time determination with laser light scattering.

In time, dental health care has slowly expanded beyond emergency treatment to treat oral diseases. How to reduce the cross-transmission risk in dental surgery has raised much more attention. Considering the lack of consistency of fallow time (FT) in its necessity and duration, the highly sensitive laser light scattering method has been proposed to visualize the airborne lifetime and decay rate of suspended particles in the dental surgery environment. The FT is defined as when the number of suspended particles drops to the level that the next patient can safely enter after the aerosol-generating procedures (AGPs). The ultrasonic scaling was performed in the mock-up experimental dental clinic with 6 air changes per hour (ACH), and the instantaneous moments of the droplets were recorded by a high-speed camera. Without any mitigation measures, the estimated FT in the single dental surgery environment with 6 ACH was in the range of 27-35 min, significantly affecting the number of daily dental services. Despite the cooperation of high-volume evacuation (HVE [IO]) cannot eliminate the FT to zero minutes, the equipment could reduce the required FT by 3-11 min for the suspended particles reducing the baseline levels. Owing to the longer airborne lifetime of suspended particles, the relevant protection equipment, especially respiratory protection, is quite essential in dental surgery. The obtained results of this study will provide evidence to establish the revised FT in dental surgery guidelines and protect the health and wellbeing of urban dwellers.

The Role of Organic and Inorganic Structure-Directing Agents in Selective Al Substitution of Zeolite.

Organic and inorganic structure-directing agents (SDAs) impact Al distributions in zeolite, but the insights into how SDAs manipulate Al distribution have not been elucidated yet. Herein, the roles of different SDAs such as cyclohexylamine (CHA), hexamethylenimine (HMI), and Na+ in selective Al substitution of MCM-49 zeolite are investigated comprehensively by multinuclear solid-state NMR. The results demonstrate that MCM-49 synthesized with HMI shows relatively more T6 and T7 Al, while more T2 Al is observed using CHA. The formation of T2 Al in both MCM-49(HMI) and MCM-49(CHA) is derived from Na+, while protonated HMIs show bias in incorporation of T6 and T7 Al. Most HMIs are occluded in protonated status, and about half of CHAs are occluded in nonprotonated status. The close spatial proximity between nonprotonated CHAs and Na+ synergistically promotes the formation of zeolite structure, leading to more Na+ ions occluded in the zeolite channel with preferential T2 Al substitution.

How the high-volume evacuation alters the flow-field and particle removal characteristics in the mock-up dental clinic.

The exposure risk of droplets and aerosols emitted from the oral cavity to the dental professionals and patients has received more attention especially the ongoing outbreak of COVID-19. The aim of this study is to address the question about how the use of the high-volume evacuation (HVE) alters the risk profiles compared with the situation only personal protective equipment (PPE). The risk profiles of the different situations were analyzed in terms of droplet velocity, flow field characteristics, and particle removal efficiency. The ultrasonic scaling with suction was performed in the mock-up experimental dental clinic, and the instantaneous moment when the HVE acted on the droplets was visualized using a laser light scattering technique. From the results of the velocity profiles, the hypothesis about the moderate effect of the HVE on high-velocity small droplets near the mannequin's mouth had been firstly proven in this study. The suction can be characterized as low-threshold equipment to bring substantial benefits to reduce the area of the contaminated region. Once the cooperation of suction, the pair of vortexes that were in the face shield area of the dental professional would be eliminated, removing the high-level contaminated region near the breathing area of dental professionals. Compared with the low and medium volume evacuation, the particle removal efficiency of the HVE was more stable at 60%. The research will provide references to the HVE recommendation in the dentistry clinical practice guidelines.

Direct Preparation of *MRE Zeolites with Ultralarge Mesoporosity: Strategy and Working Mechanism.

Introduction of mesopore is critical for applications where mass-transport limitations within microporous networks, especially for zeolite with one-dimensional microporous network, hinder their performance. Generally, the creation of mesopore in zeolite through a direct synthesis route is strongly dependent on complex and expensive organic molecules, which limits their commercial application. Here, we successfully developed a facile synthesis route for preparing ZSM-48 zeolite (*MRE topology) with ultralarge mesoporosity in which typical 1,6-hexylenediamine worked as an organic structure-directing agent, innovatively assisted by a simple crystal growth modifier (tetraethylammonium bromide, TEABr). The working mechanism of TEABr during crystallization was revealed and proposed on the basis of TEM, thermal gravimetric mass spectrum, and 13C cross-polarization magic angle spinning NMR characterization results. In the process, TEA+ ions preferentially interacted with the solid during the induction period, which effectively suppressed the aggregation of ZSM-48 primary nanorods. As a result, ultralarge mesoporosity of 0.97 cm3·g-1 was constructed through the stacking of the nanorods. Interestingly, TEA+ ions only took part in the crystallization process and did not occlude in the pores of the final zeolites indicating its potential in recyclability. Moreover, similar synthesis strategy could be applied for the preparation of hierarchical ferrierite zeolites, implying the universality of this strategy. Compared with a conventional sample, ZSM-48 zeolite with ultralarge mesoporosity showed superior catalytic stability in the m-xylene isomerization reaction due to its significantly enhanced diffusion and mass transfer capability, which will greatly promote the practical application of ZSM-48 zeolite.

