Synthesis of boron doped C3N4/NiFe2O4 nanocomposite: An enhanced visible light photocatalyst for the degradation of methylene blue

In this paper, we report the synthesis of boron doped C3N4/NiFe2O4 nanocomposite and its application as a visible-light photocatalyst for the degradation of methylene blue (MB). Boron-doped C3N4 (BCN) was prepared by simple thermal condensation of dicyandiamide with boric acid, and NiFe2O4 nanoparticles were prepared by the simple sol-gel method. The as-synthesized nanocomposite materials were characterized and confirmed by the X-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, UV-Visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The photocatalytic activity of BCN/NiFe2O4 nanocomposite was evaluated towards the degradation of MB in the presence of visible light irradiation. The obtained results confirmed that BCN/NiFe2O4 composite has higher degradation efficiency (98%) than that of BCN and NiFe2O4

Assembly of ZnO Nanoparticles on SiO2@α-Fe2O3 Nanocomposites for an Efficient Photo-Fenton Reaction

The SiO2@α-Fe2O3/ZnO metal oxide nanocomposites employed in this study were obtained using the sol-gel method. Their photocatalytic activities were enhanced by photo-Fenton reactions. The metal oxide composite of ZnO and α-Fe2O3 nanoparticles were deposited on the SiO2 nanospheres intended for visible light photocatalysis. Further, the as-synthesized SiO2@α-Fe2O3/ZnO nanocomposites exhibited a robust crystallinity and a high adsorption of dye molecules when compared to SiO2@ZnO and SiO2@α-Fe2O3 nanocomposites, respectively. The experimental results demonstrated a rapid Methylene Blue (MB) degradation among these catalysts within short intervals of time with the addition of α-Fe2O3/ZnO mixed metal oxide catalysts on the SiO2 nanospheres. Finally, a photo-Fenton reaction was implemented to confirm the presence of the hydroxyl (OH) radicals, which are powerful agents used for the degradation of organic pollutants

TRANSPARENT ZINC OXIDE THIN FILMS PREPARED BY PLD WITH DIFFERENT OXYGEN PRESSURES

ZnO thin films were prepared on silicon (001) and corning glass substrates using Pulsed laser deposition (PLD) technique with different oxygen pressures. The microstructure, crystallinity, and resistivity of the films depend on the oxygen pressure used. The effects of the films grown at room temperature and at 500°C with different oxygen pressures have been investigated by analyzing the optical and electrical properties of the film. The XRD analysis showed that the high intensity of c-axis orientation of ZnO thin films was obtained under high oxygen pressure and this leads to greater electrical and optical properties. By applying high pressure oxygen, the resistivity value was decreased and optical transmittance became higher in the visible region. The surface morphology of the films showed that the smooth surface was observed without any cracks.Pulsed laser deposition, zinc oxide, resistivity

The Preparation of Porous Sol-Gel Silica with Metal Organic Framework MIL-101(Cr) by Microwave-Assisted Hydrothermal Method for Adsorption Chillers

Abstract: Metal organic framework (MOF) of MIL-101(Cr)-Silica (SiO2) composites with highly mesoporous and uniform dispersions were synthesized by a microwave-assisted hydrothermal method followed by the sol-gel technique. Water vapor adsorption experiments were conducted on the MIL-101(Cr)-SiO2 composites for industrial adsorption chiller applications. The effects of MIL-101(Cr)-SiO2 mixing ratios (ranging from 0% to 52%), the surface area and amount of Lewis and Brønsted sites were comprehensively determined through water vapor adsorption experiments and the adsorption mechanism is also explained. The BET and Langmuir results indicate that the adsorption isotherms associated with the various MIL-101(Cr)-SiO2 ratios demonstrated Type I and IV adsorption behavior, due to the mesoporous structure of the MIL-101(Cr)-SiO2. It was observed that the increase in the amount of Lewis and Brønsted sites on the MIL-101(Cr)-SiO2 composites significantly improves the water vapor adsorption efficiency, for greater stability during the water vapor adsorption experiments

Fabrication of Hybrid Catalyst ZnO Nanorod/α-Fe2O3 Composites for Hydrogen Evolution Reaction

This report presents the synthesis of ZnO nanorod/α-Fe2O3 composites by the hydrothermal method with different weight percentages of α-Fe2O3 nanoparticles. The as-synthesized nanorod composites were characterized by different techniques, such as X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). From our results, it was found that the ZnO/α-Fe2O3 (3 wt%) nanorod composites exhibit a higher hydrogen evolution reaction (HER) activity when compared to other composites. The synergetic effect between ZnO and (3 wt%) of α-Fe2O3 nanocomposites resulted in a low onset potential of −125 mV, which can effectively produce more H2 than pure ZnO. The H2 production rate over the composite of ZnO/α-Fe2O3 (3 wt%) clearly shows a significant improvement in the photocatalytic activity in the heterojunction of the ZnO nanorods and α-Fe2O3 nanoparticles on nickel foam

Degradation of Methylene Blue Dye in the Presence of Visible Light Using SiO2@α-Fe2O3 Nanocomposites Deposited on SnS2 Flowers

Semiconductor materials have been shown to have good photocatalytic behavior and can be utilized for the photodegradation of organic pollutants. In this work, three-dimensional flower-like SnS2 (tin sulfide) was synthesized by a facile hydrothermal method. Core-shell structured SiO2@α-Fe2O3 nanocomposites were then deposited on the top of the SnS2 flowers. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis Spectroscopy, Brunauer–Emmett–Teller (BET) surface area analysis, and photoluminescence (PL) spectroscopy. The photocatalytic behavior of the SnS2-SiO2@α-Fe2O3 nanocomposites was investigated by observing the degradation of methylene blue (MB). The results show an effective enhancement of photocatalytic activity for the degradation of MB especially for the 15 wt % SiO2@α-Fe2O3 nanocomposites on SnS2 flowers

Electrical and thermal properties of 10 mol% Gd 3+ doped ceria electrolytes synthesized through citrate combustion technique

Nanocrystalline ceria electrolyte doped with 10 mol% gadolinia [Ce0.9Gd0.1O1.95] was synthesized by citric acid combustion technique involving mixtures of cerium nitrate oxidizer (O) and citric acid fuel (F) taken in the ratio of O/F=1. The as combusted precursors produced crystalline ceria particles upon calcination performed at 700°C for 2h. Ceria pellets were made and sintered at temperatures 1200, 1400 and 1500°C with a dwell time of 2, 4 and 6 h. The sintered microstructures, electrical and thermal conductivities and thermal diffusivity properties were evaluated in addition to the powder properties such as crystalline structure, surface area, particle size and morphology. Sintered ceria samples had 99% theoretical density at 1500°C/6h. The sintered microstructures exhibit dense ceria grains with sizes 500 nm to one micron. The electrical conductivity versus temperature showed conductivity in the order of 10^(-2) and 10^(-1) S·cm-1 at 500 and 700°C, respectively. The ceria sintered at 1500°C has the maximum thermal conductivity of ~2.79 W·m-1K-1 at room temperature