Mixed Glycol Research Articles

Cellulose eutecticgel electrolytes based on ethylene glycol/zinc chloride deep eutectic solvent for flexible solid-state capacitors

In the present work, we successfully prepared a conductive eutecticgel with good mechanical properties, adhesion properties and excellent antifreeze properties by mixing ethylene glycol (EG) as the hydrogen bonding donor and zinc chloride (ZnCl2) as the hydrogen bonding acceptor in different molar ratios to form an anhydrous deep eutectic solvent (DES). Water-soluble cellulose acetate (WSCA), monomer acrylamide (AM), initiator ammonium persulfate (APS) and cross-linking agent MBA (N, N′-methylene bis(acrylamide)) were added into the prepared DES to form a eutecticgel by a simple one-pot cooking strategy. The mechanical properties of the eutecticgel were strengthened by cross-linking of WSCA and PAM chains through hydrogen bonding, and the addition of the DES and ZnCl2 increased the freezing-resistant property of the eutecticgel. The stresses of DES-WSCA/PAM eutecticgel increased with the content of WSCA. The stress of DES-WSCA/PAM eutecticgel gradually becomes larger with the increase of WSCA content, and it can reach 184.07 kPa at 2 % WSCA content. In addition, the capacitor prepared by DES-WSCA/PAM eutecticgel shows excellent performance, with a voltage window of 2 V and a capacitance of 371.5 F/g, which can be operated stably for a long period, and the capacitance can still reach 145.4 F/g even under the condition of −40 °C. Moreover, DES-WSCA/PAM eutecticgel capacitor has a long service life, its capacitance retention rate and coulombic efficiency can reach more than 91 % and 95 %, respectively, after 10,000 times of charging and discharging tests. In summary, DES-WSCA/PAM eutecticgel electrolyte is an ideal material for capacitors, which opens up a new way of thinking for the development of multifunctional cellulose-based eutecticgels with low-temperature resistance, good mechanical properties, and non-irritating for wearable energy storage devices.

Pengaruh Pencampuran Etilen Glikol dan Propilen Glikol Terhadap Sifat Optik Kawat Nano Perak yang Disintesis Menggunakan Metode Polyol

Research has been carried out aimed for looking effect of mixing Ethylene Glycol (EG) and propylene glycol (PG) on optical characteristics of silver nano wire (AgNWs) which synthesized using the polyol method. Synthesis was carried out for ± 5 hours on temperature of 130 oC inside erlenmeyer flask. The material used are silver (Ag) which is obtained from AgNO3, mixed solution of EG/PG with a concentration ratio of 100:0%; 75:25%; 50:50%; 25:75%; and 0:100%, FeCl3.6H2O, and capping agent in the form of Polyvynil Phyrolidone (PVP). The optical characteristics of AgNWs were observed through UV-Vis, FTIR, and length distribution through optical microscopy. The results of UV-Vis analysis showed four absorption peak at a wavelength of around 340, 350, 360 and at a wavelength of 390 nm as well as a change in the absorbance value. While the optical microscope test results also show that the length of the AgNWs increased on sample EG/PG 75:25% and 50:50%. Based on these results, it can be concluded that the mixing of EG and PG can affect the optical characteristics of AgNWs.

Low-cost temperature transition mixtures (TTM) based on ethylene glycol/potassium hydroxide as reversible CO2 sorbents

A low-cost Transition Temperature Mixture (TTM) has been synthesized by mixing ethylene glycol and potassium hydroxide as a new non-aqueous CO2 sorbent. Boric acid has been added to ensure the reversibility of the system and a small amount of water to modulate the viscosity and optimize the performances. The resulting mixtures have been characterized in terms of viscosity, conductivity and density over temperature (therefore ionicity via Walden plots) and the effect of temperature, pressure and the kinetics of the absorption have been evaluated. Under optimized conditions, the four-component mixture EG/KOH/BA/H2O 3:1:1:3 can absorb 24 gCO2/kgsorbent in 30 min at 35 °C at 1 atm (59 after 4 h) and 60 gCO2/kgsorbent in 30 min at high pressure (10 and 20 atm, 80 gCO2/kgsorbent after 50 min), while the desorption is quantitative after 30 min at only 60 °C under a gentle N2 flow. The system is robust enough to ensure multiple absorption/desorption cycles.

