Mixed Solvent Of Ethylene Glycol Research Articles

Flexible organohydrogel ionic skin with Ultra-Low temperature freezing resistance and Ultra-Durable moisture retention

HypothesisOne prevailing method to construct excellent temperature tolerance/long-lasting moisture hydrogels is to couple the original hydrogel networks with freezing-tolerant/moisture retaining agents, including ionic liquids, inorganic salts, zwitterionic osmolytes, and polyhydric alcohols. Among them, organohydrogels have shed new light on the development of ionic skins with long-term usability and stable sensing performance at subzero temperatures due to their long-lasting water retention and anti-freezing capability. ExperimentsWe report a dual network organohydrogel by doping conductive ZnSO4 into the double network hydrogel of polyvinyl alcohol-polyacrylamide (PVA-PAM) with subsequent immersing in a mixed solvent of ethylene glycol (EG) and H2O. The anti-freezing and moisture retaining abilities of the PVA/PAM/Zn/EG (PPZE) organohydrogel were studied and the sensing performances of the PPZE organohydrogel-based ionic skin were investigated. FindingsThe organohydrogel exhibits a high conductivity (0.44 S m−1), excellent fatigue resistance and exceptional moisture retaining ability with more than 99.3% of the initial weight retention after 31 days storage at ambient temperature. Importantly, the PPZE organohydrogel-based ionic skin shows an ultra-low temperature anti-freezing ability and remains flexibility and sensing capability with a high sensitivity (signal response time ∼ 0.23 s) even at -50 °C. The PPZE organohydrogel demonstrates a tremendous potential in artificial skin and health monitoring.

Shape-Controlled Syntheses of Magnetite Microparticles and Their Magnetorheology.

Magnetic microspheres in a concentrated suspension can be self-assembled to form chain structures under a magnetic field, resulting in an enhanced viscosity and elasticity of the suspension (i.e., the magnetorheological (MR) effect). Recently, interest has been raised about the relationship between nonspherical particles, such as octahedral particles and the MR effect. However, experimental studies have not made much progress toward clarifying this issue due to the difficulty associated with synthesizing microparticles with well-defined shapes and sizes. Here, we presented a method for the shape-controlled synthesis of magnetite (Fe3O4) microparticles and investigated the MR effects of two suspensions prepared from the two shape-controlled samples of Fe3O4 microparticles. Our method, which was based on the polyol method, enabled the preparation of spherical and octahedral Fe3O4 microparticles with similar sizes and magnetic properties, through a reduction of α-FeOOH in a mixed solvent of ethylene glycol (a polyol) and water. The water played an important role in both the phase transition (α-FeOOH to Fe3O4) and the shape control. No substantial difference in the MR effect was observed between an octahedral-particle-based suspension and a spherical-particle-based one. Therefore, in this study, the shape of the microparticles did not strongly influence the MR effect, i.e., the properties of the chain structures.

High‐Performance 3D Pinecone‐Like LiNi1/3Co1/3Mn1/3O2 Cathode for Lithium‐Ion Batteries

A high‐performance LiNi1/3Co1/3Mn1/3O2 cathode with a uniform pinecone‐like morphology is reported, which is prepared by a solvothermal process, using urea to tune the pH of a mixed solvent of ethylene glycol and water, and a subsequent calcination process. The material has uniform, well‐defined pinecone‐like particles with lengths of 3–4 μm and widths of 1–2 μm. It exhibits a significantly enhanced cathodic performance in a Li‐ion battery, with a reversible discharging capacity of up to 199 mAh g−1 when it is charged to 4.6 V at a charge/discharge rate of 0.2 C and of 159.2 mAh g−1 at a rate of 2 C. After 100 charge/discharge cycles, the capacity retention is 91%, demonstrating its superior capacity and stability in comparison with a sample prepared via the coprecipitation method. The cyclic voltammetry and electrochemical impendence spectroscopy results reveal that the pinecone‐like LiNi1/3Co1/3Mn1/3O2 material has markedly lower polarization and lower resistance to the migration of lithium ions than the coprecipitation sample. The material's high performance, especially its outstanding capacity at a high discharge rate and its significantly enhanced cyclability, makes the synthesized pinecone‐like LiNi1/3Co1/3Mn1/3O2 a promising high‐performance cathode material for lithium‐ion batteries.

