Assistance Of Ionic Liquid Research Articles

Unusual emission from 2F5/2 two lowest excited levels of Yb3+-doped LuPO4 nano/micro-crystalline materials

Yb3+-doped inorganic materials are constantly in demand due to a strong interest in fundamental and applied research. The simplicity of the 4f1³ electronic structure minimizes de-excitation processes and enables a quasi-three-level laser emission scheme at 1 μm employed for IR laser devices.In this work, we present an unusual simultaneous emission from two of the lowest levels of the 2F5/2 excited state observed at 77 K, measured for the first time and confirmed by the barycenter law for Yb3+-doped tetragonal LuPO4 revealing the lowest crystal field among Yb3+ ion-activated oxide crystals.Three series of tetragonal lutetium orthophosphate powders, containing various concentrations of Yb3+ ions (0.5–5 mol %), were analyzed in nano and micro-crystalline forms. The ionic liquid-assisted (IL) hydrothermal (HT) method was used for the nano-powders' preparation. This route enabled the fabrication of fine nano-powders with particle sizes of 15 nm in an ethylene glycol (GE) reaction medium and 30 nm in a water (W) medium, each exhibiting the desired well-crystallized single-phase phosphate. For comparative studies, the micro-crystalline samples were synthesized via reaction in the solid phase at a relatively high temperature.The Yb3+ ion also served as a structural probe, its spectroscopy i.e., absorption at 4.2 K, selectively excited luminescence at 77 K, and fluorescence decays were used to assign Yb3+ energy levels in only one D2d center precisely. This assignment was based on exceptional features due to the unique emissions observed from the two lowest levels of the 2F5/2 excited state, split only by 27 cm−1, confirmed by calculation of the crystal field parameters from Zeeman spectra.

Catalytic One-pot Solvent Free Synthesis, Biological Activity, and Docking Study of New Series of 1, 3-thiazolidine-4-one Derivatives Derived from 2- (P-tolyl) Benzoxazol-5-amine.

In this study, a simple triethylammonium salt of phosphoric acid (triethylammonium dihydrogen phosphate) (4) in the liquid state was utilized as an inexpensive, efficient one-pot three components, solvent-free synthesis of thiazolidine-4-one derivatives, with good to excellent yields. Techniques such as FT-IR, 1H-NMR, 13C-NMR, 13C-NMR-DEPT-135, and MS. were used for the structural elucidation. The high biotic efficiency of the newly obtained compounds was confirmed by in vitro antimicrobial action against Gram-positive (S. Aureus), Gram-negative bacteria (P. Aeruginosa and E. Coli) and antifungal activity (C. Albicans) via microplate titer dilution technique. Finally, a molecular docking study was performed with a resolved crystal structure of S. Aureus D-alanine alanyl carrier protein ligase (PDB ID: 7VHV). This investigation aimed to synthesize a new series of thiazolidine-4-one derivatives combined with benzoxazole moiety. Ionic liquid assistance one-pot solvent-free synthesis method used to synthesize a new series of thiazolidine-4-one derivative 10(a-e). Structural identification of new synthesis and biological evaluation via techniques of (IR, 1H-NMR, 13C-NMR, 13C-NMR-DEPT-135, and MS). Ionic liquid is utilized as an inexpensive, efficient one-pot three-component solvent-free synthesis of thiazolidine-4-one derivatives with good to excellent yields. Most of the synthesized compounds showed high biological and anti-fungal activity, in line with the docking study against mentioned microorganism and crystal structure of PDB (ID: 7VHV), respectively.

