Search

The scaled-up synthesis of organic-free monolayer nanomaterials is highly desirable, especially in obtaining green energy by electrocatalysis. In this study, a method for the scaled-up synthesis of the series of monolayer layered double hydroxides (LDHs) without the addition of organic solvents is reported via the separate nucleation and aging steps process. The resulting monolayer LDHs with the thicknesses of less than 1 nm showed a narrow thickness distribution. X-ray absorption fine-structure revealed that monolayer NiFe-LDH nanosheets have a number of oxygen and metal vacancies defects. As a practical application, monolayer NiFe-LDH nanosheets containing defects showed an enhanced electrocatalytic water oxidation activity compared with that of bulk NiFe-LDH. Density functional theory calculations uncovered that excellent catalytic activity is attributed to vacancies defects. The proposed method is an economical and universally applicable strategy for the scaled-up production of monolayer LDHs.

A triangular prism cage 2 with benzene triimide (BTI) as the base and 2,7-naphthalene dimethylene as the supporting pillars was designed and synthesized efficiently. The two parallel BTI planes con...

Surfactants with polyoxometalates (POMs) as polar head groups have shown fascinating self-assembly behaviors and various functional applications. However, self-assembly them into reverse micelles is still challenging owing to the large molecular size and intermolecular strong electrostatic repulsions of POM heads. In this work, a zwitterionic POM-based surfactant was synthesized by covalently grafting two cationic long alkyl tails onto the lacunary site of [PW11O39]7−. With decreased electrostatic repulsions and increased hydrophobic effect, the POM-based reverse micelles with an average diameter of 5 nm were obtained. Interestingly, when these reverse micelles were applied for catalyzing the oxidation of styrene, an unprecedented β-hydroxyl peroxide compound of 2-hydroxyl-2-phenylethan-1-tert-butylperoxide was produced in high selectivity of 95.2%. In comparison, the cetyltrimethylammonium electrostatically encapsulated POMs mainly generated the epoxides or 1,2-diols. A free radical mechanism was proposed for the oxidation reaction catalyzed by the zwitterionic POM surfactants.

Background: A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method had been developed for the quantification of acotiamide in rat plasma and been applied to pharmacokinetic studies. However, there was no LC-MS/MS method been developed for the determination of acotiamide in human plasma and its pharmacokinetic study. Objective: A simple and fast LC-MS/MS method was established and validated for the quantification of acotiamide in human Received: plasma and was applied to a pharmacokinetic study. Methods: Sample preparation was accomplished Revised: Accepted: through protein precipitation, and chromatographic separation was achieved on a Welch, Ultimate XB-C18 column (2.1×50 mm, 3 μm) with a security guard cartridge C18 using a binary gradient with DOI: mobile phase A (Methanol) and B (the solution of 10 mM Ammonium acetate with 0.1% Formic acid) at a flow rate of 400 μL/min. Results: The retention time of acotiamide and its internal standard, acotiamide-d6 was 1.78 min and 1.79 min, respectively. The total run time was 4.0 min. The method was developed and validated over the concentration range of 0.500-100 ng/mL for acotiamide, with correlation coefficient greater than 0.9987. The extraction recovery was more than 108.43% and the matrix effect was not significant. The inter- and intra-day precisions were below 5.80% and accuracies ranged from 92.7 to 103.0%. Acotiamide was demonstrated to be stable in human plasma under the tested conditions. Conclusion: The validated LC-MS/MS method was successfully applied to study the pharmacokinetic profiles of acotiamide in human plasma after oral administration and has achieved satisfactory results.

As a family of two-dimensional functional materials, layered double hydroxides(LDHs) have the characteristics of adjustable lamellar element type and proportion, variable interlamellar anion, controllable particle size and thickness, providing a robust platform for photo/electro/thermal-catalysis. With the continuous progress of materials science, the synthesis of LDHs is becoming more and more refined. Herein, to achieve the fine preparation of LDHs materials, especailly for the no-chemical/material researchers, we successfully assembled the automatic synthesis device and wrote corresponding computer software to control this device, and the automatic synthesis of bulk and monolayer LDHs nanosheets on a laboratory scale can be realized. This work paves a new labor-saving way for the fine synthesis of LDHs nanostructures, further improving the development of LDHs-based materials.

The solution dynamics behavior of polyoxometalates (POMs) is essential to understand their catalytic mechanism under real conditions. Herein, the phase-transfer process of a novel catalyst PVDB-VBC...

Hydrazine (N2 H4 ) is considered as one of the most potential energy storage materials in liquid fuel cells, as it contains high energy and power density, and the high-efficiency oxidation of N2 H4 in fuel cells has drawn great attention. However, the most used catalysts are expensive noble metal catalysts, thus the development of highly efficient non-noble metal catalysts is crucial to reduce the cost of hydrazine oxidation in practical industry. Herein, we synthesized a series of CoFe-layered double hydroxides (CoFe-LDHs) intercalated with different anions via a simple one-step co-precipitation method for the electrooxidation of hydrazine. Through altering the intercalated anions of CoFe-LDHs, the defects and the electronic structure can be well controlled, and the catalytic performance for the electrooxidation of hydrazine were well promoted by using NO3- intercalated into CoFe-LDH compared with other anions (like Cl- , BO33- , CO32- ). This work developed a series of hydrazine electrooxidation catalysts and established the relationship between the intercalated anions, the fine structure of the catalyst and the electrocatalytic performance.