Evaluating flow-field and expelled droplets in the mockup dental clinic during the COVID-19 pandemic.

In the setting of widespread severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) community transmission, reducing the exposure risk on dental professionals and the next patients is the key to reopening dental services in this pandemic environment. The study is motivated by the lack of understanding of the flow-field characteristics and droplet distribution during aerosol-generating procedures. The particle image velocimetry measurements with high temporal and spatial resolutions were performed under ultrasonic scaling in the mockup experimental dental clinic. Compared with other methods focusing on the settled droplet particles, the study focused on the visualization of suspended droplets. From the results of the velocity vector and trajectory map, the high-level contaminated area will be within 1 m from the oral cavity. The vortex structures were identified by the vorticity index. In the surface near the patient's head, a counterclockwise vortex would carry some droplets and contaminate this region. The small droplets circulated in the turbulence cloud and the droplet nuclei generated by dehydration are the two primary sources of suspended particles, which may cause airborne transmission in the dental clinic. About 65%-74% of the droplets in ultrasonic scaling were in the range of 50-180 µ m . The research will provide references to the development of the precaution measures to reduce the SARS-CoV-2 exposure risk of dental professionals.

Scorpion venom heat-resistant synthesized peptide ameliorates 6-OHDA-induced neurotoxicity and neuroinflammation: likely role of Nav 1.6 inhibition in microglia.

BACKGROUND AND PURPOSE: Microglia-related inflammation is associated with the pathology of Parkinson's disease. Functional voltage-gated sodium channels (VGSCs) are involved in regulating microglial function. Here, we aim to investigate the effects of scorpion venom heat-resistant synthesized peptide (SVHRSP) on 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease-like mouse model and reveal its underlying mechanism. EXPERIMENTAL APPROACH: Unilateral brain injection of 6-OHDA was performed to establish Parkinson's disease mouse model. After behaviour test, brain tissues were collected for morphological analysis and protein/gene expression examination. Primary microglia culture was used to investigate the role of sodium channel Nav 1.6 in the regulation of microglia inflammation by SVHRSP. KEY RESULTS: SVHRSP treatment attenuated motor deficits, dopamine neuron degeneration, activation of glial cells and expression of pro-inflammatory cytokines induced by 6-OHDA lesion. Primary microglia activation and the production of pro-inflammatory cytokines induced by lipopolysaccharide (LPS) were also suppressed by SVHRSP treatment. In addition, SVHRSP could inhibit mitogen-activated protein kinases (MAPKs) pathway, which plays pivotal roles in the pro-inflammatory response. Notably, SVHRSP treatment suppressed the overexpression of microglial Nav 1.6 induced by 6-OHDA and LPS. Finally, it was shown that the anti-inflammatory effect of SVHRSP in microglia was Nav 1.6 dependent and was related to suppression of sodium current and probably the consequent Na+ /Ca2+ exchange. CONCLUSIONS AND IMPLICATIONS: SVHRSP might inhibit neuroinflammation and protect dopamine neurons via down-regulating microglial Nav 1.6 and subsequently suppressing intracellular Ca2+ accumulation to attenuate the activation of MAPKs signalling pathway in microglia.

Generating Assembled MFI Nanocrystals with Reduced b-Axis through Structure-Directing Agent Exchange Induced Recrystallization.

Controlling crystal size and shape of zeolitic materials is an effective way to promote their mass transport and catalytic properties. Herein, we report a single step, Na+ - and porogen- free crystallization of MFI hierarchical architecture made up of aligned nanocrystals with reduced b-axis thickness (5-23 nm) and adjustable Si/Al ratios between 35 to 120, employing the commonly used tetrapropylammonium hydroxide (TPAOH) and tetrabutylammonium hydroxide (TBAOH) as structure-directing agents (SDAs). Homogeneous nucleation driven by both SDAs and subsequent SDA-exchange induced dissolution-recrystallization are responsible for the formation of such structure. The enhanced textural and diffusion properties account for a notable exaggeration of propene selectivity and catalyst lifetime in dimethyl ether-to-olefins (DTO) conversion. This protocol is extendable to the rational synthesis of other hierarchical zeolites through crystallization process control.