A Review on Preparation of ZnO Nanorods and Their Use in Ethanol Vapors Sensing

The devices of polycrystalline film have small sensitivity that can be overthrown by using high aspect ratio of 1D nanostructures, such as ZnO nanostructures. Sensors based on 1D nanostructures show very quick response time and high sensitivity for their high impact factor. The purpose of this article is to provide a comparison of different methods and the quality of the sensors thus produced. Currently, metal oxide 1D nanoarchitectures like ZnO have great attraction due to their applications in sensors. Metal oxide nanostructures have high aspect ratio, with small consumption of power and low weight, however, keeping excellent chemical and thermal dependability. Different techniques have been adopted to fabricate metal oxide one-dimensional nanostructures like hydrothermal, electro-spinning, sol-gel, ultrasonic irradiation, anodization, solid state chemical reaction, molten-salt, thermal evaporation, carbothermal reduction, aerosol, vapor-phase transport, chemical vapor deposition, RF sputtering, gas-phase-assisted nanocarving, molecular beam epitaxy, dry plasma etching, and UV lithography. The sensitivity depends upon the materials; synthesis technique and morphology of the sensor performance toward a particular gas have different range of success. This article estimates the efficiency of ZnO 1D nanoarchitectures, gas sensors. Finally, in this review, we had mentioned the future directions of investigations in this field

Structure and photoluminescence properties of red-emitting apatite-type phosphor NaY9(SiO4)6O2:Sm3+ with excellent quantum efficiency and thermal stability for solid-state lighting.

A novel red-emitting phosphor NaY9(SiO4)6O2:Sm3+ (NYS:Sm3+) was synthesized and the X-ray diffraction and high-resolution TEM testified that the NYS compound belongs to the apatite structure which crystallized in a hexagonal unit cell with space group P63/m. The novel phosphor boasts of such three advantageous properties as perfect compatible match with the commercial UV chips, 73.2% quantum efficiency and 90.9% thermal stability at 150 °C. Details are as follows. NYS:Sm3+ phosphor showed obvious absorption in the UV regions centered at 407 nm, which can be perfectly compatible with the commercial UV chips. The property investigations showed that NYS:Sm3+ phosphor emitted reddish emission with CIE coordination of (0.563, 0.417). The optimum quenching concentration of Sm3+ in NYS phosphor was about 10%mol, and the corresponding concentration quenching mechanism was verified to be the electric dipole-dipole interaction. Upon excitation at 407 nm, the composition-optimized NYS:0.10Sm3+ exhibited a high quantum efficiency of 73.2%, and its luminescence intensity at 150 °C decreased simply to 90.9% of the initial value at room temperature. All of the results indicated that NYS:Sm3+ is a promising candidate as a reddish-emitting UV convertible phosphor for application in white light emitting diodes (w-LEDs)

Microwave- and Formaldehyde-Assisted Synthesis of Ag–Ag₃PO₄ with Enhanced Photocatalytic Activity for the Degradation of Rhodamine B Dye and Crude Oil Fractions

The release of crude oil and water-soluble dyes into our marine environment is a major global problem. An efficient semiconductor Ag–Ag3PO4 photocatalyst was synthesized using formaldehyde as a reducing agent to form surface active Ag on Ag3PO4 under microwave radiation for heating, and its potential in destroying environmental pollutants has been examined. The diffuse reflectance spectroscopy of Ag–Ag3PO4 revealed an enhanced absorption in the visible light region. The rate of photocatalytic degradation of rhodamine B by Ag–Ag3PO4 was over 4-fold compared to Ag3PO4. The potential application of Ag–Ag3PO4 in oil spill remediation was also examined through photocatalytic degradation of benzene, n-hexane, and 1:1 v/v benzene/methanol crude oil-soluble fractions. UV–vis and gas chromatography–mass spectrometry analysis of the crude oil components after visible light irradiation showed excellent degradation. The photocatalytic efficiency enhancement of Ag–Ag3PO4 is attributed to the excellent electron trapping of silver nanoparticles deposited on the surface of Ag3PO4. This work will motivate future studies to develop recyclable visible light photocatalysts for many applications

