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Nanoscale zero-valent iron particles have large specific surface area and high reaction activity, and have been increasingly used for the degradation of environmental contaminants. However, rapid aggregation and deactivation hinder their wide applications. In this work, nanoscale zero-valent iron (NZVI) particles were prepared in vesicles, which were formed by self-assembly of amphiphilic block copolymer poly(1-vinylpyrrolidone-co-vinylacetate) (PVV) in aqueous tetrahydrofuran medium, and characterized with the aid of XRD, FTIR, SEM-EDX, TEM, XPS and DLS techniques. It was found that the NZVI particles were well encapsulated in the vesicles, and they could be stored directly in the air as solids, but the dried NZVI particles could be easily released from the vesicles once they were put in water. These NZVI particles showed some unique features, such as uniform nanometer size distribution (from 70 to 100 nm), vesicle-like morphology, and good dispersion. Activity and stability of the NZVI in vesicles were examined by using Cr(VI) and nitrobenzene as the model pollutants, and compared with the bare NZVI particles synthesized with the same procedures but without PVV. A dramatic difference in activity and stability was observed for the two different NZVI particles. The NZVI in vesicles showed a good chemical stability in the air, and still maintained its high reactivity in water. Such excellent performance might be attributed to the encapsulation of the NZVI by vesicles, which could impede well the strong agglomeration of metal particles in water and prevent metal particles from being oxidized in the air. [ABSTRACT FROM AUTHOR]

As a structure-based image compression technology, fractal image compression (FIC) has been applied not only in image coding but also in many important image processing algorithms. However, two main bottlenecks restrained the develop and application of FIC for a long time. First, the encoding phase of FIC is time-consuming. Second, the quality of the reconstructed images for some images which have low structure-similarity is usually unacceptable. Based on the absolute value of Pearson’s correlation coefficient (APCC), we had proposed an accelerating method to significantly speed up the encoding of FIC. In this paper, we make use of the sparse searching strategy to greatly improve the quality of the reconstructed images in FIC. We call it the sparse fractal image compression (SFIC). Furthermore, we combine both the APCC-based accelerating method and the sparse searching strategy to propose the fast sparse fractal image compression (FSFIC), which can effectively improve the two main bottlenecks of FIC. The experimental results show that the proposed algorithm greatly improves both the efficiency and effectiveness of FIC. [ABSTRACT FROM AUTHOR]

In this work, densities and viscosities for the binary mixtures of 1-octyl-3-methylimidazolium tetrafluoroborate, [Cmim][BF], with butanone, methyl acetate, ethyl acetate, propyl acetate and butyl acetate have been determined at 298.15 K. These data were used to calculate the excess molar volumes $$ V_{m}^{\text{E}} $$ and the viscosity deviations (ln η) for the mixtures. It is shown that values of $$ V_{m}^{\text{E}} $$ are negative, while those of (ln η) are positive in the whole concentration range. The $$ V_{m}^{\text{E}} $$ values show their minimum at the composition of x ≈ 0.3, and the (ln η) values exhibit a maximum at the same mole fraction. For the binary systems, the absolute values of $$ V_{m}^{\text{E}} $$ decrease in the order: butanone > methyl acetate > ethyl acetate > propyl acetate > butyl acetate, whereas those of (ln η) decrease in the order: methyl acetate > ethyl acetate > propyl acetate > butyl acetate > butanone. The results are discussed in terms of the ion-dipole interactions between cations of the ionic liquid and the organic molecules and hydrogen bonding interactions between anions of the ionic liquid and the organic compounds. [ABSTRACT FROM AUTHOR]

Material preparation in ionic liquids and environmental pollution control by ionic liquids are often closely dependent on the aggregation behavior of ionic liquids in solution. In the present work, conductivity, fluorescence probe, and dynamic light scattering techniques have been used to study the effect of organic solvents on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in water. It was shown that the critical aggregation concentration (CAC), the ionization degree of the aggregates (α), and the standard Gibbs energy of aggregation (ΔGm°) of the ionic liquid increase, while its aggregation number (Nagg) and aggregates’ size decrease with increasing concentration of organic additives in water. These results have been discussed from the favorable interactions of alkyl chain of the ionic liquid with the mixed solvents. It is suggested that the solvophobic parameter, characterized quantitatively by Gibbs energy of transfer of hydrocarbon from gas into a given solvent, can be used to account for the effect of organic additives on the formation and growth of the ionic liquid aggregates in water. Aggregation behavior of ionic liquids in aqueous organic solutions can be modulated simply by the solvophobic parameters of hydrocarbon in the mixed solvents. [ABSTRACT FROM AUTHOR]

Abstract: Information on the interactions between ionic liquids and molecular solvents are essential for the understanding of the function of ionic liquids in related procedures, and excess properties are sensitive probe for these interactions. In this work, excess molar volume and excess logarithmic viscosity ((ln η)E) for the binary mixtures of 1-hexyl-3-methylimidazolium tetrafluoroborate ([C6mim][BF4]) with butanone, ethyl acetate, butylamine, and tetrahydrofuran have been determined from density and viscosity measurements in the whole composition range at the temperature of 298.15K. It is found that for the studied systems, the values of are negative but those of (ln η) E are positive in the whole concentration range. The values show their minimum at the ionic liquid mole fraction of 0.3, and (ln η) E values exhibit a maximum at the same composition. The absolute values of follow the sequence: tetrahydrofuran>butanone>ethyl acetate>butylamine for the binary systems, whereas the values of (ln η) E decrease in the order: tetrahydrofuran>butylamine>ethyl acetate>butanone. The results have been analyzed through the ion–dipole interaction, the hydrogen bonding, the packing efficiency and the ion-pairs exist in the ionic liquid. [Copyright &y& Elsevier]

Abstract: Ionic liquids have potentials as green materials in a variety of fields. It is the case that in their application in industry, ionic liquids are often used together with molecular solutes/solvents. In this paper, systematical measurements of viscosities and conductivities for the binary and quasi-binary mixtures of ionic liquids with molecular solutes were performed over the whole concentration range. The variation tendency of viscosities/conductivities with composition of the mixtures was explained through the disruption of molecular solutes to ionic association or aggregation of the ionic liquids. A exponential equation with empirical parameter A suggested initially by Seddon et al. was used to describe the dependence of viscosities on the mole fraction of molecular solutes, and the physical meaning of A was analyzed based on a theoretical equation deduced from rate process theory. At the same time, another exponential equation with parameter C was proposed to correlate the experimental date of the product of conductivity and viscosity, and satisfactory results were obtained over the entire range of concentration. The main factors affecting the parameter C were discussed. It is expected that the new data and correlation equations reported in this work will be useful for the application of ionic liquids in chemical industry. [Copyright &y& Elsevier]

Abstract: Apparent molar volumes V 2,ϕ and standard partial molar volumes V 2,ϕ 0 of LiBF4 have been determined at 298.15K from precise density measurements in propylene carbonate (PC) or ethylene carbonate (EC) based mixed solvents. The chosen cosolvents were dimethylformamide (DMF), tetrahydrofuran (THF), acetonitrile (AN), 1,2-dimethoxyethane (DME) and ethyl acetate (EA). The results have been interpreted from solvation of LiBF4 in carbonate based mixed solvents. It is shown that nature of the cosolvents plays an important role for the concentration dependence of V 2,ϕ 0 values. Compared with the previous studies, the differences between ClO4 − and BF4 − have been embodied in the concentration dependence of V 2,ϕ 0 values and also interpreted by the interaction of the anion with solvents. [Copyright &y& Elsevier]