Outstanding performances of Ni2CoS4/expanded graphite with ultrafine Ni2CoS4 particles for supercapacitor applications

Nickel sulfides are desirable electrode materials for supercapacitors, while low electronic conductivity and poor cyclic stability restrict their wide applications. Herein, Ni2CoS4/expanded graphite (Ni2CoS4/EG) composite was prepared in mixed solvents of ethylene glycol and H2O via a rapid and energy-saving microwave heating method. Scanning transmission electron microscopy image shows that Ni2CoS4 particles are ultrafine with an average diameter of 2 nm and uniformly distributed on expanded graphite. The specific capacitance of the Ni2CoS4/EG composite can reach up to 2056.8 F g−1 at 5 A g−1 as compared to 1574.4 F g−1 of Ni3S4, 229.1 F g−1 of CoS and 1516.6 F g−1 of Ni2CoS4; and even at higher current density of 30 A g−1, the specific capacitance can still demonstrates 1923.3 F g−1, thus 92.5% of rate capability can be achieved as the current density increases from 5 to 30 A g−1. Moreover, it exhibits an excellent stability of 94.4% after cycling at current density of 30 A g−1 for 2000 cycles. The composite delivers high initial capacitance, excellent rate capability, and fantastic stability. Furthermore, the fabricated AC//Ni2CoS4/EG asymmetric supercapacitor also exhibits a high specific capacitance of 120.3 F g−1 at 0.5 A g−1, an superior cycle life (91% at 5 A g−1 for 5000 cycles), and an extremely high energy density of 52 Wh kg−1 at 477 W kg−1. This work offers a new insight to synthesize ultrafine bimetallic sulfides, and the superior high performances of the Ni2CoS4/EG composite can provide practical applications in supercapacitors.

Improving Ni(OH)2/C Supercapacitive Performances through Mixed Solvents and Thermal Treatment of XC-72

A Ni(OH)2/XC-72 nanocomposite was first synthesized via a solvothermal method in mixed solvents of ethylene glycol and H2O; using a smaller amount of ethylene glycol not only reduces the cost but a...

Vapor–Liquid Equilibria for 2-Propanol Dehydration through Extractive Distillation Using Mixed Solvent of Ethylene Glycol and Choline Chloride

The mixed solvent of ethylene glycol (EG) and choline chloride (ChCl) was tested as an entrainer for 2-propanol dehydration by extractive distillation. Isobaric vapor–liquid equilibrium (VLE) data were measured at 101.3 kPa for the quaternary system water + 2-propanol + EG + ChCl. The NRTL equation was used for the modeling of the quaternary VLE. Mean absolute deviations were 0.26 K and 0.0036 for equilibrium temperature and vapor mole fraction of 2-propanol, respectively. As compared with EG alone, the existence of ChCl in the solvent significantly decreases the activity coefficient of water and increases the activity coefficient of 2-propanol, both enhancing the relative volatility of 2-propanol to water. The azeotrope of water +2-propanol can be removed with the addition of the deep eutectic mixture EG + ChCl 2:1 at a solvent mass fraction of 0.157. The mixed solvent may be readily applied in extractive distillation of 2-propanol and water, replacing the frequently used mixed solvent of ethylene glycol and potassium acetate.

Solvothermal Synthesis of Mesoporous Fe3O4 Nanoparticles in Mixed Solvent of Ethylene Glycol and Water: Structure and Magnetic Properties

Mesoporous Fe3O4 nanoparticles were synthesized by a solvothermal method, via a mixed solvent of ethylene glycol (EG) and deionized water, using iron chloride and urea as the precursors. The phase, morphology, and pore structure are investigated by the characterization of X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 isotherm adsorption–desorption. The results show that the amount of water in the mixed solvent plays vital role in controlling the size of Fe3O4 nanoparticles, specific surface area, and pore size. Additionally, solid Fe3O4 nanospheres were prepared using only EG as solvent, while α-Fe2O3 nanosized polyhedrals were obtained with only water as solvent. The mesoporous Fe3O4 nanoparticles show a ferromagnetic behavior, with saturation magnetizations (Ms) of 78–82 emu g− 1 and coercivities (Hc) ranging from 13–58 Oe. The α-Fe2O3 nanoparticles also exhibit a weak-ferrimagnetic character, with a remanent magnetization (Mr) of 0.24 emu g− 1, and Hc of 558 Oe.

