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[Display omitted] An efficient strategy to construct non-noble metal-base electrocatalysts for water splitting is the direct carbonization of metal–organic aerogel composites. Herein for the first time, a novel tube-like metal–carbon nanocomposite with encapsulated small-size individual Fe, Cr and Ni nanoparticles, is prepared by the carbonization of a FeCr-doped Ni-benzenetricarboxylate aerogel. The slender skeleton of the aerogel, supercritical drying and Cr doping alleviates metal aggregation and facilitates the in-situ growth of carbon tubes. This nanocomposite exhibits remarkably low overpotential of the hydrogen evolution reaction (137 mV) and oxygen evolution reaction (220 mV). Further, the cell voltage could be as low as 1.54 V with the current density of 10 mA cm−2 and illustrates excellent stability under a continuous operation for 50 h. This non-noble metal-base electrocatalyst is comparable to noble metal-based electrocatalysts and the impressive performance is ascribed to the abundant active catalytic sites and short reactant diffusion pathways. This work demonstrates great capability of aerogel derivation in the highly active electrocatalyst design for promising electrochemical applications. [ABSTRACT FROM AUTHOR]

In this work, the high acidic crude oil deacidification study was performed with novel 1-alkyl-1,5-diazabicyclo[4.3.0]non-5-ene (DBN) based ionic liquids (ILs). Firstly, we took advantage of the systematic COSMO-RS (Conductor-like Screening Model for Real Solvents) calculations to screen the possible ILs with good acid extraction performance from the combinations of 94 cations and 56 anions. Four 1-alkyl-1,5-diazabicyclo[4.3.0]non-5-enium imidazolide ([DBN-R][IM]) ILs with varying alkyl chains were eventually identified and synthesized successfully. Their deacidification performances were tested experimentally and different factors, including the alkyl chain length, ILs/oil mass ratio, temperature, and the initial total acid number (TAN) value of the simulated acidic oil, were also studied in detail. The experimental results showed that [DBN-R][IM] exhibited excellent performances on naphthenic acids (NAs) removal and [DBN-Et][IM] could achieve 93% of NAs removal employing the ILs/oil mass ratio of 0.06 at room temperature for the acidic oil with the TAN value of 3.28 mg KOH/g. COSMO-RS analyses were also used to elucidate the unusual effects of the alkyl chain length and temperature on the NAs extraction performances. Additionally, a two-step deacidification strategy was proposed aiming at realizing more efficient NAs extraction. Finally, density functional theory (DFT) calculations were carried out and the independent gradient model (IGM) analyses were applied to the IL-NAs system to get insight into the deacidification mechanism of the ILs. [Display omitted] • Four ionic liquids were screened out theoretically from 5264 ionic liquids for naphthenic acids extraction. • Four novel 1,5-diazabicyclo[4.3.0]non-5-ene based ionic liquids were synthesized successfully. • Deacidification factors were experimentally investigated and analyzed theoretically. • A two-step deacidification strategy was proposed. • DFT calculations and independent gradient model analyses were performed to study the mechanism. [ABSTRACT FROM AUTHOR]

Abstract: The first and last melting points (FLMP) method was employed to measure the melting temperature–composition () data at solid–liquid–gas (SLG) equilibrium for the naphthalene–biphenyl–CO2 system. Results show that the system''s phase diagram is simple eutectic under all investigated pressures (0.1, 3.0, 6.0 and 8.0MPa), and the system''s eutectic composition is almost constant. The () data measured with a high-pressure differential scanning calorimetry are in good agreement with these from FLMP. The semi-predictive model using solubility data (SMS) and the calculation model combining with GE models (CMG) for binary systems were extended to this ternary system. For the SMS model, the Peng–Robinson equation of state (PR-EoS) with the van der Waals one-fluid mixing rule was used to correlate the solubility data of the two solutes in CO2 to obtain the two interaction parameters k 12 and k 13 and calculate the fugacity coefficients of the solutes in the liquid and vapor phases; the UNIFAC method was also applied to the activity coefficient of the solutes in the liquid phase. For the CMG model, the PR-EoS combining respectively the MHV1, LCVM, and modified LCVM (mLCVM) mixing rules was applied to the fugacity coefficients of the solutes. Results show that the CMG model with MHV1 gives the best prediction of the system''s SLG equilibrium, while the SMS model and the CMG model with mLCVM provide comparable and acceptable results. [Copyright &y& Elsevier]

The mesoporous poly(N , N ′-methylene-bis(1-(3-vinylimidazolium)) chloride), labeled as PDVIm-Cl, with double anions (Cl−) and low monomer molecular weight was synthesized and applied in the adsorption of anionic dyes (acid orange 7 (AO7), sunset yellow (SY), reactive blue 19 (RB19), congo red (CR)). Due to the mesoporous structure, abundant Cl− and positively charged imidazole rings, the poly(ionic liquid) (PIL) exhibited superior adsorption ability towards anionic dyes. What is more, the RB19 adsorption by PDVIm-Cl could achieve the highest capacity (2605 ± 254 mg g−1) which was nearly twice higher than the maximum adsorption capacity of the previously reported materials. All the adsorption kinetic data and isotherms fitted well with the pseudo second-order model and Langmuir-Freundlich model. To better explore the practical potential of the PIL for dye adsorption, the adsorption under different pH values and column adsorption performances were also evaluated. Results showed that PDVIm-Cl exhibited high removal efficiencies for anionic dyes over a wide pH range (2−10). Also, the great reusability could be well demonstrated by the achievable continuous column adsorption-desorption process. It is worth mentioning that the regeneration could be realized with very little desorbent which was far less than the adsorption volume flowing through the column and the desorption efficiency was well maintained after three consecutive cycles. At last, the adsorption mechanism was explored by experiments combined with quantum chemical calculations and showed anionic dyes adsorption by PDVIm-Cl was a joint process dominated by the ion exchange, electrostatic interaction, hydrogen bond and π-π stacking. • PDVIm-Cl is capable to adsorb various anionic dyes with high capacities. • PDVIm-Cl shows unprecedented adsorption capacity of 2605 ± 254 mg g−1 for RB19 dye. • PDVIm-Cl could be used to adsorb different anionic dyes in a wide range of pH. • PDVIm-Cl can easily realize continuous column adsorption-desorption process. • The adsorption mechanism is studied by experimental and theoretical calculations. [ABSTRACT FROM AUTHOR]