Abstract: The standard partial molar volumes, viscosity B-coefficients and activation free energies of lithium salts (LiClO4 and LiBr) in propylene carbonate (PC) with 1,2-dimethoxyethane (DME) mixed solvents have been determined as a function of the mole fraction of DME at 298.15K from precise density and viscosity measurements. The values studied are all positive and decrease monotonously with addition of DME in the PC, which indicates that nature of the solvents plays an important role. The effects are discussed in terms of preferential solvation and packing effect in the solvation shell and electrostriction. The differences between ClO4 − and Br− have also been discussed. [Copyright &y& Elsevier]

The apparent molar volumes (Vm,2) and relative viscosities (ηr) at T=(298.15 and 308.15) K have been obtained for glycine, dl-α-alanine, and dl-α-amino-butyric acid in aqueous sodium caproate solutions from measurements of density and the flow time. The standard partial molar volumes (V∘m,2), standard volumes of transfer (ΔtV∘), the viscosity B-coefficients, and the activation thermodynamic quantities (Δμ2∘≠ and ΔS2∘≠) of viscous flow have been calculated for the amino acids. It is shown that the standard partial molar volumes, viscosity B-coefficients, and activation free energies for viscous flow increase with increasing number of carbon atoms in the alkyl chain of the amino acids. An increase in V∘m,2 and ΔtV∘ with increasing electrolyte concentrations have been explained due to the interactions of sodium caproate with the charged center of zwitterions for the amino acids. A comparison of the V∘m,2 values for glycine, dl-α-alanine, and dl-α-aminon-n-butyric acid in different aqueous salts solutions showed that carboxylate ions have stronger interactions with amino acid than chloride, thiocyanate, and nitrate ions. Results of viscosity are discussed in terms of changes in solvent structure. [Copyright &y& Elsevier]

Densities and viscosities for solutions of some α-amino acids in aqueous calcium chloride (3.0 mol kg−1) have been determined at 278.15, 288.15, 298.15 and 308.15 K. These data have been used to calculate apparent molar volumes and viscosity B-coefficients of the amino acids. The standard partial molar volumes, V°2,φ, and hydration numbers of the amino acids have been determined at different temperatures. Free energies of activation, Δμ°2≠, for viscous flow of the solutions were obtained by application of the transition-state theory to the B-coefficient data, and the corresponding activation enthalpy ΔH°2≠ and entropy ΔS°2≠ were also given. It has been shown that V°2,φ, B-coefficients and the free energies of activation vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids, and they were split into contributions from the zwitterionic end group (NH3+, COO−) and the methylene groups of the amino acids. The volumetric data have been interpreted in terms of the hydration of the hydrophobic and hydrophilic parts of the amino acids. From the viscosity data, structural effects of the amino acids in the solutions have been discussed. [Copyright &y& Elsevier]

Apparent molar volumes V2,φ and standard partial molar volumes V2,φ0 of LiClO4, LiBr and three symmetrical tetraalkylammonium bromides R4NBr (R=ethyl, propyl, butyl) have been determined at 298.15 K from precise density measurements in solvent mixtures of ethylene carbonate with tetrahydrofuran (THF), acetonitrile (AN), ethyl acetate (EA) and dimethoxyethane (DME). It is shown that the V2,φ0 values of LiClO4 and LiBr are dependent strongly on the nature of the solvents, whereas the contribution of CH2 group to the partial molar volume of the tetraalkylammonium salts has nothing to do with the nature of the solvents and the composition of the solvent mixtures. This provided a helpful evidence for the unsolvation of large tetraalkylammonium cations in organic solvents. The results have been discussed from ion–solvent interactions and the dielectric effect of the solvents. [Copyright &y& Elsevier]

Apparent molar volumes (V[sub 2, f] ) and standard partial-molar volumes (V[sub 2] [sup 0] [sub , f] ) of LiClO[sub 4] and LiBr at 298.15 K have been determined from precise density measurements in solvent mixtures of propylene carbonate (PC) with dimethylformamide (DMF), tetrahydrofuran (THF), acetonitrile (AN), and methyl formate (MF). The scaled particle theory is used to calculate the contributions of the cavity formation and the electrolyte-solvent interactions to the standard partial-molar volumes. It is shown that V[sub 2] [sup 0] [sub , f] is strongly dependent on the nature of the solvents, and the trends in V[sub 2] [sup 0] [sub , f] with composition of the solvent mixtures are determined by the interaction volumes of electrolytes with solvents. The results are discussed in terms of ionic preferential solvation, packing effect of solvents in the solvation shell, and electrostriction of solvents by ion.Key words: partial-molar volume, scaled particle theory, lithium salts, propylene carbonate, solvent mixtures, lithium battery electrolytes.En se basant sur des mesures précises de densité dans des mélanges de solvants de carbonate de propylène (PC) avec du diméthylformamide (DMF), du tétrahydrofurane (THF), de l'acétonitrile (AN) et de formiate de méthyle (MF), on a déterminé les volumes molaires apparents (V[sub 2, f] ) et les volumes molaires partiels standards, (V[sub 2] [sup 0] [sub , f] ) du LiClO[sub 4] et du LiBr, à 298,15 K. On a utilisé la théorie de la particule pour calculer les contributions de la formation de la cavité et de l'interaction de l'électrolyte-solvant aux volumes molaires partiels standards. On a démontré que la valeur de V[sub 2] [sup 0] [sub , f] , dépend fortement de la nature des solvants et les tendances dans les valeurs de V[sub 2] [sup 0] [sub , f] avec la composition des mélanges de solvant sont déterminées ceux qui sont présents dans les volumes d'interaction des électrolytes avec les solvants. On discute des résultats sur la base de la solvatation ionique préférencielle, de l'effet du tassement des solvants dans la couche de solvatation et de l'électrostriction des solvants par l'ion.Mots clés : volume molaire partiel, théorie de la particule scalaire, sels de lithium, carbonate de propylène, mélanges de solvants, électrolytes de piles au lithium.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Looks at a study which synthesized the marine metabolites verongamine, hemibastadin-2, and aerothionin. Details on the conversion process of a carboxylic acid into an acyl cyano phosphorane; Conversion of the electrophilic intermediate to alpha-keto amides, by amines; Methodology used to conduct the study; Results of the study.

