Controlling the Morphology and Titanium Coordination States of TS-1 Zeolites by Crystal Growth Modifier.

Developing an effective strategy to synthesize perfect titanosilicate TS-1 zeolite crystals with desirable morphologies, enriched isolated framework Ti species, and thus enhanced catalytic oxidation properties is a pervasive challenge in zeolite crystal engineering. We here used an amino acid l-carnitine as a crystal growth modifier and ethanol as a cosolvent to regulate the morphologies and the Ti coordination states of TS-1 zeolites. During the hydrothermal crystallization process, the introduced l-carnitine can not only tailor the anisotropic growth rates of zeolite crystals but also induce the formation of uniformly distributed framework Ti species through building a suitable chemical interaction with the Ti precursor species. Condition optimizations could afford the generation of perfect hexagonal plate TS-1 crystals and elongated platelet TS-1 crystals enriched in tetrahedral framework Ti sites (TiO4) or mononuclear octahedrally coordinated Ti species (TiO6). Both samples showed significant improvement in catalytic activity for the H2O2-mediated epoxidation of alkenes. In particular, the elongated platelet TS-1 enriched in "TiO6" species afforded the highest activity in 1-hexene epoxidation, with a turnover frequency (TOF) of up to 131 h-1, which is approximately twice as high as that of the conventional TS-1 zeolite (TOF: 65 h-1) and even higher than those of the literature-reported TiO6-containting TS-1 catalysts derived from the hydrothermal post-treatment of TS-1 zeolites. This work demonstrates that the morphologies and the titanium coordination states of TS-1 zeolites can be effectively tuned by directly introducing suitable crystal growth modifiers, thus providing new opportunities for developing highly efficient titanosilicate zeolite catalysts for important catalytic applications.

Electrochemical Synthesis and Catalytic Properties of Encapsulated Metal Clusters within Zeolitic Imidazolate Frameworks.

It is very interesting and also a big challenge to encapsulate metal clusters within microporous solids to expand their application diversity. For this target, herein, we present an electrochemical synthesis strategy for the encapsulation of noble metals (Au, Pd, Pt) within ZIF-8 cavities. In this method, metal precursors of AuCl42- , PtCl62- , and PdCl42- are introduced into ZIF-8 crystals during the concurrent crystallization of ZIF-8 at the anode. As a consequence, very small metal clusters with sizes around 1.2 nm are obtained within ZIF-8 crystals after hydrogen reduction; these clusters exhibit high thermal stability, as evident from the good maintenance of their original sizes after a high-temperature test. The catalytic properties of the encapsulated metal clusters within ZIF-8 are evaluated for CO oxidations. Because of the small pore window of ZIF-8 (0.34 nm) and the confinement effect of small pores, about 80 % of the metal clusters (fractions of 0.74, 0.77, and 0.75 for Au, Pt, and Pd in ZIF-8, respectively) retain their catalytic activity after exposure to the organosulfur poison thiophene (0.46 nm), which is in contrast to their counterparts (fractions of 0.22, 0.25, and 0.20 for Au, Pt, and Pd on the SiO2 support). The excellent performances of metal clusters encapsulated within ZIF-8 crystals give new opportunities for catalytic reactions.

Nonionic polymer and amino acid-assisted synthesis of ZSM-5 nanocrystals and their catalytic application in the alkylation of 2-methylnaphthalene.

