Material characterizations and light/gas dual-sensing properties of ZnO nanorods incorporating buried carbon nanotube in the seed layer

Zinc oxide (ZnO) is well-recognized as a biocompatible multifunctional material with outstanding properties as well as low toxicity and biodegradability. In this work, a simple and versatile technique was developed to prepare highly crystalline ZnO nanorods by introducing egg white to a bio-inspired approach. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern results indicated that the ZnO nanorods have single phase nature with the wurtzite structure. Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) results showed the nanometer dimension of the nanorods. Raman, FTIR, and TGA/DTA analyses revealed the formation of wurtzite ZnO. The antibacterial properties of ZnO nanorods were investigated using both Gram-positive and Gram-negative microorganisms. These studies demonstrate that ZnO nanorods have a wide range of antibacterial activities toward various microorganisms that are commonly found in environmental settings. Survival ratio of bacteria decreased with increasing powder concentration, i.e., increase in antibacterial activity. The antibacterial activity of the ZnO nanorods toward Pseudomonas aeruginosa was stronger than that of Escherichia coli and Staphylococcus aureus. Surprisingly, the antibacterial activity did not require specific UV activation using artificial lamps, rather activation was achieved under ambient lighting conditions. Overall, the experimental results suggest that ZnO nanorods could be developed as antibacterial agents against a wide range of microorganisms to control and prevent the spreading and persistence of bacterial infections. This research introduces a new concept to synthesize ZnO nanorods by using egg white as a biological template for various applications including food science, animal science, biochemistry, microbiology and medicine.

Improving reinforcement properties of CNTs in aluminium matrix composites: a case of surface modification through AlN nano-particle grafting

ZnO nanorods were prepared using dimethylamine (DMA) controlled Sol-Gel process. Dimethylamine was added as an additive to control the sol-gel process for growing ZnO nanorods. DMA would exhibit stabilizing effect, promote dissolution of precursor and control the rate of sol-gel reactions because of its basic nature and significant miscibility. The Structural and microstructural properties of the powders were characterized by X-Ray Diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). FESEM and TEM analysis revealed that the ZnO powder prepared were nanorods in nature. The optical properties of powders were characterized by UV-Visible and Photoluminescence (PL) spectroscopy. The Structural, morphological, optical and photoluminescence properties of so obtained ZnO powders consisting of nanorods were studied. DMA is simple amine but found to be very effective to control the aspect ratio of nanorods. The role of DMA in growing wurtzite structured hexagonal ZnO nanorods with [0001] orientation was interpreted and growth mechanism of ZnO nanorods was explained.

Phase control of yttrium (Y)-doped TiO2 nanofibers and intensive visible photoluminescence

Influence of dispersion states of carbon nanotubes on physical properties of epoxy nanocomposites

Conducting polythiophene (PTh)/single‐wall carbon nanotubes (SWNTs) composites were synthesized by the in situ chemical oxidative polymerization method. The resulting cablelike morphology of the composite (SWNT–PTh) structures was characterized with elemental analysis, X‐ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared, ultraviolet–visible spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, X‐ray diffraction, and transmission electron microscopy. The standard four‐point‐probe method was used to measure the conductivity of the samples. Field emission scanning electron microscopy and transmission electron microscopy analysis revealed that the SWNT–PTh composites were core (SWNTs) and shell (PTh) hybrid structures. Spectroscopic analysis data for the composites were almost identical to those for PTh, supporting the idea that SWNTs served as templates in the formation of a coaxial nanostructure for the composites. The physical properties of the composites were measured and also showed that the SWNTs were modified by conducting PTh with an enhancement of various properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5283–5290, 2006

Carbon nanomaterials (CNMs) are promising in many potential applications for their attractive physical and chemical properties. Chemical vapor deposition technique (CVD) is used to synthesize CNMs on fixed substrate. Powdered activated carbon (PAC) was used as a successful substrate for CNMs growth in CVD reaction process. Iron clustered nano particles Fe3+ was impregnated successfully on PAC surface under sonication. EDX characterization results showed the evidence of impregnation and growth of CNMs on PAC surface. The optimum weight percentage of Fe3+ impregnation on PAC was found to be 5%. The CVD reactor used in thisstudy was locally fabricated and modified to reduce the process time and cost. CNMs were synthesized at different temperatures (850, 750, 650 and 550°C) and the maximum yield was obtained at 550°C with majority of CNFs. Various types of CNMs were grown: carbon nanotubes (CNTs), carbon nanofibers (CNFs), CN spheres and CN-coils. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images were studied for all the samples to investigate the nanostructures for CNMs. Key words: Carbon nanomaterials, carbon nanotube, carbon nanofibers, nanotechnology, chemical vapor deposition, catalyst impregnation, activated carbon

