Ionic Liquid Precursor Research Articles

Water oxidation coupled singlet oxygen electrochemiluminescence at C4N3 nanosheets/TiO2 nanotubes/Ti electrodes and its sensing application

Singlet oxygen (1O2) electrochemiluminescence (ECL) induced by water oxidation might intrigue new kinds of ECL-based sensors to be developed, but remains nascent due to its difficulty to be achieved. Herein, we report a water oxidation coupled ECL emission from dimeric aggregates of 1O2 at C4N3 nanosheets (NSs)/TiO2 nanotubes (NTs)/Ti electrodes (C4N3/TiO2/Ti) in the presence of triethanolamine (TEOA) as the co-reactant. The half-metallic C4N3 NSs were introduced to TiO2 NTs/Ti electrodes via in-situ thermal polymorization of ionic liquid precursor, which endows the TiO2 NTs with more oxygen vacancies and faster charge transfer ability as well as provides more sites for oxygen enriching, leading to an ECL intensity being 5.5 folds that at the TiO2 NTs/Ti electrodes. Besides, the tubelike shape of TiO2 makes it easier for the generated 1O2 to react each other to form dimeric aggregates, resulting in a typical ECL emission peak at ∼ 642 nm. Using the 1O2 ECL to detect dopamine (DA) as a model target, a wide linear range from 20 pM to 400 nM is obtained with detection limit of 7.6 pM (S/N = 3). This work offers a deep insight into water oxidation coupled 1O2 ECL and also accelerates its biosensing applications.

Structural and magnetic properties of nitrogen-doped carbon materials derived from an ionic liquid precursor

In this report, effects of pyrolysis conditions on the structure and magnetic properties of nitrogen-doped graphitic carbon materials prepared from 1-Buthyl-3-methyl imidazolium tricyano methanide ( [BMIm] [TCM]) ionic liquids(ILs) were investigated. It was found that nitrogen-containing graphitic carbon was formed under pyrolysis temperature of 400 °C or higher. Under the experimental conditions, the maximum nitrogen content of the obtained sample was C4N1.10 at a pyrolysis temperature of 400 °C and it was found that the nitrogen content in the obtained samples decreased with increasing pyrolysis temperature. Ferromagnetism was not observed in all the obtained samples to 2 K. From the value of the orbital diamagnetic susceptibility and XRD, it was found that the obtained sample had the structural characteristics of soft carbon.

Microwave-assisted fast preparation of functionalized carbon dots: The impact of ionic liquid precursor on corrosion inhibition

In this study, functionalized carbon dots were synthesized in one step from L-histidine and imidazolyl ionic liquids using an ionic liquid-assisted microwave method as green corrosion inhibitors for steel in a 1 M HCl solution. Different ionic liquid anions (CF3COO- and HSO4-) were introduced in the preparation of the carbon dots, and their microstructures and surface properties were characterized. Notably, the corrosion inhibition efficiency of the prepared CDs (assisted by CF3COO-) reached 94.2% at 5 mg‧dm−3. The corrosion inhibition behavior of CDs on mild steel in 1 M HCl was investigated through DFT calculations. Our investigation revealed that the anions of the selected ionic liquids have a certain influence on the structure of the carbon dots, which correlates with the performance of the carbon dot corrosion inhibitor. Therefore, this study provides guidance for the preparation of functionalized carbon dot corrosion inhibitors using a one-step microwave method and the selection of ionic liquids (as solvents, modifiers, and mediums for microwave conversion).

Utilizing Carbonaceous Materials Derived from [BMIM][TCM] Ionic Liquid Precursor: Dual Role as Catalysts for Oxygen Reduction Reaction and Adsorbents for Aromatics and CO2.