The synthesis of nanosized ZSM-5 zeolites with high crystallinity and suitable acidity is very significant for their great potential in various catalytic applications. Herein, a series of zeolite ZSM-5 crystals with different particle sizes and SiO2/Al2O3 ratios (10-30) were synthesized by a temperature-varying two-step crystallization method in a concentrated gel system containing L-lysine and/or polyvinylpyrrolidone (PVP) additives. By optimizing the addition amounts of the two additives, the crystal size of the ZSM-5 zeolite could be reduced to less than 100 nm. Meanwhile, relatively high crystallinity and framework Al incorporation rates could be achieved, resulting in the generation of high-quality ZSM-5 nanocrystals. The nanosized H-form ZSM-5 zeolite with a SiO2/Al2O3 ratio of 20 showed enhanced catalytic efficiency and stability for the alkylation of 2-methylnaphthalene (2-MN) with methanol to produce an important intermediate, 2,6-dimethylnaphthalene (2,6-DMN). A relatively high and steady yield of 2,6-DMN (above 7.2%) could be achieved during 20 h time-on-stream at 400 °C. The smaller crystal size, higher crystallinity and framework Al content could provide more accessible Brønsted acid sites in the 10-membered ring channel of the ZSM-5 nanocrystals, which are the main active sites responsible for the shape-selectivity of the targeted product of 2,6-DMN. As a result, the formation of other side products like 1-MN and poly-MN could be effectively inhibited, thus leading to an improved 2,6-DMN yield and coke resistance over the nanosized ZSM-5 catalyst.

Fulminant myocarditis induced by SARS-CoV-2 infection without severe lung involvement: insights into COVID-19 pathogenesis.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection often leads to pulmonary complications. Cardiovascular sequelae, including myocarditis and heart failure, have also been reported. Here, the study presents two fulminant myocarditis cases infected by SARS-CoV-2 exhibiting remarkable elevation of cardiac biomarkers without significant pulmonary injury, as determined by imaging examinations. Immunohistochemical staining reveals the viral antigen within cardiomyocytes, indicating that SARS-CoV-2 could directly infect the myocardium. The full viral genomes from respiratory, anal, and myocardial specimens are obtained via next-generation sequencing. Phylogenetic analyses of the whole genome and spike gene indicate that viruses in the myocardium/pericardial effusion and anal swabs are closely related and cluster together yet diverge from those in the respiratory samples. In addition, unique mutations are found in the anal/myocardial strains compared to the respiratory strains, suggesting tissue-specific virus mutation and adaptation. These findings indicate genetically distinct SARS-CoV-2 variants have infiltrated and disseminated within myocardial tissues, independent of pulmonary injury, and point to different infection routes between the myocardium and respiratory tract, with myocardial infections potentially arising from intestinal infection. These findings highlight the potential for systemic SARS-CoV-2 infection and the importance of a thorough multi-organ assessment in patients for a comprehensive understanding of the pathogenesis of COVID-19.

Preparation, characterization of NiB amorphous alloy nanoparticles and their catalytic performance in hydrogenation reactions.

Nano-sized NiB amorphous alloy catalysts were prepared by chemical reduction method through introducing AlCl3 into the preparation system. The formation of Al(OH)3 sol plays an important role in inhibiting the agglomeration of NiB nanoparticles during the reduction process. The NiB amorphous alloy nanoparticles could be obtained after the removal of Al(OH)3 by NaOH solution. The particle sizes of these alloy catalysts could be adjusted in a certain range by changing the amount of AlCl3. The resultant NiB catalysts exhibited high catalytic activity in the hydrogenation of furfural and methyl isobutyl ketone, which is much higher than the NiB amorphous alloy catalyst prepared by direct reduction method. The excellent catalytic performance of NiB nanoparticles is apparently owing to the smaller particle size and higher surface area.

Anti-infection effects of heparin on SARS-CoV-2 in a diabetic mouse model.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can result in more severe syndromes and poorer outcomes in patients with diabetes and obesity. However, the precise mechanisms responsible for the combined impact of corona virus disease 2019 (COVID-19) and diabetes have not yet been elucidated, and effective treatment options for SARS-CoV-2-infected diabetic patients remain limited. To investigate the disease pathogenesis, K18-hACE2 transgenic (hACE2 Tg) mice with a leptin receptor deficiency (hACE2-Lepr -/-) or high-fat diet (hACE2-HFD) background were generated. The two mouse models were intranasally infected with a 5×10 5 median tissue culture infectious dose (TCID 50) of SARS-CoV-2, with serum and lung tissue samples collected at 3 days post-infection. The hACE2-Lepr -/- mice were then administered a combination of low-molecular-weight heparin (LMWH) (1 mg/kg or 5 mg/kg) and insulin via subcutaneous injection prior to intranasal infection with 1×10 4 TCID 50 of SARS-CoV-2. Daily drug administration continued until the euthanasia of the mice. Analyses of viral RNA loads, histopathological changes in lung tissue, and inflammation factors were conducted. Results demonstrated similar SARS-CoV-2 susceptibility in hACE2 Tg mice under both lean (chow diet) and obese (HFD) conditions. However, compared to the hACE2-Lepr +/+ mice, hACE2-Lepr -/- mice exhibited more severe lung injury, enhanced expression of inflammatory cytokines and hypoxia-inducible factor-1α, and increased apoptosis. Moreover, combined LMWH and insulin treatment effectively reduced disease progression and severity, attenuated lung pathological changes, and mitigated inflammatory responses. In conclusion, pre-existing diabetes can lead to more severe lung damage upon SARS-CoV-2 infection, and LMWH may be a valuable therapeutic approach for managing COVID-19 patients with diabetes.

