Facile Fabrication of Three-Dimensional Fusiform-Like α-Fe2O3 for Enhanced Photocatalytic Performance

α-Fe2O3 fusiform nanorods were prepared by a simple hydrothermal method employing the mixture of FeCl3·6H2O and urea as raw materials. The samples were examined by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and UV–vis diffuse reflectance spectra (UV–DRS). Its visible-light photocatalytic performances were evaluated by photocatalytic decolorization methylene blue (MB) in visible light irradiation. It was found that pure phase α-Fe2O3 nanorods with a length of about 125 nm and a diameter of 50 nm were successfully synthesized. The photocatalytic decolorization of MB results indicated that α-Fe2O3 nanorods showed higher photocatalytic activity than that of commercial Fe2O3 nanoparticles—these are attributed to its unique three-dimensional structure and lower electron-hole recombination rate.

Fabrication, Characterization and Photocatalytic Activity of Copper Oxide Nanowires Formed by Anodization of Copper Foams

In recent paper anodization of copper foams in 0.1 M K2CO3 is reported. Anodization was performed in the voltage range of 5–25 V and in all the cases oxides with a developed surface area were obtained. However, anodizing only at 20 and 25 V resulted in the formation of nanostruc-tures. In all the cases, the products of anodizing consisted of crystalline phases like cuprite (Cu2O), tenorite (CuO), parameconite (Cu4O3) as well as spertiniite (Cu(OH)2). Copper foams after ano-dizing were applied as catalysts in the photocatalytic decolorization of a model organic compound such as methylene blue. The highest photocatalytic activity was observed for samples anodized at 25 V and closely followed by samples anodized at 5 V. The anodized copper foams proved to be a useful material in enhancing the photocatalytic efficiency of organic dye decomposition.

A reusable chitosan/TiO2@g-C3N4 nanocomposite membrane for photocatalytic removal of multiple toxic water pollutants under visible light

Photocatalysis has been proved to be a promising approach in wastewater purification. However, it's hard to recycle powdery photocatalysts from wastewater in the industry, and immobilization of them using materials of larger size can overcome the drawback. Thus, TiO2@g-C3N4 are embedded into chitosan to synthesize a highly reusable and visible-light-driven chitosan/TiO2@g-C3N4 nanocomposite membrane (CTGM) through a facile process in this paper. CTGM performs enhanced photoactivity and the photocatalytic efficiencies of multiple toxic water pollutants are above 90%, containing methyl orange (M.O.), rhodamine B (Rh.B), chromium (VI) (Cr (VI)), 2,4-dichlorophenol (2, 4-DCP) and atrazine (ATZ) under visible light at ambient conditions. Significantly, CTGM is easy to be recycled and performs excellent reusability. There isn't any decrease in the photocatalytic decolorization efficiency of Rh.B throughout 10 cycles, and CTGM still keeps the pristine look. Meanwhile, a continuous-flow photocatalysis system is set up and 90% of Rh.B can be effectively decolorized. In general, a simple approach is developed to prepare a novel, effective and visible-light-driven membrane with easiness to reuse, and a feasible photocatalysis continuous-flow system is designed to be a reference to wastewater treatment in the industry.

Photocatalytic Decolorization of Methyl Red on Nanoporous Anodic ZrO2 of Different Crystal Structures

High surface area, self-organized nanoporous ZrO2 arrays with perfect adhesion to the Zr substrate were synthesized by anodization in an aqueous electrolyte containing (NH4)2SO4 and NH4F. The obtained semiconductor materials were tested as photocatalysts for decolorization of the methyl red (MR) as a model azo dye pollutant. It was demonstrated that as-synthesized anodic ZrO2 anodic layers are already crystalline and, therefore, do not require further thermal treatment to provide a high photocatalytic performance. However, photocatalytic efficiency could be improved by annealing at a relatively low-temperature of 350 °C. Higher annealing temperatures caused a gradual drop of photocatalytic activity. The photocatalytic behavior was correlated with the crystal phase transformation in anodic ZrO2. It was found that higher photocatalytic activity was observed for the tetragonal phase over the monoclinic phase (predominant at elevated temperatures). It results from the optimal and complex electronic structure of annealed ZrO2 with three different energy states having absorption edges at 2.0, 4.01 and 5.28 eV.

Visible Light Driven Photocatalytic Decolorization and Disinfection of Water Employing Reduced TiO2 Nanopowders

Defect-engineering of TiO2 can have a major impact on its photocatalytic properties for the degradation of persisting and non-biodegradable pollutants. Herein, a series of intrinsic and extrinsic defects are induced by post annealing of crystalline TiO2 under different reducing atmospheres. A detailed optoelectronic characterization sheds light on the key characteristics of the defect-engineered TiO2 nanopowders that are linked to the photocatalytic performance of the prepared photocatalysts. The photodegradation of a model dye, malachite green, as well as the inactivation of bacterial endospores of the Geobacillus stearothermophilus species were studied in the presence of the developed catalysts under visible light illumination. Our results indicate that a combination of certain defects is necessary for the improvement of the photocatalytic process for water purification and disinfection under visible light.