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Attapulgite: from clay minerals to functional materials
Abstract
Attapulgite is a kind of natural one-dimensional nanomaterial. Attapulgite has unique nanorod-like crystals, nanochannels and reactive groups on the surface, and has been widely used in many fields including agriculture, chemical engineering, environmental protection, adsorption materials and composites. Recently, the disaggregation of
the crystal bundles of attapulgite into mono-dispersed ones has been achieved, while keeping their environment-friendly property. This has changed attapulgite from clay mineral to a very interesting nanomaterial. With unique nanorods-like crystals and nanochannels, attapulgite can be used to prepare nanocomposites via the crystals and reactive groups on the surface, and also can be used to prepare hybrid materials via the nanochannels. Attapulgite is the new focus for the preparation of diverse functional materials. Thus, it is now pertinent to give an overview of the recent progress in the
field. First, we hope to overview the structure and physicochemical properties of attapulgite. Subsequently, we will review the progress about disaggregation of the attapulgite crystal bundles and regulation of attapulgite structures. We will then focus on the development of attapulgite-based functional materials (e.g., adsorbents, colloidal materials, hybrid materials, polymer/attapulgite composites, bio-inspired materials, catalysts and energy materials) and recycling of attapulgite. In the conclusions, we will summarize the progress of attapulgite-based functional materials, and the challenges in the field. Overall, this review will hopefully promote the development of attapulgite and attapulgite-based functional materials, or even the clay-based ones.
... Palygorskite (Pal) is a magnesium (Mg)-Al silicate-based clay mineral commonly found in soils and sediments of arid and semiarid regions (Singer 1989;Murray et al. 2011). Pal is mainly distributed in several countries including China, USA, Spain and France ( Wang et al. 2018). China holds over 50% of the world's Pal reserves, mainly distributed in Xuyi County of Jiangsu Province, Mingguang City of Anhui Province and Linze County of Gansu Province ( Wang et al. 2018). ...
... Pal is mainly distributed in several countries including China, USA, Spain and France ( Wang et al. 2018). China holds over 50% of the world's Pal reserves, mainly distributed in Xuyi County of Jiangsu Province, Mingguang City of Anhui Province and Linze County of Gansu Province ( Wang et al. 2018). In Xuyi County and Mingguang City, Pal content is more than 80% relative to total clay content and is highly suitable as a raw material for industrial processes. ...
Mineral composition and alkaline properties of palygorskite (Pal), and its ameliorative effects on chemical properties of acid soil were investigated. Dolomite was the main form of alkali in Pal and the acid neutralisation capacity of Pal was 215 cmol kg–1. Incubation experiments indicated that Pal incorporation increased soil pH, cation exchange capacity, base saturation and exchangeable K⁺, Na⁺, Ca²⁺ and Mg²⁺ contents, and decreased the levels of exchangeable H⁺, Al³⁺ and acidity, over a 1-year period. The ameliorative mechanisms were the dissolution of major alkaline matter in Pal (i.e. dolomite), and the exchange between released Ca²⁺ and Mg²⁺ with H⁺ in acidic soil. Hence, Pal can be used as a moderate acidic soil amendment.
... Palygorskite (PAL) nanorods, a type of natural clay nano ber, are characterized by the presence of wellde ned one-dimensional (1D) sub-1-nm channels that run parallel to the long axis of the PAL nanorod. 21 The cross-sectional dimensions of these channels are approximately 3.7 Å × 6.4 Å, 22 which renders them a promising candidate for utilization as selective pathways with a de ned size, capable of repelling solute ions or dye molecules 23,24,25,26 and rapidly transferring water molecules with a diameter of 3.2 Å. 27 PAL nanorods are rich in functional groups, metal active sites, and ion exchange capabilities, 28, 29 thereby providing a exible platform for the customization of membrane properties. Furthermore, PAL nanorods may be a cost-effective and suitable raw material for fabricating NF membranes. ...
Nanofiltration membranes featuring sub-1-nm channels have demonstrated considerable potential for desalination and ion separation. However, the construction of both high selectivity and permeance membranes with tailorable one-dimensional (1D) sub-1-nm channels using a versatile and eco-friendly protocol remains a formidable challenge. Here, high selectivity PAL-CMC hybrid (PCH) nanofiltration membranes were successfully prepared based on the coordination-driven self-assembly between natural Palygorskite (PAL) nanorods and carboxymethylcellulose (CMC) in water. We first discovered the ion-imprinting adsorption feature of Mg ²⁺ on PAL. By adjusting the coordination ratio, the PCH membrane retains only the natural 1D straight sub-1-nm channels of PAL nanorods, rendering it one of the few membranes capable of ultra-fast water transport (> 25 L m ⁻² h ⁻¹ bar ⁻¹ ) and exceptional salt retention (97.4% for Na 2 SO 4 and 86.2% for NaCl). Through applying ion imprinting technology, Mg ²⁺ -imprinting sites enable the membrane to transport Li ⁺ rapidly and selectively in mixture solutions containing Mg ²⁺ , achieving a Li ⁺ /Mg ²⁺ selectivity of up to 175. Molecular dynamics simulations indicate that water and lithium ions can be transported rapidly through the intrinsic and tailored sub-1-nm channels of PAL nanorods, respectively. These findings establish PCH membranes as prospective candidates for desalination and lithium extraction from lagoons.
... As one kind of natural crystalline hydrated magnesium aluminum silicate mineral, natural Palygorskite (PAL) nanorods possess well-de ned 1D sub-1 nm channels paralleling to the long axis of PAL nanorod and the cross-section area of the channel is about 3.7 Å ×6.4 Å, [15] making it promising to serve as pathways with size screening to repulse solute ions or dye molecules (~ 7.0 Å) and allow the fast transfer of water molecules with a diameter of 3.2 Å. [16] Furthermore, PAL nanorods are rich in functional groups, metal active sites, and ion exchange capabilities, providing a exible platform for customizing membrane properties. Meanwhile, the pore size of PAL nanorods can be tuned by crosslinker contents and ion-imprinting techniques. ...
Nanofiltration membranes featuring sub-1 nm channels have shown significant potential for desalination and ion separation. However, the construction of scalable membranes with tailorable one-dimensional (1D) sub-1 nm channels using a versatile and eco-friendly protocol remains a formidable challenge. In this study, we present an approach to tuning sub-1 nm channels using natural palygorskite (PAL) nanorods with carboxymethylcellulose (CMC) cross-linkers to control density and enhance stability of membrane. The sub-1 nm channels of the membrane were further regulated by an ion-imprinting technique to enable fast and selective transport of Li ⁺ . The resulting PAL-CMC hybrid (PCH) membranes only retained the natural 1D straight sub-1 nm channels of PAL nanorods by adjusting the CMC content, making them among the few membranes capable of ultra-fast water transport (> 25 L m − 2 h − 1 bar − 1 ) and exceptional salt retention (97.4% for Na 2 SO 4 and 86.2% for NaCl). Notably, PCH membranes regulated by ion-imprinting technique exhibit unprecedented Li ⁺ selectivity from ionic mixture solutions containing Mg ²⁺ , achieving a separation factor ( S Mg 2+ / Li + ) up to 32.5. Molecular dynamics simulations revealed rapid Li ⁺ transport through the sub-1 nm channel of PAL. These findings position PCH membranes as next-generation candidates for desalination and Li ⁺ extraction from lagoons.
... Palygorskite (PAL), a hydrous layer-ribbon magnesium aluminum silicate, is common in many parts of the world. PAL possesses particular rod-like nanostructure, moderate surface charge, cation exchange capacity, high specific surface area and high adsorption capacity [7][8][9][10]. In addition, it was confirmed that the nanorods of PAL could destroy the cell wall to inhibit the growth of microorganism [11]. ...
