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Under UV-visible light irradiation, multiple synergetic promotion effects on the photocatalytic activity of TiO2 by gold deposition can be observed, and plasmonic Au/TiO2 shows great potential for photocatalytic solar conversion. [ABSTRACT FROM AUTHOR]

Sn-containing MFI zeolites with controllable Al contents were successfully synthesized with the utilization of the EDTA-Sn complex as tin source and citrate as buffer solution for the first time. The elaborately strategy achieves a right release of Sn 4+ ions rate to combine with the silicon tetrahedron species in the synthesis process which could make the heteroatom tin warmly incorporate into the zeolite frameworks. The structural information about the Sn-containing MFI zeolites was confirmed by XRD, FTIR, and solid-state NMR spectroscopy. Characterization results of HRTEM, FTIR, XPS, and UV-vis spectroscopy illustrated that most Sn species exist as isolated tetrahedral Sn(IV) in the as-prepared zeolites. The creation of Lewis acid sites in Sn-MFI and Sn-Al-MFI zeolites, and Brønsted acid sites in Sn-Al-MFI zeolites were determined by FTIR spectroscopy of pyridine adsorption and 1 H and 31 P MAS NMR spectroscopy after ammonia and trimethylphosphine oxide (TMPO) adsorption. Both the Sn-MFI and Sn-Al-MFI zeolite catalysts exhibit a remarkable catalytic performance in the conversion of dihydroxyacetone (DHA) to methyl lactate (ML), while the bifunctional Sn-Al-MFI catalyst exhibits a significant combination effect, and a remarkable active site-based turnover frequency with a high methyl lactate productivity can be achieved. [ABSTRACT FROM AUTHOR]

Efficient synthesis of zeolites with different topologies is of great significance for both fundamental research and industrial application. Herein, the SSZ-23 zeolite, an odd zeolite containing 7-membered ring (7-MR) and 9-MR channels, has been synthesized under fluorine-free conditions via the route of pre-aging and pH regulation. By this novel synthesis route, the crystallization time can be significantly shortened to 3 days, nearly half as that by the conventional route in fluoride media. The pH value of the aging gel, i.e., the basicity, is found to play a key role in the synthesis, as SSZ-13 and SSZ-25 zeolites can be synthesized simply by changing the basicity of the same aging gel. Characterization results indicate that decreasing the basicity can promote the condensation between Si and Si/Al species and thus increase the framework density of the resulting zeolites. Finally, the dimethyl ether (DME) carbonylation reaction is employed to evaluate the catalytic properties of the above three zeolites with an identical chemical composition, and to reveal the unique confinement effect in various zeolite topologies. [ABSTRACT FROM AUTHOR]

The selective hydrogenation of CO2 to methanol by renewable hydrogen source represents an attractive route for CO2 recycling and is carbon neutral. Stable catalysts with high activity and methanol selectivity are being vigorously pursued, and current debates on the active site and reaction pathway need to be clarified. Here, we report a design of faujasite-encaged mononuclear Cu centers, namely Cu@FAU, for this challenging reaction. Stable methanol space-time-yield (STY) of 12.8 mmol gcat-1 h-1 and methanol selectivity of 89.5% are simultaneously achieved at a relatively low reaction temperature of 513 K, making Cu@FAU a potential methanol synthesis catalyst from CO2 hydrogenation. With zeolite-encaged mononuclear Cu centers as the destined active sites, the unique reaction pathway of stepwise CO2 hydrogenation over Cu@FAU is illustrated. This work provides a clear example of catalytic reaction with explicit structure-activity relationship and highlights the power of zeolite catalysis in complex chemical transformations. [ABSTRACT FROM AUTHOR]

Hierarchical Meso-Zr-Al-beta zeolites are successfully prepared through a multiple-step post-synthesis strategy composed of controlled dealumination, desilicication and metal incorporation. The presence of both Brønsted and Lewis acid sites with a certain extent of strength in Meso-Zr-Al-beta is demonstrated by NH 3 -TPD and FTIR spectroscopy with pyridine adsorption/desorption. The creation of mesopores via desilicication through alkaline treatment is confirmed by N 2 adsorption/desorption isotherms. Meso-Zr-Al-beta, with Brønsted acid sites, Lewis acid sites and mesopores, is applied as a zeolite catalyst for the cascade conversion of biomass platform molecule furfural to γ-valerolactone. Owing to the presence of multiple functional sites and their mutual compatibility, remarkable activity for γ-valerolactone production and catalyst recyclability could be achieved with a single Meso-Zr-Al-beta, which appears to be a better catalyst than the commonly-employed combination catalyst systems. The multifunctional Meso-Zr-Al-beta zeolite is also applied as a promising catalyst in other cascade reactions in biomass valorization, i.e. glucose conversion to 5-hydromethylfurfural and trioses conversion to ethyl lactate. Similar zeolite catalysts containing multiple functional sites could be prepared via similar routes, and the number of acid sites and their strength can be adjusted to some extent to derive an optimized catalyst by changing the preparation parameters. [ABSTRACT FROM AUTHOR]