Due to the effectiveness in learning the subspace structures, low-rank representation (LRR) and its variations have been widely applied in various fields, such as computer vision and pattern recognition. However, in real applications, it is a challenge to handle the complex noises. To address this problem, we propose a novel robust LRR method based on kernel risk-sensitive loss (KRSL) with high-order manifold constraint, called RHLRR, in which the KRSL is introduced to deal with the noises and the multiple hypergraph regularization term is used as a high order manifold constraint to effectively capture the locality, similarity and the intrinsic geometric information in data. Besides, an iterative algorithm based on the half-quadratic (HQ) and the accelerated block coordinate update (BCU) is developed. The experimental results demonstrate that the proposed method can outperform other state-of-the-art LRR variants. [ABSTRACT FROM AUTHOR]

Background: Knee osteoarthritis (KOA) is one of the most common chronic diseases in the elderly and is the primary cause of the loss of motor function and disability in this population. Exercise therapy is a core, basic and matureand treatment method of treating patients with KOA. Exercise therapy is "strongly recommended" or "recommended" in the diagnosis and treatment guidelines of osteoarthritis in many countries, and most scholars advocate exercise therapy as the preferred rehabilitation method for KOA patients. However, poor long-term adherence is a serious problem affecting the therapeutic effect of this mature treatment. The objective of this study was to construct a concise and practical adherence rating scale (ARS) based on the exercise therapy adherence prediction model in patients with knee osteoarthritis.Methods: A binary logistic regression model was established, with the adherence of 218 cases of KOA patients as the dependent variable. The patients' general information, exercise habits, knowledge, attitude, and exercise therapy were independent variables. The regression coefficients were assigned to various variables in the model, and the ARS was constructed accordingly. Receiver operating characteristic curves and curve fitting were used to analyse the effect of the ARS in predicting the adherence and to determine the goodness of fit for the adherence. The external validity of the ARS was examined in a randomized controlled trial.Results: The construction of the adherence model and the ARS included the following variables: age (1 point), education level (1 point), degree of social support (2 points), exercise habits (3 points), knowledge of KOA prevention and treatment (2 points), degree of care needed to treat the disease (1 point), familiarity with exercise therapy (4 points) and treatment confidence (3 points). The critical value of the total score of the ARS was 6.50, with a sensitivity of 87.20% and a specificity of 76.34%.Conclusions: A KOA exercise therapy adherence model and a simple and practical ARS were constructed. The ARS has good internal validity and external validity and can be used to evaluate the adherence to exercise therapy in patients with KOA. [ABSTRACT FROM AUTHOR]

Abstract Pb-Zr mixed oxides with 15.2 wt% PbO loading were prepared by four different preparation processes, and their catalytic performances for the disproportionation of methyl phenyl carbonate (MPC) to synthesize diphenyl carbonate (DPC) were evaluated. Physicochemical characterizations including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence spectroscopy (XRF), BET surface area measurement, H 2 -temperature programmed reduction (H 2 -TPR), ammonia temperature programmed desorption (NH 3 -TPD) and infrared spectroscopy of pyridine adsorption (Py-IR), as well as catalytic tests of MPC disproportionation reaction showed that catalyst preparation process exerted significant influence on the composition, structural property, catalytic performance of obtained catalysts, and the catalyst prepared by co-precipitation method (PbZr-CP) demonstrated better dispersion of active phase, larger specific surface area and more Lewis acid sites on the surface due to the strong interaction of Pb and Zr, and thus exhibited higher catalytic activity than those prepared by other processes. Graphical abstract Image 1 Highlights • Preparation process exerts significant influence on structural property and catalytic performance of Pb-Zr mixed oxide. • Pb-Zr mixed oxide prepared by co-precipitation is more active. • Well-dispersed PbO and large specific surface area are formed on Pb-Zr catalyst prepared by co-precipitation. • This work provides an effective technology for Pb-Zr catalyst preparation to transform MPC into DPC. [ABSTRACT FROM AUTHOR]

Zero-shot detection (ZSD) aims to locate and classify unseen objects in pictures or videos by semantic auxiliary information without additional training examples. Most of the existing ZSD methods are based on two-stage models, which achieve the detection of unseen classes by aligning object region proposals with semantic embeddings. However, these methods have several limitations, including poor region proposals for unseen classes, lack of consideration of semantic representations of unseen classes or their inter-class correlations, and domain bias towards seen classes, which can degrade overall performance. To address these issues, the Trans-ZSD framework is proposed, which is a transformer-based multi-scale contextual detection framework that explicitly exploits inter-class correlations between seen and unseen classes and optimizes feature distribution to learn discriminative features. Trans-ZSD is a single-stage approach that skips proposal generation and performs detection directly, allowing the encoding of long-term dependencies at multiple scales to learn contextual features while requiring fewer inductive biases. Trans-ZSD also introduces a foreground–background separation branch to alleviate the confusion of unseen classes and backgrounds, contrastive learning to learn inter-class uniqueness and reduce misclassification between similar classes, and explicit inter-class commonality learning to facilitate generalization between related classes. Trans-ZSD addresses the domain bias problem in end-to-end generalized zero-shot detection (GZSD) models by using balance loss to maximize response consistency between seen and unseen predictions, ensuring that the model does not bias towards seen classes. The Trans-ZSD framework is evaluated on the PASCAL VOC and MS COCO datasets, demonstrating significant improvements over existing ZSD models. [ABSTRACT FROM AUTHOR]

Fitness yoga is now a popular form of national fitness and sportive physical therapy. At present, Microsoft Kinect, a depth sensor, and other applications are widely used to monitor and guide yoga performance, but they are inconvenient to use and still a little expensive. To solve these problems, we propose spatial–temporal self-attention enhanced graph convolutional networks (STSAE-GCNs) that can analyze RGB yoga video data captured by cameras or smartphones. In the STSAE-GCN, we build a spatial–temporal self-attention module (STSAM), which can effectively enhance the spatial–temporal expression ability of the model and improve the performance of the proposed model. The STSAM has the characteristics of plug-and-play so that it can be applied in other skeleton-based action recognition methods and improve their performance. To prove the effectiveness of the proposed model in recognizing fitness yoga actions, we collected 960 fitness yoga action video clips in 10 action classes and built the dataset Yoga10. The recognition accuracy of the model on Yoga10 achieves 93.83%, outperforming the state-of-the-art methods, which proves that this model can better recognize fitness yoga actions and help students learn fitness yoga independently. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have been used for carbon dioxide (CO2) capture, however, which have never been used as catalysts to accelerate CO2 capture. The record is broken by a uniquely designed IL, [EMmim][NTf2]. The IL can universally catalyze both CO2 sorption and desorption of all the chemisorption‐based technologies. As demonstrated in monoethanolamine (MEA) based CO2 capture, even with the addition of only 2000 ppm IL catalyst, the rate of CO2 desorption—the key to reducing the overall CO2 capture energy consumption or breaking the bottleneck of the state‐of‐the‐art technologies and Paris Agreement implementation—can be increased by 791% at 85 °C, which makes use of low‐temperature waste heat and avoids secondary pollution during CO2 capture feasible. Furthermore, the catalytic CO2 capture mechanism is experimentally and theoretically revealed. [ABSTRACT FROM AUTHOR]

Volume and viscosity data of ionic liquid (IL)-molecular solvent mixtures are very important for the design of process engineering involving these mixtures. In this work, densities and viscosities for the binary solutions of [C n mim]Br (n = 4, 6, 8) ionic liquids with methanol, 1-propanol, and 1-pentanol have been determined at 298.15 K as a function of IL concentrations. From these experimental data, apparent molar volumes, standard partial molar volumes, and viscosity B -coefficient of ILs were derived. The effect of the alkyl chain length in the imidazolium cation and properties of alcohol on the standard partial molar volumes of ILs and viscosity B -coefficient was discussed. In a given alcohol, the standard partial molar volumes of ILs and viscosity B -coefficient increase linearly with increasing alkyl chain length of ILs. For a given IL, unexpectedly, its standard partial molar volume in the three molecular solvents is not a constant, but increases in the order: 1-pentanol > 1-propanol > methanol. The viscosity B -coefficients of a given IL in the alcohols also change in the same sequential order. These results suggest that the interactions between ILs and the alcohols increase with the decrease of alkyl chain length of the alcohols. [ABSTRACT FROM AUTHOR]

