Nanoparticles In Ethanol Research Articles

Kinetics of Photocatalytic Degradation of Methylene Blue by TiO₂-Graphene Nanocomposites.

Reduced graphene oxide (RGO)/TiO₂ nanocomposite was successfully prepared by UV-assisted photocatalytic reduction of graphene oxide (XGO) by TiO₂ nanoparticles in ethanol. The effects of XGO and RGO addition in TiO₂were characterized by transmission electron microscopy (TEM), X-ray diffractometer (XRD), diffuse reflectance UV-vis spectrophotometer (UV-vis), fourier-transform infrared spectroscopy (FTIR), photoluminescence (PL), and Brunauer-Emmett-Teller (BET) and Barrett-Joiner-Halenda (BJH) porosity analysis. The photocatalytic activity of prepared nanocomposites was evaluated from the kinetics of the photocatalytic degradation of cationic methylene blue dye under UV irradiation. Bandgap, the electron-hole recombination, specific surface area, surface functional groups, and adsorption capacity of nanocomposites were found to play a significant role in the degradation. The results revealed that RGO/TiO₂ and XGO/TiO₂ nanocomposites exhibited efficient charge separation and enhanced photocatalytic activity, compared to pristine TiO₂. Nearly 500% improvement was observed in this work.

Effect of Deposition Parameters on Electrophoretically Deposited TiO2

In the current study, TiO2 coatings on stainless steel substrates were prepared by Electrophoretic Deposition (EPD) of colloidal dispersions of TiO2 nanoparticles in ethanol. The effects of deposition parameters on surface morphology, phase composition and mechanical properties were investigated. The surface morphology of the EPD layers was observed using Atomic Force Microscopy (AFM). The composition of the EPD layer was determined from the peak intensity using an X-ray Diffractometer (XRD) and mechanical properties of films were investigated by nanoindentation techniques. Characterization of the obtained films by atomic force microscope showed a relatively uniform microstructure. The coatings mainly consisted of anatase and rutile; anatase is the predominant phase with an average percentage of 71%. As a result of nanoindentation experiments, load–displacement curves were obtained and two mechanical characteristics of the substrate and investigated films – indentation hard-ness (HIT) and indentation modulus (EIT) – were calculated using Oliver & Pharr’s approximation methods. Mechanical properties show an improvement with the applied voltage. The results illustrate that Young's modulus and hardness of TiO2 thin films are increased with increasing voltage.

Electrophoretic Deposition of Hydroxyapatite and 58S Bioactive Glass Coatings on the Ti6Al4V Alloy Subjected to Surface Mechanical Attrition Treatment

Hydroxyapatite (HAP) and 58S Bioactive Glasses (BG) coatings are successfully synthesized by Electrophoretic Deposition (EPD) on Ti6Al4V alloy subjected to Surface Mechanical Attrition Treatment (SMAT). This process uses steel balls impacts on the Ti6Al4V surface to improve its mechanical properties. However when the Ti6Al4V substrate is treated by SMAT the industrial plasma spray technique is not efficient to obtain adherent HAP coatings. This problem is mainly related to the modifications of the Ti6Al4V surface topography due to the SMAT process. Therefore, in this work we demonstrate that EPD offers an efficient solution to solve this technical problem. Indeed we obtain a homogeneous and adherent HAP coating on the SMATed Ti6Al4V surface from a suspension of nanoparticles in ethanol. Moreover EPD is successfully employed to produce a 58S BG coating on the SMATed Ti6Al4V surface. Scanning Electron Microscopy (SEM) associated to Energy Dispersive X-Ray Spectroscopy (EDXS) reveals that the coatings obtained by EPD are adherent and compact without alteration of their chemical composition.

Time-Resolved Investigations of the Cooling Dynamics of Metal Nanoparticles: Impact of Environment

Tunable two-color ultrafast pump–probe experiments are performed on colloidal metal nanospheres in water and ethanol, and the results are interpreted through a model including thermal dynamics in both the nanoparticle and its environment. Transient optical signals measured for gold nanoparticles in ethanol display a complex temporal response strongly dependent on the wavelength of the probe beam. We demonstrate that its origin is related to a large contribution of liquid environment transient heating to the optical response, in contrast to the usual assumption that optical transmission changes reflect the evolution of nanoparticle temperature only. Accounting for this contribution enables an accurate measurement of thermal conductances at gold–ethanol and gold–water interfaces. Moreover, the thermal dynamics of the solvent can be selectively probed through a specific choice of probe wavelength.