CNTs-copper oxide nanocomposite photocatalyst with high visible light degradation efficiency

Zinc oxide (ZnO) nanorods synthesized by an explosive oxidation reaction in a microwave plasma torch flame were presented. The structural characteristics and morphology of the as-synthesized ZnO nanorods were investigated by X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FESEM), field-emission transmission electron microscopy (FETEM), and photoluminescence (PL) spectroscopy. It was revealed by FETEM that most of the ZnO nanorods were pure and had an average diameter of 80 nm and a length of up to 300 nm, and some ZnO nanorods had a hexagonal tip, tripod-like shape with a length of up to 1 µm. PL spectra show only strong UV emission at approximately 380 nm without any defect-related emissions, indicating good crystalline ZnO. Also, a possible mechanism of the growth of the ZnO nanorods is discussed.

Single-Crystalline Mesoporous Palladium and Palladium-Copper Nanocubes for Highly Efficient Electrochemical CO ₂ Reduction

This work presented controllable growth of ZnO nanostructures with different aspect ratios by the microwave irradiation method and investigated the photocatalytic degradation of methyl red (MR). X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) measurements showed that all ZnO nanostructures were of a hexagonal phase structure. It was revealed by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images that the morphology of ZnO can be effectively controlled as sheet-like, rod-like, brush-like, flower-like, prism-like, and pyramid-like only by changing the molar ratio (zinc acetate: KOH) and reaction time. With the increase of molar ratio and reaction time, modification in the E2(high) and E1(LO) Raman modes was observed. The energy band gap was found to be tuned by the aspect ratio of ZnO nanostructures. Photoluminescence spectroscopy revealed the low-intensity NBE emission and high and broad defect-related emission for high aspect ratio (14) nanorods. BET surface area porosity analysis confirmed the presence of a mesoporous network in all the nanostructures, showed high surface area and a uniform pore-size distribution for high aspect ratio nanorods. A terephthalic acid assay study confirmed the formation of hydroxyl radicals (OH) in MR dye solution treated with a ZnO nanostructures photocatalyst. The photodegradation of MR under UV light irradiation showed that ZnO nanorods with a high aspect ratio of ∼14 showed superior photodegradation (∼98% degradation of MR within 60 min) than that of the lower aspect ratio nanostructures. The apparent reaction rate constant for high aspect ratio (14) nanorods was higher than that of the lower aspect ratio nanostructures. The enhancement in photocatalytic performance could be due to the high surface area and enhanced charge separation and transfer efficiency of photoinduced charge carriers in the high aspect ratio nanorods.

Here, we have designed a noble composite nanostructure by embedding gold (Au) nanoparticles into zinc oxide (ZnO) nanorods surface in one pot synthesis as a photocatalyst. The formation the composite nanostructure was confirmed by X‐ray diffraction, X‐ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy and transmission electron microscopy investigations. Microscopic studies suggest that spherical Au nanoparticles are nucleated on the ZnO nanorods surface. XPS shows shifting of peak positions towards higher binding energy which indicates charge transfer from ZnO to Au in the composite nanostructures. This is unambiguously confirmed by the steady state spectroscopic studies. It was found that 95.7% (1.8 × 10 −5 mM) of Methylene blue dye is degraded by the composite nanostructure after 140 min under UV light illumination and the apparent rate constant was found to be 0.015 min −1 . This new class of Au nanoparticles embedded ZnO nanorods composite nanostructure opens up new possibilities in photocatalytic, solar energy conversion, photovoltaic, and other new emerging applications.

Facile growth of ZnO nanorod arrays by a microwave-assisted solution method for oxygen gas sensing

RuO 2 nanocrystals (NCs) were deposited on carbon nanotubes (CNTs) by reactive RF magnetron sputtering using a Ru target under different conditions. Their surface morphology, structural, spectroscopic and field emission (FE) properties were studied using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), Raman spectroscopy, and a home made high vacuum FE measurement system. FESEM micrographs showed that the surface morphology of the as-deposited RuO 2 varied from nanoparticles-like to tube-like NCs as the oxygen flux increased from 2 to 10 sccm. The TEM image of RuO 2 -coated CNTs revealed that uniform distribution and random direction of RuO 2 NCs had been deposited on the surface of the CNTs. The red-shifts of the peak positions and broadening of linewidths of the Raman features were attributed to both the size and residual stress effects. The FE characteristics revealed a low operating electric field and stable emission current in the RuO 2 -coated CNTs.

Synthesis of ZnO nanorods by spray pyrolysis for H2S gas sensor