As a class of green and designable solvents, ionic liquids (ILs) have been used extensively in inorganic synthesis. In those schemes, ILs were usually used as reaction media to replace water and organic solvents, and/or used as stabilizer and capping agents to act like an amphiphilic molecule or polymer. However, the unique properties of ILs were not fully utilized in the area of material preparation. In this study, a new protocol of “ILs–water interfacial synthesis” was developed and used for the preparation of Ag nanomaterials. Taking the advantage of tunable property of ILs–water interface, Ag nanomaterials with different morphology such as triangular nanoplates, polygonal nanoplates, and nanoparticles could be facilely obtained. Growth mechanism of the triangular Ag nanoplates has been investigated from structural characterization and molecular dynamics (MD) simulation. It was shown that growth of the nanoplates was under kinetic control mainly due to high viscosity and ionicity of the ILs. Furthermore, the antimicrobial performance of these Ag samples was tested to study the influence of shape of the Ag nanomaterials on the antimicrobial activity and the related antimicrobial mechanism. The results suggested that the efficient antimicrobial activity of the triangular Ag nanoplates was ascribed to their sharp corners and edges and large areas of active (1 1 1) crystal plane, which leads to the higher amount of leaching Ag + ion. [ABSTRACT FROM AUTHOR]

[Display omitted] Developing high-performance catalysts for water splitting via renewable electricity is of great significance for the clean production of hydrogen. This work reports rational design and controllable fabrication of metal oxide hybrid catalyst CoNiFe 2 O 5 ·2CuO with unique biphasic microstructures for electrochemical water splitting. Benefited from the presence of CuO nanoparticles as the second phase, more defects and active sites were formed around the interfaces of CoNiFe 2 O 5 and CuO, which led to excellent performances for electrocatalytic water splitting. In particular, the catalyst exhibited outstanding activity for hydrogen evolution reaction with a small overpotential of 30 mV to reach a current density of 10 mA cm−2 and showed a higher turnover frequency (0.3 s−1) than commercial catalyst Pt/C (0.1 s−1) under an overpotential of 50 mV. Moreover, it also displayed good activity for oxygen evolution reaction with an overpotential of 264 mV at 10 mA cm−2. Using CoNiFe 2 O 5 ·2CuO as the catalyst for electrode pair to construct a cell, a very low cell voltage of 1.53 V is enough to achieve overall water splitting at 10 mA cm−2 in 1 M KOH electrolyte, and the cell could maintain the stable performance at 10 mA cm−2 within 100 h. The as-prepared metal oxide hybrids with biphasic microstructures may have promising application potentials in water splitting. [ABSTRACT FROM AUTHOR]

Thermodynamicdissociation constants of the Brønsted acidicionic liquids (ILs) are important for their catalytic and separationapplications. In this work, a series of imidazolium bromides withone carboxylic acid substitute group in their alkyl chain ([{(CH2)nCOOH}mim]Br, n= 1,3,5,7) have been synthesized, and their dissociation constants(pKa) at different ionic strengths havebeen determined in aqueous and aqueous organic solvents at 0.1 molefraction (x) of ethanol, glycol, iso-propanol, anddimethyl sulfoxide by potentiometric titrations at 298.2 K. The standardthermodynamic dissociation constants (pKaT) of the ILs in these solvents were calculated from theextended Debye–Hückel equation. It was found that thepKavalues increased with the increaseof ionic strength of the media and of the addition of organic solventin water. The pKaTvalues alsoincreased with the increase of the alkyl chain length of cations ofthe ILs. In addition, the effect of solvent nature on pKaTvalues is interpreted from solvation ofthe dissociation components and their Gibbs energy of transfer fromwater to aqueous organic solutions. [ABSTRACT FROM AUTHOR]

Recently,it has been reported that addition of a cosolvent significantlyinfluences solubility of cellulose in ionic liquids (ILs), but littleis known about the influence mechanism of the cosolvent on the molecularlevel. In this work, four kinds of typical molecular solvents (dimethylsulfoxide (DMSO), N,N-dimethylformamide(DMF), CH3OH, and H2O) were used to investigatethe effect of cosolvents on cellulose dissolution in [C4mim][CH3COO] by molecular dynamics simulations and quantumchemistry calculations. It was found that dissolution of cellulosein IL/cosolvent systems is mainly determined by the hydrogen bondinteractions between [CH3COO]−anionsand the hydroxyl protons of cellulose. The effect of cosolvents onthe solubility of cellulose is indirectly achieved by influencingsuch hydrogen bond interactions. The strong preferential solvationof [CH3COO]−by the protic solvents (CH3OH and H2O) can compete with the cellulose–[CH3COO]−interaction in the dissolution process,resulting in decreased cellulose solubility. On the other hand, theaprotic solvents (DMSO and DMF) can partially break down the ionicassociation of [C4mim][CH3COO] by solvationof the cation and anion, but no preferential solvation was observed.The dissociated [CH3COO]−would readilyinteract with cellulose to improve the dissolution of cellulose. Furthermore,the effect of the aprotic solvent-to-IL molar ratio on the dissolutionof cellulose in [C4mim][CH3COO]/DMSO systemswas investigated, and a possible mechanism is proposed. These simulationresults provide insight into how a cosolvent affects the dissolutionof cellulose in ILs and may motivate further experimental studiesin related fields. [ABSTRACT FROM AUTHOR]

The concerted catalysis throughout multiple elementary steps is key to impel sluggish hydrogen evolution reaction (HER). Herein, NiMo/Mo 2 N/NC(500-R) array is constructed by embedding densely packed NiMo/Mo 2 N heterojunctions into nanorod skeleton of nitrogen-rich derived carbons (NC), then followed by electrochemical surface reconstruction. The great electrochemical surface area of resultant electrocatalyst implies fully-exposed concerted diatomic-ensembles. The ensemble effect of unique heteronanojunction induces charge polarizations between Mo and Ni species, gives pseudocapacitance comparable to supercapacitors, and pumps mass transfers to refresh entire HER process. The exceptional activity is demonstrated by ultra-low overpotentials of 5.8 and 200.6 mV respectively at 10 and 1000 mA cm−2, the impressive durability is indicated by lasting alkaline HER for 1000 h at 1 A cm−2. Moreover, the performances in water-alkali electrolyzer outperform most reported catalysts. This work presents valuable insights into concerted catalysis and designing efficient and durable electrocatalysts by ensemble effect from different metal heterojunctions for commercial applications. [Display omitted] • Well-separated heteronanojunctions impart the enhanced intrinsic activity to array. • Ensemble effect refreshes the concerted diatomic sites by charge polarizations. • Electrocatalyst delivers ultra-low overpotentials in alkaline hydrogen evolution. • Striking durability makes electrocatalyst commercializable in hydrogen production. • In-depth insights offer guidance to design efficient and durable electrocatalysts. [ABSTRACT FROM AUTHOR]