Here, we report an unprecedented catalytic enantioselective cyanation of ketonitrones enabled by the bifunctional cyanating reagent Me2(CH2Cl)SiCN. This approach allows facile access to optically active N-hydroxyl-α-amino nitriles that are of high synthetic value but difficult to acquire by other methods. The use of bifunctional cyanating reagent Me2(CH2Cl)SiCN not only achieves an enantioselectivity higher than that with TMSCN but also enables various diversification reactions of the resulting silylated adducts. This represents the first enantioselective catalytic nucleophilic addition reaction of unactivated ketone-derived nitrones, exhibiting the potential of such tetrasubstituted C═N bonds for asymmetric synthesis of N-hydroxy α-amino acids and other N-hydroxy tertiary amines.

Exploiting noncovalent π-interactions particularly emerging anion-π interactions to drive efficient catalysis is fascinating. Even with exciting progresses, can anion-π activation operate in water remains elusive. Here we report the design, synthesis and catalytic studies of a class of water-soluble electron-deficient molecular cages and relevant aromatic slide compounds. The prism-like cages contain three divided, long, cationic aromatic walls which constitute three highly electron-deficient V-shape cavities. They were efficiently synthesized in two steps from a parent triformyl cage in gram-scale. Crystal structure showed the π-walls bind to the counter bromide through strong anion-π interactions. Just 5 mol% of cages were effective in catalyzing decarboxylative Aldol reactions of aldehydes and malonic acid half thioesters in water but not in organic solvents, showing a pronounced hydrophobic amplification effect. Meantime, a series of single π-slides resembling the π-wall of the cage performed equally well, while those lacking an extended π-surface were ineffective, highlighting the essential role of electron-deficient π-face on promoting the conversion.

Direct conversion of methane (CH4 ) to fuels and other high value-added chemicals is an attractive technology in the chemical industry; however, practical challenges to sustainable processes remain. Herein, we report the preparation of a heterostructured Co-doped MgO-based catalyst through topological transformation of a MgCo-layered double hydroxide (LDH) calcination from 200 to 1100 °C. Remarkably, the catalyst can activate CH4 coupling to produce C2 H6 with a selectivity of 41.60 % within 3 h under full-spectrum irradiation through calcination of LDH at 800 °C. Characterization studies and catalytic results suggest that the highly dispersed active sites and large interfaces amongst the Co-doped MgO-based catalysts enable surface activation of CH4 to methyl (CH3 *), in turn promoting coupling of CH3 * to C2 H6 . This study introduces a promising pathway for photodriven CH4 coupling to give high value-added chemicals by using layered double hydroxides as a precursor.

Background: High-performance liquid chromatography (HPLC) method has been used to detect related impurities of perampanel. However, the detection of impurities is incomplete, and the limits of quantification and detection are high. A sensitive, reliable method is in badly to be developed and applied for impurity detection of perampanel bulk drug. Objective: Methodologies utilising HPLC and gas chromatography (GC) were established and validated for quantitative determination of perampanel and its related impurities (a total of 10 impurities including 2 genotoxic impurities). Methods: The separation was achieved on a Dikma Diamonsil C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase of 0.01 mol/L potassium dihydrogen phosphate solution (A) and acetonitrile (B) in gradient elution mode. The compound 2-bromopropane was determined on an Agilent DB-624 column (0.32 mm × 30 m, 1.8 μm) by electron capture detector (μ-ECD) with split injection ratio of 1:5 and proper gradient temperature program. Result: Both HPLC and GC methods were established and validated to be sensitive, accurate and robust according to the International Council for Harmonization (ICH) guidelines. The methods developed were linear in the selected concentration range (R2≥0.9944). The average recovery of all impurities was between 92.6% and 103.3%. The possible production mechanism of impurities during the synthesis and degradation processes of perampanel bulk drug was also discussed. Five impurities were analyzed by liquid chromatography–mass spectrometry (LC-MS). Moreover, two of them were simultaneously characterized by LC-MS, IR and NMR. Conclusion: The HPLC and GC methods were developed and optimized, which could be applied for quantitative detection of the impurities, and further stability study of perampanel.

Simply constructing multiple responsive polymers with obvious shape and dimension variations on their assemblies upon different stimuli is still rarely reported. In this study, we report a hyperbranched polymer named HPAzoBAHB-star-PEG9 with quadruple-response to light, temperature, pH and oxidation stimuli. The polymer contains azobenzene chromophore, sulfide, amide and amine groups in its hydrophobic hyperbranched core, and the core is capped with hydrophilic polyethylene glycol (PEG9) arms. HPAzoBAHB-star-PEG9 could assemble into unusual leaf-like lamellar micelles at 25 °C under the guidance of orderly arranged H-aggregate of azobenzene moieties. These leaf-like lamellar micelles can transform into vesicles upon UV irradiation and lower temperature, or convert to smaller spherical micelles in acidic or oxidative environments, respectively, with the destroy of ordered azobenzene arrangements. This quadruple-responsive hyperbranched polymer is suitable to construct multiple stimuli-responsive micro/nanostructures, or accurate delivery and release following subtle stimuli sequences.

A Cd(ΙI)-based luminescent coordination polymer, namely [Cd(L)2(H2O)2]n (1), has been synthesized by 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene ligand (HL) and structurally characterized. The selectiv...