Suzuki-Miyaura cross-coupling reaction by homogeneous Pd complex is a powerful route to construct carbon-carbon bond and is now widely applied in the synthesis of functional organic compounds. Heterogeneous Pd catalysts are highly desired as alternatives to homogeneous ones due to their facile reusability and good compatibility. Herein, zeolite-encaged Pd particles, namely Pd@MFI, have been successfully prepared via an in-situ hydrothermal strategy and investigated as promising heterogeneous catalysts for Suzuki-Miyaura cross-coupling reactions. Characterization results demonstrate that high dispersed Pd particles with apparent sizes of 1–2 nm have been encaged in and efficiently stabilized by the matrix of MFI zeolite. The as-prepared Pd@MFI catalysts are active in the Suzuki-Miyaura coupling reaction between bromobenzene and phenylboronic acid, and the presence of basic sites adjacent to Pd sites are crucial to achieving high catalytic activity via effective cooperation. Pd@K-ZSM-5 can be optimized for the coupling between bromobenzene and phenylboronic acid and can catalyze the reaction with a low apparent activation energy value of 41.2 kJ/mol. Pd@K-ZSM-5 also shows good stability and can be recycled for at least five times without obvious loss in activity, demonstrating its great potential as a heterogeneous catalyst for Suzuki-Miyaura cross-coupling reactions. Encapsulation of metal species in zeolite matrix offers a big opportunity to the heterogenization of homogeneous metal catalysts for practical chemical transformations. [Display omitted] • Zeolite-encaged palladium catalysts constructed for heterogeneous Suzuki-Miyaura cross-coupling reactions. • High catalytic activity and good stability achieved with Pd@K-ZSM-5 catalysts. • Structural confinement promoting the catalytic reactions within zeolite channels. [ABSTRACT FROM AUTHOR]

Background: To assess the interaction of sleep duration and depression on the risk of cardiovascular disease (CVD).Methods: A total of 13,488 eligible participants were enrolled in this retrospective cohort study eventually. Baseline characteristics were extracted from the China Health and Retirement Longitudinal Study (CHARLS) database, including age, sex, diabetes, high-density lipoprotein (HDL), blood glucose (GLU), glycosylated hemoglobin (GHB) etc. Univariate and multivariate negative binomial regression models were carried out to assess the statistical correlation of sleep duration and depression on CVD separately. Additionally, multivariate negative binomial regression model was used to estimate the interaction of sleep duration and depression on CVD risk.Results: After adjusting for age, sex, educational background, hypertension, diabetes, dyslipidemia, the use of hypnotics, disability, nap, drinking, deposit, sleep disturbance, HDL, triglyceride, total cholesterol, GLU and GHB, the risk of CVD in participants with the short sleep duration was increased in comparison with the normal sleep duration [relative risk (RR)=1.02, 95% confidence interval (CI):1.01-1.03]; compared to the participants with non-depression, participants suffered from depression had an increased risk of CVD (RR=1.05, 95%CI:1.04-1.06). Additionally, the result also suggested that the interaction between short sleep duration and depression on the risk of CVD was statistically significant in these patients with diabetes and was a multiplicative interaction.Conclusion: An interaction between short sleep duration and depression in relation to an increased risk of CVD among Chinese middle-aged and elderly individuals was noticed, which may provide a reference that people with diabetes should focus on their sleep duration and the occurrence of depression, and coexisting short sleep duration and depression may expose them to a higher risk of CVD. [ABSTRACT FROM AUTHOR]

The development of cost‐effective sorbents for direct capture of trace CO2 (<1 %) from the atmosphere is an important and challenging task. Natural or commercial zeolites are promising sorbents, but their performance in adsorption of trace CO2 has been poorly explored to date. A systematic study on capture of trace CO2 by commercial faujasite zeolites reveals that the extra‐framework cations play a key role on their performance. Under dry conditions, Ba−X displays high dynamic uptake of 1.79 and 0.69 mmol g−1 at CO2 concentrations of 10000 and 1000 ppm, respectively, and shows excellent recyclability in the temperature‐swing adsorption processes. K−X exhibits perfect moisture resistance, and >95 % dry CO2 uptake can be preserved under relative humidity of 74 %. In situ solid‐state NMR spectroscopy, synchrotron X‐ray diffraction and neutron diffraction reveal two binding sites for CO2 in these zeolites, namely the basic framework oxygen atoms and the divalent alkaline earth metal ions. This study unlocks the potential of low‐cost natural zeolites for applications in direct air capture. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a series of phosphorus-modified HMCM-22-x%P samples are prepared by impregnation of HMCM-22 with aqueous solution of (NH4)2HPO4 and subsequent calcination. The phosphorus-modified HMCM-22 samples were characterized by means of XRD, NH3-TPD, and multinuclear (31P, 29Si, 27Al and 1H) MAS NMR techniques. The phosphorus-modified HMCM-22 samples, together with parent HMCM-22, are studied as possible catalysts for methanol-to-hydrocarbons (MTH) reaction. HMCM-22-3%P exhibits very good MTH performance and 100% methanol conversion with ca. 70% selectivity to light olefins can be achieved within time-on-stream of 40h at 723K. The MTH reaction over H-MCM-22 and phosphorus-modified HMCM-22 is monitored by in situ UV/Vis spectra, and the hydrocarbon pool species occluded in spent catalysts are analyzed by ex situ GC–MS spectra. Based on the characterization and catalytic results, the modification effects of phosphorus on HMCM-22 and corresponding impacts on the MTH reaction are discussed. [Copyright &y& Elsevier]