Pd/C-[BMIm][BF 4 ] catalyst displayed high activity for acceptorless dehydrogenation of biomass-derived alcohols to produce aromatic ketones under mild conditions without any acid/base additives, and this catalyst could be recovered and reused for 5 runs without obvious activity loss. This work provides a potential approach for the effective utilization of renewable biomass resources to produce aromatic compounds and clean H 2. [Display omitted] • The combination of Pd/C with specific ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]) displayed high activity for the dehydrogenation of aromatic alcohols to produce aromatic ketones. • The Pd/C-[BMIm][BF 4 ] pair promoted the dehydrogenation of aromatic alcohols and inhabited the hydrogenation of aromatic alcohols. • The catalyst could be recycled for 5 runs without obvious loss of activity. • Pd/C could be anchored and stabilized by the IL through interacting with [BMIm]+ cation, and both the [BMIm]+ cation and the [BF 4 ]- anion play vital roles in activating hydroxyl-H and hydroxyl α-H of the aromatic alcohol. Acceptorless dehydrogenation of alcohols is a promising pathway for biomass resource utilization and hydrogen supply, but still lacking for simple and effective catalysts. Herein, we report a metal-ionic liquids (ILs) catalyst for synergistical catalytic dehydrogenation of aromatic alcohols to aromatic ketones under mild conditions without any acid/base additives. It is found that the combination of Pd/C with 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]) displays high activity for the dehydrogenation of biomass-derived alcohols including 1-phenyl-1-ethanol, 1-phenyl-1-propanol and 1-(4-methoxyphenyl)ethanol. Mechanistic studies reveal that the Pd/C can be anchored and stabilized by the IL via interacting with [BMIm]+ cation, and the [BF 4 ]- anion plays vital role in the activation of hydroxyl-H and α-H protons via hydrogen bonding interactions. These interactions create an effective microenvironmental for Pd/C catalyzing the cleavage of the hydroxyl-H and α-C H bonds of α-hydroxyl aromatic alcohols to generate aromatic ketones and H 2. Moreover, the Pd/C-[BMIm][BF 4 ] catalyst could be recovered and reused for 5 runs without obvious activity loss. This strategy provides more evidences for the synergetic catalysis of metal and ionic liquids and exhibits potential application prospects for hydrogen supply from renewable biomass-derived alcohols. [ABSTRACT FROM AUTHOR]

Abstract: Densities of (d-xylose+HCl+water) have been measured at temperature in the range (278.15 to 318.15) K as a function of concentration of both d-xylose and hydrochloric acid. The densities have been used to estimate the molar volumes and isobaric expansivity of the ternary solutions. The molar volumes of the ternary solutions vary linearly with mole fraction of d-xylose. The standard partial molar volumes for d-xylose in aqueous solutions of molality (0.2, 0.4, 0.7, 1.1, 1.6, and 2.1) mol·kg−1 HCl have been determined. In the investigated temperature range, the relation: , can be used to describe the temperature dependence of the standard partial molar volumes. These results have, in conjunction with the results obtained in water, been used to deduce the standard volumes of transfer, Δt V ∘, of d-xylose from water to aqueous HCl solutions. An increase in the transfer volume of d-xylose with increasing HCl concentrations has been explained by the stronger interactions of H+ with the hydrophilic groups of d-xylose. [Copyright &y& Elsevier]

Vibrational spectroscopic studies have been carried out on solutions of LiBF4 in acetonitrile as a function of concentrations of lithium salt. Great changes in the vibrational characteristics of C⋮N and C−C stretches were observed as a result of solvation. The solvation numbers of Li+ determined from spectroscopic data are found to decrease from 3.2 to 1.4 with increasing concentration of the lithium salt. It is expected that the solvation number is 4 in the infinite diluted solution. Solvation structures of the lithium ion were suggested by density functional theory and the results were compared with the spectroscopic data. Changes of the ν1 mode of BF4- with concentration of the salt were also analyzed, and the bands at 763, 771, and 780 cm-1 indicate the coexisting of free ion, contact ion pairs, and dimers. The structures of ion pairs in gas phase and in acetonitrile solutions were suggested on the basis of DFT calculations. [ABSTRACT FROM AUTHOR]

Density measurements have been carried out at T=298.15 K for the CsCl–monosaccharide (d-galactose, d-xylose and d-arabinose)–water systems. The apparent molar volume of saccharides Vφ,S in the ternary solutions, the corresponding infinite dilution apparent molar volume Vφ,S∘, and the standard transfer volume ΔtVφ,S∘ of saccharides from water to aqueous CsCl solutions have been determined. The McMillan–Mayer theory was employed to relate the excess thermodynamic functions to a series of interaction parameters to obtain the volumetric interaction parameters of CsCl with monosaccharide in water. These parameters are interpreted by the group additivity principle and the stereochemistry of these monosaccharide molecules. [Copyright &y& Elsevier]

[Display omitted] • Hierarchical porous MXene/TiO 2 -Fe-G aerogel is prepared via a hydrothermal strategy. • The EmimTFSI-ACN-LiTFSI electrolyte is formulated to match the electrode material. • MXene/TiO 2 -Fe-G exhibits enhanced specific capacitance and good rate capability. • Fabricated ASC achieves energy density of 54 Wh kg−1 at power density of 1737 W kg−1. To achieve pseudocapacitance by driving reversible redox reactions is scientifically appealing to realize high energy density of supercapacitors (SCs). In this work, a unique ferric ions-assisted self-assembly MXene/TiO 2 -graphene aerogel composite (MXene/TiO 2 -Fe-G) is developed. The MXene/TiO 2 -Fe-G composite has a 3D hierarchical porous framework, large accessible specific surface area, and amorphous TiO 2 modified on the surface of MXene nanosheets. Importantly, amorphous TiO 2 , generated from the partial oxidation of MXene, can contribute enormous pseudocapacitance via the reversible redox reaction with Lithium ions. In addition, ferric cations with variable valence states can also provide pseudocapacitance. A trinary ionic liquid-based electrolyte (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide-acetonitrile-lithium bis(trifluoromethanesulfonyl)imide, EmimTFSI-ACN-LiTFSI) with a wide electrochemical stability potential window is also formulated to match the new material. Consequently, the MXene/TiO 2 -Fe-G composite as the negative electrode shows a superb specific capacitance of 196.4 F g−1 at 1 A g−1. An asymmetric supercapacitor assembled with the MXene/TiO 2 -Fe-G anode and self-synthesized nitrogen-doped reduced graphene oxide aerogel (N-RGA) cathode can deliver a high energy density of 54 Wh kg−1 at a high-power density of 1737 W kg−1. This work provides a possibility of implementing pseudocapacitance by changing the morphology and structure of MXene composites to match the ionic liquid-based electrolyte, which can considerably enhance the performance of MXene-based SCs. [ABSTRACT FROM AUTHOR]