In intercropping systems, high-positioned crops often exert shading stress on low-positioned crops, thus affecting the agronomic characteristics of the low-positioned crops. This study determined the mechanisms of photosynthetic, physiological and yield variations among peanut cultivars under shading stress. Four peanut cultivars, S60, C4, P12, and YS151, were grown in the field and subjected to shading stress for 77 days during reproductive stages. S60 and P12 showed lower yield and reduced biomass accumulation than C4 and YS151 under shading stress. Shading stress induced higher antioxidant enzyme activities in S60 and P12, relative to C4 and YS151. Under shading stress, S60 and P12 showed a higher light-trapping capability than C4 and YS151, which was associated with changes in chlorophyll (Chl) a and b contents, and Chl a/b ratio. The net photosynthetic rate, stomatal conductance and transpiration rates of C4 and YS151 were decreased, but the intercellular CO2 concentration increased under shading stress. The results demonstrated that non-stomatal limiting factors decreased the photosynthetic capacity of peanut under shading stress. The maximum photochemical efficiency of PSII (Fv/Fm) and non-photochemical quenching (NPQ) were higher in S60 and P12 than in C4 and YS151 under shading stress. These results suggest that S60 and P12 could absorb more light energy from weak light environments for photosynthesis than C4 and YS151 and dissipate the excess energy in the form of heat to improve their light protection ability. This study explains the inter-variety differences in shading stress tolerance in peanut and provides physiological parameters for guiding the selection of shade-tolerant cultivars.

Co(II) and Cu(II) complexes, [Co2(H2L)2(phen)2(H2O)4](H2O)2 (1) and [Cu2(L)0.5(phen)2Cl2]n (2) [H4L = 5,5'-(diazene-1,2-diyl)diisophthalic acid, phen = 1,10-phenanthroline], have been solvothermall...

Two-dimensional (2D) nanosheets have been widely reported and applied. Among them, 2D VOPO4·2H2O (HVPO) is widely used in the chemical industry and energy storage field because of its polyanionic l...

Epoxidized soybean oil (ESO)-based thermosets are attracting increasing attention because they are derived from renewable resources. To date, unfortunately, they have not been able to replace petroleum-based epoxy resins yet due to their poor mechanical properties and unsatisfactory thermal performances. To address the drawbacks, quercetin (QC) as a biobased polyphenol-type curing agent was chosen to increase the rigidity of ESO-QC thermosets. Meanwhile, three imidazole-type accelerators, including N-methylimidazole (N-MI), 4-methylimidazole (4-MI), and biobased histidine (His), were introduced to reduce the activation energy during curing and to tailor the network structures after curing. All ESO-QC thermosets possessed excellent thermal stabilities, thanks to the high rigidity and cross-linking density, among which the initial decomposition temperature of ESO-QC/His was up to 348 °C. Due to the different topological structures of ESO-QC thermosets resulted from different catalytic mechanisms of N-MI and 4-MI, superior tensile and flexural strengths of 44.7 and 81.8 MPa were obtained in ESO-QC/4-MI thermosets, respectively, while the ESO-QC/N-MI thermosets displayed outstanding tensile modulus of 1058 MPa, which could rarely be discovered in biobased systems. In addition, the Izod unnotched impact strength of ESO-QC/His thermosets reached 23.5 kJ·m–2, which was even higher than that of the commercial petroleum-based epoxy resins. These features provide great potential for the sustainable polymers for versatile applications.

A novel kind of fully bio-based PSAs were obtained through the curing reaction between two components derived from the plant oils: carboxyl-terminated polyricinoleate (PRA) from the castor oil and epoxidized soybean oil (ESO). The gel content, glass transition temperature (Tg), rheological behavior, tensile strength, creep resistance and 180° peel strength of the PSAs were feasibly tailored by adjusting the component ratio of ESO to PRA. At low cross-linking level, the PSAs behaved like a viscous liquid and did not possess enough cohesiveness to sustain the mechanical stress during peeling. The PSAs cross-linked at or near the optimal stoichiometric conditions displayed an adhesive (interfacial) failure between the substrate and the adhesive layer, which were associated with the lowest adhesion levels. The PSAs with the dosage amount of ESO ranging from 10∼20 wt% were tacky and flexible, which exhibited 180° peel strength ranging from 0.4∼2.3 N/cm; and could be easily removed without any residues on the adherend. The process for the preparation of the fully bio-based PSAs was environmentally friendly without using any organic solvent or other toxic chemical, herein showing the great potential as sustainable materials.

The rational design of highly efficient bifunctional electrocatalysts for water splitting is extremely urgent for application in sustainable energy conversion processes to alleviate the energy crisis and environmental pollution. In this work, through simple deposition of layered double hydroxides (LDH) on Co3 O4 /NF (NF=nickel foam) nanosheets arrays, hierarchical Co3+ -rich materials based on LDH-Co3 O4 /NF are prepared as highly active and stable electrocatalysts for water splitting. The NiFe-LDH-Co3 O4 /NF demonstrates excellent electrochemical activity with an overpotential of 214 mV for the OER and an overpotential of 162 mV for the HER at 10 mA cm-2 . Such a performance is attributed to the optimized electronic states with a high concentration of Co3+ , which improves the intrinsic activity, and the sheet-on-sheet hierarchical structure, which increases the number of active sites. The unique synchronous design of both the architectural and electronic structure of nanomaterials can simultaneously accelerate the reaction kinetics and provide a more convenient charge transfer path. Therefore, the strategy reported herein may open a new pathway for the design of excellent electrocatalysts for water splitting.