Preparation and properties of polyetherimide fibers based on the synergistic effect of carbon nanotubes and ionic liquids

AbstractPolyetherimide (PEI) has been widely applied in the form of plastics, films, and foam materials. But PEI fiber is confronted with some challenges, such as high melt viscosity and high spinning temperature during the spinning process, poor mechanical properties because of its amorphous structure. In this study, ionic liquids (ILs) and carbon nanotubes (CNTs) were used to prepare PEI composite fibers (PEI/CNT‐IL) successfully, which were further characterized by scanning electron microscope (SEM), Raman spectra, differential scanning calorimetry, dynamic mechanical analysis, thermalgravimetric analysis, mechanical property, and conductivity measurements. IL showed a plasticizing effect to reduce the processing temperature of PEI and SEM images showed that CNTs were uniformly dispersed in the PEI matrix by the assistance of IL. The synergistic effect of CNT and IL thus improved the tensile strength and antistatic properties of PEI fibers. When the contents of CNT and IL were 0.5 and 1.0 wt%, respectively, the optimal properties were obtained. PEI/CNT‐IL fibers exhibited a maximum tensile strength of 2.0 cN/dtex with the elongation at break being 90%, and the enhanced electrical conductivity of 10−5 S·cm−1, which was increased by 13 orders of magnitude compared to that of pristine PEI fiber.Highlights PEI composite fibers were prepared via melt spinning with the assistance of IL and CNT. IL can effectively disperse CNT and plasticize PEI to reduce the processing temperature. The synergistic effect of CNT and IL has improved the tensile strength and antistatic properties of PEI fibers.

Trace Ionic Liquid-Assisted Orientational Growth of Cu2O (110) Facets Promote CO2 Electroreduction to C2 Products.

Cu2O has great advantages for CO2 electroreduction to C2 products, of which the activity and selectivity are closely related to its crystal facets. In this work, density functional theory calculation indicated that the (110) facets of Cu2O had a lower energy barrier for the C-C coupling compared to the (100) and (111) facets. Therefore, Cu2O(110) facets were successfully synthesized with the assistance of trace ionic liquid ([Bmim]BF4) by a sample wet-chemical method. A high faradaic efficiency of 71.1% and a large current density of 265.1 mA cm-2 toward C2H4 and C2H5OH were achieved at -1.1 V (vs. reversible hydrogen electrode) in a flow cell. The in-situ and electrochemical analysis indicated that it possessed the synergy effects of strong adsorption of *CO2 and *CO, large active area and excellent conductivity. This study provided a new way to enhance the C2 selectivity of CO2 electroreduction on Cu2O by crystal structure engineering.

Highly Stable CsPbBr3 Nanocrystals for Photocatalytic Reduction of CO2: Ionic Liquid as a Surface Passivation Ligand and Reaction Precursor

All inorganic metal halide perovskites (MHPs) have been regarded as a new type of promising photocatalyst for the reduction of CO2. However, due to their strong ionicity and the labile surface ligands, there is still much room for improvement of the stability and efficiency of MHP photocatalysts. Here, we propose a new strategy simultaneously using ionic liquid (IL) as a surface passivation ligand and a precursor to mediate the growth and then stabilize CsPbBr3 MHPs for the photocatalytic reduction of CO2. First, the TEM and XRD results show that the prepared CsPbBr3 has a cubic morphology with the monoclinic phase when the IL of 1-octyl-3-methylimidazolium bromide ([Omim]Br) is used as the surface ligand. When the molar ratio of [Omim]Br to Pb(CH3COO)2 is optimized to 2, the photoluminescence quantum yield of the prepared CsPbBr3 can reach as high as 90.93%, suggesting the effective reduction of surface defects by the IL ligand. Importantly, the CsPbBr3 nanocrystals show high stability under the ambient stimuli of light, heat, and humidity. The subsequent FT-IR and XPS characterizations indicate that the presence of [Omim]Br on the surface of CsPbBr3 increases the Br-rich state, which accounts for the excellent optical property and stability of the CsPbBr3 nanocrystals. Finally, with the assistance of IL as the activator of CO2, the CsPbBr3 photocatalysts provide a high evolution rate of 24.56 and 6.66 μmol g–1 h–1 for CO and CH4, respectively. Multifunctional ILs as passivation ligands, reaction precursors, and CO2 activators provide an efficient pathway to fabricate stable metal halide perovskites for photocatalytic CO2 conversion.