Abstract: Bimetallic Pd–Cu/TiO2 is prepared by successive photo-deposition process and characterized by means of TEM, H2-TPR and FTIR spectra of CO adsorption. The as-prepared Pd–Cu/TiO2 is studied as promising catalyst for nitrate hydrogenation and a step-wise reaction process, divided into nitrate hydrogenation to nitrite and nitrite hydrogenation to nitrogen, is observed. The active sites for nitrate and nitrite hydrogenation over Pd–Cu/TiO2 are discussed individually. It is observed that basic conditions of reaction solution favor the hydrogenation of nitrate to nitrite, while acidic conditions favor the hydrogenation of nitrite to nitrogen. For nitrite hydrogenation, acetic acid is more efficient acidic buffer than hydrochloric acid due to an in situ buffering effect. Based on these results, a two-step process, by changing the reaction solution from basic conditions to acidic conditions at midterm, is developed to realize the hydrogenation of nitrate to nitrogen over bimetallic Pd–Cu/TiO2. [Copyright &y& Elsevier]

Entrapping the small NbO x clusters into MFI zeolite crystals was directly prepared via a facile hydrothermal method, assisting with the sodium citrate and EDTA-2Na to dissolve and chelate the niobium precursors. The existing states and configurations of Nb species in the zeolites were carefully characterized by a series of techniques including XRD, FTIR, SEM, TEM, UV–Vis, XPS and Raman. These results clearly indicated that the entrapped oligomeric NbO x clusters in MFI zeolite crystals contained Nb-OH, Nb=O and Nb-O-Si bonds. These characters were the origin of both Lewis and Brønsted acid sites for these Nb-MFI samples, which was vividly confirmed by FTIR spectroscopy with pyridine absorption and solid-state NMR spectroscopy with ammonia and TMPO as probing molecules techniques. The as-prepared Nb-MFI zeolites were employed as sustainable Lewis acids in several catalytic reactions. Especially, Nb-MFI zeolites exhibited remarkable catalytic performance in the cross-aldol condensation between furfural and acetone for biomass upgrading, surpassing traditional Lewis acidic zeolites Sn-MFI and Sn-BEA in terms of activity and selectivity, respectively. The 2.6%Nb-MFI also showed very good stability during reaction and it could be recycled for six times without loss in activity. Finally, 2.6%Nb-MFI was verified as a general catalyst for the cross-aldol condensation reaction between small-molecule aldehydes and ketones. All these results demonstrate the great potential of Nb-MFI as a robust catalyst for the shape-selective Lewis acid catalysis. The synthesis strategy developed herein could be readily extended to the construction of zeolite entrapped high-valence transition metal clusters for catalytic applications. The NbO x entrapped MFI zeolites were prepared by a facile direct hydrothermal route, employing the sodium citrate and EDTA-2Na to dissolve and chelate the niobium precursors. Image 1 • Oligomeric NbO x clusters entrapped into MFI zeolite crystals via direct hydrothermal synthesis. • Nb-MFI zeolites are served as robust catalysts in the aldol condensation reaction for biomass upgrading. • General strategy to entrap high-valence transition metal species in zeolite crystals for shape-selective acid catalysis. [ABSTRACT FROM AUTHOR]

Background: Gold nanoparticles (AuNPs) have been widely studied for biomedical applications, although their safety and potential toxicity in pregnancy remains unknown. The aim of this study is to explore the effect of AuNPs maternal exposure at different gestational ages on fetal survival and development, as well as the potential mechanism of AuNPs affecting embryos and fetuses. Methods: Thirty nm polyethylene glycol (PEG)-coated AuNPs (A30) were administered to pregnant mice via intravenous injection (5 μg Au/g body weight) over three days at either early or late pregnancy. Fetal abortion rate and morphological development in E16.5 were then detected in detail. The pregnant mice physiological states with A30 exposure were examined by biochemical, histological or imaging methods; and materno-fetal distribution of gold elements was assayed by electron microscopy and mass spectrometry. Murine embryonic stem cells derived embryoid-bodies or neuroectodermal cells were treated with A30 (0.0025 to 0.25 μg Au/mL) to examine A30 effects on expression levels of the germ differentiation marker genes. Tukey's method was used for statistical analysis. Results: Exposure to A30 during early (A30E) but not late (A30L) pregnancy caused a high abortion rate (53.5%), lower fetal survival rate and abnormal decidualization compared with non-exposed counterparts. The developmental damage caused by A30 followed an "all-or-nothing" pattern, as the non-aborted fetuses developed normally and pregnancies maintained normal endocrine values. A30 caused minor impairment of liver and kidney function of A30E but not A30L mice. TEM imaging of fetal tissue sections confirmed the transfer of A30 into fetal brain and live as aggregates. qPCR assays showed A30 suppressed the expression of ectodermal, but not mesodermal and endodermal differentiation markers. Conclusions: These results illustrate that maternal A30 exposure in early pregnant results in A30 transfer into embryonic tissues, inhibiting ectodermal differentiation of embryonic stem cells, leading to abnormal embryonic development and abortion. While exposure to A30 during late pregnancy had little or no impact on dams and fetuses. These findings suggest the safety of biomedical applications employing AuNPs during pregnancy is strongly influenced by fetal maturity and gestational age at exposure and provide the clues for AuNPs safe application period in pregnancy. [ABSTRACT FROM AUTHOR]