3-Methyl-6-(3,5-difluorophenyl)imidazo[2,1-b]thiazole (mdfpit) and 3-methyl-6-(3,4,5-trifluorophenyl)imidazo[2,1-b]thiazole (mtfpit) were easily prepared from thiourea, acetone, and 3,5-difluorobenzoyl bromide or 3,4,5-trifluorobenzoyl bromide. These were used as primary ligands to synthesize twelve phosphorescent IrIII complexes with picolinic acid (pic), isoquinoline-3-carboxylic acid (3-IQA), quinoline-2-carboxylic acid (2-QA), 2-(pyridin-2-yl)phenol (2-ylppy), 2-(2,4-difluorophenyl)pyridine (dfppy), and pyridine-2-sulfonic acid (2-sappy) as auxiliary ligands. Their structures, photoluminescence, and electrochemical properties were investigated. Upon introducing more fluorine atoms into the benzene ring of the primary ligand, the thermal stability, photoluminescence quantum yield (PLQY), LUMO energy level, and luminous efficiency of the resulting IrIII complexes are significantly improved, and the photoluminescence emission spectra are blue-shifted. Their maximum emission wavelengths are present in the range of 517–618 nm, and the luminous colors span from the green to red light region. Using the synthesized IrIII complexes as emitters, LED chips based on InGaN chip excitation were developed, which showed good performances. Among all LEDs, the PLQY of the (mtfpmt)2Ir(pic) based LED is 58.4%, and the luminous efficiency is as high as 17.11 lm W−1; the luminous efficiency of the (mdfpmt)2Ir(2-QA) based LED is 3.41 lm W−1 with CIE coordinates of 0.60 and 0.38, which are very similar to the saturated standard red light emission. The results demonstrate the potential of the studied IrIII complexes as candidates for LED materials.

Benzaldehyde is a highly desirable chemical due to its extensive application in medicine, chemical synthesis and food sector among others. However, its production generally involves hazardous solvents such as trifluorotoluene or acetonitrile, and its conversion, especially selectivity in the aqueous phase, is still not up to expectations. Hence, developing an environmentally benign, synthetic process for benzaldehyde production is of paramount importance. Herein, we report the preparation of a photocatalyst (PW12-P-UCNS, where PW12 is H3PW12O40·xH2O and P-UCNS is phosphoric acid-modified unstack graphitic carbon nitride) by incorporating phosphotungstic acid on phosphoric acid-functionalised graphitic carbon nitride (g-C3N4) nanosheets. The performance of PW12-P-UCNS was tested using the benzyl alcohol photo-oxidation reaction to produce benzaldehyde in H2O, at room temperature (20 °C). The as-prepared PW12-P-UCNS photocatalyst showed excellent photocatalytic performance with 58.3% conversion and 99.5% selectivity within 2 h. Moreover, the catalyst could be reused for at least five times without significant activity loss. Most importantly, a proposed Z-scheme mechanism of the PW12-P-UCNS-catalysed model reaction was revealed. We carefully investigated its transient photocurrent and electrochemical impedance, and identified superoxide radicals and photogenerated holes as the main active species through electron spin-resonance spectroscopy and scavenger experiments. Results show that the designed PW12-P-UCNS photocatalyst is a highly promising candidate for benzaldehyde production through the photo-oxidation reaction in aqueous phase, under mild conditions.

Synthesis of syngas (CO, H2) by photocatalytic reduction of CO2 and H2O represents an eco-friendly pathway for large-scale CO2 utilization for the production of chemical raw materials with high added value. However, the precise control of the CO : H2 ratio from 1 : 1 to the stoichiometric ratio of 1 : 3 is a major challenge in the process of photocatalytic CO2 reduction, especially under long-wavelength irradiation (like green light of 550 nm). Herein, under visible light (λ > 400 nm), a heterostructured layered double hydroxide nanosheets/TiC (denoted as LDH/TiC) photocatalyst was prepared and exhibited tunable syngas synthesis with different CO/H2 ratios (from 1 : 1–1 : 3). More importantly, such performance can be well controlled even under green light irradiation (550 nm) in conjunction with a Ru-complex photosensitizer and triethanolamine (TEOA) as a sacrificial agent. Theory calculations revealed that the excellent performance came from the assembly between LDH and TiC, which could not only improve the charge transfer efficiency but also change the desorption energy of H2, resulting in the precise tunable ratio of syngas. This work offers an excellent strategy to design photocatalysts for reducing CO2 to syngas for potential applications.

Noble metal-based catalysts have attracted huge attention owing to their intriguing activity and selectivity. Revealing noble metal active sites and keeping them in a form of stable and high loading are crucial to improving the catalytic performance and understanding the reaction mechanism. Herein, a feasible preparation method was used to synthesize a Rh-based ultrathin NiFe layered double hydroxide (Rh/NiFe). The detailed study proved that the existence form of Rh atoms is atomically dispersed. Moreover, extended X-ray absorption fine structure (EXAFS) with theoretical calculation of X-ray absorption near-edge structure (XANES) and density functional theory (DFT) were used to identify at the atomic level the precise location and coordination environment of the introduced Rh atoms. It was found that Rh atoms are doped in the LDH layer in a coplanar position with Ni and Fe atoms. With a 5.4 wt% loading amount of Rh, the modified catalyst of Rh/NiFe-5.4 requires 80 mV less than unmodified ultrathin NiFe layered double hydroxide (NiFe) for hydrazine electrooxidation. The XAFS fitting revealed that the doping of Rh atoms results in the distortion of the laminate and then introduces certain defects, which may be attributed to electron transport, thus endowing them with exceptional electrocatalytic performance.