Study of the H2O/Al2O3 Interface and the Acting Mechanism of Water in the Working Electrolyte

Using a working electrolyte containing mixed solvents of ethylene glycol and N,N-dimethylformamide, this paper presents a study of the reactions on the H2O/Al2O3 interface with sum frequency vibrational spectroscopy and the effects of different water content on the performance of the working electrolyte and an aluminum electrolytic capacitor and summarizes the rules of the variations in the performance parameters of the working electrolyte and aluminum electrolytic capacitor with respect to the water content. The results demonstrate that, when the water content is increased from 2.5 to 15%, the conductivity of the working electrolyte increased by 930 μS/cm, and the sparking voltage decreased by 27 V. Also, the increased water content causes lower oxidation efficiency and lower thermal stability. The leakage current of the aluminum electrolytic capacitor after high-temperature storage increases with an increase in the water content, and the attenuation rate of capacitor’s the low-temperature capacitance decreases with an increase in the water content.

High Photocatalytic Activity of Oliver-Like BiVO<sub>4</sub> for Rhodamine B Degradation under Visible Light Irradiation

We report the facial synthesis of BiVO4crystals with different morphologies by the solvothermal and hydrothermal process. The phase structure and morphology as-synthesized samples were characterized by XRD, FE-SEM, and UV-vis DRS spectroscopy. We also investigated the photocatalytic activity of BiVO4for the decomposition of rhodamine B (RhB) under visible light irradiation. The results showed that oliver-like BiVO4was obtained when using the mixed solvent of ethylene glycol and water while starflower-like BiVO4was obtained using the mixed solvent of ethylene glycol monomethyl ether and water. The hydrothermal evolution process the BiVO4product with a rod-like morphology. Oliver-like BiVO4with pure monoclinic scheelite phase and high specific surface area exhibits efficient photodegradation of RhB (k = 7.82x10-3min-1).

Systematic Investigation on Synthesis of CuInS2 Powder and its Influencing Factors

AbstractCuInS2 powders were prepared by solvothermal method. The effects of experimental conditions on crystal structure, composition phase and morphology were investigated systematically. The phases of product samples were analyzed by X‐ray diffraction (XRD) on the Bruker D8 Advance XRD system with Nifiltered Cu‐Kα (λ = 1.5059 Å). The morphology of the product powders were observed using scanning electron microscope (SEM) with a model of JSM‐6380LA made by Japan Electronics Co., Ltd. The elemental compositions of the product powders were analyzed by energy dispersive spectroscopy (EDS). The results show that, different solvents have important effects on the crystal structures of CuInS2 powders. With CuC12·2H2O, InCl3 and SC(NH2)2 as raw materials, the wurtzite CuInS2 obtained with the mixed solvent of ethanol and hydrazine hydrate has better crystallinity than that obtained by the mixed solvent of ethylene glycol and hydrazine hydrate. The product powder obtained with ethanol without hydrazine hydrate has major phase chalcopyrite CuInS2. The wurtzite CuInS2 powder consists of aggregated particles with diameters of 0.1 ∼ 0.5 μm. The sample with chalcopyrite has relatively more large particles with diameters of 3 ∼ 5 μm which consist of smaller flakes. The optimum conditions for preparing wurtzite CuInS2 powder are at 160 °C for 20 h using CuC12·2H2O, InCl3 and SC(NH2)2 as raw materials and the mixed solution of ethanol and hydrazine hydrate as solvent. With the increase of reaction temperature, the XRD peaks of chalcopyrite CuInS2 are more obvious, but the new impurity phase Cu2S appears at 220 °C. With holding time prolonging, it is helpful to eliminate the XRD peaks of impurity and promote chalcopyrite CuInS2 formation. The optimum conditions for chalcopyrite CuInS2 are reacting at 220 °C for 30 h with ethanol without hydrazine hydrate as solvent and CuC12·2H2O, InCl3 and SC(NH2)2 as raw materials.

Catalytic activity of Pd-Ag nanoparticles supported on carbon nanotubes for the electro-oxidation of ethanol and propanol

Pd and Pd-Ag nanoparticles supported on multi-walled carbon nanotubes (MWCNT) were prepared by using the NaBH4 reduction method in a mixed solvent of ethylene glycol and water; their catalytic activity for the electro-oxidation of ethanol, n-propanol and iso-propanol was investigated in alkaline media by the voltammetric method. The results indicate that Pd and Pd-Ag nanoparticles are well-dispersed on the surface of MWCNTs and the average sizes of metal particles on the Pd/MWCNT, Pd4Ag1/MWCNT, Pd2Ag1/MWCNT and Pd1Ag1/MWCNT catalysts are 7, 4, 7 and 11 nm, respectively. Over these catalysts, the electro-oxidation of n-propanol exhibits larger current density than the oxidation of ethanol and iso-propanol. Moreover, the binary PdnAg1/MWCNT catalysts (n = 4, 2, 1), especially Pd4Ag1/MWCNT, gives higher current density for the oxidation of ethanol and propanols than the Pd/MWCNT catalyst, suggesting that the addition of Ag can enhance the activity of Pd-based catalyst for the electro-oxidation of alcohols. The excellent activity of binary Pd-Ag/MWCNT catalysts is probably attributed to the weak absorption of intermediate species on Pd due to the interaction between Pd and Ag, which may promote the oxidation of alcohols.