The selective catalytic reduction of nitric oxide by methane (CH 4 -SCR) represents the most desirable technique for the post-treatment of nitrogen oxide emissions from gas-fired power plants and the efficient CH 4 -SCR catalysts are being explored. We herein report the construction of bimetallic Ru-In/H-SSZ-13 catalyst, which exhibited remarkable performance in CH 4 -SCR under the reaction conditions of a high gas hourly space velocity (GHSV) of 75,000 h −1 and in the presence of 6% H 2 O. In Ru-In/H-SSZ-13, the close contact between Ru and In species was confirmed by transmission electron microscopy (TEM) analysis, and their electronic interaction was verified by means of X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H 2 -TPR). All these features made Ru-In/H-SSZ-13 an elegant example of zeolite-based cooperative catalytic system for CH 4 -SCR. The surface species formed and their stability on Ru/H-SSZ-13, In/H-SSZ-13 and Ru-In/H-SSZ-13 were investigated by temperature-programmed desorption (TPD) experiments, from which the individual role of H-SSZ-13, Ru and In sites and their cooperation in CH 4 -SCR were discussed in detail. [ABSTRACT FROM AUTHOR]

Graphical abstract Coverage of active sites by large unsaturated aldehydes/ketones transformed from the intermediate acetaldehyde and by-product acetone responsible for catalyst deactivation in ethanol-to-butadiene conversion. Highlights • Deactivation mechanism of Zn-Y/Beta catalyst in ethanol-to-butadiene conversion investigated by complementary approaches. • Both the intermediate acetaldehyde and by-product acetone participate in the aldol condensation. • Large unsaturated aldehydes/ketones formed from condensation and cyclization reactions. • Coverage of active sites by large unsaturated aldehydes/ketones responsible for the catalyst deactivation. Abstract Despite of extensive attention on the ethanol to butadiene (ETB) conversion, the catalyst deactivation during ETB conversion is rarely investigated and poorly understood. Here, the mechanism of the catalyst deactivation during the ETB conversion over Zn-Y/Beta was investigated through several complementary approaches, including XPS, TGA, GC–MS, in situ DRIFTS, UV–vis and 13C CP MAS NMR spectroscopy. Acetaldehyde was observed to be the first reactive intermediate formed in the ETB conversion, which was rapidly involved in a subsequent aldol condensation with the simultaneous production of acetone. Due to a self- and cross-condensation of acetaldehyde and acetone, long chain unsaturated aldehydes/ketones were formed and further converted to 2,4-dimethyl benzaldehyde via a cyclization reaction, which could gradually cover the active sites and led to catalyst deactivation. Fortunately, the deactivating species could be removed from catalyst surface via simple calcination and the complete regeneration of Zn-Y/Beta could be realized. [ABSTRACT FROM AUTHOR]

Pb-Beta, a heteroatom zeolite containing out-size atoms of lead, has been successfully prepared via a scalable post-synthesis strategy composed of dealumination of H-Beta to create associated silanol and subsequent dry impregnation of the resulting Si-Beta with lead nitrate. The incorporated lead species exist in the form of well-isolated tetra-coordinated Pb 2+ ions with open configurations, as revealed by the characterization results from high angle annular dark filed scanning transmission electron microscopy (HAADF-STEM), UV-Vis, X-ray photoelectron spectroscopy (XPS) and 29 Si solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. Sufficient Lewis acid sites with moderate acid strength are created by lead incorporation into zeolite framework, as confirmed by the temperature-programmed desorption of ammonia (NH 3 -TPD). The as-prepared Pb-Beta Lewis acid zeolites exhibit remarkable catalytic activity in the ring-opening aminolysis of epoxides to β-amino alcohols with high regio-selectivity. The presence of wide-open lead sites can promote the simultaneous activation of epoxide and amine substrates and, therefore, catalyze the aminolysis of epoxides with strong basic amines, e.g. butylamine. [ABSTRACT FROM AUTHOR]