Solvothermal synthesis of CZTS nanoparticles in ethanol: Preparation and characterization

In this work, a low-cost, non-toxic and convenient one-pot solvothermal route to synthesize Cu2ZnSnS4 (CZTS) nanoparticles is reported. The effects of solvothermal temperature and reaction time on the structure, morphology and optical properties of the as-synthesized product were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) measurements and X-ray photoelectron spectroscopy (XPS). The results showed that the crystallinity of the CZTS powders was influenced by the solvothermal temperature and reaction time. The band gap of selected CZTS samples was near the optimum value for photovoltaic solar conversion in a single-band-gap device.

Iron-doped nickel oxide nanocrystals as highly efficient electrocatalysts for alkaline water splitting.

Efficient electrochemical water splitting to hydrogen and oxygen is considered a promising technology to overcome our dependency on fossil fuels. Searching for novel catalytic materials for electrochemical oxygen generation is essential for improving the total efficiency of water splitting processes. We report the synthesis, structural characterization, and electrochemical performance in the oxygen evolution reaction of Fe-doped NiO nanocrystals. The facile solvothermal synthesis in tert-butanol leads to the formation of ultrasmall crystalline and highly dispersible FexNi1-xO nanoparticles with dopant concentrations of up to 20%. The increase in Fe content is accompanied by a decrease in particle size, resulting in nonagglomerated nanocrystals of 1.5-3.8 nm in size. The Fe content and composition of the nanoparticles are determined by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy measurements, while Mössbauer and extended X-ray absorption fine structure analyses reveal a substitutional incorporation of Fe(III) into the NiO rock salt structure. The excellent dispersibility of the nanoparticles in ethanol allows for the preparation of homogeneous ca. 8 nm thin films with a smooth surface on various substrates. The turnover frequencies (TOF) of these films could be precisely calculated using a quartz crystal microbalance. Fe0.1Ni0.9O was found to have the highest electrocatalytic water oxidation activity in basic media with a TOF of 1.9 s(-1) at the overpotential of 300 mV. The current density of 10 mA cm(-2) is reached at an overpotential of 297 mV with a Tafel slope of 37 mV dec(-1). The extremely high catalytic activity, facile preparation, and low cost of the single crystalline FexNi1-xO nanoparticles make them very promising catalysts for the oxygen evolution reaction.

Engineering of air-stable Fe/C/Pd composite nanoparticles for environmental remediation applications

The present manuscript presents a convenient method for the synthesis of iron/carbon (Fe/C) nanoparticles (NPs) coated with much smaller Pd NPs for the removal of halogenated organic pollutants. For this purpose, iron oxide/polyvinylpyrrolidone (IO/PVP) NPs were first prepared by the thermal decomposition of ferrocene mixed with PVP at 350°C under an inert atmosphere. IO,Fe/C and Fe/C NPs coated with graphitic and amorphous carbon layers were then produced by annealing the IO/PVP NPs at 500 and 600°C, respectively, under an inert atmosphere. The effect of the annealing temperature on the chemical composition, shape, crystallinity, surface area and magnetic properties of the IO/PVP, IO,Fe/C and Fe/C NPs has been elucidated. Air-stable Fe/C/Pd NPs were produced by mixing the precursor palladium acetate with the air-stable Fe/C NPs in ethanol. The obtained Fe/C/Pd NPs demonstrated significantly higher environmental activity than the Fe/C NPs on eosin Y, a model halogenated organic pollutant. The environmental activity of the Fe/C/Pd NPs also increased with their increasing Pd content.