Synthetic anion exchange membranes (AEMs) usually suffer from low conductivity, bad alkaline stability and poor dimensional stability. Constructing efficient ion transport channels is considered to be one of the most effective ways for preparing the AEMs with the high conductivity and low swelling ratio. Herein we demonstrate a facile strategy to achieve this goal via using the rigid crosslinkers to expend the interchain spacing of polymer chains. Three crosslinkers are chose to modify poly (ether ketone) (PEK) AEMs. The AEMs with rigid crosslinkers have more efficient ion transport channels and thus show both higher water uptake and higher ionic conductivity, compared with the AEM with the flexible crosslinker. Especially, the hydroxide conductivity of the AEM increases from 63.2 to 110.3 mS cm−1 at 80 °C when the short flexible crosslinker is replaced by the long rigid crosslinker. Meanwhile, the swelling ratios (SR) are less than 25%. The rigid crosslinkers should be beneficial to construct efficient ion channel and overcome the trade-off relation between the ionic conductivity and dimensional stability of the synthetic AEMs. Image 1 • The rigid crosslinkers are developed to construct fast ion transport channels in AEMs. • The steric effect of crosslinkers affect the structure and performance of AEMs largely. • The long rigid crosslinker contributes to form highly-efficient ion channels. • The rigid crosslinker addresses the dilemma between conductivity and swelling of AEMs. [ABSTRACT FROM AUTHOR]

Ion exchange membranes (IEMs) are widely used in various fields including ion-selective separation processes and fuel cells. However, synthetic IEMs with a high ion conductivity usually suffer a high swelling ratio in working surroundings. Herein we demonstrate a versatile strategy to develop novel microporous copolymers for the high-performance IEMs via combining merits of polymers of intrinsic microporosity (PIMs) and common functional polymers. As a sample, a series of PIM-1/PES copolymers are synthesized accordingly. These copolymers, other than many PIMs, exhibit a good solubility in common organic solvents including N -methyl-2-pyrrolidone (NMP), and are successfully applied to prepare the high-performance IEMs by chloromethylation and multi-cation crosslinking. The introduction of PIM-1 segments exhibits distinct advantages in the effective water management, swelling control and construction of well-developed ion channels. The resulting PIM-1/PES 0.50 anion exchange membrane (AEM), with an ion exchange capacity (IEC) of 1.075 mmol g−1, has a low swelling ratio of 11.0% and a high hydroxide conductivity of 87.6 mS cm−1 at 80 °C. The developed strategy has wide applications in the development of new IEMs materials. Image 1 • A strategy is developed to prepare microporous copolymers for high-performance IEMs. • The copolymers exhibit good solubility in common organic solvents including NMP. • The copolymers are easily grafted with functional groups for high-performance IEMs. • The PIM-1 segment favors to construct well-developed ion channels in the AEMs. • The prepared AEMs show the high ion conductivity and low swelling at low IEC. [ABSTRACT FROM AUTHOR]

Anion exchange membrane (AEMs) as a kind of important functional material are widely used in many fields including fuel cell, electrodialysis and water treatment. However, synthetic AEMs generally suffer a pernicious trade-off: high ion-conductive AEMs lack dimensional stability and vice versa. Herein we demonstrate a versatile strategy to prepare the AEMs with both high ion conductivity and excellent dimensional stability (i.e. , low swelling ratio) via hydrophobic crosslinking and introducing hydrophobic chains. The hydrophobic length of crosslinkers has great influence on construction of highly efficient ion channels in the AEMs. Amazingly, the hydrophilic poly (phenylene oxide) (PPO) AEM crosslinked by 1,8-diaminooctane has the highest hydroxide conductivity that is further improved to 157.2 mS cm−1 (10% increases) with a low swelling ratio of 12.9% at 80 °C by introducing hydrophobic PPO backbone. This AEM not only overcomes the trade-off between the ion conductivity and the dimensional stability of crosslinked AEMs, but also breaks the upper bound between the ion conductivity and the water uptake. The newly developed strategy of hydrophobic dual-modifications promises to be an effective approach to develop the high-performance AEMs. Image 1 • A novel strategy was developed by combining both hydrophobic crosslinker and chain. • The hydrophobic length of crosslinkers has great influence on ion channels of AEMs. • The hydrophobic chains increase ion conductivity and decrease the swelling ratio. • The formed AEM has the OH− conductivity of 157 mS cm−1 with a SR of 12.9% at 80 °C. • This work breaks the trade-off between ion conductivity and dimensional stability. [ABSTRACT FROM AUTHOR]