Reasonable design of electrode materials to match ionic liquid electrolytes is important for the development of high-performance supercapacitors in the future. Herein, we demonstrate a nitrogen-doped agar-derived porous carbon (NAGC) electrode material with high specific capacitance and long cycling life, which was prepared using agar as precursor, potassium carbonate as activator, and melamine as nitrogen source via one-step activation doping method. The combined action of melamine and potassium carbonate can regulate and control the physical and electrochemical properties of the prepared materials. NAGC presents a high specific surface area (3228 m2/g) and micropores-dominated hierarchical porous structure, which can provide more adsorption sites and benefit rapid ions transport. The NAGC electrode in 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF 4 ]) ionic liquid electrolyte has a specific capacitance of 183 F/g at 1 A/g and 91 % capacitance retention from 1 to 10 A/g. Additionally, the assembled device with NAGC as both positive and negative electrode material has a wide operating voltage (3.6 V) and high energy density of 70.2 Wh/kg at a power density of 1.81 kW/kg. Also, it possesses a capacitance retention of 83.3 % after 50,000 cycles. This work provides a simple and effective way to achieve porous carbon materials with high specific capacitance and long cycle life. [Display omitted] • Nitrogen-doped agar-derived porous carbon is synthesized via a simple method. • NAGC material has large specific surface area and suitable pore size distribution. • Pore size distribution of NAGC matches to the size of ionic liquid electrolytes. • The NAGC-2//NAGC-2 device has high energy density and ultra-long cycle life. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) molybdenum disulfide (MoS 2) has drawn increasing attention due to its great potential for advanced electronics, photonics, optoelectronics, energy storage, catalysis and solar cell. However, high effective exfoliation for the mass production of 2D MoS 2 is still a challenge. To improve the exfoliation efficiency of MoS 2 nanosheets, a facile liquid-phase exfoliation strategy has been developed by using organic electrolyte solutions in this work. It is shown that the dispersion concentration of MoS 2 nanosheets has been significantly enhanced in organic electrolyte solutions. For example, by adding sodium tartrate into dimethyl sulphoxide, the dispersion concentration of MoS 2 nanosheets is 85 times that in neat dimethyl sulphoxide. About 80% of MoS 2 nanosheets obtained in such a strategy is 1–4 layers and the nanosheets remain 2H phase structure. In addition, the photocatalytic hydrogen evolution performance of the as-prepared few-layer MoS 2 nanosheets is evaluated. The photocatalytic hydrogen evolution rate is as high as 0.5 mmolg−1 h−1, which is 71 and 10 times higher than that of bulk MoS 2 and the 2H-MoS 2 nanosheets, respectively, reported to date. Exfoliation mechanism investigation suggests that the size of cation and the intensity of Lewis basicity of anion in the salts have played an important role in the exfoliation of MoS 2. The liquid exfoliation strategy reported here has great potential in the large-scale and high quality production of few-layer MoS 2 nanosheets for efficient photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

The abnormal concentration of lysozyme in body fluids and tissues is a potential indicator for diseases such as leukemia and meningitis. In this work, by combining the excellent optical properties of carbon dots (CDs) with the favorable selectivity of molecularly imprinted polymer (MIP), a novel fluorescent probe for lysozyme detection and cell imaging was constructed, where silanized CDs with low cytotoxicity (CDs/SiO2) were used as the fluorescence signal reporter and N-isopropylacrylamide (NIPAM) was used as the temperature-sensitive monomer. The as-prepared CDs/SiO2/MIP showed a thermo-sensitive property for the response to lysozyme. Moreover, this probe could be used for quantitative detection of lysozyme, with a wider detection range (0.001~0.01 mg/mL), a low detection limit (0.55 μg/mL), and a high selectivity. Importantly, the MTT assay testified that the fluorescent CDs/SiO2/MIP probe had low cytotoxicity. In addition, human hepatoma carcinoma cells (HepG-2 cells) could be stained by the CDs/SiO2/MIP, and showed a bright intracellular green fluorescence, indicating that the imaging of live cells was possible. This study provides a new way to detect lysozyme in vitro and an attractive perspective to probe intracellular lysozyme in vivo. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metal chloride functionalized MOF-253(Al) was designed and prepared for NH 3 capture and separation. • NH 3 capture capacity of the optimal functionalized MOF is 3.33 times that of the pristine MOF. • Highly selective separation of NH 3 from NH 3 /N 2 /H 2 mixture was achieved. • The excellent performance is ascribed to NH 3 coordination toward Ni2+ and its hydrogen bonding with Cl− and carboxyl. Ammonia (NH 3) is produced from nitrogen (N 2) and hydrogen (H 2) by the Harber-Bosch process at high pressure and high temperature. Due to the reversibility and low conversion efficiency of the reaction, the product contains a large amount of raw gas, which seriously affects the production efficiency of ammonia. Therefore, it is essential to exploit high-performance adsorbents for separating NH 3 from NH 3 /N 2 /H 2 mixtures. Herein, we designed and synthesized a kind of metal–organic framework (MOF) composites by anchoring metal chloride (NiCl 2 , CoCl 2 , or SnCl 2) on the bipyridinium groups in the MOF-253(Al) pores. It is found that the optimal composite shows an NH 3 uptake capacity of 18.0 mmol/g at 25.0 °C and 1.0 bar, which is 3.33 times that of the pristine MOF-253(Al), and the composite exhibits a much faster adsorption kinetics of NH 3 than the pristine MOF-253(Al). Significantly, the excellent NH 3 uptake capacity at low pressure allows selective trapping of NH 3 from NH 3 /N 2 /H 2 at 25.0 °C with the selectivity coefficients of 5708 to N 2 and 2320 to H 2. Spectral measurements reveal that the synergistic action of NH 3 coordination to the metal in the MOF and the hydrogen bonding of NH 3 with both O atoms of the carboxyl groups and Cl− of the guest molecules account for such an excellent capture and selectivity. In general, the strategy developed here is simple and effective for improving the selectivity of NH 3 separation, which opens a new way for the design of high-performance solid adsorbents. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aqueous solution of quaternary ammonium hydroxide is used to exfoliate MONs from bulk MOF powder. • The exfoliation yield of MONs is high up to 27.5%. • The MONs is mainly in the range from 1 to 3 layers. • The basicity and molecular size of quaternary ammonium hydroxide play vital roles in exfoliation. • The CO production rate catalyzed by MON is 118.7 μmol g−1 h−1 and the selectivity for CO is ca.100%. Metal−organic framework nanosheets (MONs) show promising applications in many fields, but the production of large amounts of high-quality MONs remains a challenge. Here, we report a general liquid-phase stripped approach to exfoliate a benzoic acid linked MOF (Al 2 (OH) 2 TCPP-Co) in water by using quaternary ammonium hydroxides as deprotonation reagent, intercalator and stabilizer simultaneously. It is shown that the stripped yield is high up to 27.5%, the thickness of MONs is mainly 1–3 nm, and the horizontal size is less than one hundred nanometers. The molecular geometry and alkalinity of quaternary ammonium hydroxides play vital roles in the exfoliation of MONs. Moreover, the MONs have been applied as photocatalysts for the conversion of CO 2 to CO in a gas–solid model under UV–visible light illumination without using any photosensitizer and sacrificial agents. The productivity rate of CO is 118.7 μmol g−1 h−1, which outperforms most of the photocatalysts reported previously. Thus, the liquid phase stripping method reported in this work has great potential in the large-scale production of MONs for efficient photocatalysis of CO 2 reduction in the gaseous phase. [ABSTRACT FROM AUTHOR]