A metal-organic framework with rich accessible nitrogen sites for rapid dye adsorption and highly efficient dehydrogenation of formic acid.

MOFs with adequate free nitrogen sites have potential applications in dye adsorption and formic acid dehydrogenation. Here, we successfully synthesized a novel 3-D MOF 1 ([(CH3)2NH2][Cd(L)DMA]·0.5DMA·1.5H2O) with a special two-fold interpenetrating framework through a simple solvothermal reaction between CdCl2·1.5H2O and a nitrogen-rich triangular tricarboxylate-based linker (H3L, 4,4',4''-s-triazine-2,4,6-tribenzoic acid). After removing the guest molecules of dimethylacetamide (DMA) and H2O, including the coordinated DMA from 1 by vacuum activation at 423 K, a compound named 1' with a formula of [(CH3)2NH2][Cd(L)] and a similar interpenetrating framework structure was obtained. In comparison with compound 1, the total void volume of 1' is nearly doubled, and thus may provide higher potential for the adsorption of other guest molecules. Notably, the pyridine N atoms located in the middle of the triangular tricarboxylate-based linker are not involved in the coordination with Cd2+, and are all uniformly dispersed throughout the whole framework of the 3-D MOFs. Due to its unique structural features, the 3-D MOF 1' could effectively adsorb the cationic dye MB+ for recycling purposes. The rapid adsorption rate (0.7 × 10-2 g mg-1 min-1) and the relatively high capacity (900 mg g-1) for MB+ demonstrate the potential of 1' in dye adsorption. In addition, 1' may also be used as an effective support to immobilize PdAu NPs via the double-solvent method. The resultant catalyst Pd0.8Au0.2/1' exhibits decent catalytic activity for the dehydrogenation of formic acid with a TOF value of 1854 h-1 at 333 K. The existence of a large void volume and accessible pyridine N atoms provide a suitable environment for achieving a high dispersion of PdAu NPs, thereby leading to the formation of a catalytically active and stable supported noble-metal NP catalyst for H2 generation from formic acid decomposition.

Porous 3,4-di(3,5-dicarboxyphenyl)phthalate-based Cd2+ coordination polymer and its potential applications.

Porous coordination polymers with organic aminium as one of the guest species possess a potential application in dye adsorption and white-light material manufacture. Polycarboxylic acid with multiple COOH substituents tends to form this type of porous material (with metal ion). Here the solvothermal self-assembly between Cd2+ and a hexacarboxylic acid creates such a porous material [(CH3)2NH2]6[Cd3(L)2]·5DMF·3H2O (H6L = 3,4-di(3,5-dicarboxyphenyl)phthalic acid) 1. Total potential guest accessible void volume in 3-D 1 is found to be 4327 Å3. Based on its better porous structure and stability, the ability of 1 to adsorb organic dyes is investigated. It has been proved that (i) 1 can selectively adsorb cationic dyes as Azure A (AA+) and/or Methylene Blue (MB+), rather than neutral and anionic ones; (ii) the maximum adsorption capacity is 698.2 mg·g-1 for AA+ and 573.2 mg·g-1 for MB+, respectively; and (iii) to the adsorption of AA+, it can be recycled for at least five rounds. Also, it is utilized to fabricate the while-light emitting material. Based on the blue-light emission of 1, the trace Eu3+ and Tb3+ ions are introduced into the pores of 1 successfully, obtaining a white-light emitting material Eu3+/Tb3+@1 (CIE chromaticity coordinates: (0.33, 0.32)). Meanwhile, Eu3+/Tb3+@1 is found to be a potential fluorescence photochromic material, showing a yellow-white-blue light emission. According to these investigations, the relationship between material structure and its adsorption property for dyes, the points that should be paid attention to in the construction of white-light emitting materials as well as the potential adsorption mechanism for dyes and rare earth ions are deeply discussed.

