Facile synthesis of g-C3N4/ZnO composite with enhanced visible light photooxidation and photoreduction properties

Doping with metals and non-metals is a popular technique that facilitates visible light activity of titanium dioxide. More recently, rare-earth metals have shown tremendous potential as dopants not only in red-shifting the absorption but also in improving the photocatalysis of TiO2. This feature article discusses recent developments in making TiO2 visible-light active through single and co-doping with rare earth metals. An emphasis is placed on wet chemical techniques and their associated effects on the phase, adsorption, surface area, and photocatalytic activity of TiO2. New techniques, such as electrospinning, magnetron sputtering, co-precipitation, and complexation, as well as the use of nanotubes and physical support are also discussed.

Recent advances in making nano-sized TiO2 visible-light active through rare-earth metal doping

Organophosphates are one of the major constituent of herbicides, pesticides, insecticides and nerve gas. Azinophos-methyl, chlorpyrifos, diazinon, fonofos and disulfoton are well-known organophosph...

Toxicity, monitoring and biodegradation of organophosphate pesticides: A review

In this work, Eu-doped, Tb-doped and Eu, Tb-codoped Y2O3 nanophosphors were synthesized by the combustion synthesis method The prepared phosphors were characterized by x-ray diffraction (XRD), Rietveld refinement and Fourier transform infrared (FTIR) spectroscopy XRD studies and Rietveld refinement confirmed the body-centred cubic structure of doped and codoped phosphors FTIR studies also confirmed the formation of these compounds Thermal analysis results indicated that there was no phase transition for all the phosphors in the studied temperature range In the optical properties, diffuse reflectance (DR) and photoluminescence (PL) measurements were performed DR spectra were used to determine the bandgap and it increased in the doped and codoped samples due to the crystallite size effect A strong characteristic emission from Eu3+ and Tb3+ ions was identified and the influence of doping concentration and annealing temperature on PL properties was systematically studied Transfer of energy was observed from Tb3+ to Eu3+ ions in the codoped phosphor at room temperature

https://iopscience.iop.org/article/10.1088/0022-3727/45/41/415102/pdf

Eu3+/Tb3+-codoped Y2O3 nanophosphors: Rietveld refinement, bandgap and photoluminescence optimization

The nanocrystalline ZnO:Fe semiconductor oxides were successfully synthesized via the sol–gel calcination method. Structural, optical and electrical properties of the investigated samples were characterized by various techniques such as atomic force microscopy (AFM), UV–vis absorption and electrical transport measurements. The optical band gap for undoped ZnO (3.19 eV) decreases (2.75 eV) with increasing Fe-doped ZnO (20%). The temperature dependences of the electrical conductivities of undoped ZnO and Fe-doped ZnO were measured and analyzed by Arrhenius equation. The electrical conductivity of the samples decreases with the increase of Fe doping ratio; hence, the electrical conductivity mechanism is controlled by thermally activated processes. To support the nanostructure of Fe-doped ZnO, AFM micrographs were performed.

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Synthesis, diffused reflectance and electrical properties of nanocrystalline Fe-doped ZnO via sol-gel calcination technique

Resumen en: Optical properties of un-supported or powdered nanostructures are frequently determined through UV-Vis absorption spectroscopy of their dispersed solutio...

Use of diffuse reflectance spectroscopy for optical characterization of un-supported nanostructures

Nanostructured Pt–ZnO composite thick films were prepared using the composite nanoparticles synthesized through Triton X-100 polymer assisted thermolysis of zinc acetate. It has been observed that only a fraction of added Pt incorporates into the ZnO lattice and the rest segregates over the ZnO nanoparticle surface to form metallic nanoclusters. Morphology, crystallinity, and optical properties of the ZnO and Pt–ZnO nanostructures have been studied. Photocatalytic behavior of the samples for phenol degradation process has been studied in a high performance liquid chromatography system. It has been observed that though the phenol degradation rate is higher for pure ZnO nanostructures, Pt–ZnO nanostructures act as selective catalyst, producing only one intermediate product and dissociating it faster than ZnO.

/pdf/photocatalytic-behavior-of-zno-and-pt-incorporated-zno-1qtro43aui.pdf

Photocatalytic behavior of ZnO and Pt-incorporated ZnO nanoparticles in phenol degradation

Developing new semiconductor materials with improved photocatalytic activity is a promising technology for the remedy of environmental pollution. Here we report on the synthesis of Yb containing TiO2 nanoparticles and their catalytic activity under visible light. Highly monodispersed, spherical TiO2 and TiO2 :Yb nanoparticles of 27- 40 nm size range were prepared through controlled hydrolysis of titanium tetrabutoxide (TTB) and characterized by X-ray diffraction (XRD), energy dispersion spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), high angle annular dark field (HAADF), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) techniques. Average size of the nanoparticles was found to decrease with the increase of Yb doping concentration. The photocatalytic activity of Yb doped TiO2 was evaluated by measuring the degradation rates of methylene blue (MB) under UV and visible lights. Doping with ytterbium ions enhanced significantly the photocatalytic activity of TiO2 nanoparticles for MB oxidation under visible light.

E. Sánchez Mora

Papers

Use of diffuse reflectance spectroscopy for optical characterization of un-supported nanostructures

Photocatalytic behavior of ZnO and Pt-incorporated ZnO nanoparticles in phenol degradation

Synthesis and Photocatalytic Activity of Yb Doped TiO2 Nanoparticles under Visible Light