ZnO/palygorskite nanocomposites were facilely synthesized as antibacterial agent by a hydrothermal method using different types of surfactants including sodium dodecyl sulfate, polyvinyl pyrrolidone and cetyltrimethylammonium bromide. The nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction field emission scanning electron microscopy, transmission electron microscope, energy dispersive spectrometer, Brunauer–Emmett–Teller analysis and zeta potential. The results showed that the morphologies and antibacterial properties of ZnO/palygorskite nanocomposites could be controlled by changing the types of surfactants. The minimum inhibitory concentration of ZnO/palygorskite nanocomposites prepared with sodium dodecyl sulfate against E. coli was 1.5 mg/mL, while it was 0.5 mg/mL for ZnO/palygorskite prepared with cetyltrimethylammonium bromide against S. aureus. The experimental results suggested that the ZnO/palygorskite nanocomposites might be served as a potential antibacterial agent in animal feeding.
Graphical Abstract
Palygorskite (Pal) shows great potential for physical, chemical and biological uses due to its colloidal, catalytic and adsorption properties. Pal mines, however, are facing the challenge of low-grade materials (5–15%), making it difficult to use Pal in emerging fields such as new materials, environmental protection and health. Therefore, there is an urgent need to develop an efficient method for separating and purifying Pal to obtain high purity levels. Hence, we have developed a dispersant-assisted rotating liquid film reactor separation strategy based on sodium hexametaphosphate as the dispersant. This strategy utilizes the double electron layer of Pal and the density difference between impurities to achieve effective disaggregation and purification of Pal bundles through the promotion of repulsive driving effects. Under optimal conditions, the purity of Pal can be increased from less than 10% to over 80%. This research presents a novel approach to the efficient refining of low-grade Pal. The crudely purified Pal’s adsorption capacity for methylene blue increased from 84.2 to 256.4 mg g –1 .
The newly reclaimed soil is an important reserve land resource, while it faces challenges such as poor water retention and low fertility. Therefore, it requires improvement through the use of soil amendments. Attapulgite (ATP) is abundant in northwest China with excellent properties and can be used as an amendment for newly reclaimed soil. The effects of ATP and its addition rate on infiltration and evaporation characteristics in newly reclaimed soil were studied by experiments and model simulation. Three addition gradients (2%, 4%, and 6%) were set in this study, and no ATP addition was used as a control (CK). The results show that ATP treatment prolonged the infiltration duration, reduced the wetting front migration distance, and reduced the accumulated evaporation. Both the Philip model and the Kostiakov model can accurately describe the infiltration process of newly reclaimed soil with ATP addition; the soil evaporation process can be fitted well with the Rose model. In this study, ATP addition affected both sorptivity and the stable infiltration rate of the reclaimed soil. During the evaporation, the soil evaporation effect was inversely proportional to the addition rates of ATP, and the ATP addition rate at 2% had the best effect on reducing soil evaporation. In summary, the ATP addition was beneficial top soil infiltration and evaporation, thus improving the poor water retention of newly reclaimed land and is a reasonable choice for efficient construction of new reclaimed land.
Natural minerals, such as kaolinite, halloysite, montmorillonite, attapulgite, bentonite, sepiolite, forsterite, and wollastonite, have considerable potential for use in CO2 capture and mineralization due to their abundant reserves, low cost, excellent mechanical properties, and chemical stability. Over the past decades, various methods, such as those involving heat, acid, alkali, organic amine, amino silane, and ionic liquid, have been employed to enhance the CO2 capture performance of natural minerals to attain high specific surface area, a large number of pore structures, and rich active sites. Future research on CO2 capture by natural minerals will focus on the full utilization of the properties of natural minerals, adoption of suitable modification methods, and preparation of composite materials with high specific surface area and rich active sites. In addition, we provide a summary of the principle and technical route of direct and indirect mineralization of CO2 by natural minerals. This process uses minerals with high calcium and magnesium contents, such as forsterite (Mg2SiO4), serpentine [Mg3Si2O(OH)4], and wollastonite (CaSiO3). The research status of indirect mineralization of CO2 using hydrochloric acid, acetic acid, molten salt, and ammonium salt as media is also introduced in detail. The recovery of additives and high-value-added products during the mineralization process to increase economic benefits is another focus of future research on CO2 mineralization by natural minerals.
Ammonia nitrogen pollutant in aqueous media is difficult to treat, which leads to a deterioration of pristine water ecosystems because of eutrophication and poses significant risks to human health. The efficient treatment of low-concentration ammonia nitrogen wastewater remains difficult. Adsorption is a promising remediation strategy, but suitable adsorbent materials that are abundant, low-cost, environmentally friendly, and efficient remain challenging to find. Recent developments in low-cost adsorbent materials for ammonia nitrogen removal from aqueous solution have been summarized. The physicochemical properties; ammonia removal mechanism; and advantages and disadvantages of representative adsorbent materials, including natural mineral materials, industrial byproducts, biochar, biopolymers, and their modified forms, have been compared. Future perspectives and research directions on the use of inexpensive adsorbents for ammonia nitrogen removal have been provided.
In this study, various kinds of attapulgite and biochar were selected as the raw material. Attapulgite, being an inorganic carrier, was used to prepare the mineral materials of the modified composite-clay, and iron of Fe (II/III) and biochar was loaded on the surface of the attapulgite through chemical precipitation. Both attapulgite and biochar samples loaded with Fe2+/3+ were characterized using the FTIR, FESEM, XRD, surface area analysis and zeta potentials. A soil culture pot experiment was also carried out. The results showed that APT5 and BAC5 were selected as the best raw materials for the preparation of Fe2+/3+ loaded attapulgite and biochar. The composite had the highest adsorption rate, while the ratio of BAC5 to ATP5 was 1:10. The crystal structure of attapulgite was changed significantly after surface modification, being converted into montmorillonite, as being illustrated by the analysis of FESEM, XRD and FTIR. XRD, FTIR and Zeta potential biocarbon and Fe2+/3+ were successfully loaded on the surface of attapulgite, while Cd²⁺ was mainly bonded with Fe on the surface of the composite to form stable chemical covalent bonds. Combining with the results of soil culture pot experiment, we further indicate that under the material of proportion of 3%, Cd²⁺ passivation effect in the soil was the best. Moreover, plant Cd content in plants decreased by 89.3%, fresh weight of plants increased by 514% and height increased by 34.6%. Fe(II/III) loaded attapulgite-biochar can provide a potential remedy for Cd-contamination in soil environment.
High-density polyethylene (HDPE) is used as the matrix and attapulgite (ATT) is used as the reinforcing phase. HDPE/ATT nanocomposites are prepared by melt blending. The effect of ATT content on the mechanical properties, water absorption and morphology of HDPE/ATT composites was studied. The results show that adding a small amount of ATT can improve the mechanical properties of HDPE, but excessive addition will reduce the mechanical properties of HDPE. The water absorption and contact angle test results show that as the ATT content increases, the composite material becomes more and more hydrophilic. After joining ATT, the performance of HDPE / ATT composite material has a significant improvement effect, and it is believed that it will have broad application prospects in the future.
Commercial separators for lithium-ion batteries still have shortcomings such as inferior electrolyte wettability, serious thermal shrinkage (polyolefin separators) and intrinsic brittleness (ceramic separators), which result in poor electrochemical performance and serious potential safety hazard. Here, a waterborne separator is fabricated by deposition and in situ crosslinking of a homogeneous aqueous suspension containing natural clay nanorods (attapulgite, ATP) and polyvinylalcohol (PVA) onto both the external and internal surfaces of the Celgard@2400 matrix. Different from conventional grafted or coated functional separators, the ATP-PVA/Celgard separator has a unique sandwiching/infusing structure. The separator features super-electrolyte-philicity with a liquid electrolyte contact angle of 0°, high Li⁺ conductivity (0.782 mS cm⁻¹), excellent mechanical properties and high thermostability. Consequently, the 4.9 V Li/LiNi0.5Mn1.5O4 cell with the separator shows higher cycling stability (94.7% after 100 cycles), better rate performance and lower resistance than the cell with commercial ceramic separator. Moreover, the separator could improve performance of the Li/LiFePO4 cell and stable open circuit voltage at 160 °C. This work provides an avenue for the design of advanced separators for high-voltage lithium-ion batteries via an environmentally friendly method using natural nanomaterials.