Formation of nickel-doped magnetite hollow nanospheres with high specific surface area and superior removal capability for organic molecules

A strategy for the formation of magnetic NixFe3−xO4 hollow nanospheres with very high specific surface areas was designed through a facile solvothermal method in mixed solvents of ethylene glycol and water in this work. The Ni/Fe ratios and the crystal phases of the NixFe3−xO4 hollow nanocrystals can be readily tuned by changing the molar ratios of Ni to Fe in the precursors. An inside-out Ostwald ripening mechanism was proposed for the formation of uniform NixFe3−xO4 hollow nanospheres. Moreover, the obtained NixFe3−xO4 hollow nanospheres exhibited excellent adsorption capacity towards organic molecules such as Congo red in water. The maximum adsorption capacities of NixFe3−xO4 hollow nanospheres for Congo red increase dramatically from 263 to 500 mg g−1 with the increase of the Ni contents (x) in NixFe3−xO4 hollow nanospheres from 0.2 to 0.85. The synthesized NixFe3−xO4 nanoparticles can be potentially applied for waste water treatment.

Room-temperature homogeneous precipitation of highly uniform BaCO3 dumbbells in a mixed solvent of ethylene glycol and water

We describe the successful synthesis of highly uniform BaCO3 dumbbells by using different carbonate esters (namely (CH3)2CO3 and (CH3CH2)2CO3) as the precipitating agent in a mixed solvent of ethylene glycol (EG) and water. The products were obtained at room temperature without any extra additives. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic studies identified orthorhombic BaCO3 structure of the prepared samples. The effects of reactant concentration and solvent composition on the morphology of BaCO3 were investigated. In spite of the different carbonate esters used, uniform BaCO3 dumbbells with excellent monodispersity can be generated by adjusting the reactant concentration and volume ratio of EG to water at appropriate values. The synergic effect of carbonate ester and EG modified the acicular habit of BaCO3 and facilitated the formation of dumbbells.

Pd–Cu alloy with hierarchical network structure as enhanced electrocatalysts for formic acid oxidation

Pd–Cu alloy with hierarchical porous network structure is prepared via a facile one-pot hydrothermal reaction, by using a mixed solvent of ethylene glycol and water as the reaction media, and the block copolymer Pluronic P123 as the structure-directing agent. The Pd–Cu alloy networks are constructed by hierarchically assembled nanorods as building blocks. The structure, porosity, surface chemical state and electrochemical properties of as-prepared Pd–Cu alloy are characterized and analyzed. Owing to the superior hierarchical porous network structure, the Pt–Cu alloy catalysts present remarkably enhanced catalytic performance toward formic acid oxidation, in comparison with the commercial Pd black.

Cationic cetylpyridinium micelle as a novel electrolyte system for dye-sensitized solar cells

The charge transfer process within the electrolyte system is an active area for further improving the conversion efficiency of the dye-sensitized solar cell (DSSC). In this work, micelle formed by cationic surfactant cetylpyridinium (CP) chloride was used in the electrolyte to enhance the ion transport of the redox couple. Using a mixed solvent of ethylene glycol and acetonitrile at 1:9 volume ratio and 0.50 M CP, an 83% improvement in DSSC efficiency was observed. Because of a strong correlation between the efficiency and the current density as a function of the CP concentration, the presence of CP micelle likely caused a favorable shift in the ion transport within the electrolyte. According to the cyclic voltammetry, such improved ion transport can be attributed to a faster diffusion of the redox couple, particularly the I3- diffusion. In addition, the impedance analysis also revealed a short electron lifetime for the diffusion process in the presence of the CP micelle. From these results, it is plausible that the CP micelle in the electrolyte provides an extensive network of positively-charged interfaces, which facilitates the diffusion of the redox couple and enhances the overall performance of the DSSC.

Rapid double-dye-layer coating for dye-sensitized solar cells using a new method.