Keggin clusters are the most widely used polyoxometalate building blocks for the construction advanced materials, but effective methods for precisely recognizing the isostructural analogues of Keggins are still limited. In this study we employed the zwitterionic molecule 4,4'-dipyridyl N,N'-dioxide as a recognition receptor to specifically bind to the three Keggin analogues PW12 O403- , PMo12 O403- , and SiW12 O404- , which separately co-assembled into three different types of spherical charged colloids of different sizes. The recognition phenomena were confirmed by electrochemical methods and their crystallization behavior. Compared with solely anion-cation interaction-driven systems, the synergism with the anion-π interactions between the superchaotropic Keggins and the electron-deficient pyridine rings is believed to enhance the recognition. This observation is intriguing as the long-range solution assembly of Keggins is mainly driven by short-range anion-π interactions. Our results show that the little-noticed hydration shell of Keggins is significantly influenced by the superchaotropic effect, leading to differentiated binding affinity to the receptors and more obvious recognition phenomena between tungsten/molybdenum Keggin analogues.

Diabetes is a disorder of glucose metabolism, and over 90% are type 2 diabetes. Diabetic cardiomyopathy (DCM) is one of the type 2 diabetes complications, usually accompanied by changes in myocardial structure and function, together with cardiomyocyte apoptosis. Our study investigated the effect of curcumin on regulating oxidative stress (OS) and apoptosis in DCM. In vivo, diabetes was induced in an experimental rat model by streptozoticin (STZ) together with high‐glucose and high‐fat (HG/HF) diet feeding. In vitro, H9c2 cardiomyocytes were cultured with high‐glucose and saturated free fatty acid palmitate. Curcumin was orally or directly administered to rats or cells, respectively. Streptozoticin ‐induced diabetic rats showed metabolism abnormalities and elevated markers of OS (superoxide dismutase [SOD], malondialdehyde [MDA], gp91phox, Cyt‐Cyto C), enhanced cell apoptosis (Bax/Bcl‐2, Cleaved caspase‐3, TUNEL‐positive cells), together with reduced Akt phosphorylation and increased Foxo1 acetylation. Curcumin attenuated the myocardial dysfunction, OS and apoptosis in the heart of diabetic rats. Curcumin treatment also enhanced phosphorylation of Akt and inhibited acetylation of Foxo1. These results strongly suggest that apoptosis was increased in the heart of diabetic rats, and curcumin played a role in diabetic cardiomyopathy treatment by modulating the Sirt1‐Foxo1 and PI3K‐Akt pathways.

In this paper, as a possible alternative to conventional petroleum-based pressure-sensitive adhesives (PSAs), a fully bio-based PSA with tunable adhesivity was designed and prepared, and the struct...

Solid oxide fuel cells (SOFCs) based on Ni-based cermet anodes suffer from severe sulfur poisoning when operated on H2S-containing fuels (

Solid oxide fuel cells (SOFCs) as one of the clean electrochemical energy conversion devices have acquired increasing attention recently due to the high efficiency, low emission, and excellent fuel...

The rational design of photocatalyst that can effectively reduce CO2 under visible light (λ > 400 nm), and simultaneously precise control of the products syngas (CO/H2) ratio is highly desirable for the Fischer-Tropsch reaction. In this work, we synthesized a series of CeO2-decorated layered double hydroxides (LDHs, Ce-x) samples for photocatalytic CO2 reduction. It was found that the selectivity and productivity of CO and H2 from photoreduction of CO2 in conjunction with Ru-complex as photosensitizer performed an obvious “volcano-like” trend, with the highest point at Ce-0.15 and the CO/H2 ratio can be widely tunable from 1/7.7 to 1/1.3. Furthermore, compared with LDH, Ce-0.15 also drove photocatalytic CO2 to syngas under 600 nm irradiation. It implied that an optimum amount of CeO2 modifying LDH promoted the photoreduction of CO2 to syngas. This report gives the way to fully utilize the rare earth elements and provides a promising route to enhance the photo-response ability and charge injection efficiency of LDH-based photocatalysts in the synthesis of syngas with a tunable ratio under visible light irradiation.

The development of clean and efficient energy conversion and storage systems is becoming increasingly vital as a result of accelerated global energy consumption. Solid oxide fuel cells (SOFCs) as one key class of fuel cells have attracted much attention, owing to their high energy conversion efficiency and low emissions. However, some serious problems appeared because of the scorching operating temperatures of SOFCs (800–1000 °C), such as poor thermomechanical stability and difficult sealing, resulting in a short lifespan and high cost of SOFCs. Therefore, lowering the operating temperature of SOFCs to mid-range and even low range has become one of the main goals for SOFC development in the recent years. Looking for new cathode materials with high electrocatalytic activity and robust stability at relatively low temperatures is one of the essential requirements for intermediate-to-low-temperature SOFCs (ILT-SOFCs). During the past 15 years, we put considerable efforts into the development of alternative cathode materials for ILT-SOFCs. In this review, we give a summary of our progress from such efforts. We first summarize several strategies that have been adopted for developing cathode materials with high activity and durability toward reducing operating temperatures of SOFCs. Then, our new ideas and progress on cathode development with respect to activity and stability are provided. Both the cathodes of oxygen-ion-conducting SOFCs and protonic-conducting SOFCs are discussed. In the end, we outline the opportunities, challenges, and future approaches for the development of cathodes for ILT-SOFCs.