Background
This study explored the possible mechanism of flavones from Vitis vinifera L. (VTF) on neurotransmitters, synaptic transmission and related learning and memory in rats with Alzheimer disease (AD). Methods
The researchers injected amyloid-β(25–35) into the hippocampus to establish AD model rats. The Sprague-Dawley (SD) rats were divided into a control group, a donepezil group, an AD model group, a VTF low-dose group, a VTF medium-dose group and a VTF high-dose group. The researchers detected the activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) according to kit instructions. The protein expression of brain-derived neurotrophic factor (BDNF), synaptotagmin-1 (SYT1) and cyclic adenosine monophosphate response element binding protein (CREB) in the rats’ hippocampi was detected by immunohistochemistry and Western blot, and the gene expression of cAMP-regulated enhancer (CRE) was detected by real-time quantitative polymerase chain reaction (PCR). ResultsVTF may enhance the protein expression of p-CREB, BDNF and SYT1 in rat hippocampi, depending on dose. The messenger RNA (mRNA) level of CREB was significantly higher in the VTF high-dose group than in the model group, which was consistent with the results of Western blotting. VTF may reduce the activity of AChE and increase that of ChAT in rat hippocampi. Finally, VTF effectively improved the learning and memory abilities of AD rats. ConclusionsVTF can promote synaptic plasticity and indirectly affect the expression of cholinergic neurotransmitters, which may be one mechanism of VTF protection in AD rats.
BACKGROUND
In this research, a new extraction method based on dispersive liquid–liquid microextraction and the solidification of deep eutectic solvent has been developed for the determination of heavy metals in soil and vegetables prior to their analysis by graphite furnace atomic absorption spectrometry (GFAAS). In this method, a green solvent consisting of 1‐decyl‐3‐methylimidazolium chloride and 1‐undecanol was used as an extraction solvent, yielding the advantages of material stability, low density and a suitable freezing point near room temperature.
RESULTS
Under optimal conditions, enrichment factors are in the range of 114–172. The calibration graphs are linear in the range of 0.02–200 µg kg⁻¹ and limits of detection are in the range of 0.01–0.03 µg kg⁻¹. Repeatability and reproducibility of the method based on seven replicate measurements of 0.80 µg kg⁻¹ of Hg and 0.20 µg kg⁻¹ of Pb and Cd in analyzed samples were in the range of 2.3–4.1% and 3.7–6.6%, respectively.
CONCLUSION
A new deep eutectic solvent consists of two parts: 1‐decyl‐3‐methylimidazolium chloride and 1‐undecanol in a molar ratio of 1:2. The accuracy of the proposed procedure was also assessed by determining the concentration of the studied metal ions in a polluted farmland soil standard reference material. © 2018 Society of Chemical Industry
Sodium‐ion hybrid capacitors (SIHCs) can potentially combine the virtues of high‐energy density of batteries and high‐power output as well as long cycle life of capacitors in one device. The key point of constructing a high‐performance SIHC is to couple appropriate anode and cathode materials, which can well match in capacity and kinetics behavior simultaneously. In this work, a novel SIHC, coupling a titanium dioxide/carbon nanocomposite (TiO2/C) anode with a 3D nanoporous carbon cathode, which are both prepared from metal–organic frameworks (MOFs, MIL‐125 (Ti) and ZIF‐8, respectively), is designed and fabricated. The robust architecture and extrinsic pseudocapacitance of TiO2/C nanocomposite contribute to the excellent cyclic stability and rate capability in half‐cell. Hierarchical 3D nanoporous carbon displays superior capacity and rate performance. Benefiting from the merits of structures and performances of anode and cathode materials, the as‐built SIHC achieves a high energy density of 142.7 W h kg⁻¹ and a high power output of 25 kW kg⁻¹ within 1–4 V, as well as an outstanding life span of 10 000 cycles with over 90% of the capacity retention. The results make it competitive in high energy and power–required electricity storage applications.
Research on metal-ion hybrid capacitor is emerging as one of the hottest topics in energy storage fields because of their combination of high power and energy densities. To improve the sluggish faradaic reaction in traditional electrode materials for metal-ion hybrid capaitors, intercalation pseudocapacitive materials have been developed as attractive candidates. However, all the previously reported pseudocapacitances in intercalation/deintercalation reactions are based on cations (Li+, Na+, Zn2+ etc). In this work, we demonstrated the high pseudocapacitance contribution in boron-doped graphite (BG) sheets by taking advantage of anion storage. The BG electrode can reversibly store anion (PF6−) through both surface-controlled pseudocapacitive reaction and diffusion-limited intercalation/deintercalation reaction. The fabricated Na-ion hybrid capacitor with BG cathode exhibits superior electrochemical performance. Density functional theory (DFT) calculation reveals that B-doping can significantly reduce the PF6− diffusion energy barrier in graphite layers.
In this research, a new extraction method based on liquid-phase microextraction and the freezing of deep eutectic solvent (LPME-FDES) has been developed for the determination of common pesticides in water samples prior to their analysis by high performance liquid chromatography-ultraviolet detection (HPLC-UV). In this method, a green solvent consisting of 1-octyl-3-methylimidazolium chloride and 1-undecanol was used as an extraction solvent, yielding the advantages of material stability, low density, and a suitable freezing point near room temperature. Under the optimum conditions, enrichment factors and extraction recoveries are in the range of 150–180 and 75–90%, respectively. The calibration graphs are linear in the range of 0.2–500 μg L⁻¹ and limit of detections (LODs) are in the range of 0.05–0.50 μg L⁻¹. Relative standard deviation (RSD) values for intra-day and inter-day of the method based on seven replicate measurements of 200 μg L⁻¹ of diazinon and endosulfan, 100 μg L⁻¹ of phosalone, 50.0 μg L⁻¹ of atrazine, desethylatrazine and deisopropylatrazine in water were in the range of 1.3–2.5% and 2.2–3.6%, respectively. The relative recoveries of well, tap and river water samples which have been spiked with different levels of target pesticides are 97–106, 90–108 and 95–107%, respectively. The extraction methodology is simple, rapid, cheap and green since small amounts of non-toxic solvents are necessary.
Modern optoelectronics needs development of new materials characterized not only by high optical transparency and electrical conductivity, but also by mechanical strength, and flexibility. Recent advances employ grids of metallic micro- and nanowires, but the overall performance of the resulting material composites remains unsatisfactory. In this work, we propose a new strategy: application of natural scaffoldings perfected by evolution. In this context, we study two bio-inspired networks for two specific optoelectronic applications. The first network, intended for solar cells, light sources and similar devices, has a quasi-fractal structure and is derived directly from a chemically extracted leaf venation system. The second network is intended for touch screens and flexible displays, and is obtained by metalizing a spider's silk web. We demonstrate that each of these networks attain an exceptional optoelectonic and mechanical performance for its intended purpose, providing a promising direction in the development of more efficient optoelectronic devices.
Construction of functionalized chemical compounds from small molecules in a highly selective and efficient manner is crucial for sustainable development. The chemical-based manufacturing sector of the future should aim to produce chemicals from very simple and abundant resources, just as nature uses CO2 and N2 to generate sugars, amino acids, and so forth. In practice, however, the utilization of CO2 for the generation of industrial products, such as drugs and related intermediates, still remains a major challenge. Here, we describe the facile cyanide-free production of high-value nitriles with CO2 and NH3 as the sole sources of carbon and nitrogen, respectively. This practical and catalytic methodology provides a unique strategy for the utilization of small molecules for sustainable and cost-effective applications.
Catalytic Amination for N-Alkyl Amine Synthesis provides a useful survey of this key type of reaction for chemistry researchers in academia and industry. Beginning with an introduction to amination and the development of the field, the book focuses on useful and high potential methods, such as the catalytic amination of alcohol with homogeneous and heterogeneous catalysts, the coupling reaction of olefin and amine, and the reductive amination of carbon dioxide with different reducing agents. The work also discusses two key examples of one-pot synthesis, the oxidative amination of alkane and amine and synthesis of N-alkyl amine with nitrobenzene and nitrile as starting materials. Valuable for chemists, materials scientists, chemical engineers and others, the book offers a unique overview of this growing area and its future possibilities.