Nitrogen-doped carbon supported ZnO as highly stable heterogeneous catalysts for transesterification synthesis of ethyl methyl carbonate.

Nitrogen-doped carbon material (NCM) supported ZnO catalysts were prepared by wet impregnation method, following a high-temperature thermal treatment process. The resultant ZnO/NCM catalysts calcined at different temperatures were characterized by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption-desorption, elemental analysis, X-ray photoelectron spectroscopy (XPS) to investigate their physicochemical properties and the interaction between ZnO and NCM support. Their catalytic properties were studied by liquid phase transesterification of dimethyl carbonate (DMC) with diethyl carbonate (DEC). Of these the catalyst calcined at 800 °C, named ZnO/NCM-800 exhibits the highest catalytic activity, as well as excellent stability and recyclability for the synthesis of ethyl methyl carbonate (EMC). The NCM support possesses abundant mesopores, rich surface oxygen-containing and nitrogen-containing functional groups, which are beneficial to build relatively strong interaction between ZnO nanoparticles and the NCM support, resulting in the generation of a highly active and stable acidic-basic bifunctional catalyst for the transesterification of DMC with DEC.

Use of Amidoxime Polyacrylonitrile Bead-Supported Pd-Based Nanoparticles as High Efficiency Catalysts for Dehydrogenation of Formic Acid.

Amidoxime polyacrylonitrile (AOPAN) beads with diameter of around 2 mm were prepared by a simple ball-dropping method, and were used as support for the immobilization of Pd or PdNi nanoparticles for catalytic application in formic acid dehydrogenation. The Pd-based nanoparticles showed uniform distribution on the surface of the AOPAN beads, with good accessibility to reagents. The optimized PdNi/AOPAN catalyst can efficiently convert formic acid to hydrogen with a turn over frequency of 3041 h-1 under ambient conditions, and this catalytic activity was maintained well for at least seven cycles. The millimeter-sized beads can float on water, making them easy to manipulate and recover without any weight loss. The amidoxime and cyano groups on the surface of the AOPAN beads play critical roles in stabilizing and distributing Pd-based nanoparticles, and may also participate in the synergistic activation of formic acid dehydrogenation.

Preformed precursor of microporous aluminophosphate coating on mesoporous SBA-15: synthesis, characterization, and catalytic property for selective O-methylation of catechol.

The synthesis of mesoporous SBA-15 coated with the preformed precursor of microporous aluminophosphate (AlPO) has been reported. The physicochemical properties of the coated samples were investigated by using XRD, FT-IR, N(2)-adsorption, ICP, (29)Si MAS NMR, NH(3)-TPD and CO(2)-TPD. The characterization results suggest that the nanometer-scaled zeolite units are present on the wall surface of SBA-15, thus bringing the weak acid-base characteristics to the resulting mesoporous materials, and that the acid-base properties of these materials can be modified by the aging treatment in glycol. Moreover, vapor-phase O-methylation of catechol with methanol has been studied on these coated samples as catalysts. It is found that the coated sample bearing suitable weak acid-base sites exhibits the relatively high activity and selectivity to guaiacol.

N-doped nanoporous carbon as efficient catalyst for nitrobenzene reduction in sulfide-containing aqueous solutions.