The reduction of C═C is of great importance, while H2 is the most widely used source usually in the harsh condition in the industry. However, under mild conditions, the H2-free reduction of C═C bon...

Endowing achiral polyoxometalates (POMs) with asymmetric catalytic properties is always an intriguing but challenging topic because of their high catalytic activities yet highly symmetrical molecular structures. In this work, a novel strategy was proposed to fabricate a series of two-dimensional chiral POM catalysts. Following the steps of exfoliation, covalent modification, and reassembly, the achiral POMs were orderly confined into the chiral interstitial domains of chiral ionic liquid (CIL)-modified layered double hydroxide materials with a decreased molecular symmetry. The chirality of POM molecules was induced by the l- or d-pyrrolidine-type CILs, and their asymmetric catalytic activity was enhanced by the confinement effect. Compared with the reported chiral POM-based catalysts [e.g., 8 turnover frequency (TOF) and 79% enantiomeric excess (ee) for chiral POM-based metal-organic frameworks], the constructed chiral POM catalysts showed a significantly higher TOF and enantioselectivity (up to 240 TOF and 93% ee) for the asymmetric epoxidation of allylic alcohols. The facilitated mass transfer in the IL channels and the increased binding efficiency between the chiral catalytic sites and reactants render this strategy highly promising for constructing efficient chiral catalysts from the catalytically active while achiral building blocks.

Photocatalytic reduction of CO2 with H2O to syngas is an effective way for producing high value-added chemical feedstocks such as methanol and light olefins in industry. Nevertheless, the precise control of CO/H2 ratio from photocatalytic CO2 reduction reaction still poses a great challenge for the further application. Herein, we prepared a series of highly efficient heterostructure based on highly dispersed palladium supported on ultrathin CoAl-layered double hydroxide (LDH). In conjunction with a Ru-complex sensitizer, the molar ratios of CO/H2 can be tuned from 1:0.74 to 1:3 under visible-light irradiation (λ > 400 nm). More interestingly, the syngas can be obtained under light irradiation at λ > 600 nm. Structure characterization and density functional theory calculations revealed that the remarkable catalytic activity can be due to the supported palladium, which improved the charge transfer efficiency. Meanwhile, more H atoms were used to generate H2 on the supported palladium for further tunable CO/H2 ratio. This work demonstrates a new strategy for harnessing abundant solar-energy to produce syngas from a CO2 feedstock.

Downy mildew is one of the most serious diseases threatening grapevine cultivation. The PYR/PYL/RCAR proteins, which act as abscisic acid (ABA) receptors, are multifunctional, highly conserved, and reportedly play a crucial role in plant stress resistance in the ABA signaling pathway. In this study, we cloned a putative abscisic acid receptor gene, VvPYL4, from the ‘Beta’ grapevine cultivar. An analysis of the subcellular localization demonstrated that overexpressed VvPYL4 was localized in both the cytoplasm and the nucleus. The resistance of grapevine cultivars to downy mildew increased after the application of the exogenous hormones MeJA and ABA. The expression of VvPYL4 was significantly induced when exposed to Plasmopara viticola, MeJA, and ABA. The transcript of the VvPYL4 gene in ‘Beta’ grapevine leaves treated with tobacco rattle virus-induced gene silencing (VIGS) was significantly down-regulated. Silencing VvPYL4 had a slight effect on P. viticola resistance. Furthermore, silencing VvPYL4 significantly altered the transcripts of ABA and JA responsive genes, including the ABA signaling pathway-related genes ABF1, SnRK2.2, and PP2C2, as well as the genes related to the JA signaling pathway, MYC2, JAR1, and JAZ. Altogether, the data provide new evidence that VvPYL4 positively regulates grapevine response to downy mildew. This study also discusses the regulation mechanism of VvPYL4 on ABA and JA signaling transduction. Finally, these results provide a basis for additional research on the mechanisms behind grapevine resistance to downy mildew. Silencing VvPYL4 impaired resistance to P. viticola, and this was associated with inhibited the expression of the ABA and JA signaling pathway-related genes. P. viticola, MeJA, and ABA induced the up-regulated expression of VvPYL4.

The tight binding enabled by tailor-made macrocycles can be manipulated for tuning the catalysis process. In parallel to well-developed crown ether-based cation-binding catalysis, a macrocycle-enabled counteranion trapping strategy is presented for boosting highly efficient and enantioselective catalysis. A set of bis-diarylthiourea macrocycles containing two BINOL moieties were designed and synthesized. They possess a well-confined chiral cavity and strong binding affinities towards disulfonate anions. Caused by the tight binding, just 1 mol % macrocycle in combination with 1 mol % ethanedisulfonic acid can promote excellent conversion and up to 99 % ee in the Friedel-Crafts reaction of indoles with imines. The acid or the macrocycle alone do not afford any reactivity. The high catalytic efficiency and excellent stereocontrol was ascribed to large, complexation-induced acidity enhancement and tight ion-pairing facilitated by cave-like macrocyclic cavity.

