Nano

Ag nanoparticles were deposited by polyol process onto the as-synthesized anatase TiO₂ cubes with single crystals by hydrothermal method. The materials were characterized by SEM, XRD, TEM, XPS and UV-vis spectroscopy and their photoconversion efficiencies were also evaluated. The photocurrent measurements revealed that the modification of the anatase TiO₂ cubes with Ag nanoparticles improved the photoelectrochemical properties of electrodes.

In the present work, maghemite nanoparticles (MNP) was synthesized by a simplified method and then modified by sodium dodecyl benzene sulfonate (NaDBS) for the removal of nitrite from aqueous solution. The prepared nanoparticles were characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The SEM image and XRD analysis showed that the average particle size and crystallite of the maghemite nanopaticles are ca. 32.7 nm and 33.5 nm, respectively. Different parameters namely, pH of the adsorption solution, adsorbent dosage and spectrophotometric reagents were optimized. Spectrophotometric determination of nitrite in an optimized condition showed that the MNP is able to deplete over 88% of nitrite from the initial solution. Moreover, dynamic adsorption study per se confirmed the shortest necessary contact time (ca. 6 min) in the adsorption process of nitrite which is quite encouraging from a practical and industrial point of view. The kinematic study revealed that the nitrite adsorption is a pseudo-first-order process. In addition, two different models (Freundlich- and kinetic-type model) were developed for the adsorbent dosage effect on nitrite adsorption. A Freundlich-type model manifested high coefficients of regression, indicating its robustness.

Zn₃P₂ is an acute and effective rodenticide used widely to protect grains in stores and domestically to kill rodents. This study aims to postpone the time of poisoning symptoms after eating Zn₃P₂ and improve the effect of killing rodents. Zn₃P₂/calcium alginate (Zn₃P₂/CA) was synthesized through the reaction of sodium alginate and calcium chloride by the reversed-phase microemulsion method and then loaded with Zn₃P₂ technical. It was characterized by X-ray diffractometer, laser particle size analyzer, scanning electron microscope (SEM) and transmission electron microscopy (TEM). The drug loading capacity, slow-controlled release performances and toxic effects were also investigated. The results showed that Zn₃P₂/CA was spherical, average particle size was 353.9 nm, and particle dispersion index (PDI) was 0.195. The mass ratios of calcium alginate and Zn₃P₂ technical (CA/Zn₃P₂) had significant impacts to drug loading capacity and slow-controlled release performances of Zn₃P₂/CA. The palatability and efficacy of Zn₃P₂/CA were significantly improved and enhanced compared with Zn₃P₂ technical. The results showed that Zn₃P₂/CA presented high loading efficiency, commendable sustained-release performance and good environmental compatibility, and this delivery carrier may be extended to other slow-controlled release and high-efficient pesticide formulation in future.

The removal of CIP from the environment has become a mandatory issue. In our paper, we have realized the visible-light-driven degradation of CIP on the BiVO₄–Bi₂WO₆ nano-heterojunction photocatalysts. The synthesized photocatalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-Vis) absorption spectra and photoluminescence (PL) spectra. Compared with the single-phase BiVO₄ and Bi₂WO₆ counterparts, BiVO₄–Bi₂WO₆ nano-heterojunction photocatalysts show enhanced photocatalytic degradation activities in visible-light-driven CIP degradation. Particularly, when R_{(Bi2WO6∕BiVO4)} = 10 wt.%, the products exhibit the highest CIP degradation ratio in 60 min of 76.8% under visible light illumination. The tentative mechanism of the interface charge transfer (IFCT) effect in the BiVO₄–Bi₂WO₆ heterojunction structure is also discussed by using the band position calculation.

Magnetic nanoparticles (MNPs) were prepared by the coprecipitation method using a molar ratio of Fe³⁺:Fe²⁺ of 2:1. The surface of MNP was coated with chitosan (CS) and polyethylene glycol (PEG) to form CS–MNP and PEG–MNP nanoparticles, respectively. Anthranilic acid (AA) was loaded on the surface of the resulting nanoparticles to form AA–CS–MNP and AA–PEG–MNP nanocomposites, respectively. The nanocomposites obtained were characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM). XRD results showed that the as-synthesized nanocomposites are pure magnetite. FTIR results analysis indicated the existence of two polymers on the particle surface of the MNP and the presence of loaded AA on the surface of CS–MNP and PEG–MNP nanoparticles. Anthranilic acid loading and the release profiles of AA–CS–MNP and AA–PEG–MNP nanocomposites showed that up to 8.8% and 5.5% of the adsorbed drug were released in 670 min and 771 min, respectively. Anthranilic acid release profiles followed a pseudo-second-order kinetic controlled process. The cytotoxicity of the as-synthesized anthranilic acid nanocomposities were determined using MTT assay using murine macrophage RAW 264.7 cells. MTT results showed that the cytotoxic effects of AA–CS–MNP were higher than AA–PEG–MNP against the tested cells as compared to free anthranilic acid. In this manner, this study introduces novel anthranilic acid nanocomposites that can be used on-demand for biomedical applications.