This paper presents a way to prepare three-dimensional carbon framework (3DCF) anode material for sodium ion batteries (SIBs) and hybrid capacitors (SIHCs). Based on ethanol/sodium hydroxide electrolyte, 3DCFs are synthesized by electrolysis combined with subsequent calcination process. The obtained 3DCFs have the unique structure with interconnected, porous structure and defective features, which facilitates the sodium ion storage. When used as anode material for SIBs, 3DCFs display high specific capacity and rate capability, and excellent long-term cyclability. We have also assembled the SIHC devices by employing the 3DCFs as anode and sodium alginate derived activated carbon (SDAC) as cathode, the optimal 3DCFs//SDAC devices display high energy density of 133.2 Wh kg⁻¹ and high power output of 20.0 kW kg⁻¹ within the voltage window of 0–4.0 V, as well as long-term cycling life for 4000 cycles. This work provides opens up opportunities for fabricating novel nano-structured electrode material and constructing high performance sodium ion storage devices.
In this paper, using one-step method of sub-surface initiated atom transfer radical polymerization (SSI-ATRP), the novel polymer brushes accompanied with structured surface were prepared on the resin base. Compared with the traditional surface initiated atom transfer radical polymerization (SI-ATRP) method, either surface chemical composition or topography was obtained through SSI-ATRP synchronously. Besides, we found that the structured polymers brush interface had better stability and long-term synergistic antifouling effect under seawater medium through soaking experiment and ocean field assay for long time. While, the bio-fouling assay results indicated that their excellent antifouling performances would be hindered by salt responsiveness of 3-sulfopropyl methacrylate potassium salt (SPMA) polymer brushes. Because it could be screened by high salt (e.g. Ca²⁺ or Mg²⁺) concentration, which decreased the hydration effect and further weakened the antifouling effect. The zwitterionic polymer (sulfobetaine methacrylate, SBMA), however, still showed excellent antifouling performances under high salt concentration since it produced stabilized ionic bonds with water molecules than those created from other hydrophilic materials. Given this, the structured zwitterionic and anionic copolymer brushes were fabricated as well, which realized the ideal stability and long-term antifouling effect under marine environment, ever high salt concentration medium. This research is of great value to marine antifouling in the long run and some other relevant fields.
A new mechanism of catalyst has been demonstrated in this article. With the interaction between carbon nitride (CN) and encapsulated nickel, the CN in the catalyst has been endowed with new active sites for the adsorption and activation of hydrogen while nickel itself is physically isolated from the contact with reactive molecules. For the selective hydrogenation of acetylene in large amount of ethylene, the catalyst shows excellent ethylene selectivity than the nickel catalyst itself, which is almost totally unselective. Meanwhile, the CN itself is inactive for the reaction. The results of characterization demonstrate that pyridinic nitrogen doped in the carbon matrix should be the active sites for hydrogen dissociative adsorption. The theoretical calculations further confirm the results and provide with the detail in the electron transfer between nickel and CN in the catalyst. The current results supply a new concept for design of high performance catalyst.
Due to the poor mechanical stability, the practical applications of superhydrophobic materials are limited. Inspired by the excellent adhesion of polydopamine (PDA), a kind of superhydrophobic coating is successfully fabricated on the textile. Herein, under weak acidic conditions (pH = 5.0), sodium periodate is selected as oxidant and the concentration of dopamine is controlled at 8 mg/mL, which leads to the fast and homogeneous deposition of PDA nanoaggregates on the pristine textile. Subsequently, the nanoaggregates are modified by octadecyl thiol. The PDA nanoaggregates work as a stable bond between the pristine textile and hydrophobic groups introduced from thiol, which contributes to the mechanical stability of the superhydrophobic textile. In addition, the superhydrophobic textiles display resistance to acetone, UV irradiation, and hot water. Significantly, the textiles can be used for oil/water separation with flux around 4500 Lm⁻² h⁻¹ and the separation efficiency more than 97%. These advantages provide the superhydrophobic textiles with multiple applications.
Here, surprising results are presented in bulk Pd catalyzed carbonylation reactions. Three types of carbonylation reactions can be realized efficiently under organic ligand-free conditions, i.e., hydroaminocarbonylation of olefins, aminocarbonylation of aryl iodides and oxidative carbonylation of amines, which almost covers all the known mechanisms in carbonylation reactions. Noteworthy, the bulk Pd catalyst system exhibited better catalytic activity than the classical homogeneous PdCl2/(2-OMePh)3P catalyst system. This study will create a momentous and new field in green carbonylation reactions.
Ice accumulation on solid surfaces can incur irretrievable loss and catastrophic affairs in daily life. These issues can be addressed and alleviated strategically with proper methods adopted. Compared with conventional deicing strategies, such as electro-impulse, chemical method and mechanical deicing approach, passive anti-icing and ice-phobic surfaces inspired by nature animals and plants have been manifested exceedingly profound advantage. Herein, the kinetics of ice nucleation on solid surfaces and heat transformation during ice formation are investigated first. Then, the reducing attachment pathway of water droplets on substrate surfaces are reviewed for the purpose of achieving water droplets self-removal and averting wettability transition on superhydrophobic surfaces. Furthermore, special attention is poured into recent biomimetic anti-icing strategies regarding reduction of ice adhesion, decrease of ice nucleation temperature and delay of freeze time. Significantly, other external factors, such as environmental humidity and exoteric gas flow, affecting ice formation and growth are comprehensively discussed. Finally, outstanding mechanical and chemical stability are vital for lengthening durability and longevity of anti-icing/ice-phobic surfaces. All of these matters and outlooks for future research directions of anti-icing and ice-phobic are also revealed in this article.
An ultrasensitive self-powered ammonia (NH3) sensing system based on a vertical contact-separate mode triboelectric nanogenerator (TENG) has been proposed for room temperature detection of NH3 concentrations both in the ambient environment and in human exhaled gases. Owing to the special output characteristics of the TENG adjusted by the load resistance of the NH3 sensor, output voltage of the fabricated gas sensor has a proportional relationship with NH3 concentration, which is the fundamental working mechanism of the self-powered gas-sensing system. The triboelectric ammonia sensor (TEAS) based on PANI-MWCNTs composite thin film possesses a NH3-sensing response of 10% at 0.01 ppm NH3 and exhibits a great response of 255% at 100 ppm NH3. Meanwhile, the TEAS also holds fast response/recovery time (89–120 s/103–127 s for 0.6–100 ppm NH3), excellent long-term stability, satisfactory selectivity and good anti-bending ability. Furthermore, a preliminary test of human exhaled NH3 concentration has been carried out to further expand the practical application of the developed TEAS. The results not only provide an effective technique in ultrasensitive NH3 sensing but also greatly broaden the applicability of TENG in the detection of human kidney health through comparing to average NH3 concentrations within exhaled gases of healthy people.
Superamphiphobic surfaces have drawn much attention owning to their significant advantages in interfacial applications. However, the existing preparation strategies are suffering from the complex process, substrate-independent, and copious usage of organic liquids. Moreover, the required high roughness and fairly low surface-energy components are very vulnerable to physical and chemical damages. Thus, it is highly desirable to develop a facile, universal, and environmental friendly method to fabricate robust superamphiphobic surfaces. Herein, an all-water-based spraying aqueous solution of perfluorooctanoic acid and aluminum oxide nanoparticles is formed with the aid of a fluorocarbon surfactant, which is suitable for preparing superamphiphobic coating on various substrates. The obtained coating displays excellent repellence to liquids with surface tensions higher than 27.5 mN/m. Importantly, the superamphiphobic coating still extremely repels those liquids after physical damages, and can withstand rigorous conditions including acid/base attacks, high/low temperatures, UV irradiation, and organic solvent corrosion. Moreover, the coating has a self-repairing ability against O2-plasma etching and the superamphiphobicity can be recovered after high-temperature treatment. The low-cost and environmental-friendly approach may promote the development of superamphiphobic surfaces in practical applications.