SYNTHESIS AND APPLICATION OF MIXED ETHYLENE GLYCOL DIESTERS BASED ON PETROLEUM ACIDS CHEMISTRY AND CHEMICAL TECHNOLOGY

In order to increase the range of plasticizers and antioxidants using the ZnO catalyst, mixed ethylene glycol diesters based on petroleum and fatty acids were synthesized by a waste-free method. To determine the optimal conditions for obtaining the target products, the effect of temperature, the amount of catalyst, the molar ratio of the components involved in the reaction for the maximum yield were studied and the optimal condition was established with a yield of 90-93. The properties of mixed diesters of petroleum acids have been studied, the physicochemical parameters have been determined by analytical and spectral methods. The degree of compatibility of ethers with polyvinyl chloride and the ability to prolong the life of diesel fuel have been determined. It was found that ethers can be recommended as effective plasticizers for polyvinyl chloride and antioxidants for diesel fuel. Taking into account the wide practical application of mixed esters, including esters of petroleum acids, and their high demand, the main goal of the article is to obtain mixed ethylene glycol esters based on natural, synthetic and fatty acids with a high yield without waste method, as well as to study their properties and applications. In this article, to solve the problem posed, natural petroleum acids of the fraction 90-230ºC / 6.65 × 10-4 MPa were used in the studies, taken from the "Meriken" unit of the H. Aliyev`s New Baku Oil Refinery, as well as synthetic petroleum acids synthesized by liquid-phase oxidation with atmospheric oxygen at a temperature of 135-140°С. In the following studies, asymmetric ethylene glycol diesters were synthesized based on natural, synthetic and fatty acids of the C6-C8 series at temperatures of 80-140oC, with a catalyst amount of 0.6-1.6% by weight (with respect to acid), molar ratio of components 2:1.1-1.6, the optimal conditions were determined (T,°C = 110-120, acid: alcohol - 2:1.3-1.5 mol, ZnO - 0.8-1.5% by weight ( in relation to acid)), the properties of the synthesized mixed diesters have been studied, their indicators have been determined by modern analytical and spectral methods, and the material balance of these ethers has been compiled. Other representatives of ethylene glycol based on oil and fatty acids in a similar way were synthesized and the physicochemical parameters were determined. The synthesized products are light yellow, transparent, odorless, insoluble in water, readily soluble in organic solvents. The compatibility of mixed diesters with polyvinyl chloride (PVC), as well as the effect of diesel fuel on thermal-oxidative stability in laboratory conditions has been studied. The research results are presented below: • mixed diesters of petroleum acids have been synthesized in the presence of a ZnO catalyst by one-stage method, which makes it possible to reduce intermedi; • the influence of various amounts of catalyst, the molar ratio of the components involved in the reaction, the temperature range the course of the reaction in order to select the optimal synthesis conditions were studied, mixed esters in high yield were synthesized and their physicochemical parameters by analytical and spectral methods were determined; • the degree of compatibility of mixed diesters synthesized on the basis of petroleum and fatty acids with PVC has been studied and tested as a new component to improve the thermal stability of diesel fuel. These esters can be recommended as effective plasticizers and antioxidants. Keywords: natural petroleum acids, synthetic petroleum acids, ethylene glycol, mixed diester, plasticizer, antioxidant

Ethaline deep eutectic solvent as a hydrophilic additive in modification of polyethersulfone membrane for antifouling and separation improvement

In this research, fabricating and modifying of polyethersulfone (PES) nanofiltration membrane were reported by using deep eutectic solvents (DESs) as a novel modifier for the membranes. The applied DES was produced by mixing ethylene glycol (EG) and choline chloride (ChCl). It is commonly known as ethaline. Ethaline was exploited as a hydrophilic additive into casting solution to formulate a novel PES/DES membrane by the non-solvent induced phase separation (NIPS) process. The PES/DES membranes were characterized by scanning electron microscope (SEM), contact angle measurement, atomic force microscope (AFM), attenuated total reflection-Fourier-transform infrared spectroscopy, mechanical strength and hydraulic testing of distilled water. Their performances were evaluated by bovine serum albumin (BSA) and dye solutions filtration and separation tests. The effects of different concentrations of DES loading were evaluated systemically on the membrane performance. The maximum pure water flux was 241.3 L/m2h for 2 wt% PES/polyvinyl pyrrolidone (PVP)/DES membrane, which it was 23 times of neat PES membrane (without PVP and DES) and 1.3 times of PES/PVP membrane. The pure water flux of PES/DES membrane (without PVP) was 17.6 L/m2h, presenting that the ethaline is not a good pore former. The dye and BSA rejections for all membranes were higher than 98% and 99%, respectively, showing suitable separation ability. Also, the influence of the DES on antifouling properties shows that the flux recover ratio of the DES blended membranes improved. The results showed that the ethaline DES is not a good pore former, but it is a good antifouling additive.