A new-type photocatalyst of cadmium sulfide carbon nanotubes (CdS/CNTs) was prepared by the hydrothermal method. This as-prepared CdS/CNTs composite photocatalyst was proved to exhibit an excellent photocatalytic activity for degradation of tetracycline (TC). Specially, the 95%-CdS–5%-CNTs composite photocatalyst played the best degradation rate (81.2%) in 60 min under the visible light irradiation. Moreover, this 95%-CdS–5%-CNTs composite photocatalyst possessed great stability and could be used at least four cycles with almost no loss of photocatalytic efficiency. Furthermore, the as-synthesized CdS/CNTs composite photocatalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffused reflectance spectra (UV-Vis), Raman and thermal gravimetry (TG). In addition, the possible mechanism and kinetics of photodegradation of TC with CdS/CNTs photocatalyst was also discussed.

High-performance carbon nanotubes-supported Pt catalysts (Pt/CNTs) catalysts were prepared on the basis of Pt precursors reduced by hydrogen plasma (Pt/CNTs-HP) generated by microwave. The other two Pt/CNTs catalysts prepared by hydrogen (Pt/CNTs-H) and NaBH₄ (Pt/CNTs-N) reduction were also involved for comparison. The practical composition of the catalysts was characterized with energy dispersive analysis of X-ray (EDAX). It was shown from transmission electron microscopy (TEM) and X-ray diffraction (XRD) that the Pt nanoparticles in Pt/CNTs-HP were uniformly dispersed on CNTs with smaller particle size around 2 nm and narrower size distribution as compared with the other two catalysts. Additionally, X-ray photoelectron spectrum (XPS) analysis indicated higher amount of zero-valence states of Pt in Pt/CNTs-HP caused by hydrogen plasma treatment. The electrooxidation of liquid methanol on these catalysts was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. The long-time durability is very comparable to all the three catalysts. Remarkably, the Pt/CNTs-HP possessed the highest electrocatalytic activity, suggesting that the hydrogen plasma reduction approach can be a promising reduction method for preparing high-performance Pt-based electrocatalysts.

The composite of carbon nanotubes/graphene networks loaded-Ni (CNTs/GR-Ni) were successfully synthesized by spray drying and post-calcinating method for the first time. The synthesized products were systematically studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The result showed the hybrid of CNTs and graphene composed the 3D network structure and Ni nanoparticles were attaching on their surface. Adsorption performance evidenced that the obtained nanocomposite possessed high adsorption efficiency and excellent separation property.

The electronic transport property and band structure of pure gallium nitride, oxygen, fluorine, indium substituted gallium nitride nanoribbon and defect structured GaN nanoribbons are investigated by employing first-principles studies using density functional theory. The band structure of pure GaN and indium substituted GaN nanoribbon shows a semiconducting nature. The oxygen, fluorine substituted GaN and defect structured GaN results in metallic behavior. The density of states provides the insight for the localization of charges in the valence band and conduction band. The substitution of oxygen and fluorine enhance the density of charges in valence band and conduction band. The substitution of indium shows an increase in the peak amplitude in density of states. The presence of defect also increases the density of states. The transport properties are studied in terms of transmission spectrum; pure GaN and indium substituted shows a same trend in transmission. In contrast, the transmission can be enhanced by the substitution of oxygen, fluorine and defect in nanoribbon. The information provided in the present study will pave its way to tailor a new material of GaN nanostructures with improved performance in the optoelectronic devices.

Folate-modified iron ferrite nanoparticles with high doxorubicin loading (FDMP) were developed for dual targeting of tumor cells. Large quantities of doxorubicin and folate ligand were chemically coupled to the synthesized dual-functional magnetic nanoparticles by using the multihand cross-linker poly-L-glutamic acid. FDMP exhibits high drug loading ability, narrow size distribution and pH sensitivity to drug release. The drug loading ratio and the magnetic response can be adjusted by controlling the reactant ratio. FDMP possesses high magnetic-guided ability and exhibits enhanced uptake by folate receptors expressing tumor cells and increased cancer cell cytotoxicity.

