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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]

[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]

[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]

• 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]

• A pore environment tailoring strategy for COFs was proposed to boost Pd(II) capture. • The adsorbent exhibited a high adsorption capacity for Pd(II) (532 mg/g). • Excellent selectivity, fast kinetics, and good reusability for Pd(II) recovery. • The remarkable performances depended on synergistic multiple interactions. Palladium is a rare resource, and its content in the earth's crust is very low. Thus, its selective recovery from a secondary source is of great importance but a challenging task. Herein, we have constructed a series of bipyridine-based two dimensional (2D) covalent organic frameworks (COFs) TFBBPY-COF, TFBBPY-OH-COF and TFBBPY-OMe-COF, and explored their extraction performance towards palladium in aqueous solutions. It is found that by tailoring the pore environment of these COFs, TFBBPY-OMe-COF shows a highly efficient adsorption and excellent selectivity for palladium recovery, and the maximum sorption capacity is up to 532 mg g−1, which is the highest value among the crystalline porous adsorbents reported up to now. Furthermore, TFBBPY-OMe-COF has been successfully employed to capture Pd(II) with a high selectivity (92.3%) in a simulated solution derived from a waste printed circuit boards. Spectral experiments and theoretical calculations reveal that the excellent adsorption of palladium is mainly attributed to the multiple hydrogen bonds of C–H---Cl and coordination of O and pyridine-N to Pd(II). [ABSTRACT FROM AUTHOR]

• A pore environment tailoring strategy for COFs was proposed to boost Pd(II) capture. • The adsorbent exhibited a high adsorption capacity for Pd(II) (532 mg/g). • Excellent selectivity, fast kinetics, and good reusability for Pd(II) recovery. • The remarkable performances depended on synergistic multiple interactions. Palladium is a rare resource, and its content in the earth's crust is very low. Thus, its selective recovery from a secondary source is of great importance but a challenging task. Herein, we have constructed a series of bipyridine-based two dimensional (2D) covalent organic frameworks (COFs) TFBBPY-COF, TFBBPY-OH-COF and TFBBPY-OMe-COF, and explored their extraction performance towards palladium in aqueous solutions. It is found that by tailoring the pore environment of these COFs, TFBBPY-OMe-COF shows a highly efficient adsorption and excellent selectivity for palladium recovery, and the maximum sorption capacity is up to 532 mg g−1, which is the highest value among the crystalline porous adsorbents reported up to now. Furthermore, TFBBPY-OMe-COF has been successfully employed to capture Pd(II) with a high selectivity (92.3%) in a simulated solution derived from a waste printed circuit boards. Spectral experiments and theoretical calculations reveal that the excellent adsorption of palladium is mainly attributed to the multiple hydrogen bonds of C–H---Cl and coordination of O and pyridine-N to Pd(II). [ABSTRACT FROM AUTHOR]

[Display omitted] • A crosslinking Sb-NC/PoMXene network with fully-active species is designed. • The network greatly enhances ion/electron transport and alleviates volume variation. • Interweaved polar interfaces benefit rich binding/catalytic sites to polysulfides. • Long cyclability is achieved for 700 cycles with capacity retention over 99%. The performances of lithium-sulfur batteries (LSBs) depend heavily on sulfur hosts with the desired properties including excellent electronic conductivity, high sulfur loading, strong polysulfide capture, and active catalytic centers. Here, we demonstrate 2D partially oxidized Ti 3 C 2 T x MXene (PoMXene) can be cross-linked by Sb, N co-implanted carbon (Sb-NC) through Ti-O-Sb bond to synthetize Sb-NC/PoMXene. It is shown that the nanostructuring Sb-NC/PoMXene provides fast ion/electron transport channel and robust 3D architecture to alleviate volume variations. Significantly, the interweaved polar interfaces benefit rich binding sites from Sb nanoparticles, N atoms, TiO 2 and Ti 3 C 2 T x towards polysulfides, and the Sb-NC could catalytically accelerate redox kinetics, thus efficiently suppressing polysulfide shuttle. As a result, the Sb-NC/PoMXene/S hybrids represent high capacity (1148.4 mAh g−1 at 0.1C) and long cyclability (570.6 mAh g−1 after 700 cycles at 2C). When the sulfur loading is increased to 4 mg cm−2, the thick cathode still maintains a high areal capacity of 3.8 mAh cm−2 with a decay of only 0.10% per cycle over 100 cycles at 0.2C. The studies pave a novel pathway to design nanostructured electrodes and promote catalytic performances in LSBs. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a novel Bi-based oxyhalide Bi4TaO8I was prepared and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectroscopy. Photocatalytic activity of this material was evaluated by using methyl orange (MO) as a representative azo dye. It was found that Bi4TaO8I had a visible light absorption, and the band-gap energy was estimated to be 2.43eV. This material exhibited good photocatalytic activity under both ultraviolet and visible light irradiation. The effects of initial MO concentration, aqueous pH, catalyst dosage and irradiation time on the photocatalytic activity were studied systematically. The photocatalytic degradation of MO by Bi4TaO8I under visible-light irradiation was found to follow the pseudo first-order reaction at the low initial concentrations of MO. Reuse of the catalyst was also examined, and the degradation efficiency of MO was still as high as 60% after 3cycles of 28h visible-light irradiation. Furthermore, it was found that the degradation of MO was also effective under solar irradiation. Five main degradation products were observed by HPLC/MS and their chemical structures were suggested. In order to exclude the photosensitization effect, the photocatalytic degradation efficiency of pentachlorophenol (PCP) by Bi4TaO8I was also determined under visible light irradiation. It is expected that Bi4TaO8I would have potential application in the degradation of azo dye wastewaters under solar irradiation. [Copyright &y& Elsevier]