Stainless steel-like FeCrNi nanostructures via electrodeposition into AAO templates using a mixed-solvent Cr(III)-based electrolyte

Electrodeposition of stainless steel-like materials such as FeCrNi alloy into micro- and nanotemplates provides a sustainable framework for creating biomedical-oriented micro- and nanocomponents with outstanding characteristics. While Cr(III)-based electrodeposition represents a ‘green’ alternative to toxic Cr(VI), its use is limited by Cr(III) aqueous chemistry which leads to the incorporation of impurities and the hydrogen evolution reaction (HER). These factors are responsible for low deposition efficiencies, brittleness and porosity. The current work sought to investigate the use of ‘green’ Cr(III)-glycine electrolyte to improve FeCrNi electrodeposition from Cr(III) precursors. Mixed-solvent electrolyte containing ethylene glycol (EG) was employed to reduce HER aftereffects. FeCrNi mixed EG electrolytes were compared to their aqueous counterparts to observe differences in Cr(III)-glycine complexation, coatings' composition and current efficiency. The feasibility of this method for creating nanostructures was verified by template-assisted electrodeposition using anodic aluminium oxide (AAO) templates. This study established that mixed-solvent electrolytes are an effective strategy to improve Cr(III)-based plating of alloys into miniaturised moulds. For the first time, electrodeposited FeCrNi nanowires (NWs) and nanotubes (NTs) were achieved via the framework developed in this work. The possible mechanisms controlling the morphological variations in FeCrNi nanostructures were discussed in relation to the kinetic and growth models in single metal electroplating into nanotemplates.

Effect of polyol synthesis on sintering of microsized Ag particles

This study focuses on improving the sintering performance of microsized Ag pastes via in situ chemical synthesis. Ag particles of three different average sizes, 1.5, 2, and 5 μm, were used as the Ag fillers. Two kinds of Ag pastes were prepared: conventional Ag pastes and new Ag pastes via polyol synthesis by mixing ethylene glycol (EG) and AgNO3. The effect of the polyol synthesis on sintering was evaluated with respect to the microstructure and material properties, such as the electrical resistivity and shear strength. The conventional pastes showed a low sintering performance and poor necking, leading to low shear strengths of 8.8, 9.2, and 6.8 MPa at 300 °C for the 1.5, 2, and 5 μm Ag particles, respectively. The new pastes exhibited decreased electrical resistivity and shear strengths of 11.8, 15, and 13.0 MPa with a substantial coalescence of the Ag particles and thick necking. Moreover, the XRD and TG-DTA results indicated that the method can be applied to achieve pure metallic bonding with increased sintering performance. The increased sintering performance of the new pastes could be due to the membrane-like morphology from the synthesis process, which connects the Ag particles and may provide a diffusion layer between the Ag particles. The thermal aging test of the new paste with the 2.5 μm fillers indicated a high reliability, and the shear strength of the Ag joint was maintained.

The photocatalytic performance of cesium tungsten oxide particles under visible-light irradiation and preparation using a glycothermal process

Abstract This study investigated the role of cesium tungsten oxide particles in the photocatalytic degradation of dyes under visible-light irradiation. A cesium tungsten oxide compound with c-CsW1.6O6 particles was prepared by rapidly mixing ethylene glycol with ammonium tungstate parapentahydrate ((NH4)10W12O41•5H2O) and cesium nitrite (CsNO3) and heated at 120 °C for 1 h as part of the glycothermal process. Results indicated that the cesium tungsten oxide particles had a low band gap and generated holes (h+) and electrons (e−), which subsequently produced O2•− and •HO that degraded the methylene blue (MB) dye under visible-light irradiation. This study determined that the c-CsW1.6O6 structure of the 200 °C-calcined particles exhibited the best photocatalytic degradation of MB. The polymorphous structures of cesium tungsten oxide particles calcined at 400 °C or higher temperatures exhibited poor photocatalytic degradation of MB.

