Eu-Doped Zeolitic Imidazolate Framework-8 Modified Mixed-Crystal TiO2 for Efficient Removal of Basic Fuchsin from Effluent

Zeolitic imidazolate framework-8 (ZIF-8) was doped with a rare-earth metal, Eu, using a solvent synthesis method evenly on the surface of a mixed-crystal TiO2(Mc-TiO2) structure in order to produce a core–shell structure composite ZIF-8(Eu)@Mc-TiO2 adsorption photocatalyst with good adsorption and photocatalytic properties. The characterisation of ZIF-8(Eu)@Mc-TiO2 was performed via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller analysis (BET) and ultraviolet–visible light differential reflectance spectroscopy (UV-DRs). The results indicated that Eu-doped ZIF-8 was formed evenly on the Mc-TiO2 surface, a core–shell structure formed and the light-response range was enhanced greatly. The ZIF-8(Eu)@Mc-TiO2 for basic fuchsin was investigated to validate its photocatalytic performance. The effect of the Eu doping amount, basic fuchsin concentration and photocatalyst dosage on the photocatalytic efficiency were investigated. The results revealed that, when 5%-Eu-doped ZIF-8(Eu)@Mc-TiO2 (20 mg) was combined with 30 mg/L basic fuchsin (100 mL) under UV irradiation for 1 h, the photocatalytic efficiency could reach 99%. Further, it exhibited a good recycling performance. Thus, it shows certain advantages in its degradation rate and repeatability compared with previously reported materials. All of these factors suggested that, in an aqueous medium, ZIF-8(Eu)@Mc-TiO2 is an eco-friendly, sustainable and efficient material for the photocatalytic degradation of basic fuchsin.

The Influence of Supercooling and Hydrodynamics on the Mosaic and Radial Inhomogeneity of K2NiXCo(1–X)(SO4)2·6H2O Mixed Crystal

The mosaic and radial inhomogeneity of shaped mixed crystals of K2NixCo(1–x)(SO4)2·6H2O (KCNSH) were studied depending on the supercooling of solution, its velocity and its method of supply into the shaper. It was shown that mosaic inhomogeneity could be suppressed when solution is supercooled to about 2 °C. Peripheral supply of the solution (tangential to the wall of the shaper to create a “swirling” flow) with a rate of 55–135 cm/s provides better composition uniformity along the crystal surface in comparison with upright supply of the solution (flow is perpendicular to the crystal surface).

Synthesis and Characterization of Sn/Ni Single Doped and Co–Doped Anatase/Rutile Mixed–Crystal Nanomaterials and Their Photocatalytic Performance under UV–Visible Light

Pure and Sn/Ni co–doped TiO2 nanomaterials with anatase/rutile mixed crystal were prepared and characterized. The results show that pure TiO2 is a mixed crystal structure composed of a large amount of anatase and a small amount of rutile. Sn doping promotes the phase transformation from anatase to rutile, while Ni doping inhibits the transformation. Both single doping and co–doping are beneficial to the inhibition of photoinduced charge recombination. Sn doping shows the best inhibitory effect on photogenerated charge recombination, and increases the utilization of visible light, displaying the highest photocatalytic activity. The decolorization degree of methylene blue (MB) by Sn–TiO2 is 79.5% after 150 min. The reaction rate constant of Sn–TiO2 is 0.01022 min−1, which is 5.6 times higher than pure TiO2 (0.00181 min–1).

Work function of polytypic gallium phosphide nanowires

In this work we investigate the work function of gallium phosphide nanowires by the means of frequency-modulated Kelvin probe force microscopy. Polytypic wurtzite/zinc blende nanowires were synthesized via self-catalytic molecular beam epitaxy. Mixed crystal phase was achieved by controlling the catalytic droplet contact angle and confirmed via transmission electron microscopy and Raman spectroscopy. Kelvin probe study showed a contrast between the work function of (110) zinc blende and (1120) wurtzite gallium phosphide: ϕZB = 4.28 eV and ϕWZ = 4.2 eV. Also, it was shown that sub-monolayer arsenic shell increases the work function up to 4.75 eV. Thus, two mechanisms for work function adjustment in the range 4.2-4.75 eV are shown. The results are important for optimization of Schottky barriers in nanowire-based devices.

Effects of Hydrothermal Time on Structure and Photocatalytic Property of Titanium Dioxide for Degradation of Rhodamine B and Tetracycline Hydrochloride

Using butyl titanate and absolute ethanol as raw materials, TiO2 was prepared by a hydrothermal method with different hydrothermal times, and the influences of hydrothermal time on the structure and photocatalytic performance of TiO2 were investigated. The obtained samples were characterized by XRD, SEM, TEM, BET, PL and DRS, separately. The results show that TiO2 forms anatase when the hydrothermal time is 12 h, forms a mixed crystal composed of anatase and rutile when the hydrothermal time is 24 h, and forms rutile when the hydrothermal time is 36 h. With the extension of hydrothermal time, anatase gradually transforms into rutile and the surface area decreases. Although TiO2-24 h and TiO2-36 h show lower photoinduced charge recombination and higher light source utilization, TiO2-12 h exhibits the highest photocatalytic activity owing to its largest surface area (145.3 m2/g). The degradation degree of rhodamine B and tetracycline hydrochloride reach 99.6% and 90.0% after 45 min.

Structural, Optical, and Electrical Properties of Copper Oxide Films Grown by the SILAR Method with Post-Annealing

Copper oxides are widely used in photocatalysts, sensors, batteries, optoelectronic, and electronic devices. In order to obtain different material properties to meet the requirements of different application fields, varied technologies and process conditions are used to prepare copper oxides. In this work, copper oxide films were grown on glass substrates by a successive ionic layer adsorption and reaction (SILAR) method with subsequent annealing under an atmospheric environment. The films were characterized by using an X-ray diffractometer, Raman spectrometer, Scanning electron microscope, UV-Visible-NIR spectrophotometer, and Hall Effect measurement. The results show that the as-deposited film has a Cu2O crystal structure, which begins to transform into Cu2O-CuO mixed crystal and CuO crystal structure after annealing at 300 °C for a period of time, resulting in the bandgap of being reduced from 1.90 to 1.34 eV. The results show that not only are the crystal structure and bandgap of the films affected by the post-annealing temperature and time, but also the resistivity, carrier concentration, and mobility of the films are varied with the annealing conditions. In addition, the film with a Cu2O-CuO mixed crystal shows a high carrier mobility of 93.7 cm2·V−1·s−1 and a low carrier concentration of 1.8 × 1012 cm−3 due to the formation of a Cu2O-CuO heterojuction.