Diuretic activity of aqueous extract of roots of Cissampelos pareira in albino rats

Background: Diuretic compounds that stimulate the excretion of water with small traceable ions are potentially useful in most of disorders including those exhibiting edema such as congestive heart failure, nephritis, toxemia of pregnancy, premenstrual tension, and hypertension. The aim was to evaluate the diuretic activity of aqueous extract of roots of Cissampelos pareira (AQERCP) by Lipschitz method in albino rats.Methods: Five groups of Albino rats were used to evaluate the diuretic activity of AQERCP by using metabolic cages. The Group I serves as normal control received vehicle (carboxymethyl cellulose 2% in normal saline), the Group II furosemide (10 mg/Kg, p.o) in vehicle; other Groups III, IV, and V were treated with low (100 mg/kg), medium (200 mg/kg), and high (400 mg/kg) doses of AQERCP in vehicle. Immediately, after the extract treatment all the rats were hydrated with saline (15 ml/kg, p.o) and placed in the metabolic cages (3/cage), specially designed to separate urine and faeces, kept at 21°C±0.5°C.The total volume of urine collected was measured at the end of 5th hr. During this period, no food and water was made available to animals. Various parameters such as total urine volume and concentration of sodium, potassium, chloride ions in the urine were measured and estimated respectively.Results: In this model, when compared to vehicle treated control group the AQERCP at different dose levels (100, 200 and 400 mg/kg) has significantly increased the urine volume and also enhanced the elimination of sodium, potassium and chloride ions in urine.Conclusion: The results showed that single dose administration of AQERCP as 100, 200 and 400 mg/Kg and standard frusemide (10 mg/kg b.wt) has significantly (p<0.05*, p<0.01**, p<0.001***) increased the urine output along with an increase in concentration of sodium, potassium, and chloride. AQERCP 400 mg/Kg produced a greater diuretic activity, which is comparable to the effect of standard furosemide (10 mg/kg).The present study has supported and justified the basis for folklore use of roots of C. pareira as a diuretic agent

Binder free three-dimensional sulphur/few-layer graphene foam cathode with enhanced high-rate capability for rechargeable lithium sulphur batteries.

A novel ultra-lightweight three-dimensional (3-D) cathode system for lithium sulphur (Li-S) batteries has been synthesised by loading sulphur on to an interconnected 3-D network of few-layered graphene (FLG) via a sulphur solution infiltration method. A free-standing FLG monolithic network foam was formed as a negative of a Ni metallic foam template by CVD followed by etching away of Ni. The FLG foam offers excellent electrical conductivity, an appropriate hierarchical pore structure for containing the electro-active sulphur and facilitates rapid electron/ion transport. This cathode system does not require any additional binding agents, conductive additives or a separate metallic current collector thus decreasing the weight of the cathode by typically ∼20-30 wt%. A Li-S battery with the sulphur-FLG foam cathode shows good electrochemical stability and high rate discharge capacity retention for up to 400 discharge/charge cycles at a high current density of 3200 mA g(-1). Even after 400 cycles the capacity decay is only ∼0.064% per cycle relative to the early (e.g. the 5th cycle) discharge capacity, while yielding an average columbic efficiency of ∼96.2%. Our results indicate the potential suitability of graphene foam for efficient, ultra-light and high-performance batteries.Kai Xi thanks the Cambridge Overseas Trust. P.R.K. acknowledges funding from the Cambridge Commonwealth Trust. S.H. acknowledges funding from ERC grant InsituNANO (no. 279342), EPSRC under grant GRAPHTED (project reference EP/K016636/1) and Grant EP/H047565/1. This research was partially supported by the EU FP7 Work Programme under grant GRAFOL (project reference 285275). XP and CD acknowledge funding from the ERC under grant number 259619 PHOTO EM.This is the accepted manuscript. The final version is available from RSC at http://pubs.rsc.org/en/Content/ArticleLanding/2014/NR/C4NR00326H#!divAbstract