Performance of mixture of ethylene glycol and glycine in inhibiting methane hydrate formation

This study investigates synergistic hydrate inhibition performance of conventional thermodynamic hydrate inhibitors (THIs) combined with amino acids. For this purpose, hydrate-liquid-vapor equilibrium (HLVE) data for methane were measured in the presence of mixed ethylene glycol and glycine using 1:1 mixtures at concentrations of 1 wt% (0.5 wt% ethylene glycol +0.5 wt% glycine), 5 wt% (2.5 wt% ethylene glycol +2.5 wt% glycine), 10 wt% (5 wt% ethylene glycol +5 wt% glycine), 20 wt% (10 wt% ethylene glycol +10 wt% glycine), and 30 wt% (15 wt% ethylene glycol +15 wt% glycine) by the isochoric pressure search method. Thermodynamic inhibition efficiency has been investigated by observing the shifts in the hydrate equilibrium curves and trends of the calculated hydrate suppression temperatures at various concentrations and pressures. The results were also obtained for ethylene glycol, glycine and ionic liquids for comparison. An improving inhibition performance by mixing ethylene glycol and glycine was observed, indicating the potential of amino acids as inhibition synergists in hydrate exploitation, oil/gas transportation and flow assurance. Molar hydrate dissociation enthalpies were calculated by using the Clausius-Clapeyron equation and showed that the interaction of ethylene glycol and glycine has no impact on the hydrate structure.

Structures and properties of N-doped TiO2 nanotubes arrays synthesized by the anodization method for hydrogen production

The films of TiO2 nanotube arrays were fabricated by the anodization of Ti metal sheets for photocatalytic hydrogen production. The anodization was carried out in electrolytes prepared by mixing ethylene glycol (EG), ammonium fluoride (0.3 wt% NH4F) and deionized water (2 Vol% H2O). DC power supply was used at a constant voltage of 50 Volts. The nanotube arrays were aged in different amounts of ammonia (NH3) as nitrogen dopants. The morphology of the nanotube arrays was characterized by scanning electron microscopy (SEM). The phase and structure of the TiO2 nanotube arrays were determined by X-ray diffraction (XRD). The phase of the nanotubes is transformed from anatase to rutile when annealing temperature is changed from 450 °C to 500 °C or higher. The phase of the nanotubes became completely rutile when the nanotube arrays were 700 °C or higher, and the nanotubes were transformed to nanacrystalline. X-ray Photoelectron spectroscopy (XPS) was used to determine the dopant presenting in TiO2 structure. UV-vis spectroscopy was used to study the optical property of the nanotubes. The diameters of TiO2 nanotubes were about 200 nm. The highest density of TiO2 nanotubes was obtained when the nanotubes were doped with 6% by volume of ammonia. The photocatalytic activity was examined without an external applied potential. The maximum photocurrent density was 2.7 mA/cm2 under illumination of 100 mW/cm2 corresponding with photoconversion efficiency of 3.3%.

Effects of additives and post‐treatment on the thermoelectric performance of vapor‐phase polymerized PEDOT films

ABSTRACTVapor‐phase polymerization (VPP) is an important method for the fabrication of high‐quality conducting polymers, especially poly(3,4‐ethylenedioxythiophene) (PEDOT). In this work, the effects of additives and post‐treatment solvents on the thermoelectric (TE) performance of VPP‐PEDOT films were systematically investigated. The use of 1‐butyl‐3‐menthylinidazolium tetrafluoroborate ([BMIm][BF4], an ionic liquid) was shown to significantly enhance the electrical conductivity of VPP‐PEDOT films compared with other additives. The VPP‐PEDOT film post‐treated with mixed ethylene glycol (EG)/[BMIm][BF4] solvent displayed the high power factor of 45.3 μW m−1 K−2 which is 122% higher than that prepared without any additive or post‐treatment solvent, along with enhanced electrical conductivity and Seebeck coefficient. This work highlighted the superior effect of the [BMIm][BF4] additive and the EG/[BMIm][BF4] solvent post‐treatment on the TE performance of the VPP‐PEDOT film. These results should help with developing the VPP method to fabricate high‐performance PEDOT films. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1738–1744

Preparation of Structural Phase Diagram of Nd2Ni1-X Cu x O4+δ As New Cathode Materials – Clarification of Existence of Miscibility Gap