A non-precious metal catalyst Ni/NiO is developed for the efficient hydrogenation of levulinic acid to γ-valerolactone under mild conditions. Treating nickel oxide in hydrogen at controlled temperature of 473–573 K results in its partial reduction to metallic nickel and the formation of Ni/NiO heterojunctions, as indicated by the characterization results from in situ XRD, XPS and TEM. The as-prepared Ni/NiO catalyst exhibits remarkable activity in levulinic acid hydrogenation with a high mass activity of 14.1 mmol/h/g at 393 K, being over 18 times higher than NiO and 10 times higher than metallic Ni. Besides, Ni/NiO shows very good stability and recyclability during the reaction, making it a promising catalyst for practical levulinic acid hydrogenation. The formation of Ni/NiO heterojunctions is crucial for the remarkable activity of Ni/NiO composite catalyst and a cooperative Langmuir-Hinshelwood mechanism is proposed for levulinic acid hydrogenation on the basis of kinetic analysis and theoretical calculations. The concept of cooperative catalysis on metal/oxide heterojunctions can be expanded to other hydrogenation reactions. [ABSTRACT FROM AUTHOR]

Triglycerides represent a type of sustainable energy source and robust catalysts for triglycerides refining to biofuels are very challenging. Herein, we report supported ruthenium catalysts, optimized from group VIII metal catalysts, for the selective conversion of triglycerides to diesel-range alkanes under mild conditions. The catalyst supports and ruthenium loadings show significant impacts on the performance of ruthenium catalysts, and Ru/TiO 2 with ruthenium weight loading of 1.68% is optimized for the reaction. Typically, the platform compound stearic acid could be directly converted, or via 1-octadecanol as an intermediate product, to n -heptadecane and n -octadecane in n -heptane solvent using the optimized Ru/TiO 2 catalyst at 473 K and under 3 MPa H 2 . On the basis of catalytic and spectroscopic characterization results, large ruthenium metal particles are established as the preferred active sites for stearic acid conversion. The complete reaction network of stearic acid deoxygenation on flat Ru (0001) is investigated by theoretical calculations. It is revealed that different pathways run simultaneously during the reaction and the adsorbed acyl species C 17 H 35 CO* are the key reaction intermediates for the catalytic deoxygenation on Ru (0001). The removal of adsorbed CO by hydrogenation is the rate-controlling step contributing to the highest energy barrier within the reaction network. [ABSTRACT FROM AUTHOR]

[Display omitted] • An excellent adsorbent Ba-FAU with dynamic N 2 O uptake of 2.25 mmol/g at 50000 ppm. • N 2 O uptakes relate with surface area, electrostatic field and diffusion resistance. • N 2 O is electrostatically anchored by extraframework cations and framework oxygen. Nitrous oxide is a strong greenhouse gas contributing over 300 times global warming potential higher than carbon dioxide. The capture of nitrous oxide from industrial emission source represents an efficient and promising strategy for its further treatment or recycling, which receives less attention in the past decades. Herein, a comprehensive study on nitrous oxide capture by alkali and alkaline-earth metal ions (Li, Na, K, Mg, Ca and Ba) exchanged FAU and CHA zeolites was conducted, with focuses on the underlying adsorption mechanism and the structure-performance relationship. Under ambient conditions, Ba-FAU and Na-CHA show remarkable nitrous oxide dynamic uptakes of 2.25 and 2.41 mmol/g, respectively, at high concentration of 50000 ppm, and Ba-FAU shows good dynamic uptake of 0.35 mmol/g at extremely low concentration of 1000 ppm. The dynamic nitrous oxide uptakes by zeolites at high concentrations are related to the surface area and the adsorption strength controlled by local electrostatic field, while the diffusion resistance shows serious negative impacts at low concentrations. The intrinsic stability of zeolite and the perfect recyclability make Ba-FAU an eligible industrial adsorbent for nitrous oxide capture. In situ Fourier transform infrared spectroscopy and Grand Canonical Monte Carlo simulations reveal that nitrous oxide molecules prefer to anchor to extraframework cations via terminal-oxygen atoms and meanwhile stabilized by framework oxygen through electrostatic interaction via central nitrogen atoms. The explicit structure-performance relationship and the underlying mechanism are very important for the understanding of nitrous oxide capture by zeolites and most helpful for the rational design of robust adsorbents. [ABSTRACT FROM AUTHOR]

High aspect ratio zeolite crystals and their seeding on support are of high desire for the fabrication of oriented zeolite membranes. Here, platelike MFI crystals, as zeolite seeds, are successfully seeded on a α-Al 2 O 3 disk support through a transfer printing method. Firstly, platelike MFI crystals are spread on a flat substrate pre-coated with films of polyvinyl alcohol (PVA) and a fluoropolymer (4200UR) followed by coating a polymethyl methacrylate (PMMA) film. After dissolving the PVA film, the free-standing sandwich-like 4200UR-MFI-PMMA film is transferred onto the support. Then, platelike MFI crystals are successfully seeded after removing the organic species by calcination. Finally, highly (h0h)-oriented, dense and continuous silicalite-1 membranes are fabricated after a secondary growth in a zeolitic synthesis system, confirmed by XRD and SEM techniques. Binary separation of butane isomer has been performed on the silicalite-1 membranes prepared with different synthesis time, achieving a n -butane permeance and a separation factor of 2.27 × 10−7 mol m−2 s−1∙Pa−1) and 28.8 for an equimolar n -butane/ i -butane mixture at 343 K, respectively. [Display omitted] • A transfer printing approach was proposed. • Platelike MFI crystals were used as the seeds. • Sandwich-like films containing seed layers were transferred to the porous support. • High n-butane selective silicalite-1 membranes were prepared after a secondary growth. [ABSTRACT FROM AUTHOR]