The ever-increasing boom in smart yet miniaturized electronics urgently requires on-chip energy storage systems with high performance, safety, flexibility, and robust integration, but tremendous challenges exist. Here we demonstrate the first prototype of all-solid-state planar lithium ion micro-capacitors (LIMCs) based on interdigital patterns of lithium titanate nanospheres as anode and activated graphene as cathode. The interdigital LIMCs were fabricated via layer-by-layer mask-assisted deposition of graphene and electrode materials, without metal current collector, additive and polymer binder. The as-assembled LIMCs delivered the record volumetric energy density of 53.5 mWh cm-3. Furthermore, they exhibited outstanding mechanical flexibility without performance degradation under repeated bending, superior electrochemical metrics and safety at high temperature of 80 oC due to high-stable ionogel electrolyte and free of separator, and remarkably modular integration of constructing bipolar cells for boosting high voltage, thereby holding great potential for future flexible and wearable electronics.
Energy storage devices, which can combine the advantages of lithium-ion battery with that of electric double layer capacitor, are of prime interest. Recently, composite cathodes, which combine a battery material with capacitor material, have shown promise in enhancing life cycle and energy/power performances. Lithium-ion capacitor (LIC), with unique charge storage mechanism of combining a pre-lithiated battery anode with a capacitor cathode, is one such device which has the potential to synergistically incorporate the composite cathode to enhance capacity and cycle life. We report here a hybrid LIC consisting of a lithium iron phosphate (LiFePO4-LFP)/Activated Carbon composite cathode in combination with a hard carbon anode, by integrating the cycle life and capacity enhancing strategies of a dry method of electrode fabrication, anode pre-lithiation and a 3:1 anode to cathode capacity ratio, demonstrating a long cycle life, while elaborating on the charge sharing between the faradaic and non-faradaic mechanism in the battery and capacitor materials, respectively in the composite cathode. An excellent cell capacity retention of 94% (1000 cycles at 1C) and 92% (100,000 cycles at 60C) were demonstrated, while retaining 78% (over 6000 cycles at 2.7C) and 67% (over 70,000 cycles at 43C) of the LFP capacity in the composite cathode.
Sodium‐ion hybrid supercapacitors (Na‐HSCs) by virtue of synergizing the merits of batteries and supercapacitors have attracted considerable attention for high‐energy and high‐power energy‐storage applications. Orthorhombic Nb2O5 (T‐Nb2O5) has recently been recognized as a promising anode material for Na‐HSCs due to its typical pseudocapacitive feature, but it suffers from intrinsically low electrical conductivity. Reasonably high electrochemical performance of T‐Nb2O5‐based electrodes could merely be gained to date when sufficient carbon content was introduced. In addition, flexible Na‐HSC devices have scarcely been demonstrated by far. Herein, an in situ encapsulation strategy is devised to directly grow ultrathin graphene shells over T‐Nb2O5 nanowires (denoted as Gr‐Nb2O5 composites) by plasma‐enhanced chemical vapor deposition, targeting a highly conductive anode material for Na‐HSCs. The few‐layered graphene capsules with ample topological defects would enable facile electron and Na⁺ ion transport, guaranteeing rapid pseudocapacitive processes at the Nb2O5/electrolyte interface. The Na‐HSC full‐cell comprising a Gr‐Nb2O5 anode and an activated carbon cathode delivers high energy/power densities (112.9 Wh kg⁻¹/80.1 W kg⁻¹ and 62.2 Wh kg⁻¹/5330 W kg⁻¹), outperforming those of recently reported Na‐HSC counterparts. Proof‐of‐concept Na‐HSC devices with favorable mechanical robustness manifest stable electrochemical performances under different bending conditions and after various bending–release cycles.
In last years, a plethora of extraction techniques has emerged as environmental-friendly alternatives to conventional extraction procedures. In this particular field, a novel class of solvents known as deep eutectic solvents (DES) has arisen as a new and very promising tool. Compared with conventional organic solvents, DES as well as the so-called natural deep eutectic solvents (NADES) have attracted considerable attention due to the fact that they not only are eco-friendly, non-toxic, and biodegradable organic compounds but also have a low cost, being easy to produce in the own laboratory. The present review provides a critical and organized overview of novel extraction techniques using DES as extracting solvents that were applied in food, biological and environmental sample analysis. An evaluation of how these DES/NADES could improve extraction yields of a variety of analytes and advantages and limitations of each proposal will be discussed and compared with earlier studies.
Driven by the advent of fullerenes, carbon nanotubes and graphene, designing or tailoring sp²-rich carbon clusters in carbon based films attains very interesting properties which can be ideal in various applications. Depositing sp²-rich clusters evolve toward a three-dimensional arrangement (composed of extended, bent, and cross-linked graphite basal planes, i.e. fullerene-like carbon (FLC)) or nanocrystalline planar graphitic configurations with the promotion in size and ordering of six-membered ring clusters (i.e. graphite-like carbon (GLC)). However, the films are studied separately and their structure effects on sliding-induced structure changes has never enjoyed elaboration. Here we built the self-mated friction groups of single structural films coated at two sliding surfaces, and designed a smart device to gather the transformed products under different load and sliding cycles. Super-low friction was realized under higher load by low-shear strength from graphene formed at the GLC interface (0.005), or reduced contact area from spherical nanoparticles with outer graphite shells produced at the FLC interface (0.009), resulting by different rehybridization pathways from different film structures. The role of film and rehybridized structures under super-low friction contact was discussed. The results could enrich the understanding of friction-induced rehybridization mechanism and help to deposit suitable films to significantly reduce friction.
Combination of transition metal catalysis with organocatalysis in ways of synergetic catalysis, cooperative catalysis, or/and sequential catalysis has been emerged as a powerful strategy to promote organic transformations that cannot be achieved by each individual independently. Herein, a new protocol for the synthesis of primary amides from olefins, CO and NH3 through one-pot tandem methoxycarbonylation-aminolys was presented over a bi-functional ligand (L1) based rhodium catalyst with functions of co-catalysis. L1 is composed of the phosphino-fragment and the amino-/imino- tautomeric moiety. Then L1-based Rh-catalytic system demonstrated a combination of Rh-P transition metal catalysis and the tautomeric catalysis. In this tandem methoxycarbonylation-aminolysis, NH3 also served as a ligand to work together with the phosphino-fragment to synergetically modify the performance of Rh-catalyst responsible for the first-step methoxycarbonylation of olefin to generate the esters, and the Rh-tailed tautomeric catalyst was in charge of the subsequent aminolysis to generate the targeted primary amides.
In this study, we carried out the transition experiments of graphite-like (GL) to fullerene-like (FL) structures by placing high temperature steel substrates in the depositing environment which can form FL hydrogenated carbon films. We investigated the changes of bond mixtures, H content, aromatic clusters and internal stress at the transition process, and proposed the transformation mechanism inferred from Raman, TEM cross-section, FTIR and XPS results. It was found that the size of aromatic clusters and accordingly graphene planes and the formation of edge dangling bonds were the key steps. H⁺ bombardment leaded to the splitting of large graphene planes (at GL stage) into more and smaller planes (at FL stage) and the formation of edge dangling bonds; Some of these dangling bonds were reduced by the formation of pentagons and subsequent curving of the smaller planes, which were an indicator of FL structures.