This work presents the synthesis of N-doped nanoporous carbon materials using the Ionic Liquid (IL) 1-butyl-3-methylimidazolium tricyanomethanide [BMIM][TCM] as a fluidic carbon precursor, employing two carbonization pathways: templated precursor and pyrolysis/activation. Operando monitoring of mass loss during pyrolytic and activation treatments provides insights into chemical processes, including IL decomposition, polycondensation reactions and pore formation. Comparatively low mass reduction rates were observed at all stages. Heat treatments indicated stable pore size and increasing volume/surface area over time. The resulting N-doped carbon structures were evaluated as electrocatalysts for the oxygen reduction reaction (ORR) and adsorbents for gases and organic vapors. Materials from the templated precursor pathway exhibited high electrocatalytic performance in ORR, analyzed using Rotating Ring-Disk electrode (RRDE). Enhanced adsorption of m-xylene was attributed to wide micropores, while satisfactory CO2 adsorption efficiency was linked to specific morphological features and a relatively high content of N-sites within the C-networks. This research contributes valuable insights into the synthesis and applications of N-doped nanoporous carbon materials, highlighting their potential in electrocatalysis and adsorption processes.

P-n heterogeneous Sb2S3/SnO2 quantum dot anchored reduced graphene oxide nanosheets for high-performance lithium-ion batteries.

Antimony sulfide (Sb2S3) has a high theoretical specific capacity due to its two reaction mechanisms of conversion and alloying during the Li+-(de)intercalation process, thus becoming a promising lithium-ion battery (LIB) anode material. However, its poor inherent conductivity and large volume expansion during repeated Li+-(de)intercalation processes greatly hinder the in-depth development of Sb2S3 based LIB anode materials. Herein, an Sb2S3/SnO2@rGO composite was prepared by using an interface engineering technique involving metal-containing ionic liquid precursors, in which Sb2S3/SnO2 quantum dots (QDs) as p-n heterojunctions are uniformly anchored on the surface of reduced graphene oxide (rGO). The p-n heterogeneous interface between Sb2S3 and SnO2 QDs induces an internal electric field, promoting the electronic/ion transport during electrochemical reactions, and the QD-sized Sb2S3/SnO2 heterostructure with a larger surface area provides more active sites for Li+-(de)intercalation reactions. In addition, the rGO matrix acts as a buffer to prevent the aggregation of active Sb2S3 and SnO2 QDs, alleviate the volume expansion, and enhance the conductivity of the composite during repeated cycles. These advantages endow the designed Sb2S3/SnO2@rGO electrode with excellent reaction kinetics and good long cycling stability. As an anode material of LIBs, it can still provide a reversible specific capacity of 474 mA h g-1 after 2000 cycles at a high current density of 3.0 A g-1, which is superior to those of most of the previously reported Sb2S3-based carbon materials. The p-n heterostructure construction strategy of nano-metal sulfide/metal oxides in this work can provide inspiration for the design and synthesis of other advanced energy storage materials.

(Invited) Plasma-Synthesized Coupled Nanoplasmonic Gold for DNA Sersing

The facilitated electrochemical properties of plasma play a critical role in enhancing the synthesis and design of functional nanomaterials for the development of novel sensors. The targeted challenge is to customize and tailor functionality at multiple scales to improve detection device performance. In the realm of optoelectronics, plasmonic sensing is considered an efficient tool for investigating molecular properties, often accompanied by Raman, FTIR or Fluorescent spectroscopy. Specifically, Raman scattering, also known as SERS (surface-enhanced Raman scattering), is commonly used to probe analytes at a reduced scale using plasmonic enhancers. This technique is especially useful for rapidly and accurately investigating biologically relevant samples, such as DNA and RNA. DNA/RNA-related investigations are crucial in modern nanomedicine due to the progress made in bionanotechnology, DNA vaccines, and functional gene engineering. DNA, in particular, is highly valued by microbiologists because it contains information about the nature of bio-species. Currently, PCR-related methods dominate the field for molecular-sensitive DNA-level studies, but it is challenging to investigate using optical techniques like SERS. Despite its promise, SERS still requires technological and analytical improvements. A sophisticated plasmonic nanomaterial provides considerably improved photon scattering due to the strongly localized field confinement effect, resulting in better performance. In this report, a nanoplasmonic sensor was designed using a plasma-driven electrochemical reduction mechanism, achieved through an atmospheric pressure He-plasma jet setup operating at kHz frequency. The reactive oxidative species donated electrons via liquid-gas electrochemistry towards the Ar-delivered Au(3+)-containing microdroplets, resulting in microscaled aggregates composed of AuNPs obtained from the nebulized ionic gold liquid precursor. Due to the strong coupling between nanoparticles, a high analytical enhancement factor of about 107 was achieved, and the substrate enabled obtaining Raman fingerprints of bacterial DNA fragments (M. luteus and S. aureus, E. coli, J. lividum) at nanovolume sample quantities. Additionally, the main DNA molecular vibrational signatures associated with nucleobase motions were extracted from the collected spectra and used to reliably classify bacterial strains using statistical principal component analysis.[1] References[1] Shvalya, V., Vasudevan, A., Modic, M., Abutoama, M., Skubic, C., Nadižar, N., ... & Cvelbar, U. (2022). Bacterial DNA Recognition by SERS Active Plasma-Coupled Nanogold. Nano Letters.