Abstract: Rapid aggregation and deactivation of nanoscale zero-valent iron (nZVI) hinder its application in environmental remediation. In this work, micro-scale CaCO 3 is used as a dispersive carrier of nZVI to create a novel composite, CaCO 3 -supported nZVI (nZVI@CaCO 3), through simplified liquid-phase reduction strategy. The morphology analysis shows that CaCO 3 exhibits a fagot-like structure, and Fe0 particles are well dispersed on CaCO 3 with an average diameter of around 15 nm. The removal of Pb(II) from water by nZVI@CaCO 3 is studied, and it is found that the removal capacity of lead is as high as 3828 mg/g, which is much greater than that by neat CaCO 3 (2209 mg/g) and bare nZVI (1308 mg/g). Owing to the loading of Fe (50%) in nZVI@CaCO 3 , a significant synergistic effect is observed between CaCO 3 and nZVI in high performance removal of lead. Furthermore, a possible removal mechanism is proposed from a comparative investigation on the surface valence state and nZVI@CaCO 3 phase before and after absorption of Pb(II). Considering the advantages of improved dispersibility, easy preparation and remarkable performance, the as-prepared nZVI@CaCO 3 has the potential to become a promising remediation material for Pb(II) polluted water. Graphical abstract NZVI@CaCO 3 exhibited an enhanced performance in lead removal due to a significant synergistic effect of CaCO 3 and nanoscale zero-valent iron. Image 1 Highlights • CaCO 3 supported nanoscale zero-valent iron (nZVI@CaCO 3) was prepared under mild conditions. • A significant synergistic effect between CaCO 3 and nZVI was found. • NZVI@CaCO 3 could remove 98% Pb(II) from water in the concentration range from 10 to 1000 mg/L. • Adsorption and reduction of Pb(II) were the main steps in the removal of Pb(II) from water. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Liquid phase exfoliation (LPE) method has great potential for the large-scale production of graphene due to its simplicity, scalability, and low cost. In this work, fulvic acid (FA) was chosen to assist the exfoliation of graphite into graphene for the first time via sonication in aqueous medium. The concentration of obtained graphene dispersion can reach 0.63 ± 0.04 mg mL−1. The graphene flakes mostly consisted of 1–5 layers with sizes range in submicron to micron and few defects in the basal-plane. The π–π interaction between graphene and FA, along with the electrostatic repulsion between negatively charged FA, played a major role in stabilization of the graphene dispersion. By adjusting the pH of graphene dispersion to 14, the nanosheets of graphene came to flocculation. The formed graphene slurry is favorable for storage and transportation due to the greatly decreased volume. The annealed coating of FA-graphene on aluminum sheets was used as corrosion inhibitor for aluminum in 0.5 M H 2 SO 4 and 0.6 M NaCl solutions, with inhibition efficiencies of up to 85.5% and 99.4%, respectively. This shows that as-prepared graphene has great potential applications in the anti-corrosion of aluminum. [ABSTRACT FROM AUTHOR]

Abstract At present, it is still a challenge for reversible regulation of phase behavior and microstructure of microemulsions with less energy input and no composition change of the system. Photo-responsive microemulsions provide a potential way to solve these problems. In this work, 10 kinds of photo-responsive ionic liquids (ILs) with azobenzene group were used as photo-responsive surfactants to form microemulsions with water and some alcohols. Factors affecting the phase behavior and sub-regions of microemulsions, such as chemical structure of the ILs, temperature, alcohols properties and UV irradiation, were studied by conductivity, small-angle X-ray scattering, dynamic light scattering and cryo-TEM techniques. It was found that azobenzene-based ILs with a more hydrophilic head group and a shorter alkyl spacer length were favor of the formation of the microemulsions. The phase behavior of the microemulsions only slightly changed after UV irradiation, however, the area of O/W and bi-continuous sub-regions of the microemulsion could be regulated by UV irradiation. At the same time, droplets size increased after UV light irradiation, and could be restored close to the initial value by alternative vis-light irradiation. Highlights • Photo-responsive microemulsions were formed by azobenzene-based ionic liquids as photo-responsive surfactants. • Factors affect the phase behavior were investigated. • The area of sub-regions of the microemulsion could be regulated by UV irradiation. • The droplets size could be modulated by alternatively irradiation of UV and visible light. [ABSTRACT FROM AUTHOR]

Abstract Stimuli-responsive Pickering emulsions have attracted increasing interest because of the advantages of applications in numerous industrial processes. In this work, Pickering emulsions have been obtained by using negatively charged silica nanoparticles in association with very small amount of CO 2 -responsive ionic liquids as stabilizer. Ionic liquids N -alkylimidazole bicarbonates ([C n im]+HCO 3 −, n = 6, 8, 10, 12, 14) are in-situ generated by bubbling CO 2 into aqueous solution of N -alkylimidazoles (C n im, n = 6, 8, 10, 12, 14), and this process is reversible by removal of CO 2 with bubbling of N 2. Thus the Pickering emulsions may be switched multiple times between emulsification and demulsification states by alternatively bubbling and removal of CO 2 at 25 °C. The effect of concentration and alkyl chain length of [C n im]+HCO 3 − on Pickering emulsions is investigated systematically, and the possible mechanism of CO 2 -responsive Pickering emulsion is also studied by conductivity, surface tension, zeta potential, adsorption isotherm, water contact angle and 13C NMR spectroscopy. This CO 2 -responsive Pickering emulsion is cheap, simple, eco-friendly, and may have potential applications in emulsification and demulsification. Graphical abstract For the first time, in situ generated ionic liquids N -alkylimidazole bicarbonates were used as a emulsifier to prepare CO 2 -responsive Pickering emulsions, which may be switched between emulsification and demulsification by alternatively bubbling and removal of CO 2 at room temperature. Unlabelled Image Highlights • Emulsion was stabilized by silica and very small amount of ionic liquids. • Formation and breaking of emulsion was reversible by bubbling and removal of CO 2. • Minimum concentration of Ionic liquids required is 83 times smaller than its CMC. • The possible mechanism for the CO 2 -responsive Pickering emulsion is studied. [ABSTRACT FROM AUTHOR]

Developing a simple and green route for the controlled synthesis of hierarchical nanomaterials with anisotropic particles as subunits is highly desirable and technically important. Here, a functionalized ionic liquid (FIL) assisted strategy is developed for the preparation of hierarchical Au nanomaterials at room temperature. Various morphologies of Au products, including nanoplate-built flowers, nanobar-built flowers and nanourchins, have been well achieved using the current route in aqueous solutions of imidazolium ILs with different functional groups, such as 1-carboxymethy-3-methylimidazolium chloride ([CMmim]Cl), 1-hydroxylethyl- 3-methylimidazolium chloride ([HEmim]Cl), and 1-(3-aminopropyl)-3- methylimidazolium chloride ([APmim]Cl). The influence of these FILs on the morphology of Au products and their growth process has been studied systematically. It is shown that the functionalized ILs play important roles in the construction of these interesting Au hierarchies. The seed, IL concentration (within a certain range), reaction temperature have negligible influence, but stirring and anions of the ILs have important influences, on the product morphologies. Based on these results, the possible growth mechanism is proposed for the formation of different Au hierarchies. In addition, all the Au samples prepared with the assistance of the functionalized ILs, especially the nanoplate-built flowers, exhibit striking SERS sensitivity and high reproducibility. [ABSTRACT FROM AUTHOR]

Liquid-phase exfoliation of graphite is a promising method to produce graphene in large quantities. Selection of the solvent is the most important factor in determining the productivity of liquid-phase exfoliation and stability of the graphene dispersion. However, only low concentrations of graphene dispersion have been achieved in most of the solvents, and the solvents usually employed are toxic up to now. To address the performance and environmental safety issues of solvent, renewable solvents water and 1, 1, 3, 3-tetramethylurea (TMU) are explored as a mixture to exfoliate graphite into graphene in the present work. It is found that water-TMU mixed solvent is a powerful solvent to obtain a few-layer graphene, and the yield at the water volume faction of 0.3 was 4.5 times that in neat N -methylpyrrolidinone (NMP). The solvent-cosolvent interactions (water-TMU heteroassociation) are a critical factor in the liquid-phase exfoliation of graphene. The results reported in this work may provide a guide to rational design of a sustainable solvent system and to improve the yield and stability of the exfoliated graphene. [ABSTRACT FROM AUTHOR]