To circumvent the imbalances of electrochemical kinetic and capacity between Li+ storage anode and capacitive cathode for lithium ion capacitors (LICs), we herein, demonstrate an efficient solution by boosting the capacitive charge storage contributions of carbon electrode to construct a high performance LIC. Such a strategy is achieved by in-situ and highly doping nitrogen atoms into carbon nanospheres (ANCS), which increases the carbon defects/active sites, inducing more rapidly capacitive charge-storage contributions for both Li+ storage anode and PF6- storage cathode. High level N doping induced capacitive enhancement is successfully evidenced by constructing a symmetric supercapacitor using commercial organic electrolyte. Coupling a pre-lithiated ANCS anode with a fresh ANCS cathode enables a full-carbon LIC with a high operation voltage of 4.5 V and high energy/power densities thereof. The assembled LIC device delivers high energy densities of 206.7 Wh kg-1 and 115.4 Wh kg-1 at power densities of 225 W kg-1 and 22.5 kW kg-1, respectively, as well as an unprecedented high-power cycling stability with only 0.0013% capacitance decay per cycle within 10000 cycles at a high power-output of 9 kW kg-1.
The paper presents a new procedure for the determination of organic acids in a complex aqueous matrix using ultrasound-assisted dispersive liquid–liquid microextraction followed by injection port derivatization and GC–MS analysis. A deep eutectic solvent (choline chloride: 4-methylphenol in a 1:2 mol ratio) was used both as an extracting solvent and as a derivatizing agent to yield ion pairs which were next converted to methyl esters of organic acids in a hot GC injection port. The procedure was optimized in terms of selection of a deep eutectic solvent, disperser solvent, and the ratio of their volumes, pH, salting out effect, extraction time, injection port temperature and time of opening the split valve. The developed procedure is characterized by low LOD (1.7–8.3 μg/L) and LOQ (5.1–25 μg/L) values, good repeatability (RSD ranging from 4.0 to 6.7%), good recoveries for most of the studied analyte (81,5–106%) and a wide linear range. The procedure was used for the determination of carboxylic acids in real effluents from the production of petroleum bitumens. A total of ten analytes at concentrations ranging from 0.33 to 43.3 μg/mL were identified and determined in the effluents before and after chemical treatment. The study revealed that in effluents treated by hydrodynamic cavitation an increase in concentration of benzoic acid and related compounds was observed.
The Namib Desert beetle-Stenocara can adapt to the arid environment by its fog harvesting ability. A series of samples with different topography and wettability that mimicked the elytra of the beetle were fabricated to study the effect of these factors on fog harvesting. The superhydrophobic bulgy sample harvested 1.5 times the amount of water than the sample with combinational pattern of hydrophilic bulgy/superhydrophobic surrounding and 2.83 times than the superhydrophobic surface without bulge. These bulges focused the droplets around them which endowed droplets with higher velocity and induced the highest dynamic pressure atop them. Superhydrophobicity was beneficial for the departure of harvested water on the surface of sample. The bulgy topography, together with surface wettability, dominated the process of water supply and water removal.
Superhydrophobic coating have presented enormous application value in mechanical, architectural and other engineering in decade. However, there are some problems that we have to envisage, such as weak mechanical strength, complex technologies and toxic modifiers, which greatly limits its applications in real-life. Here, an omnipotent robust silicon dioxide @ epoxy resin coating was successfully prepared by a facile and environment friendly process, and the whole process can be accomplished in a beaker without any usage of toxic reagents. The as-prepared coating presents excellent waterproof ability, mechanical stability, long-time stability and can be coated almost on any solid substrates. What is more, the superhydrophobic coating also exhibits better survivability to face various intricate environments in nature such as windy, dusty, icing and torridity. Hence, this omnipotent silicon dioxide @ epoxy resin coating possesses enormous application potential in many fields and the facile and environment friendly productive process gives it possibility to be quantity produced in industry.
In this work, for the first time, ferrofluid of magnetic montmorillonite nanoclay and deep eutectic solvent was prepared and coupled with directly suspended droplet microextraction. Incorporation of ferrofluid in a miniaturized sample preparation technique resulted in achieving high extraction efficiency while developing a green analytical method. The prepared ferrofluid has strong sorbing properties and hydrophobic characteristics. In this method, a micro-droplet of ferrofluid was suspended into the vortex of a stirring aqueous solution and after completing the extraction process, was easily separated from the solution by a magnetic rod without any operational problems. The predominant experimental variables affecting the extraction efficiency of explosives were evaluated. Under optimal conditions, the limits of detection were in the range 0.22-0.91 µg L-1. The enrichment factors were between 23 and 93 and the relative standard deviations were< 10%. The relative recoveries were ranged from 88 to 104%. This method was successfully applied for the extraction and preconcentration of explosives in water and soil samples, followed their determination by high performance liquid chromatography with ultraviolet detection (HPLC-UV).
In this research, a new vortex assisted dispersive liquid−liquid microextraction based on the freezing of deep eutectic solvent (VADLLME−FDES) has been developed for the determination of organic mercury (R-Hg) and inorganic mercury (Hg²⁺) in blood samples prior to their analysis by graphite furnace atomic absorption spectrometry (GFAAS). In this method, a green solvent consisting of 1-octyl-3-methylimidazolium chloride and 1-undecanol was used as an extraction solvent, yielding the advantages of material stability, low density, and a suitable freezing point near room temperature. Under the optimum conditions, enrichment factor is 112. The calibration graph is linear in the range of 0.30–60 µg L⁻¹ and limit of detection (LOD) is 0.10 µg L⁻¹. Repeatability and reproducibility of the method based on seven replicate measurements of 5.0 µg L⁻¹ of Hg²⁺ in analyzed samples were 3.7% and 6.2%, respectively. The relative recoveries of blood samples which have been spiked with different levels of Hg²⁺ are 90–109%. A new deep eutectic solvent consists of two parts: [DMIM]Cl and 1-undecanol in the molar ratio of 1–2. The accuracy of the proposed procedure was also assessed by determining the concentration of the mercury in a standard reference material. All organic mercury (R-Hg) species were converted to Hg²⁺ and finally, the concentration of R-Hg is simply calculated by mathematically subtracting the concentrations of Hg²⁺ from the concentration of total mercury (t-Hg). The extraction methodology is simple, rapid, cheap and green since small amounts of non-toxic solvents are necessary.
Deep eutectic solvent based on L-proline and oxalic acid has been demonstrated for the first time as an efficient catalyst for synthesis of 4, 7-dihydro-1H-pyrazolo[3, 4-b] pyridine-5-carbonitrile derivatives via one-pot three-component reaction of aldehyde, 3-oxopropanenitrile and 1H-pyrazol-5-amine. The key features of this approach include the broad substrate scope, operational simplicity, recyclable catalyst and possibility to scale up giving multigram quantities.
The superhydrophobic paper containing CMC, HAP and ZnO was prepared by a novel and facile method with eco-environmental and modifier-free process. The superhydrophobic property is effectively controlled by different amount of ZnO, which might be effect of surface roughness of the paper. Except for the common performances, such as self-cleaning property, chemical durability and mechanical abrasion durability, the excellent thermal stability and anti-bacterial properties will dramatically extend the practical applications of the paper. In addition, such paper still maintains its superhydrophobicity after flammable oil adsorption-combustion, further validating its excellent fire-resistant property. The combination of superhydrophobicity and flame retardancy can largely enhance the durability of the paper. These characteristics make the multifunctional paper a better candidate than the commercial paper, which may be a breakthrough in paper-making industries.