Plasma-Made Nanogold for DNA Sensing with SERS

Facilitated electrochemical properties of plasma are crucial for improving functional nanomaterials synthesis and design for novel sensor development. Controlled customization and functionality tailoring at multiscale is the targeted challenge for better detection devices performance. In the modern era of optoelectronics, among various probing approaches, plasmonic sensing accompanied by Raman, FTIR or Fluorescent spectroscopy is considered a tool for the efficient investigation of molecular properties. In particular, Raman scattering is often called SERS (surface-enhanced Raman scattering) due to plasmonic enhancers, which are used to improve the probing of analytes at a reduced scale. This feature is extremely useful for biologically relevant analytical tasks when samples alike DNA and similar need to be investigated fast and accurately. DNA/RNA-related investigations are highly important in modern nanomedicine due to the solid progress of bionanotechnology, DNA vaccines, and functional gene engineering. DNA is the most valued substance for microbiologists because it contains information about bio-species' nature.[1] Currently, the number of molecular-sensitive methods for DNA-level study is quite limited, among which PCR (polymer chain reaction) related methods dominate the field. However, it is challenging to investigate it with optical techniques like SERS. Despite being promising, SERS is still under technological and analytical improvement. Better performance comes with sophisticated plasmonic nanomaterials, which provide considerably improved photon scattering due to the strongly localized field confinement effect.[2] In the current report, a well-performing nanoplasmonic sensor was designed using a plasma-driven electrochemical reduction mechanism. Exploiting atmospheric pressure He-plasma jet setup operating kHz frequency, the reactive oxidative species donated electrons via liquid-gas electrochemistry towards the Ar-delivered Au(3+)-containing microdroplets. Through this method, microscaled aggregates composed of AuNPs were obtained from the nebulized ionic gold liquid precursor. Due to the strong coupling between nanoparticles, a high analytical enhancement factor of about 107 was achieved and the substrate allowed to obtain Raman fingerprints of bacterial DNA fragments (M. luteus and S. aureus, E. coli, J. lividum) at nanovolume sample quantities. In addition, main DNA molecular vibrational signatures associated with nucleobase motions were extracted from spectra collected and used to classify the bacterial strains reliably by employing statistical principal component analysis.

Construction of hierarchical ZnS/SnO2 @rGO heterostructures as high-performance anode materials for lithium-ion batteries by mixed-precursors strategy

The rational design and construction of hierarchical heterogeneous nanostructures is effective for improving the electrical and ionic conductivity of anode material for lithium-ion batteries (LIBs). Herein, a hierarchical ZnS/SnO2 @rGO (rGO = reduced graphene oxide) composite has been designed and successfully synthesized via hydrothermal method by using metal-containing ionic liquid and ZIF-8 metal organic framework precursors. The synergistic effect of precursors hinders the agglomeration of nanoparticles, which makes SnO2 quantum dots (QDs) be anchored on the surface of polyhedral ZnS and further be uniformly dispersed on the rGO. The outer rGO matrix can improve the electrical conductivity and fully alleviate the volume expansion of ZnS/SnO2 during the cycling. Meanwhile, the ZnS/SnO2 heterostructure can endow the material with excellent reaction kinetics, accelerating the charge transfer and providing more active sites for electrochemical reactions. Benefiting from the compositional and structural features, the as-prepared ZnS/SnO2 @rGO as LIB anode provides the reversible specific capacity of 1030 and 630 mA h g−1 after 1150 cycles at the current density of 1.0 and 3.0 A g−1, respectively. This mixed-precursors strategy represents a novel and effective technique to in situ synthesize hierarchical metal sulfide/metal oxide/carbon anode materials for developing high-performance battery.