Besides generating vision, light modulates various physiological functions, including mood. While light therapy applied in the daytime is known to have anti-depressive properties, excessive light exposure at night has been reportedly associated with depressive symptoms. The neural mechanisms underlying this day-night difference in the effects of light are unknown. Using a light-at-night (LAN) paradigm in mice, we showed that LAN induced depressive-like behaviors without disturbing the circadian rhythm. This effect was mediated by a neural pathway from retinal melanopsin-expressing ganglion cells to the dorsal perihabenular nucleus (dpHb) to the nucleus accumbens (NAc). Importantly, the dpHb was gated by the circadian rhythm, being more excitable at night than during the day. This indicates that the ipRGC→dpHb→NAc pathway preferentially conducts light signals at night, thereby mediating LAN-induced depressive-like behaviors. These findings may be relevant when considering the mental health effects of the prevalent nighttime illumination in the industrial world.

Direct C(sp3)-H functionalization of N-unprotected aliphatic amines represents one of the most efficient and straightforward strategies for amine synthesis. Despite some recent progress in this field, the NH2-directed γ-C(sp3)-H arylation of primary aliphatic amines except α-amino esters remained an unmet challenge. In this report, we established a simple and efficient method for site-selective C(sp3)-H arylation of primary aliphatic amines by aryl iodides. In the presence of only 5 mol% Pd(OAc)2, a wide range of aliphatic amines including O-benzyl and O-silyl amino alcohols were arylated at γ- or δ-positions by aryl iodides containing a broad scope of functional groups. The synthetic application of this method had also been demonstrated by large-scale synthesis, the synthesis of a fingolimod analogue, and the conjugation with natural d -menthol and fluorescent 1,8-naphthalimide.

A minor amount of CO2 in air usually causes a detrimental effect on oxygen activation over a solid oxide fuel cell (SOFC) cathode because insulating surface carbonate is easily formed, which inhibi...

Epigenetic alterations and metabolic dysfunction are two hallmarks of aging. However, the mechanism of how their interaction regulates aging, particularly in mammals, remains largely unknown. Here we show ELOVL fatty acid elongase 2 (Elovl2), a gene whose epigenetic alterations are most highly correlated with age prediction, contributes to aging by regulating lipid metabolism. Impaired Elovl2 function disturbs lipid synthesis with increased endoplasmic reticulum stress and mitochondrial dysfunction, leading to key accelerated aging phenotypes. Restoration of mitochondrial activity can rescue age-related macular degeneration (AMD) phenotypes induced by Elovl2 deficiency in human retinal pigmental epithelial (RPE) cells. We revealed an epigenetic–metabolism axis contributing to aging and potentially to antiaging therapy.

Molybdenum disulfide (MoS2 ) is one of the most promising alternatives to the Pt-based electrocatalysts for the hydrogen evolution reaction (HER). However, its performance is currently limited by insufficient active edge sites and poor electron transport. Hence, enormous efforts have been devoted to constructing more active edge sites and improving conductivity to obtain enhanced electrocatalytic performance. Herein, the 3D carbon foam (denoted as CF) supported edge-rich N-doped MoS2 nanoflakes were successfully fabricated by using the commercially available polyurethane foam (PU) as the 3D substrate and PMo12 O403- clusters (denoted as PMo12 ) as the Mo source through redox polymerization, followed by sulfurization. Owing to the uniform distribution of nanoscale Mo sources and 3D carbon foam substrate, the as-prepared MoS2 -CF composite possessed well-exposed active edge sites and enhanced electrical conductivity. Systematic investigation demonstrated that the MoS2 -CF composite showed high HER performance with a low overpotential of 92 mV in 1.0 m KOH and 155 mV in 0.5 m H2 SO4 at a current density of 10 mA cm-2 . This work offers a new pathway for the rational design of MoS2 -based HER electrocatalysts.

Reduction of photocatalytic CO2 into renewable hydrocarbon solar fuels is considered to be a promising strategy that can simultaneously address global energy needs as well as environmental concerns...

Photocatalytic reduction of CO2(CO2PR) to valuable solar fuels is considered as a promising route to the amelioration of fossil fuel conundrum and the mitigation of greenhouse gases. Although progress has been made to enhance CO2PR performance, the available method that can promote the selectivity of CO2PR products remains to be a challenge. In this work, we synthesized NO3− or CO32− intercalated NiAl-layered double hydroxide(NiAl-LDH) photocatalysts and investigated the performance of CO2PR in the presence of an electron donor and a photosensitizer. Compared with Ni2Al-CO32−, Ni2Al-NO3− exhibited superior catalytic performance in the CO2PR, and the resulted selectivity of CH4 in Ni2Al-NO3−(6.1%) was 12.2 times that of Ni2Al-CO32−(0.5%) under visible light irradiation. X-Ray absorption fine structure(XAFS) result reveals a relative abundance of defects in Ni2Al-NO3−, which played as active sites and promoted charge transfer in CO2PR for the efficient CH4 evolution.