Nd2NiO4+δ with K2NiF4 type structure (T-phase) composed of rock salt layer and perovskite layer has attracted much interest as new cathode material for solid oxide fuel cell. It was reported that partial substitution of Cu for Ni-site in Nd2NiO4+δ improved ionic and hole conductivity [1]. However, crystal structure must change depending on Cu content, resulting in possible variation of electrical property, since crystal structure of Nd2CuO4 is T’-phase composed of fluorite layer and [CuO2] sheet, which is completely different from T-phase. For optimization of Cu content in Nd2Ni1-x Cu x O4+δ as cathode material, structural phase diagram between Nd2NiO4+δ and Nd2CuO4+δshould be established. In this study, preparation of Nd2Ni1-x Cu x O4+δ with various compositions was attempted and stability at high temperature was evaluated to establish structural phase diagram. It has been established that there exists miscibility gap in Nd2Ni1-x Cu x O4+δ for 0.4≤x≤0.9 for the first time. Nd2Ni1-x Cu x O4+δ (0.0≤x≤1.0) were prepared by the Pechini method by which preparation of homogeneous specimens can be expected. Nd2O3, Ni(NO3)2·6H2O and CuO powders were dissolved with mixture of dilute HNO3 and H2O2, distilled H2O and dilute HNO3, respectively. They were mixed with nominal composition. After mixing ethylene glycol and citric acid, the mixture was heated at about 450 °C, resulting in precursor. The precursor obtained was calcined at 700 °C for 24 h in air, followed by pressing into pellet and heat-treatment at 1000 – 1200 °C in air for 10 h. For identification of the crystal structure and evaluation of the lattice constants, X-ray diffraction measurement (XRD) was performed. Some XRD patterns were analyzed using the Rietveld analysis employing program RIETAN-FP [2]. Homogeneity of the specimens was evaluated by SEM-EDX analysis (JEOL: JCM-5700 equipped with JED-2300). Temperature dependence of lattice constants and molar volume and existence of the structural phase transition were evaluated using high-temperature X-ray diffraction measurements in the air. XRD patterns at room temperature of Nd2Ni1-x Cu x O4+δ prepared at 1200 °C could be indexed as single orthorhombic T-phase with space group of Fmmm (No. 69) and single tetragonal T-phase with I4/mmm (No.131) for 0.0≤x≤0.1 and 0.2≤x≤0.3, respectively. For diffraction patterns of 0.4≤x≤0.9, peaks assigned as T’-phase were observed in addition to ones indexed as T-phase. With increasing Cu content, intensity of the peaks indexed as T’-phase increased and ones assigned as T-phase decreased. All the peaks of XRD pattern for the specimen with x=1.0, i, e., Nd2CuO4+δ was successfully indexed as tetragonal T'-phase with space group of I4/mmm (No.131). Rietveld analysis revealed that lattice constants and molar volume of both T-phase and T’-phase in the specimens with 0.4≤x≤0.9 were independent on Cu content, indicating existence of miscibility gap for 0.4≤x≤0.9. Also revealed by Rietveld analysis was linear relationship between Cu content and molar ratio of T’-phase which could be ascribed to satisfaction of lever rule in the miscibility gap. EDX image and spectra of Nd2Ni0.4Cu0.6O4+δ depicted in Fig. 1 indicate that two phases with Ni rich and Ni poor composition coexist in the specimen, showing agreement with proposed miscibility gap by Rietveld analysis. High temperature XRD measurements revealed that the miscibility gap for 0.4≤x≤0.9 was maintained up to 1000 °C. For the specimens prepared at 1000 °C, the miscibility gap was observed for 0.3≤x≤0.9, suggesting expansion of the miscibility gap region by decreasing temperature.

Preparation of the Sm3+-Doped Magnetic Nanoparticles via Microwave-Assisted Polyol Synthesis

Sm3+-doped magnetic nanoparticles (NPs) were prepared via microwave-assisted polyol synthesis in ethylene glycol, poly(ethylene glycol) and mixed ethylene glycol—poly(ethylene glycol) solutions. In present work, the effects of organic solvent composition on particle size, particle size distribution, extent of agglomeration, and samarium content in prepared NPs were studied. The synthesized NPs were characterized by several techniques as follows: X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetry (TGA) and X-Ray fluorescence (XRF) analysis. XRD and TEM results showed formation of ~6.0–17.9 nm NPs having different microstructure characteristics (average particle size, particle size distribution, and agglomeration). The TGA analysis indicated the presence of organic components on the surface of NPs. Cytotoxic activity of the prepared magnetic NPs towards HeLa cells was evaluated by using standard live/dead assay in comparison to a control solution. It was shown that prepared magnetic NPs are characterized by low toxicity that makes possible their use for biomedical applications.