Supercapacitive properties of MnNiSx@Ti3C2Tx MXene positive electrode assisted by functionalized ionic liquid

MnNiSx@Ti3C2Tx as the positive electrode of supercapacitor was successfully prepared by hydrothermal method with the assistance of amino-functionalized ionic liquids. The micromorphological structures of MnNiSx@Ti3C2Tx were analyzed using X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy, transmission electron microscope, and energy dispersive spectrometer to reveal the synergistic effect between MnNiSx and Ti3C2Tx MXene. MnNiSx grew into a three-dimensional coral-like structure on the surface and between layers of Ti3C2Tx nanosheets. This structure alleviated the collapse and stacking of Ti3C2Tx, increased the specific surface area of Ti3C2Tx, and promoted the charges transfer on the surface of Ti3C2Tx. The electrochemical performances of MnNiSx@Ti3C2Tx positive electrode, such as cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy, were investigated. The synergistic effect between MnNiSx and Ti3C2Tx MXene improved the specific capacitance and the capacitance retention of the MnNiSx@Ti3C2Tx electrode. An asymmetric solid-state supercapacitor (ASC) assembled using MnNiSx@Ti3C2Tx as cathode material had the power density of 816.34 W·kg−1, and the energy density of 35.11 Wh·kg−1. The capacitance retention of ASC reached 98% after 5000 cycles at a current density of 5 A·g−1.

Unraveling energy storage behavior of independent ions in carbon electrode for supercapacitors by polymeric ionic liquids and electrochemical quartz crystal microbalance

A fundamental understanding of the charge storage mechanism of electrochemical double-layer capacitors (EDLCs) requires an in-depth storage behavior investigation of independent ions (individual cations or anions) on the electrode surface. The direct in-situ observation for energy storage behavior of individual ions under realistic conditions remains challenge. Herein, in-situ monitoring the energy storage behavior of independent ions is realized with assistance of polymeric ionic liquids skillfully. Triangle cyclic voltammogram (CV) curves indicate that polymeric imidazole cations PVBIm+ with huge size cannot enter the active carbon pores upon charging, whereas only free anions can. The CV and electrochemical quartz crystal microbalance (EQCM) simultaneously detect ion adsorption/desorption during charging. It’s proposed that ion adsorption/desorption is governed by electrostatic attraction and repulsion of charged particles. PVBIm+ are adsorbed on the electrode surface due to ion adsorption mechanism during the negative polarization and have a small capacity contribution. Free anions contribute capacitance, their number entering the pore is determined by the interaction between polycaions and anions. Moreover, PVBIm(0.1)+ with higher polymerization degree may promote desorption of polycations and prevent further adsorption of anions at higher potential in positive polarization. This work not only observes the charging behavior of independent ions, but also reveals the relevant charging mechanism through EQCM, paving the way for panorama of EDLC.

Highly efficient silica coated perovskite nanocrystals with the assistance of ionic liquids for warm white LEDs.

Given the inherent characteristics of defect-tolerant, tunable emission performance, and high extinction coefficient, lead halide perovskite nanocrystals (NCs) have attracted widespread attention as a promising material in optoelectronic fields. However, their poor structural stability greatly impedes their practical applications. Herein, a novel strategy for synthesizing stable CsPbBr3@SiO2 NCs via the hydrolytic polycondensation of (3-aminopropyl)triethoxysilane (APTES) in the presence of ionic liquids (ILs) is deliberately designed. The problems of fluorescence quenching and undesirable agglomeration of NCs resulting from ligand loss and surface erosion existing in common encapsulation methods can be effectively resolved. The fast and controllable growth of the SiO2 shell around the CsPbBr3 NCs is realized owing to the high polarity and hygroscopicity of the IL. Moreover, the dual effects of the IL for passivating the surface defects and avoiding the structural degradation of NCs during the hydrolysis process of APTES are demonstrated. As a result, CsPbBr3@SiO2 NCs with a high photoluminescence quantum yield of 85.7% and excellent stability are realized. Furthermore, this method proves to be a versatile tool to obtain CsPbX3@SiO2 NCs with different halide compositions, realizing a broad tunable wavelength from 421.2 nm to 651.6 nm. A warm white LED with a high color rending index was assembled through packaging CsPbBr3@SiO2 NCs and Cu-In-Zn-S/ZnS/PVP composites on a commercial blue chip. These findings are expected to facilitate the development of perovskite NCs, which provides access to their optoelectronic applications.