Cellulose acetate propionate (CAP), a high value-added chemical, is traditionally prepared using H2SO4 as catalyst. Replacement of the mineral acids by solid acids is current research focus for green and sustainable production of CAP. Herein, we reported the fabrication of novel solid acid catalyst HPW/Si(Et)Si-Dim-SO3H (Si(Et)Si = ethyl-bridged organosilica and Dim = dihydroimidazole) by incorporating phosphotungstic acid (HPW) and sulfonic acid-based Brønsted acidic ionic liquids onto the organosilica nanospheres of the designed catalyst for efficient manufacture CAP via esterification. The results indicated that the as-prepared HPW/Si(Et)Si-Dim-SO3H with 7.5% HPW loading showed the best catalytic performance at 45 °C in 3 h and the resulting CAP exhibited viscosity of 447 mPa s, Mw of 102,882 and DS of 2.69. Most importantly, the HPW/Si(Et)Si-Dim-SO3H exhibited high catalytic stability over six consecutive cycles and the obtained products were stable too with similar DS, Mw and viscosity. As such, the designed heteropolyacids and sulfonic acid-bifunctionalized heterogeneous catalyst is highly promising for biomass conversion under mild conditions.

A series of small-membered heterocycle probes, so-called azaheterocycle-containing diphenylmethanol chiral solvating agents (CSAs), have been developed for NMR enantiodiscrimination. These chiral sensors were readily synthesized were inexpensive and efficiently used for the chiral analysis of alpha-substituted carboxylic acids. The sensing method was operationally simple and the processing was straightforward. Notably, we propose (S)-aziridinyl diphenylmethanol as a promising CSA, which has excellent chiral discriminating properties and offers multiple detectable possibilities pertaining to the 1H NMR signals of diagnostic split protons (including 25 examples, up to 0.194 ppm, 77.6 Hz). Its ability to detect the molecular recognition of fluorinated carboxylic acids were further investigated, with a good level of discrimination via the 19F NMR spectroscopic analysis. In addition, an accurate enantiomeric excess (ee) analysis of the p-methoxyl-mandelic acid with different optical compositions have been calculated based on the integration of well-separated proton signals.

Multifunctional nanoclusters based on Fe3O4 nanoparticles for magnetic resonance imaging (MRI) and drug delivery are reported here. At first, oleic acid (OA)-coated Fe3O4 nanoparticles were prepared. Then block copolymer Pluronic F127 or folic acid (FA) conjugated-Pluronic F127 was used to modify the hydrophobic nanoparticles to become hydrophilic Fe3O4@F127 nanoclusters via facile ultrasonic treatment. During this process, drug molecules can also be introduced into the nanoclusters and therefore the targeted drug delivery system was formed. Next, we verified the feasibility of the nanoclusters as drug delivery vehicles and magnetic contrast agents. The nanoclusters have an average size of 200 nm and remained stable in water for long periods. Folic acid-modified nanoclusters showed an enhanced intracellular uptake into HepG2 cells by using both cellular iron amount analysis and flow cytometry analysis. Besides, Fe3O4@F127@FA nanoclusters showed good compatibility in the tested concentration range and good sensitivity in T2-weighted MRI. The magnetic nanoclusters combined with drug delivery properties have greatly increased the significance in the diagnosis and therapy of diseases, which are suitable for systematical administration of hydrophobic drugs and simultaneously MRI diagnosis.

An ultra-sensitive T2-weighted MR imaging contrast agent was prepared based on Fe3O4 nanoparticles and Gd3+ ions (Fe3O4@Gd). Amino modified Fe3O4 nanoparticles were conjugated to diethylenetriamine pentaacetic acid, and finally coordinated with Gd3+ ions. The nanoparticles had a uniform morphology with a size of 100 nm and a Gd/Fe mass ratio of 1/110. The r2 (transverse relaxivity) of the Fe3O4 nanoparticles increased from 131.89 mM−1 s−1 to 202.06 mM−1 s−1 after coordination with Gd3+ ions. MR measurements showed that the aqueous dispersion of Fe3O4@Gd nanoparticles had an obvious concentration-dependent negative contrast enhancement. Hepatoma cells were selected to test the cytotoxicity and MR imaging effect. The application of Fe3O4@Gd nanoparticles as contrast agents was also exploited in vivo for T2-weighted MR imaging of rat livers. All the results showed the effectiveness of the nanoparticles in MR diagnosis.

Dihydroxybenzenes (DHB) are one of the most important fine chemicals used as raw materials or intermediates in industries. One-step selective phenol hydroxylation using a photo-Fenton system is an attractive and challenging strategy, especially under long-wavelength irradiation. Herein, we report that a highly selective photo-driven Fenton hydroxylation reaction of phenol to DHB can be achieved over NiFe-layered double hydroxide nanosheets (NiFe-NS) under visible-light irradiation with 70% phenol conversion and ∼99% DHB selectivity. A more interesting finding is that a high phenol conversion (∼40%) activity can be maintained even under monochromatic irradiation at 550 nm. The superior photocatalytic activity was attributed to the abundant defects in NiFe-NS, which facilitated the adsorption of hydrogen peroxide (H2O2) onto the catalyst surface and promoted the transfer efficiency of photoinduced electrons from the catalyst to H2O2, generating ˙OH radicals to participate in the hydroxylation of phenol.

Polyoxometalate-intercalated layered double hydroxide (POM-LDH) nanocomposites have received considerable attention in recent years because such nanocomposites not only inherit the intrinsic properties of POMs and LDHs but also exert significant synergistic effects during the catalytic process. In this frontier article, we present the latest advances on the POM-LDH nanocomposites ranging from new synthetic methods to catalytic applications. By making use of the host layer modification method and exfoliation assembly method, the as-prepared POM-LDH nanocomposites show a wide range of catalytic applications. The challenges and future opportunities are also discussed by highlighting some creative work on related POM- or LDH-based materials.