Highlights: [•] High yield of propene in the ETP process obtained on H-SSZ-13. [•] Improved lifetime in the ETP reaction achieved on dealuminated H-SSZ-13. [•] Polyalkylnaphthalenes as key active organic species during ETP. [•] Accumulation of large polycyclic aromatics leads the deactivation of H-SSZ-13. [ABSTRACT FROM AUTHOR]

Abstract: Selective catalytic reduction of NO by hydrogen was studied over Cr modified Pt/ZSM-35 catalysts. The preparation process greatly influenced catalytic activity and sample prepared by co-impregnation method exhibits the best activity. In situ DRIFT studies revealed that on Pt–Cr/ZSM-35, (1) new Pt-NOδ+ and NO species adsorbed on Pt were detected upon NO+O2 adsorption; (2) much more ammonia species were formed under reaction condition. Cr addition not only enhanced the adsorption of NO x but also promoted the formation of surface NH4 + species, which should be the origin of promotional effect of Cr on Pt/ZSM-35 for H2-SCR reaction. [Copyright &y& Elsevier]

Abstract: A series of Ti-containing MCM-41 were prepared by isomorphously substitution, wet impregnation and mechanical mixing. Ti-containing MCM-41 materials, together with reference Si–MCM-41, were characterized by means of XRD, TEM and low temperature N2 adsorption/desorption. The nature of Ti species on Ti-containing MCM-41 was analyzed by means of UV–vis and Raman spectroscopy. Pt catalysts supported on Si–MCM-41 and Ti-containing MCM-41 were studied for the selective catalytic reduction of NO by hydrogen in excess oxygen. Particular attention was paid to the promotion effect of different Ti species on the catalytic activity for H2-SCR and the origin thereof. Pt/Ti–MCM-41 prepared by wet impregnation with the Ti/Si ratio of 0.6 exhibited the best activity and ca. 89% NOx conversion as well as ca. 79% N2 selectivity, could be achieved at 140°C with a feed stream containing 1000ppm NO, 5000ppm H2, 6.7% O2 at a high GHSV of 80,000h−1. Moreover, Pt–Ti–MCM-41 exhibited good duration and good tolerance to co-existing 20ppm SO2 or 50ppm CO, which demonstrated its potential for future applications. [Copyright &y& Elsevier]

The selective hydrogenation of nitroaromatics plays an essential role in the chemical industry for the synthesis of anilines and their derivatives, which are known as crucial fine chemicals and pharmaceuticals. In this study, we demonstrate the preparation of Pd/Ti monolith catalyst containing well-isolated metallic Pd sites on Ti substrate through a simple impregnation method, showing remarkable catalytic properties in the selective hydrogenation of nitroaromatics containing various functional groups. Kinetic analyses reveal an apparent activation energy of 61 kJ/mol and the kinetic isotope effect (K H2 /K D2 ) of ~1.7 in the hydrogenation of 3-chloronitrobenzene over Pd/Ti-200 ppm catalyst, indicating the facile dissociation of dihydrogen and the subsequent efficient hydrogenation. The Pd/Ti-200 ppm catalyst also demonstrates good stability and recyclability, maintaining its performance over multiple cycles. This simple but innovative approach not only enhances the efficiency of Pd catalysts in the selective hydrogenation of nitroaromatics but also offers significant potential for industrial applications in aniline production., (© 2024 Wiley-VCH GmbH.)

The inherent inertness and striking physicochemical similarities of krypton and xenon pose significant challenges to their separation. Reported herein is the efficient xenon capture and xenon/krypton adsorptive separation by transition metal-free zeolites under ambient conditions. The polarized environment of zeolite, denoted as local polarity, can be tuned by changing the topology, framework composition, and counter-cations, which in turn correlates with the guest-host interaction and separation performance. Chabazite zeolite with a framework Si/Al ratio of 2.5 and Ca 2+ as the counter-cations, namely, Ca-CHA-2.5, is developed as a state-of-the-art zeolite adsorbent, showing remarkable performance, i.e. , high dynamic xenon uptake, high xenon/krypton separation selectivity, and good recyclability, in the adsorptive separation of the xenon/krypton mixture. Grand Canonical Monte Carlo simulation reveals that extraframework Ca 2+ cations act as the primary binding sites for xenon and can stabilize xenon molecules together with the chabazite framework, whereas krypton molecules are stabilized by weak guest-host interaction with the zeolite framework.