High current density at specific CO/H 2 molar ratios is the key to the industrial application of heterogeneous electrocatalytic CO 2 reduction reaction (CO 2 RR) to syngas, which is still very challenging. Here, we report a Ni-foam-supported nano-Ag catalyst for CO 2 RR in ionic liquid (IL)-acetonitrile electrolyte originally designed for CO 2 RR-to-CO. It is surprising to find that this is a highly efficient catalytic system for CO 2 RR-to-syngas, the CO/H 2 molar ratio in the syngas can be tuned from 1:5–26:1, and the current density is as high as 363.6, 458.2, and 644.7 mA cm−2 at the CO/H 2 molar ratios of 1:1, 1:2, and 1:3, respectively. The high efficiency of CO 2 RR-to-syngas is attributed to the synergistic stabilization action of nano-Ag and IL cationic C4/5-H for intermediate *COO- to produce CO, as well as cationic C2-H contribution to hydrogen evolution. This work opens a new way to improve catalytic performance of CO 2 RR-to-syngas. [Display omitted] • A nano-Ag catalyst in-situ grown on Ni foam was developed for CO 2 RR-to-syngas in [C 4 mim][PF 6 ]/MeCN electrolyte. • The CO/H 2 molar ratio could be tuned from 1:5–26:1, and the current density was high up to 644.7 mA cm−2. • By replacing the C2-H with methyl, the CO 2 RR product could be readily switched from syngas to pure CO, and the current density is high up to 528.3 mA cm−2. • A new pathway was explored to enhance CO 2 RR-to-syngas performance by adjusting the active protons of imidazolium ionic liquids. [ABSTRACT FROM AUTHOR]

• Stable ionic liquid hybrid Al-fum MOF materials were prepared by simple impregnation approach. • [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% exhibit an exceptionally high uptake at high temperature (9.9 mmol/g at 80 °C, 8.8 mmol/g at 100 °C) • [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% have an excellent selective separation performance of NH 3 from NH 3 /CO 2 mixture at 80 °C. • Coordination interactions of NH 3 to Zn centre is the key driven force for the adsorption and selective separation. Efficient adsorption and selective separation of ammonia at high temperature is a crucial and challenging issue. In this work, a series of stable ionic liquid hybrid materials have been developed by simple impregnation of ionic liquids into stable metal–organic framework Al-fum with 1D pores. The hybrid material [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% exhibited an exceptionally high uptake (9.9 mmol/g at 80 °C, 8.8 mmol/g at 100 °C) at high temperature, excellent uptake (9.8 mmol/g at 25.0 °C) at low ammonia concentration (100,000 ppm), and remarkable selective separation performance (selectivity factor is 25.1) of NH 3 from NH 3 /CO 2 mixture at high temperature. The NH 3 uptake of [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% at 100 °C was higher than the capacity of most of typical porous NH 3 adsorbents at room temperature. It is revealed that such superior NH 3 capacity and selective separation performance are mainly attributed to coordination interactions of NH 3 to Zn centre of the ionic liquids and the hydrogen bonding interactions of NH 3 with Cl of the ionic liquids and NH 3 with μ-OH of Al-fum. [ABSTRACT FROM AUTHOR]

Modeling the relationship among human joints is one of the most important components in human pose estimation. Most of previous methods define this relationship as a geometric constraint on the relative locations of two neighboring joints. In this constraint, the local appearance of the region connecting two neighboring joints is ignored. However, discarding this image appearance leads to some severe problems, such as double-counting and localization failure when the human pose is rare in the training dataset. Moreover, this image appearance, called human limb, plays an important role in human pose estimation in human visual system. Due to these reasons, we propose to solve a new task: human limb detection, which aims at detecting and representing this local image appearance. We combine this task with human joint localization as a unified framework. After getting the initial detections, we design a two-steps graphical model to capture the spatial relationship among human joints and limbs in a coarse to fine way. We evaluate the proposed method on two widely used datasets for human pose estimation: 1) frame labeled in cinema and 2) leeds sports pose datasets. The experiments results show the effectiveness of our method. [ABSTRACT FROM AUTHOR]

Self-assembly of ionic liquids (ILs) surfactants in ILs solvents is important from the viewpoint of both scientific research and practical application because of the advantages of high ionic nature and possible application at high temperature. In this work, the aggregation behavior of long-chain ionic liquids 1-alkyl-3-methylimidazolium chloride [C n mim]Cl ( n  = 12, 14, 16) and N -alkyl- N , N -dimethylethanolammonium [C n DMEA]Cl (n = 12, 14, 16) in a protic ionic liquid, ethanolammonium nitrate (EOAN), is investigated by surface tension measurements. The variation of micellization parameters with alkyl chain length and head group type of the ILs surfactants is analyzed and compared with that in water and in ethylammonium nitrate (EAN). It is found that the critical micelle concentration (cmc) values of the IL surfactants, such as [C 12 mim]Cl, in EOAN are 27 times smaller than those in EAN, and 4 times smaller than those in water. This suggests that EOAN is a better self-assembly medium for the ILs surfactants. It is also found that the contribution of head groups of the ILs surfactants to the cmc values is different in EOAN, water and EAN, while the contribution of CH 2 group in the alkyl chain of the ILs surfactants is generally independent of the solvents nature. [ABSTRACT FROM AUTHOR]

HNO 3 was demonstrated to be an effective catalyst for aerobic oxidation of benzylic sp 3 C H bonds under additive-free conditions. A series of isochromans, xanthenes and fluorenes underwent this transformation to give the targeted products in low to high yields under the catalysis of HNO 3 , which provided an effective method for the synthesis of the synthetically and biologically valued isochromanones, xanthones and 9-fluorenones. [ABSTRACT FROM AUTHOR]

Searching for environmentally friendly aqueous two-phase systems is imperative for the sustainable development of separation technologies. In this work, five kinds of environmentally benign choline derivative ionic liquids were synthesized and used for the formation of aqueous two-phase systems with K 3 PO 4 , K 3 C 6 H 5 O 7 or K 2 CO 3 . In order to understand the phase formation processes of these aqueous two-phase systems and their possible application in extraction, phase diagrams and partition coefficients of purine alkaloids were determined at T  = 298.2 K, and the effects of structure of the ionic liquids, nature of the purine alkaloids, composition and temperature of the systems on the partitioning behaviour of purine alkaloids were investigated systematically. It was shown that caffeine, theobromine and 2,6-amino purine could be extracted effectively into the ionic liquid-rich phase of the aqueous two-phase systems, and the partition coefficients were as high as 4.5–42 under the optimized conditions. The partitioning was found to decrease with the increase of the ratio of H 2 O weight fraction (in the ionic liquid-rich phase and in the salt-rich phase) and hydrophobicity of both the purine alkaloids and the ionic liquids, but not sensitive to the change of temperature. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide is usually considered as a mediator between dioxygen and the catalysts for the aerobic oxidation of alcohols. Here, we report that nitrogen dioxide has an ability to catalyze this reaction, which not only avoids the use of the cocatalysts or the acids in traditional approaches, but also reveals a method for the present transformation with a single component catalyst. A series of primary and secondary benzyl alcohols underwent this transformation to give the targeted products in low to high yields. [ABSTRACT FROM AUTHOR]