Biocompatible and electrolyte embossed wearable textile based supercapacitors from chitosan derived bio-ternary composites crafted fabric electrodes

A typical biocompatible and electrolyte inscribed textile based supercapacitor approached for wearable smart devices. The flexible electrolyte imprinted textile based supercapacitors designed from Chitosan/MnO2@MnCO3 chelate decorated fabrics. The active materials fabricated under BMIMBF4 ionic liquid assistance through hydrothermal method. The physiochemical properties, surface morphological notes are inspected by examining out X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy investigations. The XPS outlines of the composite disclose typical peaks of Mn2p1/2 (653.4 eV), Mn2p3/2 (641.5 eV), N1s (401.2 eV), and C1s (285.5 eV). The flexible supercapacitor exhibits notable areal capacitance of 2.5 Fcm−2 and 0.35 Wh cm−2 energy density. The fabric supercapacitors perform decent capacity retention around 90–89 % after 10,000 charge-discharge cycles with good mechanical flexibility performance. Moreover the obtained biocompatibility results are good to recommend for wearable devices (~90 % cell viability). The chitosan bio-ternary composite crafted textile based supercapacitor may newcomer for the suitability to wearable textile based energy storage system.

Significant boosting effect of single atom Pt towards the ultrasonic generation of H2O2: A two-way catalytic mechanism

Single atom Pt was anchored on the surface of SiO2 (Pt1/SiO2) with the assistance of ionic liquid. It was found that Pt1(0.1 %)/SiO2 could catalyze to sonically generate 3027.1 µmol L−1 h−1 H2O2, being 25.2 folds and 11.6 folds of those from pure ultrasound and sonocatalytic processes of Ptn(0.1 %)/SiO2, respectively. It was also the maximum concentration of H2O2 generated by sonocatalysis so far. The significant boosting effect of Pt1 was attributed to the synergetic role of its two-way catalytic processes proved by isotope labeling and DFT calculation. Firstly, Pt1 catalyzed the sono-splitting of H2O to generate •OH as the precursor of H2O2 formation by increasing the adsorption energy of H2O; Secondly, it catalyzed the combination of O2 and •H to selectively generate •OOH as another precursor of H2O2 by one end-on type adsorption of O2 on Pt1. These findings provided a new way to enhance the ultrasonic generation of H2O2.

Ionic Liquid Mediated Triple Catalysis for Alkylation and Methylation of Acyl Chlorides with Mechanistic Insight

Here we report a seminal triple catalysis strategy with the assistance of catalytic ionic liquid. DFT calculations reveal the detailed effect of ionic liquid in this triple catalysis mediated C(sp3)-H functionalizations and a very different mechanism has been established in contrast to all previous dual catalysis research. Based on it, direct coupling between acyl chlorides and very strong or polar C(sp3)-H bonds has been realized in high yields as well as unexpected methylation of acyl chlorides first using just 1.2 equivalent tetramethylsilane as methyl source via successive C(sp3)-H and C(sp3)-Si cleavage. One pot methylation strategy has been developed in this research. This is the first report of that ionic liquid is used for very strong C(sp3)-H bonds functionalization and the first report of that tetramethylsilane is used as methyl source.

Ionic liquid-assisted synthesis of cobalt‑iron difluoride electrocatalysts for oxygen evolution reaction

Surface reconstruction is a promising approach to obtain highly efficient electrocatalysts for oxygen evolution reaction (OER), which is vital for many renewable energy conversion and storage processes. Herein, we synthesized CoFe based difluoride by a simple solvothermal treatment process with the assistance of an ionic liquid ([Bmim]BF4). The final sample originated from Co0.67Fe0.33F2 demonstrated the highest electrocatalytic activity, generating a current density of 10 mA/cm2 at an overpotential of 270 mV. The appropriate amount of iron dopant can increase the number of active sites. Besides, the in-situ leaching of fluorine accompanied with OER was found to generate metal oxyhydroxide layer with abundant oxygen vacancies, thus leading to the high performance of the electrocatalysts.