Preparation and Characterization of UV Cured Optical Films Containing a Fluorene Compound

In this study, the high refractive coating films applicable for optical materials were produced. the conversion and the photo curing behaviors were examined through FTIR-ATR and photo-DSC, and thermal and mechanical properties of cured films were examined by using DMA and UTM, and pencil hardness, refractive index and optical transmittance of film were measured. Urethane metacrylate oligomer was synthesized by mixing bisphenoxyethanolfluorene (BPEF), polycaprolactone diol (PCL), and polytetramethylene ether glycol (PTMeG) in varying ratios. Also, as the results of mixing ethylene glycol phenyl ether acrylate (PHEA) and trimethylolpropanetriacrylate (TMPTA) in varying ratios, the more time UV irradiated, the higher conversion and the heat of enthalpy (ΔH) and the initial curing rate increased with increasing TMPTA content up to 70%. Also, as the trifunctional monomer increased, the storage modulus and Tg increased, and the stress increased while the strain decreased to reach its maximum value. Also, as the BPEF ratio increased, the maximum value of stress increased while the strain decreased, the refractive index and pencil hardness increased, and light transmittance was all over 80%.

Performance of Latent Heat Solar Thermal Energy Storage System Using Various Heat Transfer Fluids

In the present work the thermal performance of Phase Change Material (PCM) based solar thermal energy storage system under the influence of different heat transfer fluids (HTF) have been investigated. Water, Ethylene Glycol–water and Copper nanofluid are selected as HTF. Paraffin is used as PCM and encapsulated in cylindrical capsules. The thermal energy storage (TES) tank acts as a storage unit consisting PCM capsules packed in three beds surrounded by water, which acts as sensible heat storage (SHS) material. HTF circulated by a pump transfers heat from solar flat plate collector (FPC) to the TES tank. 25% ethylene glycol -75% water HTF is prepared by mixing ethylene glycol (EG) with water. Copper-distilled water nanofluids (0.3% by weight) are prepared using prolonged sonication with sodium dodecyl benzene sulphonate (SDBS) as the surfactant. Various performance parameters such as charging time, instantaneous heat stored, cumulative heat stored and system efficiency are studied for various HTFs. It is found that the charging time is reduced by 33.3% for copper nanofluid and 22.2% for ethylene glycol- water mixture HTFs. It is also observed that there is an increase in system efficiency and cumulative heat stored with reference to charging time for these HTFs when compared with conventional HTF 1 i.e. water.

Synthesis and Characterization Anodized Titania Nanotubes for Enhancing Hydrogen Production

Pure and doped Titania nanotubes (TiO2 NTs) photoanodes were fabricated by means of anodization method. The anodization was carried out in electrolytes prepared by mixing ethylene glycol (EG), ammonium fluoride (0.3 wt % NH4F) and deionized water (2 Vol % H2O) with different concentrations of dopant Fe (NO3)3∙9H2O. A constant dc power supply of 50 V was used as anodic voltage. The samples were annealed at 450 °C for 2 hours. The resultant products were characterized by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) to determine their microstructures when TiO2 NTs were doped with different amounts of Fe atoms. The diameters of TiO2 NTs were about 60-120 nm. The highest density of TiO2 NTs was obtained when the nanotubes were doped with 0.01 M of Fe. The photocatalytic activity was examined without external applied potential. The maximum photocurrent density was 3.0 mA/cm2 under illumination of 100 mW/cm2.

An Integrated Sonication Technique for Electrodeposition of Platinum and Ruthenium on Carbon Nanotubes for Methanol Oxidation

An electrodeposition technique that could significantly improve the deposition of platinum-ruthenium (Pt-Ru) nanoparticles onto carbon nanotubes (CNTs) directly grown on carbon cloths was adopted in this study. Integrated sonication (IS) was activated during the electrodeposition process conducted in a sulfuric acid (H2SO4) solution containing Pt and Ru precursor chemicals of hexachloroplatinic acid and ruthenium trichloride, respectively, and ethylene glycol (EG) as a dispersing agent. In comparison with our earlier work, this new technique would further reduce the size of Pt-Ru particles from 4-6 nm to 2-3 nm and lead to a more even and higher surface distribution of these nanoparticles on the CNTs. In addition, the loadings of Pt and Ru on the CNTs were both markedly increased. Electrochemical characteristics of methanol oxidation on specimens bearing these catalysts (Pt-Ru/CNTs) were investigated via cyclic voltammetry analysis in mixed 1 M methanol and 0.5 M sulfuric acid solutions. It was found that the peak current density of methanol oxidation obtained from the cyclic voltammogram on the new Pt-Ru/CNTs specimen was nearly three times of that on the specimen prepared with EG in the absence of IS. The outcome signified better catalyst morphology and distribution and a significantly improved methanol oxidation efficiency of the new specimen prepared in the mixed EG and H2SO4 solution by electrodeposition in the presence of IS.