Cu-doped SiC nanopowders have been prepared via combustion synthesis of the silicon and carbon system in a 0.1 MPa nitrogen atmosphere under different reaction time, using copper as the dopant and PTFE as the chemical activator, respectively. X-ray diffraction, scanning electronic microscope and Raman spectra have been used to characterize the phase and morphology of prepared nanopowders. Results indicate that the lattice constant of prepared Cu-doped SiC nanopowder decreases with extending reaction time. The prepared nanopowders have fine spherical particles and narrow particle size distribution and the particle size increases with increasing reaction time. The electric permittivities of prepared Cu-doped SiC nanopowders in the frequency range of 8.2–12.4 GHz have been determined. The real part ε′, imaginary part ε′′ and dielectric loss tgδ of complex permittivity decrease with increasing reaction time. All prepared Cu-doped SiC nanopowder exhibits good microwave absorption property in the frequency range of 8.2–12.4 GHz.

Mesoporous silica nanoparticles (MCM-41) surface was functionalized with 3-(trimethoxysilyl)propyl methacrylate (MPS). Then, the resultant double bond containing nanoparticles were used in grafting through simultaneous reverse and normal initiation technique for atom transfer radical polymerization (SR&NI ATRP) of styrene to synthesize well-defined polystyrene nanocomposites with twofold chains. Nitrogen adsorption/desorption isotherm and X-ray diffraction analysis were used to evaluate characteristics of spherical MCM-41 nanoparticles. Morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography respectively. Addition of MCM-41 nanoparticles by 3 wt.% results in a decrease of conversion from 93% to 82%. Molecular weight of the free and attached polystyrene chains decreases by adding 3 wt.% MCM-41 nanoparticles; however, PDI values increases from 1.27 to 1.78 for free chains and 1.87 to 2.48 for attached chains. A peak around 4.1 ppm which originates from hydrogen atom of terminal units of polystyrene chains in proton nuclear magnetic resonance spectra in combination with low PDI values can appropriately demonstrate the living nature of the polymerization. Increasing thermal stability of the nanocomposites is demonstrated by Thermogravimetric analysis. Differential scanning calorimetry also shows a decrease in glass transition temperature by increasing MCM-41 nanoparticles.

Molecular dynamics simulations have been performed to study the initial roll guided structural transition of graphene. The flat graphene is thermodynamic metastable and small disturbance can strike its balance and lead to fold. An initial roll at one end causes the graphene layer to transform into double-fold, multi-fold and scroll spontaneously, depending on the size of the initial roll. This unique phenomenon results from the combined action of the van der Waals interaction and the π–π stacking effect. The potential energy of the final structures decreases with the increase of compact level. This study provides crucial simulation input to help guide to designing the required graphene-based nanostructures.

This paper studies the effects of a high magnetic field on the structural evolution and magnetic properties of nanocrystalline Ni films prepared on quartz substrates by a molecular beam vapor deposition (MBVD) method. Atomic force microscope, X-ray diffractometer, transmission electron microscope and vibrating sample magnetometer were used to study the microstructures and magnetic properties of the Ni films. The results indicate that high magnetic field has no obvious influence on crystal structures except changing the lattice constant of the Ni films. However, the high magnetic field can refine particle size. The film deposited under magnetic field tends to grow through columnar mode because of the magnetized particles aligning along the direction of magnetic field. Furthermore, the ordered and dense arrangement of Ni atoms results in more spins contained in per unit volume and improves the saturation magnetization (Ms). Ms of the 6 T Ni film increases by 70% (578 emu/cm³) than that of the film without magnetic field (341 emu/cm³), and the coercivity is also slightly increased for the 6 T film.

SnO₂ nanofibers and nanotubes were synthesized by electrospinning method. Magnetization measurement indicates that the SnO₂ nanofibers and nanotubes annealed in air at 500°C exhibit the room-temperature ferromagnetism and the ferromagnetism of nanotubes is stronger than the nanofibers. Selected area electron diffraction, X-ray diffraction and Raman measurements show that all the samples possess a typical rutile structure and no other impurity phases are observed. The results of the Raman spectra also indicate that there are lots of defects existing in the fabricated samples. The observed room-temperature ferromagnetism in SnO₂ nanofibers and nanotubes possibly originates from oxygen vacancies. The field cooled (FC) and zero-field-cooled (ZFC) magnetization curves indicate that the Curie temperature T_C is above 300 K.

Multiwall carbon nanotubes (MWCNTs) have been widely applied in many fields due to the excellent physical and chemical properties. As the production and applications of nanotubes expand, public concern about their potential risks to human health has also raised. Cytotoxicity of MWCNTs was evaluated in this study using a cultured human epithelial cell line A549. Uptake of MWCNTs by cultured A549 cells was observed by TEM imaging. Dose-dependent decrease of cell viability showed the cytotoxicity of MWCNTs. Significant reactive oxygen species (ROS) generation and GSH depletion which reduced the cellular antioxidant level could be the major factor of cytotoxicity induced by MWCNTs. MWCNTs seemed to trigger the activation of cell autophagy with the intracellular ATG16L1 level increase as a defense mechanism.