Extraframework transition metal ions (TMIs) in zeolites can serve as active sites for adsorption and catalysis. However, due to the complexity and mobility of extraframework cation sites, their applications are significantly limited and the structure-performance relationship is poorly understood. In this Perspective, stable and uniform TMIs in zeolites are exemplified and their characteristics are discussed. A series of TMIs can be introduced to specific cation sites of faujasite via a ligand-protected in situ synthesis route to construct uniform TMIs in the zeolite matrix, namely, TMI@FAU (TMI= Co, Ni, Cu, Rh, and Pt). Coordinatively unsaturated TMIs within faujasite are active for small-molecule adsorption and activation, and therefore, TMI@FAU zeolites show unique properties in adsorption and catalysis. TMI@FAU zeolites appear to be ideal model systems, and the well-defined structure of TMI@FAU greatly facilitates the mechanism studies by spectroscopic investigations and theoretical simulations.

Olefin selectivity and catalyst lifetime are two key metrics for industrial methanol-to-olefin catalysts. Currently, it is very difficult to obtain high olefin selectivity and long catalyst lifetime at the same time. Herein, a feasible strategy combining precoking and steaming to directionally construct the active naphthalenic species within the crystal center of the SAPO-34 catalyst has been developed, which can not only promote the lower olefin selectivity to ∼89% (ethylene and propylene) but also prolong the catalyst lifetime by ∼3.7-fold in the methanol-to-olefin conversion. Structured illumination microscopy, in situ ultraviolet-visible spectroscopy, and online mass spectrometry elucidate the spatiotemporal distribution and evolution of the naphthalenic species during the precoking and steaming processes. This one-stone-two-birds strategy is applicable to a commercial SAPO-34 catalyst containing a binder, demonstrating its bright prospect in the methanol-to-olefin industry.

The digitization of Electronic Medical Record (EMR) provides potential access to a wealth of medical information, but also presents new challenges in privacy-preserved EMR exchanging and sharing. In this paper, we propose a blockchain-based smart healthcare system with fine-grained privacy protection for reliable data exchanging and sharing among different users. We design a blockchain-enabled dynamic access control framework combined with Local Differential Privacy (LDP) strategies to provide the attribute-based privacy protection in transaction workflow. We design four types of smart contracts in the framework to meet the requirements of anonymous transaction, dynamic access control, beneficial matching decision, and evaluation of published data in an open network. To satisfy fine-grained privacy protection, we classify sensitive attributes of EMRs into different levels and set differential privacy budgets to randomize attributes before data publishing. Also, we design data quality function to depict the disturbance incurred by LDP-based privacy preferences at the requester view, and present appropriate many-to-many matching decisions among participants for beneficial transactions. Finally, we develop a prototype system and test our approach using 200,000 real-world EMRs. Experimental results show that the proposed privacy-preserved scheme can make stable and reliable transactions between EMR publishers and requesters. The prototype system achieves individual-centric privacy configuration at the patient site, while providing error-guaranteed statistics at the requester site. Additionally, the access control policies, logs of anonymous transaction are kept in the blockchain to provide system-level traceability.

Zeolites with good acid site accessibility and high diffusion rates are highly desirable catalysts, especially when dealing with bulk molecules. In this work, ZSM-5 zeolites with similar Si/Al ratios but different thicknesses along the b -axis (from ∼30 nm to ∼5 μm), namely, two plate-like ZSM-5 zeolites and two reference zeolites have been prepared and the impacts of b -axis thickness on the surface properties and catalytic cracking performances are explored. Comprehensive physiochemical studies demonstrate that reducing the b -axis thickness of the zeolite crystals endows the samples with better acid site accessibility and more external surface acid sites. Two model compounds with different molecule sizes, namely, 1,3,5-triisopropylbenzene (TIPB) and cumene, are selected to explore the catalytic cracking performances of the as-synthesized samples. The results reveal that decreasing the b -axis thickness of zeolite crystals can effectually promote the catalytic activity and stability in catalytic cracking reactions. For TIPB cracking, the greatly enhanced catalytic activity is ascribed to the enhanced acid site accessibility in plate-like ZSM-5 zeolites, and for cumene cracking, the improved catalytic stability is ascribed to the shortened diffusion length of plate-like zeolites.

Direct propylene epoxidation with molecular oxygen is a dream reaction with 100% atom economy, but aerobic epoxidation is challenging because of the undesired over-oxidation and isomerization of epoxide products. Herein, we report the construction of uniform cobalt ions confined in faujasite zeolite, namely, Co@Y, which exhibits unprecedented catalytic performance in the aerobic epoxidation of propylene. Propylene conversion of 24.6% is achieved at propylene oxide selectivity of 57% at 773 K, giving a state-of-the-art propylene oxide production rate of 4.7 mmol/g cat /h. The catalytic performance of Co@Y is very stable, and no activity loss can be observed for over 200 h. Spectroscopic analyses reveal the details of molecular oxygen activation on isolated cobalt ions, followed by interaction with propylene to produce epoxide, in which the Co 2+ -Co δ+ -Co 2+ (2 < δ < 3) redox cycle is involved. The reaction pathway of propylene oxide and byproduct acrolein formation from propylene epoxidation is investigated by density functional theory calculations, and the unique catalytic performance of Co@Y is interpreted. This work presents an explicit example of constructing specific transition-metal ions within the zeolite matrix toward selective catalytic oxidations.