Metal-free N-doped porous carbon (NC) materials have been demonstrated to be promising catalysts in contaminated environment remediation. Two NC materials (NC-1 and NC-2) were prepared by sol-gel routes. Their catalytic properties were investigated for the reduction of nitrobenzene (NB) in sulfide-containing aqueous solution. Both NC-1 and NC-2 can efficiently catalyze the reduction of NB to aniline (AN) under ambient conditions, but also can be reused for more than 5 times. The reaction fits excellently to the pseudo-first-order kinetic. Compared with NC-1 material, NC-2 shows much higher removal efficiency (rate constant kobs: 0.283h-1vs. 2.50h-1). The important features of NC material, including high specific surface area, suitable surface functional groups (especially nitrogen-containing groups), and enhanced electron transfer ability, should be mainly factors for its excellent catalytic activity. This work demonstrates that N-doped carbon materials have great potential for degradation of NB to AN in the natural aquatic environment.

Hybrid compounds assembled from copper-triazole complexes and phosphomolybdic acid as advanced catalysts for the oxidation of olefins with oxygen.

Two hybrid compounds, namely [Cu(3atrz)4][PMoMoVO40] (1) and [Cu(3atrz)6][PMo12O40]2 (2), were synthesized through hydrothermal reactions of 3-amino-1,2,4-triazole (3atrz), phosphomolybdic acid (PMA) and appropriate copper salts. Crystal structure analysis reveals that compound 1 contains one-dimensional Cu-3atrz chains. The unit of compound 2 contains a double calyx[3]arene-shaped hexamer, which is composed of six two-coordinated CuI atoms and six 3atrz ligands. Both compounds 1 and 2 present a three-dimensional hybrid structure, which is built by the self-assembly of Cu-3atrz clusters and Keggin-type PMA units. The resulting hybrid compounds can act as highly efficient heterogeneous catalysts for the selective oxidation of olefins with molecular oxygen as the oxidant in the presence of a trace amount of tert-butyl hydroperoxide (t-BuOOH). Their excellent catalytic properties can be mainly attributed to the existence of stabilized CuI complexes with an appropriate chemical environment and a spacious structure, which can interact with t-BuOOH to form catalytic sites for the direct activation of O2. This work demonstrates that the hybrid compounds assembled from copper-3atrz complexes and phosphomolybdic acid may have great potential in molecular O2-mediated catalytic oxidation reactions, which can certainly build a platform for deep insight into the biologically relevant catalytic oxidation processes.

Thermally stable amorphous mesoporous aluminophosphates with controllable P/Al ratio: synthesis, characterization, and catalytic performance for selective O-methylation of catechol.

Amorphous mesoporous aluminophosphates (AlPO) with P/Al molar ratio in the range 0.8-1.15 are synthesized by using the citric acid (CA) route and are systematically characterized using N(2)-adsorption, XRD, SEM, solid-state CP-MAS NMR, FT-IR, TG-DTA, CO(2)-TPD, and NH(3)-TPD. The characterization studies show that the change in P/Al ratio could affect the structure, texture, thermal stability, and surface acid-base properties of AlPO. Samples with a relatively low P/Al ratio (< or =1.0) exhibit uniform amorphous mesoporous character and high thermal stability (up to 1173 K). Partial crystallization of the AlPO framework easily occurred on the sample with higher P/Al ratio (> or =1.1), thus leading to significant decrease of surface area and formation of particle pile mesopores. Both weak acid and weak base sites are observed over AlPO materials, and the amounts of acid-base sites can be effectively controlled by adjusting the P/Al ratio. The presence of suitable interaction between citric acid and AlPO framework is critical for the formation of mesoporous structures. Both CA and PO(4) units are considered to be ligands to coordinate with aluminum ions, forming relative uniform complexes (such as CA-Al-PO(4)) in the as-synthesized AlPO materials. The mesoporous structure of AlPO materials is obtained after the rapid decomposition of citric acid. Vapor phase selective O-methylation of catechol with methanol reaction is carried out to investigate the catalytic performances of AlPO materials with different P/Al ratios. Among them, AlP(1.1)O shows the highest activity (88.4% conversion of catechol) and the highest yield of guaiacol (74.3%). The presence of suitable weak acid-base pairs may play an important role on the title reaction.