Melamine-imprinted electrochemical sensor of graphene/ionic liquid composites and its use for the detection of melamine in dairy products

• Melamine-imprinted electrochemical sensor • Molecularly imprinted polymer • Dairy products supervision • Graphene/ionic liquid compound modification By exchanging the conventional role of functional monomer and template molecules, we develop a new molecularly imprinted nanospheres with grape grain structures based on multi-hydrogen bonding interactions between melamine and 6-aminouracil. Molecular imprinting-electrochemical sensor was established with the assistance of graphene and ionic liquids. The content of melamine in dairy products was detected by the molecular imprinting-electrochemical sensor. The detection limit was determined to be as low as 1.57 × 10 −3 mg kg -1 .

Ionic liquids assisted preparation of BiPO4 photocatalyst with enhanced photocatalytic activity for tetracycline and rhodamine B removal

ABSTRACT In this work, BiPO4 (BPO)-based photocatalyst was successfully synthesized by a conventional hydrothermal strategy using bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) and 1-ethyl-3-methylimidazolium dihydro phosphate ([EMIm]H2PO4). [EMIm]H2PO4 can serve as a phosphorus source and surfactant. Photocatalytic activities of the photocatalysts prepared were evaluated by the destruction of rhodamine B (RhB) and tetracycline (TC) under UV light irradiation, respectively. The results reveal that the sample (IL-BPO) synthesized with the assistance of ionic liquid exhibits enhanced photocatalytic activity in comparison with the reference BiPO4. The significantly improved photocatalytic activity of IL-BPO can be mainly attributed to the boosted separation of photoinduced electron-hole pairs (e−/h+) and richer oxygen vacancies (OVs).

Cooperative modification of PVDF electroactive films due to the exfoliated and oriented Na+‐MMT with assistance of different cationic chain length ionic liquids

AbstractPoly(vinylidene fluoride) (PVDF) based nano dielectric composites have been investigated widely due to their potential application in sensors, actuators, and energy storage fields. To achieve these goals, a novel modification of PVDF electroactive films was prepared due to the exfoliated and oriented Na+‐MMT with the assistance of different cationic chain length imidazole‐based ionic liquids. The results proved the ion exchange between Na+‐MMT and ILs promoted exfoliation and uniform dispersion of Na+‐MMT in PVDF matrix efficiently even under a low ILs content (<0.05%). Furthermore, the existence of ILs and shearing force contributed to the oriented dispersion of Na+‐MMT. The synergistic effect of Na+‐MMT and ILs induced the crystal conformation transition from non‐polar α‐crystal to electroactive β/γ crystal. The ILs with longer cationic chains behaved much higher inducibility for PVDF electroactive phases. Compared with pure PVDF, PVDF/Na+‐MMT/ILs nanocomposites with longer cationic chain ILs showed higher dielectric constant, breakdown strength, and energy density, while kept low‐dielectric loss and conductivity. The improved compatibility between PVDF and Na+‐MMT due to the ion exchange and decreased crystal size for the polar β/γ crystal enhanced the transparency and elongation at break of PVDF/Na+‐MMT/ILs nanocomposites significantly. The results proved [C16MIM][Cl] behaved optimum synergistic modification effect for the nanocomposites, and which showed potential applications in dielectric energy storage and microelectronic fields.

Enhancing the catalytic activity of MnO2 via structural phase transition for propane combustion: Promotional role of ionic liquid

A series of manganese dioxide have been synthesized by ionic liquid assisted hydrothermal method and used for propane combustion. 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM-BF4] was selected as the structure-directing agent, which could generate extended hydrogen bonds under hydrothermal conditions. These hydrogen bonds could be used for entropy driving of nanostructures self-assembly, thus regulating the growth of crystal. Meanwhile, the existence of [BMIM-BF4] could interact with [MnO6] octahedron in MnO2 through electrostatic and π-π stacking interactions, eventually leading to the transformation from α-MnO2 to β-MnO2 after calcination. A series of characterization results further indicated that with the assistance of ionic liquid, the morphology of the precursor evolved from nanoflowers to nanorods attached with nanofibers, and the specific surface areas and redox properties were also enhanced. When the molar ratio of KMnO4 to ionic liquid reached 8:1, the obtained Mn-1–500 exhibited the highest catalytic activity for propane combustion. The T90 of propane on Mn-1–500 was about 310 °C, which was nearly 110 °C lower than that of Mn-0–500 prepared without the assistance of ionic liquid. These results could offer a novel strategy for the development of high-performance catalysts.