It is challenging for flexible solid‐state hybrid capacitors to achieve high‐energy‐high‐power densities in both Li‐ion and Na‐ion systems, and the kinetics discrepancy between the sluggish faradaic anode and the rapid capacitive cathode is the most critical issue needs to be addressed. To improve Li‐ion/Na‐ion diffusion kinetics, flexible oxygen‐deficient TiO2−x/CNT composite film with ultrafast electron/ion transport network is constructed as self‐supported and light‐weight anode for a quasi‐solid‐state hybrid capacitor. It is found that the designed porous yolk–shell structure endows large surface area and provides short diffusion length, the oxygen‐deficient composite film can improve electrical conductivity, and enhance ion diffusion kinetic by introducing intercalation pseudocapacitance, therefore resulting in advance electrochemical properties. It exhibits high capacity, excellent rate performance, and long cycle life when utilized as self‐supported anodes for Li‐ion and Na‐ion batteries. When assembled with activated carbon/carbon nanotube (AC/CNT) flexible cathode, using ion conducting gel polymer as the electrolyte, high energy densities of 104 and 109 Wh kg−1 are achieved at 250 W kg−1 in quasi‐solid‐state Li‐ion and Na‐ion capacitors (LICs and SICs), respectively. Still, energy densities of 32 and 36 Wh kg−1 can be maintained at high power densities of 5000 W kg−1 in LICs and SICs. The designed TiO2−x/CNT//AC/CNT hybrid capacitors integrate the advantages of (1) large surface area and short diffusion length, (2) enhanced Na‐ion diffusion kinetics and ultrafast ion/e− transport network, (3) flexible and light‐weight features, and (4) better safety from quasi‐solid‐state electrolyte, therefore maximum energy densities of 104 and 109 Wh kg−1 are achieved in Li‐ion and Na‐ion capacitors, respectively.
It maintains as a challenging topic for N-monomethylamine synthesis as the N,N-dimethylation reaction is thermodynamically favorable. The kinetically controlled N-monomethylamine synthesis from nitroarene and paraformaldehyde/H2 is reported with super-high N-monomethylamine selectivity in the presence of a Pd/TiO2 catalyst. The superior selectivity should be attributed to the preferential adsorption of the primary amine over N-monomethylamine on the Pd/TiO2 surface, as elucidated by NH3/Me2NH-TPD, while the nice catalytic activity could be associated to the good H2 activation ability and high amine adsorbing capacity of the catalyst, as elucidated by NH3-TPD and H2-TPR tests. Good results were obtained with a variety of nitroarenes containing methyl, methoxyl, hydroxyl, fluoride, trifluoromethyl, ester, and amide substituents as starting materials, and the potential synthetic utility of this protocol in pharmaceutical is illustrated by N-monomethylation of drug molecules, such as clinidipine, nimesulide, procaine and methyl aminosalicylate.
2D transition metal carbide materials called MXene have attracted great interests in the field of electrochemical energy storage due to their high electrical conductivity and high volumetric capacity. However, the low capacity accompanied by sluggish sodiation kinetics of electrode made from multilayer MXene has limited their further application for sodium ion storage. The key challenge to overcome the above issue is to decrease the Na+ diffusion barrier and increase active site concentration in MXene electrode. In this work, a method to significantly improve the capacity and kinetic of Ti3C2 MXene for Na+ storage by facile alkali metal ion pillaring is reported. After Na+ pillaring, the MXene sheets (Na-Ti3C2) with incremental interlayer spacing exhibits delivers a high reversible capacity of 175 mAh g-1 (~170% of the origin) at 0.1 A g-1 and excellent cycling stability for 2000 cycles at 2.0 A g-1 for sodium ion storage. Combing ex-situ XPS with kinetics analysis, more active sites and lower Na+ diffusion barrier can be confirmed after Na+ pillaring than Ti3C2, Li-Ti3C2, and K-Ti3C2. The role of terminal groups (-OH) in Na-Ti3C2 has also been confirmed by analyzing the electrochemical performance of annealed Na-Ti3C2 samples (450ºC and 700 ºC). The results show that the existence of –OH groups in Na-Ti3C2 can increase Na+ storage active sites, but decrease the Na+ storage kinetics. Coupling the Na-Ti3C2 anode with activated carbon (AC) cathode, the assembled sodium-ion capacitor (SIC) delivers a high energy density of 80.2 Wh kg-1 and high power density (6172 W kg-1) with an ultra-long and stable cycling performance (capacity retention: ~78.4 at 2 A g-1 after 15000 cycles).
Active carbon with hierarchical pore structure (HPC) is massively prepared using asphalt as carbon precursor, by a template directed method. The as‐prepared HPC exhibits excellent capacitive energy‐storage capacities on symmetric supercapacitor (140 F g‐1 at 0.5 A g‐1) and Li ion capacitor (LIC) using HPC as both cathode and anode (340 F g‐1 at 0.5 A g‐1), as well as ultralong cyclability for supercapacitor (no capacity loss after 15000 cycles) and LIC (91.3% capacitance retention after 10000 cycles). The superior energy density and power density are 202 W kg‐1 and 15398 Wh kg‐1 respectively. The hierarchical pore structure coordinate with the existence of heteroatoms that originated from carbon precursor are conducive to the delivery of the electrolyte ions and electrons, greatly contributing to the high capacitance and the excellent cycle performance. The work provides a very promising opportunity for high capacitive energy storage devices by means of the high value‐added utilization of the asphalt.
High Faradaic efficiency and appreciable current density are essential for future applications of electrochemical CO2 reduction reaction (CO2RR). However, these goals are difficult to achieve simultaneously due to the severe side reaction - hydrogen evolution reaction (HER). Herein, we successfully synthesize coordinatively unsaturated nickel-nitrogen (Ni-N) sites doped within porous carbon with a nickel loading as high as 5.44 wt% by pyrolysis of Zn/Ni bimetallic zeolitic imidazolate framework-8. Over the Ni-N composite catalysts, CO current density increases with the overpotential and reaches 71.5 ± 2.9 mA cm-2 at －1.03 V (vs. reversible hydrogen electrode, RHE) while maintaining high CO Faradaic efficiency of 92.0%~98.0% over a wide potential range of －0.53 V~－1.03 V (vs. RHE). Density functional theory calculations suggest that CO2RR occurs more easily than HER over coordinatively unsaturated Ni-N site. Therefore, highly doped and coordinatively unsaturated Ni-N sites achieve high current density and Faradaic efficiency of CO2RR simultaneously, breaking current limits in metal-nitrogen composite catalysts.
Commercial paper as an indispensable material in our daily life is extremely easy to be destroyed by water and fire. And obtaining the paper with the writable, non-flammable and superhydrophobic properties is still a challenging issue compared with others. Inspired from nature, biomimetic nanowires made from hydroxyapatite (HAP) can be used as raw material to fabricate functional paper. In this work, we present a superior, fire-resistant and repairable superhydrophobic PFDS-paper@ZnO exhibiting remarkable oil absorption-combustion performance. More importantly, the layered structure of the paper might be the reason of the excellent superhydrophobicity even after 20 abrasion cycles with sandpaper (400 cW). However, the common paper is destroyed after 5 abrasion cycles with sandpaper at the same condition. It is noted that the intrinsic fire-resistant nature of the paper is expected to reduce the risk of fire and might be used as an absorbent for flammable oil. On the one hand, such burnt paper can recover its original superhydrophobicity by facile modification after multiple cycles, achieving the repairable performance of superhydrophobic surface. On the other hand, the burnt paper without subsequent modification performs superhydrophilicity in air and underwater superoleophobicity, which can be used for efficiently surfactant-stabilized oil-in-water emulsion separation. This work expands the potential applications of functional paper, which might be a breakthrough for traditional papermaking industries.
Stainless steel (SS) have been widely used in marine structures and food industry due to its high corrosion resistance and excellent mechanical strength. Marine structures such as ships, ocean engineering and offshore rigs, are easily attacked by crude oil generated by oil spills and SS vessels applied in food industry are fouled by the organic matters in the fluid. Here, fish-scale-like SS surfaces with superhydrophilic and underwater superoleophobic property, including 316 L SS mesh and 304 SS plate, are designed by a facile chemical-based oxidation method. The obtained SS surfaces show excellent underwater anti-crude-oil-fouling property and thermal stability. Furthermore, the obtained 316 L SS mesh can effectively separate crude oil/water mixture solely driven by gravity. Significantly, the as-prepared SS surfaces possess robust antifouling and self-cleaning property during multiple cycles with the aid of Fenton-like catalytic reaction between Fe (III) and H2O2 or calcination at high temperature. Therefore, the fish-scale-like SS surfaces show great potential in a wide range of fields, such as marine antifouling, oil-water separation and food industry.