Low‐Coordinated Single‐Atom Catalysts Modulated by Metal Ionic Liquids for Efficient CO2 Electroreduction

AbstractModulating the coordination environment of single‐atom catalysts (SACs) is an attractive approach for maximizing the catalytic activity of single‐atom centers. Currently, the synthesis of low‐coordinated SACs is mainly confined to increasing the pyrolysis temperature (≥900 °C) to control C─N volatile fragments. Herein, a novel and universal strategy for the low‐coordinated SACs modulation is presented using transition metal (e.g., Ni, Co, Zn) ionic liquid precursors under relatively mild temperature of 600 °C, which regulates the L‐shell electronic structure and decreases nearly 50% electrophilic reactivity by ionization of 4‐position N atom, thereby orienting synthesis of the SACs with metal‐N3 centers. The Ni‐N3 SACs exhibit exceptional CO2 electroreduction performance of 99.7% CO Faraday efficiency with an ultra‐high CO partial current density of 467.55 mA·cm−2 as well as a CO production rate up to 10417.51 µmol·h−1·cm−2 in flow cell. The superior catalytic activity achieves over twofold increase compared with the Ni‐N4 SACs prepared by non‐metal ionic liquid precursors due to the lower free energy of the key intermediate *COOH and the stronger adsorption energy.

A Hexafluorophosphate‐Based Ionic Liquid as Multifunctional Interfacial Layer between High Voltage Positive Electrode and Solid‐State Electrolyte for Sodium Secondary Batteries

AbstractSodium secondary batteries have gained accolades as future energy storage devices due to their low costs and environmental benignity, but are heavily impeded by the poor anodic stabilities of most electrolytes, including solid‐state electrolytes (SSE), that render them incompatible with high‐voltage positive materials. This study reports, for the first time, a new synthesis technique using a fluorohydrogenate ionic liquid (IL)precursor to prepare a [DEME][PF6] ([DEME]+: N,N‐diethyl‐N‐methyl‐N‐(2‐methoxyethyl) ammonium) with high yield and high purity. Herein, a Na[PF6]‐[DEME][PF6] IL is formulated and subjected to a series of electrochemical tests to validate its performance in battery applications. The present IL harbors a strong oxidative stability (up to 5.2 V on Pt and >4.5 V on conductive carbon electrodes) that aids in the suppression of oxidative decompositions of one typical SSE, for example, beta alumina solid electrolyte (BASE), thereby extending their electrochemical window in hybrid SSE systems. A hybrid solid‐state Na secondary battery employing a high voltage positive electrode, Na3V2(PO4)2F3, is assembled using the BASE/IL configuration, and features energy density and superior cycling performance. This work demonstrates that sandwiching an SSE between the oxidatively stable [PF6]− IL can be an effective design for high voltage operation Na secondary batteries.

Influence of ionic liquid and oleic acid assisted methods on the spectroscopic properties of Nd3+-doped GdPO4 nano-particles

TEM analysis revealed the most homogenous nano-material obtained via an ionic liquid microwave-assisted method. The energy level diagram for Nd3+ ions in GdPO4 was proposed for high-quality materials obtained from the ionic liquid precursor.

Surface modification of magnetic nanoparticles by bacteriophages and ionic liquids precursors.