Understanding the complete reaction network and mechanism of methanol-to-hydrocarbons remains a key challenge in the field of zeolite catalysis and C1 chemistry. Inspired by the identification of the reactive surface methoxy species on solid acids, several direct mechanisms associated with the formation of the first C-C bond in methanol conversion have been recently disclosed. Identifying the stepwise involvement of the initial intermediates containing the first C-C bond in the whole reaction process of methanol-to-hydrocarbons conversion becomes possible and attractive for the further development of this important reaction. Herein, several initial unsaturated aldehydes/ketones containing the C-C bond are identified via complementary spectroscopic techniques. With the combination of kinetic and spectroscopic analyses, a complete roadmap of the zeolite-catalyzed methanol-to-hydrocarbons conversion from the initial C-C bonds to the hydrocarbon pool species via the oxygen-containing unsaturated intermediates is clearly illustrated. With the participation of both Brønsted and Lewis acid sites in H-ZSM-5 zeolite, an initial aldol-cycle is proposed, which can be closely connected to the well-known dual-cycle mechanism in the methanol-to-hydrocarbons conversion., Competing Interests: The authors declare that they have no conflicts of interest in this work., (© 2021 The Authors. Publishing Services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.)

As a commercial MTO catalyst, SAPO-34 zeolite exhibits excellent recyclability probably due to its intrinsic good hydrothermal stability. However, the structural dynamic changes of SAPO-34 catalyst induced by hydrocarbon pool (HP) species and the water formed during the MTO conversion as well as its long-term stability after continuous regenerations are rarely investigated and poorly understood. Herein, the dynamic changes of SAPO-34 framework during the MTO conversion were identified by 1D 27 Al, 31 P MAS NMR, and 2D 31 P- 27 Al HETCOR NMR spectroscopy. The breakage of T-O-T bonds in SAPO-34 catalyst during long-term continuous regenerations in the MTO conversion could be efficiently suppressed by pre-coking. The combination of catalyst pre-coking and water co-feeding is established to be an efficient strategy to promote the catalytic efficiency and long-term stability of SAPO-34 catalysts in the commercial MTO processes, also sheds light on the development of other high stable zeolite catalyst in the commercial catalysis., (© 2021. The Author(s).)

Experimental evidence for the presence of tert-butyl cations, which are important intermediates in acid-catalyzed heterogeneous reactions, on solid acids has still not been provided to date. By combining density functional theory (DFT) calculations with (1)H/(13)C magic-angle-spinning NMR spectroscopy, the tert-butyl cation was successfully identified on zeolite H-ZSM-5 upon conversion of isobutene by capturing this intermediate with ammonia., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: To observe the protective effect of combined administration of blood-activating drug and sedative drug on myocardial injury of acute myocardial infarction (AMI) rats., Method: The acute myocardial infarction (AMI) model was established by occluding the left descending coronary artery of Wistar rats. These rats were further divided into four groups (n = 15 per group): the sham-operated group, the AMI model group, the blood-activating drug group and the combined administration group., Result: Compared with the sham-operated group, the AMI model group showed significant decrease in ejection fraction (EF) and fractional shortening (FS) (P < 0.001) and notable increase in the left ventricular end-diastolic internal diameter (LVIDd) and left ventricular end-systolic internal diameter (LVIDs) (P < 0.01), with the infarct area of left ventricular front wall up to about 70%-90%. Besides, tissue was severely replaced by collagen deposition and fibrosis, the sarcomeres disorganized and mitochondrial abnormalized. Compared with the AMI model group, the blood-activating drug group and the combined administration group showed significant increase in the values of EF and FS (P < 0.05 or P < 0.01) and obvious reduction in LVIDd and LVIDs (P < 0.05 or P < 0.01), with the infarction area of left ventricular front wall up to about 40%-60%. The collagen deposition and myocardium fibrosis, the disorganized sarcomeres and mitochondrial abnormalities relieved significantly. And compared with blood-activating drug group, the combined administration group demonstrated further increase in the values of EF and FS and further decrease in LVIDd and LVIDs (P < 0.05), the collagen deposition and myocardium fibrosis, the disorganized sarcomeres and mitochondrial abnormalities relieved even more in Huoxue plus Anshen prescription group., Conclusion: The combined administration of blood-activating drug and sedative drug can further improve cardiac structure and function after myocardial ischemia infarction and have an obvious synergistic effect which may be related to sedative drug's effect of resisting lipid peroxide, stabling myocardial cell membrane and mitochondrial membrane and relieving cardiac cell injury.