Multicomponent Pt/PtTe2/NiCoTe2 embedded in ternary heteroatoms-doped carbon for efficient and pH-universal hydrogen evolution reaction

Herein, we report a synthesis of multicomponent Pt/PtTe2/NiCoTe2 and N, P, F ternary doped carbon composites showing a morphology of folded hollow microspheres (Pt/PtTe2/NiCoTe2/NPFC HFSs) by a facile hydrothermal method with the assistance of ionic liquid. Pt, PtTe2, and NiCoTe2 produced by one step of tellurization process were encapsulated in carbon, which protected Pt/PtTe2/NiCoTe2 from corrosion in acidic and alkaline conditions. The synergistic effects of Pt/PtTe2/NiCoTe2 can improve the HER performance. With the addition of ionic liquid, abundant folds and N, P, F ternary doped carbon were obtained, leading to increased specific surface area, faster electron transfer, as well as more active sites. Thanks to these advantages, Pt/PtTe2/NiCoTe2/NPFC HFSs show excellent performance in HER (when the current density achieved 10 mA cm−2, the overpotentials were respectively 34, 43, and 36 mV in acidic (0.5 M H2SO4), alkaline (1 M KOH), and neutral (1.0 M PBS) solutions. This study offers a simple strategy for modifying the morphology and element doping to enhance electrochemical performance.

Ionic Liquids‐Assisted Highly Luminescent Copper Nanoclusters with Triangle Supramolecular Nanostructures

Main observation and conclusionA novel and facile approach towards highly luminescent CuNCs@MMI (2‐mercapto‐1‐methylimidazole) has been developed within 30 s with the assistance of ionic liquids (ILs)—[Bmim]BF4. FT‐IR spectra, Zeta potential, TEM and SEM images showed that the as‐prepared CuNCs@MMI within [Bmim]BF4 could assemble into well‐ordered triangle supramolecular nanostructures via electrostatic interaction. In addition, pH‐responsion of CuNCs@MMI in photoluminescence intensity indicated the great potential for pH sensing applications.

Ionic liquid-assisted synthesis of porous boron-doped graphitic carbon nitride for photocatalytic hydrogen production

This work presents a simple way to prepare boron-doped graphitic carbon nitride (B/g-C3N4), exhibiting an enhanced photocatalytic performance to split water for hydrogen production. B/g-C3N4 was synthesized via the pyrolysis of urea and 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF4), which was adopted as the boron source. The aggregate of B/g-C3N4 nanosheets shows a porous structure since some bubbles are generated under the heat decomposition of ionic liquids. The porous structure is conducive to the exposure of more active sites. Moreover, B-doping will form some localized electronic energy levels in the band gap of g-C3N4, thereby extending its visible light response. As impacted by the porous structure of B/g-C3N4 aggregate and the narrow the band gap, the photocatalytic hydrogen generation rate (901 μmol h−1 g−1) is increased, almost 3 times faster than g-C3N4 (309 μmol h−1 g−1). This work proposed a simple method to prepare the aggregate of B/g-C3N4 nanosheets exhibiting pores under ionic liquid assistance. It can be a novel method to design porous polymer photocatalysts.

Metal-free and mild photo-thermal synergism in ionic liquids for lignin Cα–Cβ bond cleavage to provide aldehydes

Photo-thermal synergism of UV light and heating could excite lignin molecules and induce direct cleavage of the Cα–Cβ bond in lignin β-O-4 and β-1 interlinkages under metal-free and mild conditions with the assistance of ionic liquids.