Magnetic nanoparticles (MNPs) have recently been a point of interest for many researchers due to their properties. However, the studies on the influence of bacteriophages on the synthesis of MNPs seem to be lacking. Furthermore, bacteriophage-modified MNPs have not been combined with n-alkyl quaternary ammonium ionic liquid precursors (QAS). In this study, the aim was to assess the influence of two distinctly different bacteriophages (Escherichia phage P1 and Pseudomonas phage Φ6) on MNPs synthesis in the presence or absence of QAS. Synthesized MNPs have been characterized with X-ray diffraction (XRD) and Mössbauer spectroscopy in terms of changes in the crystallographic structure; scanning electron microscopy (SEM) for changes in the morphology; and ζ-potential. Moreover, the sorption parameters and the loss of viability of bacteria that interacted with MNPs have been determined. The sorption of bacteria differs significantly among the tested samples. Furthermore, the viability of the bacteria adsorbed on MNPs varies in the presence of QAS, depending on the length of the n-alkyl chain. The study has revealed that MNPs can be bound with bacteriophages. Mössbauer spectroscopy has also revealed the probable influence of bacteriophages on the formation of crystals. However, these phenomena require further studies.

Vapor-Phase Loading of an Ionic Liquid into a Zeolitic Imidazolate Framework.

Composites formed by a metal-organic framework (MOF) and an ionic liquid (IL) are potentially interesting materials for applications ranging from gas separation to electrochemical devices. Consequently, there is a need for robust and low-cost preparation procedures that are compatible with the desired applications. We herein report a solvent-free, one-step, and vapor-based ship-in-bottle synthesis of the IL@MOF composite 1-butyl-3-methylimidazolium bromide@ZIF-8 in powder and thin film forms. In this approach, volatile IL precursors evaporate and subsequently adsorb and react within the MOF cages to form the IL.

Immobilization of Ionic Liquid on a Covalent Organic Framework for Effectively Catalyzing Cycloaddition of CO2 to Epoxides.

Transforming CO2 into value-added chemicals has been an important subject in recent years. The development of a novel heterogeneous catalyst for highly effective CO2 conversion still remains a great challenge. As an emerging class of porous organic polymers, covalent organic frameworks (COFs) have exhibited superior potential as catalysts for various chemical reactions, due to their unique structure and properties. In this study, a layered two-dimensional (2D) COF, IM4F-Py-COF, was prepared through a three-component condensation reaction. Benzimidazole moiety, as an ionic liquid precursor, was integrated onto the skeleton of the COF using a benzimidazole-containing building unit. Ionization of the benzimidazole framework was then achieved through quaternization with 1-bromobutane to produce an ionic liquid-immobilized COF, i.e., BMIM4F-Py-COF. The resulting ionic COF shows excellent catalytic activity in promoting the chemical fixation of CO2 via reaction with epoxides under solvent-free and co-catalyst-free conditions. High porosity, the one-dimensional (1D) open-channel structure of the COF and the high catalytic activity of ionic liquid may contribute to the excellent catalytic performance. Moreover, the COF catalyst could be reused at least five times without significant loss of its catalytic activity.

Modulated synthesis of N-doped porous carbons via rational design of the poly(ionic liquid) precursors towards efficient CO2 separation

A ternary copolymerized poly(ionic liquid) of bis-imidazolium-based ionic liquid and crosslinking agents (divinylbenzene (DVB), N, N′-methylene bisacrylamide (MBA)) was rationally designed as versatile precursor to synthesize nitrogen-doped porous carbons by self-templating method for efficient CO2 separation. The ionic liquid monomer and MBA could serve as nitrogen sources to enhance the surface polarity through in-situ doping, while the self-decomposed functional groups (especially -CONH-) along with halogen anions could promote the formation of pores during carbonization. By adjusting the molar ratio of ionic liquid to DVB and MBA, carbonization temperature and activator dosage (KOH), the obtained CVDM0.5-700 (0.5:1:1, 700 °C, 2 mol/L) owned a considerable specific surface area (1835 m2/g), plentiful (ultra)micropores and moderate nitrogen content (3.05 wt%). The strong van der Waals force arising from ultra-micropores (d<0.7 nm) within a narrow distribution improved the ability to capture CO2 and the abundant CO2-philic N species further strengthened the binding interactions. Consequently, CVDM0.5-700 was endowed with satisfactory CO2 uptake capacity (4.11 mmol/g), desirable CO2/N2 (15%/85%) adsorption selectivity (23.6) and excellent cyclic stability at 25 °C and normal pressure. This work provided a new pathway for the modulated fabrication of heteroatoms-doped porous carbon materials by precise design of poly(ionic liquid)-based precursors for appealing applications.