Transition metal sulfides/selenides are explored as advanced electrode materials for non-aqueous sodium-ion capacitors, using FeS2-xSex as an example. Solid solution of S/Se in FeS2-xSex allows it to combine the high capacity of FeS2 and the good diffusion kinetics of FeSe2 together, thereby exhibiting excellent cycle stability (~220 mAh g-1 after 6000 cycles at 2 A g-1) and superior rate capability (~210 mAh g-1 at 40 A g-1) within 0.8-3.0 V. These results are much better than those of FeS2 and FeSe2, confirming the advantages of S/Se solid solution as supported by EIS spectra, DFT calculations and electron conductivity. As FeS2-xSex is paired with activated carbon as Na-ion capacitors, this device is also better than sodium-ion batteries of FeS2-xSex//Na3V2(PO4)3 and sodium-ion capacitors of metal oxides//AC, particularly at high rates. These results open a new door for the applications of sulfides/selenides in another device of electrochemical energy storage.
In this study, an air assisted liquid phase microextraction based on deep eutectic solvent (AA-DES-LPME) method was developed for separation, preconcentration and determination of lead followed by graphite furnace atomic absorption spectrometry (GFAAS). The complexation of Pb(II) was carried out by using 4-(2-thiazolylazo) resorcinol as complexing agent at pH 6. Deep eutectic solvent was prepared by using choline chloride phenol (ChCl-Ph) and was added to an aqueous solution containing analyte, and then mixture was sucked up and injected nine times with the help of a syringe, and a cloudy state was attained. After extraction, the solution was centrifuged and upper layer was separated and Pb(II) ions was determined by GFAAS. Different parameters were investigated and optimized including pH, volume and type of DES, effect of ligand volume, effect of pulling and pushing cycles. Under optimum conditions, the detection limit, limit of quantitation were observed as 0.60 ng L⁻¹ and 1.98 ng L⁻¹, respectively. Preconcentration factor (PF) and relative standard deviation (RSD) were found to be 60 and 2.9%, respectively. Certified reference materials (CRMs) were used to check the accuracy of developed technique. Finally, present procedure was fruitfully used for analysis of Pb(II) in various food and water samples.
Superhydrophobic layers are extremely essential for protecting material surface in various applications. In this study, a stable superhydrophobic mixed matrix surface with a 152.2° contact angle can be fabricated through the technology of layer-by-layer hot-pressing (HoP), and then modified by 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) on the [email protected] fabric surface. The morphology and chemical composition were analyzed by the means of SEM, XRD and FTIR. The obtained superhydrophobic coatings showed excellent antiwear performance and drag reduction under desired working conditions. Moreover, we successfully applied superhydrophobic [email protected] fabric in the alcohol adsorbent with high removal capacity, and it can be reused for several times without serious efficiency loss.
Two-dimensional (2D) MoSe2/graphene nanocomposites show great potential as anode materials for sodium ion batteries (SIBs). In this work, we report the controlled growth of oriented, interlayer-expanded MoSe2 nanosheets on graphene with Mo–C bonding via a surfactant-directed hydrothermal reaction. The resulting 2D nanocomposite with strong electronic coupling facilitates both electron and Na-ion transfer across the interface and reversible insertion/extraction of Na-ion, enabling fast pseudocapacitive Na-ion storage with reduced voltage hysteresis and excellent durability over 1500 cycles. Density Functional Theory (DFT) calculation demonstrated MoSe2/graphene established a charge accumulation at the interface and promoted sodium-ion transport through the interface. Such outstanding Na-ion storage capability propels their potential application in sodium-ion capacitors (SICs). As a proof-of-concept, a model hybrid SIC was demonstrated by assembling with MoSe2/graphene composite as anode and activated carbon as cathode, delivering an impressive energy density of 82 W h kg⁻¹ and power output of 10,752 W kg⁻¹ within a voltage window of 0.5–3 V. The SIC also delivered a superior rate capability (66% capacitance retention after increasing the current density from 0.1 to 25.6 A g⁻¹) and cyclability (81% capacitance retention over 5000 cycles at 5 A g⁻¹), which shows promise for bridging the performance gap between conventional batteries and supercapacitors. The proposed strategy based on hierarchical hybridization combined with chemical bonding and interlayer engineering may hold great promise for developing advanced electrode materials for next-generation clean energy systems.
In this article, dicationic ionic liquids (DILs), including N,N,N,N′,N′,N′-hexaethyl-ethane-1,2-diammonium dibromide (HEDBr), N,N,N,N′,N′,N′-hexaethyl-propane-1,3-diammonium dibromide (HPDBr) and N,N,N,N′,N′,N′-hexaethyl-butane-1,4-diammonium dibromide (HBDBr), were designed and used to extract phenolic compounds from model oil and coal tar oil. The effects of stirring time, temperature, DIL:phenol mole ratio, and initial phenol concentration on the extraction of phenol were studied. It is found that the DIL:phenol mole ratio is only around 0.3 when the highest extraction efficiency of phenol is obtained. The extraction process completes within 5 min at room temperature, and the extraction efficiency is not dependent on temperature. Also, the ultimate phenol concentration remains constant despite the difference in initial phenol concentrations. Of these DILs, HPDBr shows the lowest ultimate phenol concentration of 3.9 g/dm³, and the extraction efficiency of phenol can reach as high as 97.0%. These DILs can be regenerated by anti-solvent method and reused several times without significant reduction in extraction efficiency. In addition, HPDBr was demonstrated to extract phenolic compounds from real coal tar oil, and its extraction efficiency of phenolic compounds is 92.7%. The mechanism, analyzed by FT-IR, shows that there is a hydrogen bond between phenol and DIL.
Deep eutectic solvents (DESs) have naturally emerged as an alternative for traditional organic solvents for their efficiency on extracting natural products from plant materials. In the present study, 12 kinds of DESs (choline chloride as the hydrogen bond acceptor) were firstly prepared and applied to extract five main flavonoids (namely rutin, quercetin-3-O-glucoside, quercetin, kaempferol and isorhamnetin) from sea buckthorn leaves (SBL) combined with microwave-assisted extraction. The results showed that the extraction efficiencies of target flavonoids by DES were significantly superior to 70% ethanol. Aiming at obtaining the optimal procedure, the extraction conditions were statistically investigated. Under the optimal conditions in pilot-scale application, the total maximum extraction yields of five main flavonoids reached to 20.820 mg/g, which was 1.321–2.400 folds to those by the traditional extraction methods. Meanwhile, the following enrichment of targets compounds from DES extraction solution exhibited excellent recoveries in the range of 72.36–84.99% were achieved by macroporous resin AB-8. In addition, the enriched flavonoids by AB-8 resin exhibited better antioxidant activities as compared with those unenriched. The results indicated that the potential of the developed method as a promising safe and sustainable alternative for selectively extraction and separation of bioactive substances from plant materials.
Energy storage is increasingly demanded in many new niches of applications from wearables to unmanned autonomous vehicles. However, current energy storage systems are unable to fulfill the power requirements (high energy at high power) needed for these novel applications. Recently, Li-ion capacitors (LICs) have been spotted as hybrid device with the potential to display high energy and high power. Nevertheless, it is still a great challenge to achieve high performance LICs due to the unmatched kinetic property and capacity between anode and cathode materials. Herein, we are presenting our first seminal report on the use of BiVO4 nanorods as a new anode material for LICs coupled with a partially reduced graphene oxide (PRGO) cathode. The BiVO4 nanorods show an excellent reversible capacity of 877 mAh/g (ultrahigh volumetric capacity of 4560 mAh/cm3) at 1.1 A/g with a great capacity retention (in half-cell design), which is highest value reported so far for metal vanadates. Later on, a LIC was constructed with BiVO4 as an anode and PRGO as a cathode electrode delivering high energy density of 152 Wh/kg and a maximum power density of 9.6 kW/kg compared to that for hard carbon and intercalation (such as Li4Ti5O12, Li3VO4) based anode materials. Additionally, BiVO4//PRGO LIC exhibits good cyclability of 81 % over 6000 cycles. Thus, this investigation opens up new opportunities to develop different LIC systems.