Effect of Baliospermum montanum nanomedicine apoptosis induction and anti-migration of prostate cancer cells

Prostate cancer has been diagnosed as the second most frequent and the sixth among the cancer causing deaths among men worldwide. There is a limited scope for the prevalent therapies as prostate cancer advances and they present adverse aftermaths that have put way for us to delve into naturally available anticancer agents. The main objective of the present work is to compile the advantages of ayurvedic herbal formulations with modern technology. Baliospermum montanum is a plant that is used in ayurveda for the treatment of cancer and the plant is studied to possess various constituents in it that are responsible for its anticancer activity. Stable nanoparticles of B. montanum were prepared from both the aqueous and ethanolic extracts of the plant and its cytotoxic effects were studied on prostate cancer and normal cell lines. Size analysis by DLS and SEM revealed the average size of nanoparticles prepared was 100±50nm and 150±50nm for the nanoparticles prepared from aqueous and ethanolic extract respectively. In vitro cytotoxicity showed a concentration and time dependent toxicity on prostate cancer cells with cell viability of 22% and 6% with maximum concentration of aqueous and ethanolic nanoparticles respectively, in 48h. In vitro hemolysis assay confirmed that the prepared nanoparticles were compatible with blood with no occurrence of hemolysis. The nanoparticles showed a significant reduction in the colony forming ability and wound healing capacity of the prostate cancer cells. These studies hold the anti cancer potential of the B. montanum nanoparticles making it an important candidate for prostate cancer therapy.

A convenient synthesis of 2-aminocyclohex-1-ene-1-carboxylic esters by FeCl3/SiO2 nanoparticles as robust and efficient catalyst

Abstract A simple and green method has been developed for the synthesis of 2-aminocyclohex-1-ene-1-carboxylic esters through a one-pot three-component condensation reaction of primary amines, ethyl acetoacetate and chalcones using FeCl3/SiO2 nanoparticles in ethanol. This method has several advantages such as high to excellent product yields in short time, using an inexpensive and reusable catalyst and available starting material.

Dispersion behaviour and agglomeration effects of zinc oxide nanoparticles in ethanol–water mixtures

Nanofluids are the new engineered fluids with particles of nanometre size as an additive to alter the effective thermal and viscous properties for different applications. Settling of nanoparticles because of agglomeration among particles in the liquid is a big challenge towards the stability of nanofluids. The dispersion behaviour of nanofluids using zinc oxide nanoparticles of 30 and 40 nm size in ethanol–water mixtures has been examined. Sediment heights are measured at different time intervals with and without ultrasonication using conventional batch sedimentation apparatus. The effect of different nanoparticle concentrations in variety of ethanol-water proportions has been studied using the photographic method. Agglomeration effect has been studied with and without sonication in terms of sedimentation ratio and with the support of transmission electron microscopy. It is found that sonication has a significant influence on the nanofluid stability. An important evaluation technique for stability of nanofluids has been presented.

Evaporation of sessile droplets affected by graphite nanoparticles and binary base fluids.

The effects of ethanol component and nanoparticle concentration on evaporation dynamics of graphite-water nanofluid droplets have been studied experimentally. The results show that the formed deposition patterns vary greatly with an increase in ethanol concentration from 0 to 50 vol %. Nanoparticles have been observed to be carried to the droplet surface and form a large piece of aggregate. The volume evaporation rate on average increases as the ethanol concentration increases from 0 to 50 vol % in the binary mixture nanofluid droplets. The evaporation rate at the initial stage is more rapid than that at the late stage to dry, revealing a deviation from a linear fitting line, standing for a constant evaporation rate. The deviation is more intense with a higher ethanol concentration. The ethanol-induced smaller liquid-vapor surface tension leads to higher wettability of the nanofluid droplets. The graphite nanoparticles in ethanol-water droplets reinforce the pinning effect in the drying process, and the droplets with more ethanol demonstrate the depinning behavior only at the late stage. The addition of graphite nanoparticles in water enhances a droplet baseline spreading at the beginning of evaporation, a pinning effect during evaporation, and the evaporation rate. However, with a relatively high nanoparticle concentration, the enhancement is attenuated.