Eco‐Friendly and Particle‐Free Copper Ionic Aqueous Precursor for In Situ Low Temperature Photothermal Synthesizing and Patterning of Highly Conductive Copper Microstructures on Flexible Substrate

Liquid precursor‐based laser‐induced reductive patterning techniques enable fast and economical fabrication of flexible electronics. Herein, an eco‐friendly and particle‐free copper ionic solution for laser‐induced reductive patterning of copper microlines on a low glass transition temperature and transparent flexible substrate is successfully developed. The solvent used is water and the reducing agent is l‐ascorbic acid. A continuous wave 640 nm laser is used as the heat source to initiate the reductive reaction and to deposit copper microlines on the substrate surface. The resistivity of the copper microlines fabricated with optimized laser parameters is remarkably low at 4.7 μΩ cm. To further improve the electrical conductivity and to enhance mechanical durability, the fabricated microlines are annealed using the same laser after the copper ionic liquid precursor is removed. The microstructures and mechanical robustness of the copper microlines, as well as the adhesion between the copper microlines and the substrate, are investigated by cyclic bending test, pull‐off test and scanning electron microscope analyses. Up to 39% reduction of electrical resistance and up to 77% enhancement of mechanical durability after a 1000 cycle bending test can be achieved by laser postprocessing.

Elechtrochemical Analysis of Metallated Ionic Liquids for Mixed Metal Sulfide Synthesis

Driven by the ongoing transition from non-renewable to renewable energy sources, organic and hybrid solar cells have been studied due to their cost-efficiency and the smaller environmental impact. The goal of the current work is the establishment of ionic liquid precursors (ILPs) for the synthesis of complex metal chalcogenides. These can then be used in different applications including being part of the active layers of organic photovoltaic systems. The major difference to more conventional approaches is that the ILP not only acts as a metal source but also as a morphology directing template and as a stabilizer for the resulting nanoparticles.1,2 The basic idea is to use metal-containing ionic liquids, where the metal is an integral part of the IL anion as the metal source and to generate mixed metal chalcogenides directly from these single source precursors.3,4 In the current proof-of-concept study, thirteen N-butylpyridinium salts, including monometallic compounds [C4Py]2[MX4], bimetallic compounds [C4Py]2[M1-y aMy bX4] and trimetallic compounds [C4Py]2[M1-y-z aMy bMz cR4] (M = Co, Cu, Mn, Ni, Zn; y/z = 0.25, 0.33, 0.50 or 0.75; and X = Br,Cl), were synthesized and their structure and thermal and electrochemical properties were analysed. All compounds are ILs with melting points between 55 and 100 °C, Figure 1. The possibility of the direct use of these ILs in electrochemical devices was further analysed. The electronic conductivity at room temperature is between 10-4 and 10-8 S cm-1. This correlates with the optical band-gap measurements indicating rather poor semiconductors with large band gaps. However, at elevated temperature approaching the melting points, the conductivities reach up to 1.47 ∙ 10-1 S/cm at 70 ºC. Therefore future electrochemical applications are possible, especially in a moisture-sensitive environment at room temperature. Furthermore, cyclic voltammetry shows promising electrochemical stability windows between 2.5 and 3.0 V.5 A further advantage of these ILPs is the fact that their properties, such as band gaps can directly be adjusted by proper choice of the metals in the ILs. Current research includes the expansion of possible ILPs by incorporating metals like zinc and nickel, and even lanthanides, such as samarium, terbium and europium. Through a reaction of these metal-containing ILs with a sulphur source the respective metal chalcogenide (MC) nanoparticles will form.1 Current research focusses on investigating the influence of different sulfur sources. The p-type semiconductor nanoparticles will then be used as a hole transport material in the bulk heterojunction to improve the charge transport as well as providing a broad optical absorption window.1 Y. Kim, B. Heyne, A. Abouserie, C. Pries, C. Ippen, C. Günter, A. Taubert and A. Wedel, J. Chem. Phys., , DOI:10.1063/1.4991622.2 A. Abouserie, G. El-Nagar, B. Heyne, R. Sarhan, Y. Kim, C. Pries, E. Ribacki and C. Günter, Hierarchically structured Copper Sulfide Microflowers with Excellent Amperometric Hydrogen Peroxide Detection Performance, 2019.3 K. Thiel, T. Klamroth, P. Strauch and A. Taubert, Phys. Chem. Chem. Phys., 2011, 13, 13537.4 A. Abouserie, K. Zehbe, P. Metzner, A. Kelling, C. Günter, U. Schilde, P. Strauch, T. Körzdörfer and A. Taubert, Eur. J. Inorg. Chem., 2017, 5640–5649.5 C. Balischewski, K. Behrens, K. Zehbe, C. Guenter, S. Mies, E. Sperlich, A. Taubert and A. Kelling, Chem. – A Eur. J., , DOI:10.1002/chem.202003097.

