Abstract: We report the sol-gel synthesis of pristine and Fe containing perovskite structured strontium stannate nanoparticles, stabilized by cetyl trimethyl ammonium bromide (CTAB). The X-ray diffraction data of pristine and Fe doped strontium stannate nanoparticles reveals the formation of orthorhombic phase with Pbnm space symmetry. Raman spectra of pristine and Fe doped SrSnO3 nanoparticles depicts peaks at 220, 256 and 561 corresponding to Sn-O-Sn, O-Sn-O and Sn-O band stretching, respectively. The dc resistivity of pristine and Fe doped SrSnO3 is found to decrease with increase in Fe content. The variation of impedance (Zʹ and Z′′) and electric modulus (Mʹ and M′′) of pristine and Fe doped strontium stannate nanoparticles as a function of frequency (20 Hz to 2 MHz) at different temperatures (310-410 K) has been studied.
Abstract: In this work, we present the effect of preparation temperature of electrolytes for fabricating undoped and silver (Ag) doped titanium dioxide (TiO2) nanotubes by the electrochemical anodic oxidation of pure titanium sheets in electrolytes, mixtures of ethylene glycol (EG), ammonium fluoride (NH4F) and deionized water, that contain with different of silver ions. Heat treatment of electrolytes was carried out at 100 °C during preparation process. The morphology and structure of prepared nanotubes were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The structures of TiO2 nanotubes obtained from heat treatment and non-heat treatment of electrolyte solutions and adding silver ions in electrolyte solution are similar. The nanotubes appear in arrays and the diameters of nanotubes were about 92 nm for non-heat treatment electrolyte solution and undoped TiO2 and about 102 nm for heat treatment electrolyte solution and all Ag-doped TiO2 nanotube arrays. When the concentration of silver nitrate (AgNO3) increases, the TiO2 nanotube arrays cracked and are not well arranged.
Abstract: Polyaniline (PANI) and polyaniline-clay (PANI-clay) composite nanostructured materials were prepared via both ultrasonic irradiation and sol-gel preparation techniques. The molecular structure of prepared PANI and PANI-clay composite samples were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The characterization results confirm the nanostructure of prepared samples. BET surface area results were obtained for the prepared matrices. TEM and SEM images showed the morphology of the fabricated nanomaterials.
Abstract: This paper presents the effect of ultrasonic treatment on the morphology and microstructure of TiO2 nanotubes prepared by DC anodization method. The TiO2 nanotubes were grown by one-face anodization at room temperature on titanium sheets of 0.25 mm thickness and 99.7% purity. The electrolyte was composed of ethylene glycol (EG), ammonium fluoride (0.3% wt NH4F) and deionized water (2% V H2O). A constant DC voltage of 50 V was applied during anodization for 2 hours. The samples were ultrasonically cleansed in ethanol for different extended periods of time: 0, 10, 30 and 50 minutes respectively. The samples were annealed at 450 °C for 2 hours. The surface morphology and microstructure of the TiO2 nanotubes formed were studied by XRD and SEM. The best result was obtained when the sampleswere ultrasonicated for 30 minutes.
Abstract: Graphene nanoplates (GNPs) was immobilized with nanomagnetite using co-precipitation technique with the aid of ultrasound for the production of magnetic graphene nanoplate composite Fe3O4/G (MGNC) production. The physico-chemical properties of graphene were compared with the fabricated magnetic graphene composite using different characterization techniques. The crystalline and chemical structures of nanographene before and after magnetic immobilization were identified using X-Ray diffraction. The morphological structure of magnetic composite was identified by using Transmission Electron Microscope (TEM).it was carried out to investigate the precipitation of nanomagnetite onto the nanographene sheets. Atomic Force Microscope (AFM) analysis of magnetic graphene composites confirms the presence of magnetic nanoparticles attached to nanographene. The Vibrating sample magnetometer (VSM) confirmed the superparamagnetic properties of the prepared composite that represented with its hysteresis curve, and the saturation moment per unit mass, Ms for the MGNCs is 22.7548 emu·g−1
Abstract: We report on the structural and biocompatibility properties of nanosized calcium phosphosilicate bioglass ceramics doped with 0, 2, 4 and 6 mol% Ag2O. Silver doped bioceramics were synthesized by sol-gel method. The prepared samples were characterized by means of powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-visible and high resolution transmission electron microscopy. The XRD reveals the glass-ceramic nature of the samples. The FT-IR spectra show the possible stretching and bending vibrations of silicate and phosphate groups. Absorptions in UV-visible spectra reveal the silver embedment as Ag+/Ago form into the glass matrix. nanosize of the glass ceramics is confirmed by HR-TEM analysis. The bioactivity of silver doped bioceramics was investigated by in-vitro method with Dulbecco’s Modified Eagel’s Medium. It confirms the formation of bone-like hydroxylapatite layer formation on the surface of bioceramics.
Abstract: We demonstrate a three-dimensional nanostructure design by combining graphene and conventional plasmonic nanostructures, to achieve the high absorbance in the visible region. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. Comparing the results of two structures which is based on different materials, Gold and Silver. The structure made of Silver present a better performance. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.
Abstract: A plasmonic photocatalytic reactor which composed of a periodic array of core-shell silver nanoparticles (CSSNPs) photodeposited onto a Titanium Dioxide (TiO2) thin film in a multilayer rotating-disk system was numerically investigated by using three-dimensional finite element method. Results show that the proposed structure can exhibit much higher photocalytic activity in a broad range of incident angle of light that are not observed for the same counterpart without the CSSNPs on the SiO2 surface. The enhanced electric field distribution and intensity could be expanded as the inner diameter of CSSNPs and incident angle of light increased.
Abstract: Nowadays, the discharge of synthetic dyes effluents into water system has created serious water contamination problems which could gravely impact the quality of human life. Photocatalytic oxidation (PCO) by TiO2 has shown superior performance on towards the remediation of various organic pollutants. In this study, two dimensional (2D) graphene oxide (GO) sheets supported titanium dioxide (TiO2) nanoparticles were successfully synthesized by a simple and efficient sol-gel method using titanium isopropoxide (TTIP) and GO as the precursor. The graphite powder was first oxidized into hydrophilic GO using modified Hummer’s method followed by the addition of titanium solution. The resulting nanocomposites were then applied in the PCO of methyl orange under UV irradiation. The TiO2 nanoparticles were spherical in shape, with a particle size of 20-30 nm were well-deposited on the GO sheets. The presence of anatase phase in GO/TiO2 was confirmed by the XRD studies. The nanocomposites exhibited enhanced photocatalytic activity than TiO2, probably due to the addition of graphene oxide which retard the electron-hole recombination in the hybrid material.
Abstract: The affinity of nanoporous biochars functional groups for immobilization Cu, Zn, and Pb in aqueous solution has been studied. BET results revealed the nanoporous structure of the chars. Batch experiments have been designed and performed.The results indicated remarkable sorption capacity in case of each char: in a multi-metal system, B1, B2, and B3 adorbed 24.39, 23.61, 35.69 mg/g copper, 63.36, 90.96, 95.36 mg/g lead, and 20.16, 21.26, and 25.44 mg/g zinc, respectively. To find out the sorption mechanism with a post-sorption FTIR analysis over the biochars has been made. The results suggest the possible competitive immobilization mechanism as Cu being mainly organically bounded to amino, hydroxyl and carboxyl functional groups, Pb forming insoluble hydroxide, phosphate or carbonate, and Zn being mostly sorbed in the residual fraction.