Synthesis and pore formation study of amorphous mesoporous aluminophosphates in the presence of citric acid.

Amorphous mesoporous aluminophosphates (AlPO) with high thermal stability were synthesized from Al(NO3)3 and H3PO4 in the presence of citric acid (CA). The effects of different synthetic conditions, such as pH value, citric acid content, and calcined temperature, on the formation of the mesoporous structure of AlPO materials were investigated. The results of N2 adsorption/desorption and other characterization means demonstrate that the presence of a certain amount of citric acid in the synthetic mixture can result in the formation of uniform mesoporous AlPO materials in a wide pH range from 3.5 to 10. Thermal gravimetry and differential thermal analysis suggest that the existence of a moderate interaction between citric acid and the AlPO network might be a critical factor in obtaining uniform mesostructure. Therefore, as an organic additive, citric acid can be regarded as a template for the mesopore formation of AlPO materials.

A green surfactant-assisted synthesis of hierarchical TS-1 zeolites with excellent catalytic properties for oxidative desulfurization.

Hierarchical TS-1 zeolites with uniform intracrystalline mesopores have been successfully synthesized through the hydrothermal method by using the green and cheap surfactant Triton X-100 as the mesoporous template. The resultant materials exhibit remarkably enhanced catalytic activity in oxidative desulfurization reactions compared to the conventional TS-1 zeolite.

Room Temperature CO Oxidation over Pt/MgFe2O4: A Stable Inverse Spinel Oxide Support for Preparing Highly Efficient Pt Catalyst.

MgFe2O4 with inverse spinel structure is demonstrated to be an efficient support for constructing practical potential Pt catalyst (Pt/MgFe2O4). The resultant Pt/MgFe2O4 exhibits excellent catalytic behavior in CO oxidation under normal temperature and humidity. TOF calculated based on the content of Pt is 0.131 s-1. The excellent performance of Pt/MgFe2O4 attributes to the presence of surface undercoordinated lattice oxygens on MgFe2O4 support. These oxygens could participate in the initial CO oxidation and then be recovered under O2 conditions. Over this Pt/MgFe2O4 catalyst, CO catalytic oxidation should mainly follow a redox mechanism.

A non-chemically selective top-down approach towards the preparation of hierarchical TS-1 zeolites with improved oxidative desulfurization catalytic performance.

Hierarchical TS-1 zeolites with secondary macropores have been successfully prepared by using two different fluoride-containing chemical etching post-treated routes. Hierarchical TS-1 zeolites exhibited a chemical composition similar to that of the parent material and showed remarkably enhanced catalytic activity in oxidative desulfurization reaction.

Adsorption behaviors of methyl orange dye on nitrogen-doped mesoporous carbon materials.

A series of nitrogen-doped mesoporous carbon materials (NMC) with different nitrogen contents (from 9.1 to 11.3 wt.%) were prepared using urea and ammonia as economical nitrogen resources by sol-gel method. The NMC materials possessed high surface areas (from 659 m(2)/g to 912 m(2)/g) as well as large number of oxygen-containing and nitrogen-containing groups. The adsorption behaviors of NMC materials for anionic dye methyl orange (MO) were investigated, which are fit excellent for the Langmuir isothermal adsorption equation. All the materials exhibited high adsorption capacity for MO at room temperature. Their adsorption capacity can be adjusted by changing the nitrogen contents in NMC materials. Moreover, treating the NMC material at higher temperature can significantly improve the adsorption capacity for MO. According to the results of characterization, the main features of NMC materials, like large pore size and abundant basic nitrogen-containing groups on the surface, should be related to the excellent adsorption property for MO.

Oxodiperoxo molybdenum modified mesoporous MCM-41 materials for the catalytic epoxidation of cyclooctene.

A hybrid heterogeneous catalyst system, which has been synthesized by covalently anchoring oxodiperoxo molybdenum chelate complexes onto the surface of mesoporous MCM-41, is highly active and truly heterogeneous for the liquid-phase epoxidation of cyclooctene with tBuOOH as the oxygen source.