Dissolution Behavior of Hydrated Tungsten Chlorides in Chloroaluminate Ionic Liquids and It's Application in Aluminum–Tungsten Alloy Electrodeposition

Introduction The demand for aluminum (Al) alloys as coating materials have increased owing to their high corrosion and oxidation resistance. In addition, electrodeposition technique has attracted attention for obtaining Al alloy coatings, and various non-aqueous electrolytic baths for Al alloy electrodeposition, including ionic liquids, have been developed. Alloying Al with refractory metals, such as tungsten (W) and molybdenum (Mo), significantly improves the pitting-corrosion resistance of Al. However, the salts of these metals have relatively low solubility in Al electrodeposition baths, and thus, it is difficult to obtain Al alloys with a high content of these metals.In our previous study, we reported that a W(II) salt, namely W6Cl12, which is dissolved in 1-ethyl-3-methylimidazolium (EMIC)–AlCl3 ionic liquids at a higher concentration than other salts such as WCl4, enables the electrodeposition of Al–W alloy films with a high W content[1]. However, the W6Cl12 used previously turned out to contain water due to the synthesis process, which may have increased the solubility of W6Cl12.In this study, we investigated the effect of water content on the solubility of W precursors in ionic liquids. Herein, three W precursors with different water contents were employed, namely anhydrous W6Cl12 and hydrated complexes W6Cl12·2H2O and (H3O)2[W6Cl14]·7H2O (Figure 1). Al–W alloy was electrodeposited using baths containing different W precursors. In addition, the chemical speciation of the hydrated complexes in the ionic liquids was conducted using, Raman, and Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Vis) spectroscopy. Experimental Herein, three electrolytic baths were prepared by adding anhydrous salt W6Cl12, hydrated complex W6Cl12·2H2O, and (H3O)2[W6Cl14]·7H2O to an EMIC–AlCl3 ionic liquid with EMIC:AlCl3 molar ratio of 1:2. The saturation concentrations of W precursors were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Potentiostatic electrodeposition was performed on copper substrates at a bath temperature of 80 °C under an Ar atmosphere in a glove box. The W content, current efficiency, and impurity content derived from the hydration water in the electrodeposited material were evaluated by energy dispersive X-ray spectroscopy (EDX), ICP-AES, and X-ray photoelectron spectroscopy (XPS), respectively. The dissolved species in the baths were analyzed by Raman, FT-IR, and UV-Vis spectroscopy. Results and Discussion The saturation concentration of each W ion source in the EMIC–AlCl3 ionic liquid was less than 1 mM for anhydrous W6Cl12; however, it increased to ~80 and 120 mM for W6Cl12·2H2O and (H3O)2[W6Cl14]·7H2O, respectively. Potentiostatic electrodeposition at potentials lower than 0 V (vs. Al/Al(III)) produced films consisting of Al and W. The W content increased to ~1 and 15 at.% from the anhydrous salt bath and hydrated complex bath, respectively. The current efficiency for electrodeposition was close to 100%, even in baths with hydrated precursors. EDX and XPS measurements of Al–15 at.% W alloy film obtained from the hydrated complex bath showed that Al and W existed in metallic states in the film.The Raman spectra of each bath showed that the Al2Cl7 − concentration decreased and AlCl4 − concentration increased in the hydrated complex bath compared to the anhydrous salt bath. This suggests that the hydrated W complex reacted with AlCl3 to form other Al species, thereby decreasing the apparent AlCl3/EMIC ratio in the bath. The FT-IR spectra of baths with the addition of hydrated complex or liquid water showed that both the hydrated water and liquid water reacted with Al anions to produce Al–OH–Cl species[2]. The UV-Vis spectra of the anhydrous salt bath and hydrated complex baths showed two prominent peaks: one at 240 nm (λ1) and the other at ~270–300 nm (λ2). λ1 was almost constant for all the W precursors, whereas λ2 shifted to a lower wavelength for the hydrated complex baths. The dissolved W species estimated from these spectroscopic data and their relationship with solubility are discussed at the meeting.