Intensive research with the specific aim of developing inexpensive renewable energy sources is currently being undertaken. In dye-sensitized solar cell (DSSC) production, the most time-consuming process is coating the dye on working electrodes: absorption of ruthenium-based dyes [e.g., N719=bis(trtrabutylammonium)-cis-di(thiocyanato)-N,N'-bis(4-carboxylato-4'-carboxylic acid-2,2'-bipyridine) ruthenium(II)] on a photoanode takes a long time. We report a simple dye-coating method using a mixed solvent of ethylene glycol (EG) and glycerol (Gly). According to our experiments, dye-coating time can be reduced to 5 min from several hours. Maximum performance was obtained with an EG/Gly ratio of 1:1. This mixture of solvents gave a performance of 9.1%. Furthermore, the viscous solvent system could control coating depth; positioning dye coatings to a specific depth was rapid and facile. A cell containing two different dyes (N719+black dye) had an efficiency of 9.4%.

Synthesis of porous ZnO in mixed solvents system.

Three porous structures of ZnO were successfully synthesized in mixed solvents of ethylene glycol and distilled water. By adjusting ratios of ethylene glycol and distilled water, ZnO morphologies changed. Small porous plates with different sizes, folded porous plates with well-proportioned pores, heavily folded porous plates and solid flowers without pores emerged in sequence. The mechanism of the synthetic process was discussed. The morphologies and microstructures were investigated by transmission electron microscopy (TEM). The phase composition was verified by X-ray diffraction (XRD). This synthetic route provides a new idea to prepare other new structure materials.

Synthesis of LiMnPO4 porous plates in mixed solvents system.

0.6 to 7.5 microm LiMnPO4 porous plates with pore sizes from 100 to 150 nm were successfully synthesized in mixed solvents of ethylene glycol and distilled water. By changing stirring time, different morphologies of LiMnPO4 were prepared. Porous plates with the percentages of more than 70%, more than 50% and 25% porous ones were formed in sequence. The according rest parts were particles, less than 40% solid plates and 25% solid ones, respectively. Stirring time is the key cause influencing the nucleation rate and diffusion rate of the initial formed growth units of LiMnPO4. Through adjusting the factor, chemicals with specific morphology can be obtained in mixed solvents. The phase composition and microstructure were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. This synthetic route provides us a new idea to prepare new structure materials.

Microwave-assisted rapid synthesis and photocatalytic activity of mesoporous Nd-doped SrTiO3 nanospheres and nanoplates

Mesoporous Nd-doped SrTiO3 nanospheres and nanoplates with high specific surface areas have been successfully synthesized using tetra-n-butyl titanate, Sr(NO3)2, Nd(NO3)3 and NaOH in mixed solvents of ethylene glycol and deionized water by a rapid microwave-assisted solvothermal method at 200°C for 10min. Mesoporous Nd-doped SrTiO3 nanospheres are obtained at lower concentrations of the reactants. However, the product undergoes a dramatic morphological change from nanosphere to nanoplate when the concentrations of the reactants are increased. The photocatalytic activities of the samples for the degradation of methylene blue under simulated solar light irradiation (λ>290nm) and visible light irradiation (λ>420nm) are also evaluated. Both the mesoporous Nd-doped SrTiO3 nanospheres and nanoplates show higher photocatalytic activities than that of the commercial TiO2 (P25) under visible light irradiation.

Synthesis, characterization and enhanced gas sensing performance of WO3 nanotube bundles

Well-defined WO3 nanotube bundles have been achieved via a facile hydrothermal method in a mixed solvent of ethylene glycol (EG) and water. The as-obtained products were systematically characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectra (XPS), photoluminescence (PL), UV-vis diffuse reflectance spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray spectroscopy (EDS), respectively. The results indicate that the products consist of hierarchically nanostructured bundles assembled with smaller nanotube subunits. Meanwhile, the photoluminescence spectra demonstrate that the obtained products contain more oxygen vacancies compared with the reported WO3 materials. The morphologies of the products are found to be strongly dependent on the reaction time and the EG/H2O volume ratio, uniform WO3 nanotube bundles can be fabricated readily just via tuning the volume ratio of EG and H2O. Through a series of time-dependent morphological evolution studies, the growth process of WO3 nanostructures has been investigated, and the corresponding growth mechanism is discussed in detail as well. Additionally, the gas-sensing performances of uniform WO3 nanotube bundles were investigated for 100 ppm of ethanol. It was found that the WO3 nanotube bundles sensor displayed significantly better sensing performance than many reported WO3 materials due to more electron donor related oxygen vacancies.