Preparation and lithium storage performance of a carbon-coated Si/graphene nanocomposite

A carbon-coated Si/graphene (Si@C/G) nanocomposite was prepared by dispersing a mixture containing graphene, citric acid, and Si nanoparticles in ethanol, followed by drying and carbonization at 800 °C for 1 h. Transmission electron microscopy revealed that a carbon layer with a uniform thickness of ca. 2 nm was formed on the surface of the Si nanoparticles. The Si@C nanoparticles were supported by graphene sheets with a strong interaction between them. However, the carbon layer on the Si@C nanoparticles without the graphene addition was not uniform. This can be ascribed to the high thermal conductivity of graphene that ensures a uniform temperature distribution on the surface of the Si nanoparticles. As an anode material for lithium ion batteries, the Si@C/G electrode exhibits a high initial coulombic efficiency of 82.7% and an excellent cycling stability with a capacity of 1431 mAh g −1 after 100 cycles at a current density of 500 mA g −1 . Such excellent electrochemical performance is attributed to the high electrical conductivity and superior flexibility of graphene. [New Carbon Materials 2014, 29(4): 295–300]

ZnFe2O4 nanoparticles as radiosensitizers in radiotherapy of human prostate cancer cells.

Nanoparticles of high-Z elements exhibit stronger photoelectric effects than soft tissues under gamma irradiation. Hence, they can be used as effective radiosensitizers for increasing the efficiency of current radiotherapy. In this work, superparamagnetic zinc ferrite spinel (ZnFe2O4) nanoparticles were synthesized by a hydrothermal reaction method and used as radiosensitizers in cancer therapy. The magnetic nanoparticles showed fast separation from solutions (e.g., ~1 min for 2 mg mL(-1) of the nanoparticles in ethanol) by applying an external magnetic field (~1T). The ZnFe2O4 nanoparticles were applied in an in vitro radiotherapy of lymph node carcinoma of prostate cells (as high radioresistant cells) under gamma irradiation of (60)Co source. The nanoparticles exhibited no significant effects on the cancer cells up to the high concentration of 100 μg mL(-1), in the absence of gamma irradiation. The gamma irradiation alone (2Gy dose) also showed no significant effects on the cells. However, gamma irradiation in the presence of 100 μg mL(-1) ZnFe2O4 nanoparticles resulted in ~53% inactivation of the cells (~17 times higher than the inactivation that occurred under gamma irradiation alone) after 24h. The higher cell inactivation was assigned to interaction of gamma radiation with nanoparticles (photoelectric effect), resulting in a high level electron release in the media of the radioresistant cells. Our results indicated that ZnFe2O4 nanoparticles not only can be applied in increasing the efficiency of radiotherapy, but also can be easily separated from the cell environment by using an external magnetic field after the radiotherapy.

Adsorption and electronic states of morin on TiO2 nanoparticles

Low temperature Stark effect spectroscopy has been used to investigate the changes in the electronic charge distribution in the flavonoid morin caused by adsorption to colloidal TiO2 nanoparticles in ethanol. The differences in the permanent dipole moment, Δμ, and in polarizability, Δα, between the ground and excited state were determined. Adsorption causes an increase in both Δμ and Δα of morin but the vector Δμ remains nearly perpendicular to the Ti-dye direction, like in the free molecule. This picture of electron movement on electronic excitation is supported by semiempirical calculations. In contrast to other dyes adsorbed on TiO2, it indicates the indirect effect of chelated Ti atom on morin electronic structure which does not involve the atomic orbitals of the metal, and the electronic structure of adsorbed morin similar to that of the anion.

Laser engineered core–shell nanodielectrics with giant electrical permittivity

This study explores the possibility of using laser engineering process to develop polymer nanodielectics with giant permittivity. It consists of core–shell architecture with metal nanoparticle as the high capacitance core and a polymer as the shell. The shell was formed via UV laser exposure of laser-generated silver nanoparticles in ethanol in presence of acryl monomer. The laser wavelength corresponds to the surface plasmon band of the silver nanoparticles. Capacitance measurements on spin-coated films show permittivity values up to 10,000. The process is shown to be a forceful and influential concept for producing giant permittivity polymer films with a minimum dielectric loss that can be incorporated into standard capacitor manufacturing processes for energy storage solutions.

High stable suspension of magnetite nanoparticles in ethanol by using sono-synthesized nanomagnetite in polyol medium

The sonochemical synthesis of magnetite nanoparticles was carried out at relatively low temperature (80°C) in ethylene glycol (EG) as a polyol solvent. The particle size was determined by transmission electron microscopy (TEM). The magnetite nanoparticles with an average size of 24nm were composed of small building blocks with an average size of 2–3nm and the particles exhibited nearly spherical shape. The surface characterization was investigated by using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The stability of magnetite nanoparticles was studied in ethanol as a polar solvent. The nanoparticles showed an enhanced stability in ethanol which is due to the hydrophilic surface of the particles. The colloidal stability of magnetite nanoparticles in ethanol was monitored by UV–visible spectrophotometer. According to the results, the nanoparticles synthesized in 30min of sonication with intensity of 35W/cm2 (50%) led to a maximum stability in ethanol as a polar solvent with respect to the other applied intensities. The obtained magnetite nanoparticles were stable for more than12 months.

