Well-dispersed Nanorods Research Articles

Rational modification in the photochromic and self-bleaching performance of hierarchical microsphere Cu@h-WO3/WO3·nH2O composites

Herein, we used a self-assembly method to synthesize novel Cu@h-WO3/WO3·nH2O hierarchical microsphere composites with enhanced photochromism and self-bleaching performance. The composite fabricated with 1.0% Cu-WO displayed a rapid change from light-yellow to dark-gray after 2 min of ultraviolet irradiation and self-bleached in less than 1 h in the dark. Composite samples were characterized to investigate changes in their morphology and structure after being doped with different amounts of Cu. The hierarchical microspheres were composed of small, well-dispersed nanorods that provided active sites capable of absorbing light. Ensuring the proper Cu content in the WO3 lattice promoted the separation of carriers through interfacial charge transfer (IFCT) and prevented the recombination of electron-hole pairs due to excessive doping. Combing hexagonal WO3 with WO3·nH2O and Cu provided unobstructed channels, proton sources, and interactions with W species, which improved the efficiency of proton insertion and extraction. The WO3 hybrid materials described in this research displayed high coloration efficiencies and reversibility and may find applications in solar energy devices.

Superhydrophobic coating of silicone/β–MnO2 nanorod composite for marine antifouling

A novel superhydrophobic series of silicone/β–MnO2 nanorod composite was successfully fabricated for marine fouling release (FR) coatings. We studied how the self-cleaning and antifouling features were affected by controlling the β–MnO2 nanorod preparation and distribution in the silicone matrix. The nanorods exhibited a single crystal structure, a mean diameter of 20–30 nm and a length of 0.5–1 μm, and they had a wurtzite structure that preferentially grew in the [100] direction which has the most stable surface, high antimicrobial, and low free energy. Nanorod fillers of different concentrations were distributed in the silicone matrix for enhancing the surface roughness, water repellency and FR features. Surface characteristics were evaluated by using the contact angle of water experiments, atomic force microscope and scanning electron microscope for studying the superhydrophobicity and antifouling attributes. Well-dispersed nanorods exhibited a particular increase in the coating roughness, superhydrophobicity, and low surface energy properties. Thermal and mechanical properties, as well as stability in different pH solutions, were tested as durability parameters. For assessing the biological and fouling repellency effects of the coating systems, chosen micro-fouling organisms were used in the laboratory for one month. Also, a field experiment was carried out by immersing the coated samples in natural seawater up to 90 days and the screening method and image analysis were used to test the FR behavior. The well-dispersed nanorods (0.5 wt.%) presented the most profound superhydrophobic FR nanostructured coating; which demonstrated a 158° and 12.65 mN/m for the surface contact angle and free energy.

Structural, electrical, and dielectric properties of nickel-doped spinel LiMn2O4 nanorods

Spinel pure and Ni-doped LiMn2O4 nanorods were synthesized by a rapid microwave-assisted hydrothermal process followed by a solid-state reaction method. Their structural, morphological, electrical, and dielectric properties were investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and impedance spectroscopy techniques. Powder XRD studies revealed that all the synthesized samples have well-defined cubic crystal structure and the Ni2+ doping in manganese sites did not affect spinel LiMn2O4 structure. TEM images of pure and Ni-doped LiMn2O4 samples clearly showed the formation of well-dispersed nanorods with uniform distribution. The Ni2+ doping did not affect the nanorod morphology of pure LiMn2O4. The spinel LiMn2O4 nanorods showed an electrical conductivity of 3.13 × 10−4 S cm−1, at room temperature. The A.C conductivity studies revealed that the pure and Ni-doped LiMn2O4 nanorods obey Jonscher’s power law. The dielectric studies revealed that the dielectric constant of the samples decreases with frequency, which is due to decrease in charge accumulation at the interface.

Optical and Magnetic Properties of Ni Doped ZnS Diluted Magnetic Semiconductors Synthesized by Hydrothermal Method

Diluted magnetic semiconductors Zn1-xNixS with different consistency ratio (x = 0, 0.01, 0.03, 0.05, and 0.07) were successfully synthesized by hydrothermal method using ethylenediamine as a modifier. The influence of Ni doping concentration on the microstructure, morphology, and optical and magnetic properties of undoped and Ni doped ZnS nanocrystals was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR), photoluminescence spectra (PL), and the vibrating sample magnetometer (VSM), respectively. The experiment results show the substitution of Ni2+ on Zn2+ sites without changing the hexagonal wurtzite structure of ZnS and generate single-phase Zn1-xNixS with good crystallization. The lattice constant causes distortion and decreases with the increase of Ni2+ doped concentration. The appearance of the samples is one-dimensional well-dispersed nanorods. UV-vis spectra reveal the band gap of all Zn1-xNixS samples greater than that of bulk ZnS (3.67 eV), and blue shift phenomenon occurs. The photoluminescence spectra of undoped and doped samples possess the broad blue emission band in the range of 400–650 nm; the PL intensities of Zn1-xNixS nanorods increase with the increase of Ni content comparing to pure ZnS and reach maximum for x = 0.03. Magnetic measurements indicated that the undoped ZnS samples are superparamagnetic, whereas the doped samples exhibit ferromagnetism.

Synthesis and physicochemical evaluation of hydroxyapatite gel biosorbent for toxic Pb(II) removal from wastewater

The agglomeration of hydroxyapatite (HAp) nanoparticles is the main challenge when it used as an adsorbent for removing toxic trace elements from aqueous solutions. In the present study, HAp gel was synthesized and evaluated as a potential bioadsorbent for treatment and sorption Pb(II) from polluted water. HAp gel was prepared by co-precipitation method and its physicochemical ability to remedy Pb(II) was tested by batch experiments under changing initial parameters such as pH and contact time. XRD, FTIR, and TEM techniques were used to characterize HAp gel, and ICP technique evaluated its physicochemical property to adsorb and remove Pb(II) from aqueous solutions. The adsorption equilibrium of Pb(II) on HAp gel was analyzed at room temperature using conventional Freundlich and Langmuir adsorption isotherm models. The synthetic HAp gel showed a pure nanocrystalline phase and well-dispersed nanorods. The HAp gel exhibited high sorption capacity at 344.8 mg/g for Pb(II) removal at a short equilibrium contact time of 10 min. The synthetic HAp gel is a promising efficient bioadsorbent to alleviate the problems accompanied conventional dried HAp agglomerates in particular for industrial and environmental applications that need an economic and eco-friendly non-agglomerated adsorbent.

Economical and simple fabrication of rod-like hydroxyapatite nanocrystal with good dispersity and crystallinity

The homogeneous hydroxyapatite rod-like nanocrystal was prepared through an economical and simple route under gentle conditions by the aqueous chemical method. The high-resolution transmission electron microscope (HRTEM) displayed that the products were well-dispersed nanorods. The diameter of the nanorods was 4 ± 0.1 nm and the length was 20 ± 0.8 nm. The corresponding selected area electron diffraction (SAED) analysis demonstrated that the products were crystalline. Additionally, both X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) spectra indicated the characteristic peaks of hydroxyapatite. Moreover, the energy dispersive system (EDS) analysis demonstrated the Ca/P ratio of the product was 1.67, which was in consistent with commercial hydroxyapatite.

Room-temperature synthesis of MnO2·3H2O ultrathin nanostructures and their morphological transformation to well-dispersed nanorods

MnO(2).3H(2)O ultrathin nanostructures with sizes of approximately 2-3 nm were synthesized at room temperature and transformation to well-dispersed nanorods was achieved after hydrothermal treatments.