Nitrogen doping carbon deriving from ionic liquid anchoring Ru coated on P-zeolite as high activity and stability catalyst for the catalytic wet air oxidation of highly concentrated ammonia

The treatment of the highly concentrated ammonia–nitrogen wastewater major produced in the coal chemical industry is a challenging problem. Herein, a novel catalyst with high activity and hydrothermal stability was designed for the catalytic wet air oxidation (CWAO) of the highly concentrated ammonia. In the designed catalytic system, P-zeolite was treated with sodium hydroxide to form defects for enhancing the adsorption of active metals. And the ionic liquid was employed as an N-doped carbon coating on treated P-zeolite to protect the ruthenium nanoparticles from leaching and improve its hydrothermal stability. The simultaneous introduction of ionic liquid and Ru precursor was beneficial to the dispersion of Ru on P-zeolite. The resulting catalyst Ru/P-zeolite(NaOH)@NC overcomes the poor hydrothermal stability of zeolite and exhibits excellent catalytic performance during the CWAO of highly concentrated ammonia. The catalyst of 1%Ru/P-zeolite(NaOH)@NC offers 100% conversion under 2 MPa at 200 °C in 4 h for 2000 ppm ammonia. No substantial deactivation was observed after five cycles. This study provides an effective strategy for the application of N-doped carbon coating on zeolite in CWAO systems.

Reduction-adsorption of chromium(VI) by using IL-imprinted resin -innovative solution for water purification

Novel sorbents (poly(vinylbenzyl chloride-co-divinylbenzene) functionalized with Ionic Liquids precursors- hydrophobic and hydrophilic 3- and 4-pyridineketone and oxime were prepared for application to chromium removal. The fabricated materials were extensively characterized (surface morphology, FT-IR, NMR, Raman, microscopy, XPS, and wettability). The efficiency of functionalization of poly(vinylbenzyl chloride-co-divinylbenzene was demonstrated not only in the process of adsorption of chromium(VI), but also in its reduction to a less toxic form of trivalent ions. I was shown that the efficiencies of both processes depended on the time, pH of the aqueous phase and the initial concentration of Cr(VI). At pH of 0 the cumulative chromium removal was preferable (removal almost 1200 mg of Cr) with the reduction as the dominant process. At pH of 3.5 and higher only adsorption was observed with the maximum capacity of 144.4 mg/g. The conducted analytical techniques, such as Raman and XPS, enabled to determine the mechanism of the sorption and the surface Cr(VI) reduction that oxidize water to O2. The studies indicated that this research direction was forward-looking and fits in with the trends of a sustainable development- simultaneous reduction and adsorption of chromium from wastewater.