Tetradecylphosphonic acid modified BaTiO3 nanoparticles and its nanocomposite

Surface-functionalization of BaTiO3 nanoparticles and subsequent utilization of simple solution casting to yield the good compatible PVDF nanocomposites were investigated. 1-Tetradecylphosphonic acid (TDPA) was synthesized and then used to functionalize the surface of BaTiO3 nanoparticles. The prepared TDPA–BaTiO3 nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). These results indicated that the surface of nanoparticles was grafted successfully with such phosphonic acid. Also, the existing ligands of surface were examined, and the coverage onto surface of BaTiO3 nanoparticles evaluated by thermogravimetric analysis (TGA) was 25.1%. The dispersion of modified nanoparticles in ethanol and dichloromethane was significantly improved. Besides of good flexibility, PVDF nanocomposite film with volume fraction of 40vol.% modified nanofillers exhibited high dielectric constant and low dielectric loss.

One-pot multicomponent synthesis of diazepine derivatives using terminal alkynes in the presence of silica-supported superparamagnetic iron oxide nanoparticles

A new, efficient, one-pot multicomponent reaction for the synthesis of diazepine derivatives in excellent yields is described. The reactions of various 1,2-diamines, terminal alkynes, and an isocyanide take place in the presence of a catalytic amount of magnetically recoverable silica-supported superparamagnetic Fe3O4 nanoparticles in ethanol (as a green reaction medium) at ambient temperature.

A facile approach to fabrication of novel CeO2–TiO2 core–shell nanocomposite leads to excellent UV-shielding ability and lower catalytic activity

This study reports the development of a fast and facile route for the synthesis of novel CeO2–TiO2 core–shell nanocomposite particles using microwave (MW) irradiation of the mixture of commercial CeO2, titanium-tetra-n-butoxide (TBOT) and aqueous ammonia. Solutions of TBOT in ethanol and ammonia were mixed with dispersed CeO2 nanoparticles in ethanol, and the mixture was rapidly MW irradiated at 70 °C for 2 min. The resulting nanocomposite particles were characterized in terms of phase, shell thickness, composition, surface charge, morphology, and chemical state of the elements by XRD, TEM, XPS, SEM, Zeta potential analyzer, XRF, and FT-IR. Conventional methods of the synthesis of CeO2–TiO2 nanocomposite require a long time, and TiO2 is rarely found as a coated material. In contrast, the MW method was able to synthesize CeO2–TiO2 core–shell nanocompsite particles within a very short time. CeO2–TiO2 nanocomposite particles were fairly unaggregated with an average titania layer thickness of 2–5 nm. The obtained nanocomposites retained the crystalline cubic phase of CeO2, and the phase of coated TiO2 was amorphous. The catalytic activities of uncoated and TiO2-coated CeO2 nanoparticles for the oxidation of organic compounds were evaluated by the degradation study of methylene blue in air atmosphere at 403 K. The enhanced UV-shielding ability and visible transparency of the nanocomposite obtained by UV visible spectroscopic measurements suggested that the core–shell material has novel characteristics for using as a sunscreen material.

Transparent PMMA/silica nanocomposites containing silica nanoparticles coating under supercritical conditions

This work reports the preparation of PMMA/silica nanocomposites with high optical transparency and enhanced mechanical properties using a melt compounding method. The surface of SiO2 particles was modified with a γ-methacryloxypropyltrimethoxy silane coupling agent in a supercritical carbon dioxide-ethanol mixture and by conventional procedure. Dispersion of silica nanoparticles in ethanol at low temperatures plays an important role in deagglomeration and dispersion of nanosilica, which leads to the optimal particle-matrix bonding in composites. The optimal mechanical and optical properties were found for composites loaded with 5wt% silica nanoparticles treated under supercritical coating method.