Size-controllable synthesis of lithium niobate nanocrystals using modified Pechini polymeric precursor method

Nanopowders of lithium niobate (LiNbO3, LN) were synthesized by a water-based modified Pechini method, in which Li2CO3 and ammonium niobate (v) oxalate hydrate (C4H4NNbO9·xH2O) are used as the Li and Nb source materials, respectively. The kinetics of formation of the intermediate gelatinous precursor was studied by thermal gravimetry and differential scanning calorimetry. The LN nanoparticles produced by calcining of the gel at various temperatures were characterized by X-ray diffraction and scanning electron microscopy. The effect of the calcination temperature on the morphology and structure of LN nanoparticles produced is investigated. The particle and crystallite sizes of the LN prepared could be controlled in the range of 20–250 nm by changing the calcination temperature of the gelatinous precursor

Graphene-wrapped sulfur/metal organic framework-derived microporous carbon composite for lithium sulfur batteries

A three-dimensional hierarchical sandwich-type graphene sheet-sulfur/carbon (GS-S/CZIF8-D) composite for use in a cathode for a lithium sulfur (Li-S) battery has been prepared by an ultrasonic method. The microporous carbon host was prepared by a one-step pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8), a typical zinc-containing metal organic framework (MOF), which offers a tunable porous structure into which electro-active sulfur can be diffused. The thin graphene sheet, wrapped around the sulfur/zeolitic imidazolate framework-8 derived carbon (S/CZIF8-D) composite, has excellent electrical conductivity and mechanical flexibility, thus facilitating rapid electron transport and accommodating the changes in volume of the sulfur electrode. Compared with the S/CZIF8-D sample, Li-S batteries with the GS-S/CZIF8-D composite cathode showed enhanced capacity, improved electrochemical stability, and relatively high columbic efficiency by taking advantage of the synergistic effects of the microporous carbon from ZIF-8 and a highly interconnected graphene network. Our results demonstrate that a porous MOF-derived scaffold with a wrapped graphene conductive network structure is a potentially efficient design for a battery electrode that can meet the challenge arising from low conductivity and volume change.National Science Foundation of China (21373028)This is the final version of the article. It first appeared from American Institute of Physics Publishing via http://dx.doi.org/10.1063/1.490175

Non-Isothermal Crystallisation Kinetics of Carbon Black- Graphene-Based Multimodal-Polyethylene Nanocomposites.

The effect of carbon black (CB) and microwave-induced plasma graphene (g) on the crystallisation kinetics of the multimodal high-density polyethylene was studied under non-isothermal conditions. The non-isothermal crystallisation behaviour of the multimodal-high-density polyethylene (HDPE), containing up to 5 wt.% graphene, was compared with that of neat multimodal-HDPE and its carbon black based nanocomposites. The results suggested that the non-isothermal crystallisation behaviour of polyethylene (PE)-g nanocomposites relied significantly on both the graphene content and the cooling rate. The addition of graphene caused a change in the mechanism of the nucleation and the crystal growth of the multimodal-HDPE, while carbon black was shown to have little effect. Combined Avrami and Ozawa equations were shown to be effective in describing the non-isothermal crystallisation behaviour of the neat multimodal-HDPE and its nanocomposites. The mean activation energy barrier (ΔE), required for the transportation of the molecular chains from the melt state to the growing crystal surface, gradually diminished as the graphene content increased, which is attributable to the nucleating agent effect of graphene platelets. On the contrary, the synergistic effect resulting from the PE-CB nanocomposite decreased the ΔE of the neat multimodal-HDPE significantly at the lowest carbon black content