ITOナノ粒子のソルボサーマル合成と透明導電膜への応用

Indium tin oxide (ITO) nanoparticles have been synthesized from the mixed ethylene glycol solution of indium (III) chloride, tin (II) chloride and sodium hydroxide by the solvothermal process with the addition of oleylamine or oleic acid as a protective reagent. The x-ray diffraction patterns of particles synthesized at 250°C show that the ITO begins to be produced after the reaction duration of 6 h when oleylamine is added to the reaction solution, indicating a promoting effect on the ITO formation, whereas only indium oxyhydroxide is formed when oleic acid is used. The transmission electron microscopic observation has revealed that ITO nanoparticles obtained by the addition of oleylamine are monodisperse and their size increases from 4-5 nm to 50-60 nm with elongating reaction duration from 6 to 96 h. ITO thin films are prepared by the multiple deposition of a collodion membrane incorporating synthesized ITO nanoparticles on the glass substrate followed by sintering at 400-500°C. They exhibit a good transparency in the visible region and a specific resistivity as low as 1.0 Ω·cm.

One-step solvothermal synthesis of cubic-shaped ITO nanoparticles precisely controlled in size and shape and their electrical resistivity

Highly crystalline cubic-shaped ITO nanoparticles with narrow size distribution were successfully prepared through a one-step process from a mixed ethylene glycol solution of indium and tin salts. The present paper is focused on the detailed study on their solvothermal synthesis, in particular, the effect of process variables on the size and shape. In the present system with using glycol as a solvent, it was observed that the direct formation of ITO nanoparticles occurred from the dissolution–recrystallisation of the amorphous-like indium hydroxides initially formed as precursors. The mean size of the ITO nanoparticles was controlled from 15.1 to 43.5 nm by changing the initial NaOH concentration. The high resolution transmission electron microscopic and the Fourier transform (FT) analyses showed that the as-prepared nanoparticles have single-crystalline structure and were bound by a {200} plane. In addition, judging from the FT image, Sn ions in the cubic crystal structure of In2O3 were substituted homogeneously to form stable oxygen defects. The effect of particle size and morphology on the resistivity of the resultant powder was found to be distinct. Namely, the lower resistivity of well-crystallized cubic-shaped nanoparticles with the larger size, compared with the finer particles with random shape, was due to the lower interparticle resistivity because of the face-to-face contact for the former, but point-to-point contact for the latter.

Using Taylor dispersion profiles to characterize polymer molecular weight distributions

Optical interferometry and NMR spectroscopy can be used to characterize polymer molecular weight distributions from diffusion measurements. The present work develops the relatively simple Taylor dispersion technique for this purpose. Small volumes of polymer solution are injected into laminar carrier streams of solvent flowing through a long capillary tube. The broadened distribution of the dispersed polymer sample is monitored at the tube outlet by a liquid-chromatography differential refractometer detector. Moments analysis of the refractive-index profiles generated by the dispersion of dilute nonionic i-mers with diffusion coefficients Di shows that the profile height and first moment divided by the profile area provide the mass-average values of Di1/2 and Di−1/2, respectively. This information can be used to estimate molecular weight distributions if the form of the distribution (Poisson, log-normal etc.) is known. Alternatively, a linear combination ∑aiP(Mi*) of a small basis set of dispersion profiles P(Mi*) for monodisperse solutes of molecular weight Mi* spanning the molecular weight range of the polydisperse sample can be fitted to measured profiles. The number-average and mass-average molecular weights (MN and MM) are evaluated using MN = ∑ai/(∑ai/Mi*) and MM = (∑aiMi*)/∑ai. The proposed methods for studying molecular weight distributions are tested by measuring dispersion profiles for aqueous solutions of mixed glycols with accurately known weight distributions prepared by mixing ethylene glycol and pure ethylene glycol oligomers.