Effect of calcination process on the gas phase photodegradation by CuO-Cu2O/TiO2 nanocomposite photocatalyst (original) (raw)
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Synthesis and characterization of nano-CuO and CuO/TiO 2 photocatalysts
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2013
CuO nanocrystals were prepared by thermal decomposition of Cu-oxalate at 400 • C; then CuO/TiO 2 core/shell nanocrystals were formed via the hydrolysis of titanium isopropoxide (TIP) on the surface of CuO nanocrystals. The characteristics of the synthesized nanocrystals were systematically studied using appropriate techniques, namely the morphology by using scanning electron microscopy (SEM), and the crystalline structure by x-ray powder diffraction (XRD) and Raman spectroscopy. The structure, shape and size of the CuO and CuO/TiO 2 nanocrystals could be tuned by changing various technological parameters: (i) the reaction/growth time (from several minutes to several hours), (ii) reaction temperature (from room temperature to 90 • C) and (iii) the molar ratios of the precursors. The results showed that the reaction temperature and the molar ratio of the precursors play important roles in controlling the morphology and size of both CuO and CuO/TiO 2 nanocrystals. With increasing reaction temperature, nano-CuO evolved from spherical shaped nanoparticles to microspheres. By shelling the large-bandgap TiO 2 layers on CuO nanocrystals, the core/shell structure is formed and the narrow-bandgap nano-CuO core is expected to be resistant to photocorrosion.
The Journal of Physical Chemistry C, 2008
Coupled CuO-TiO 2 nanocomposite photocatalysts were prepared by a deposition precipitation method and were characterized with a variety of techniques. Electron paramagnetic resonance (EPR) spectroscopy was employed to study the local structures of surface/interfacial Cu 2+ sites using Cu 2+ as a sensitive paramagnetic probe. The addition of bulk CuO to TiO 2 led to decreased photocatalytic efficiency in the degradation of methylene blue. However, doping with a very small amount of CuO (0.1 wt % copper loading) significantly enhanced the photocatalytic activity of TiO 2 . EPR study of the TiO 2 surface revealed the presence of both highly dispersed CuO clusters and substitutional Cu 2+ sites (Ti-O-Cu linkages) at 0.1 wt % copper loading. The data suggest that the Ti-O-Cu linkages contributed to the improved photooxidative activity of the 0.1% CuO-TiO 2 nanocomposite. In contrast, at higher loadings the bulk form of CuO created charge recombination centers lowering the photoactivity of the composites.
Effect of CuO doped TiO2 on Morphology, Crystal Structure and Photocatalytic Activity
International Journal of Current Research in Science, Engineering & Technology, 2018
Copper oxide doped Titanium Dioxide (CuO= 0-1.0wt.%) powders were prepared using sol-gel method and all the powder were sintered at 500 °C. The samples were characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM), Brunauer-Emmett-Teller (BET) and UV/Vis spectrophotometer. The doping concentration of CuO gave significant influenced on the structural properties of TiO2. The lattice parameter, particles size and specific surface area of TiO2 size were increased with increasing CuO concentration. The degradation rate of methylene blue (MB) was calculated to investigate the photocatalytic activity of CuO doped TiO2. The degradation rate were increased when the concentrations of CuO increased.
Journal of Materials Science: Materials in Electronics, 2019
In this study, Cu 2 O nanostructures on Cu wire were formed with in situ chemical and then thermal oxidation to obtain the desirable structure, morphology and optical properties in order to enhance visible-light photocatalytic activity. The findings suggested that the procedure involved solution phase treatment and formation of Cu 2 O on pure Cu wire with two-step oxidation in controlled environment of nitrogen and air. Results showed that Cu 2 O nanostructure on Cu substrate were formed from transformation of as-synthesized Cu(OH) 2 nanostructures. The kinetic studies for Cu(OH) 2 formation and the synthesis mechanism of Cu 2 O nanostructures were investigated. The results show that the heterogeneous Cu/Cu 2 O nanostructures display nanorod and polyhedral morphology. The MB degradation reaches 77-82% after 240 min visible light irradiation. The band gap values of the heat treated samples under nitrogen and air were obtained 1.75 and 2.00 eV, respectively. Intensity of PL spectra for the heat treated sample under nitrogen was obviously lower. Furthermore, it is observed that the first order and modified-Freundlich model fit the kinetic data well.
Desalination and Water Treatment, 2015
In this paper, various morphologies of copper oxide (CuO) were synthesized from acetate, sulfate, and nitrate precursors using hydrothermal bath method. The photoluminescence spectra revealed that CuO-Ni sample contains the strongest surface defect peak which can be related to its highest active surface area. The Fourier transform infrared (FT-IR) results showed that the concentration of the surface OH − group on the samples varies considerably according to CuO-Ac > CuO-Ni > CuO-Su. From structural results, it could be observed that all the samples crystallized into a monoclinic crystal structure. The photocatalytic activity of CuO samples was evaluated by the catalytic oxidation of methylene blue in the presence of hydrogen peroxide. Concerning the nearly same optical band gap for the samples, the best photocatalytic performance of CuO-Ni nanorods was assigned to its highest active surface area and surface hydroxyl groups.
Cu 2 O@TiO 2 heterojunction nanocomposites were prepared via ultrasonic method towards the removal of the environmental pollutant of MO by the visible light photocatalytic approach. The structure of prepared Cu 2 O@TiO 2 heterojunction nanocomposites was analyzed by X-ray diffraction, X-ray photoelectron spectro-scopy, scanning electron microscope, transmission electron microscope, photoluminescence spectroscopy, UV-Visible absorption spectroscopy, diffused reflectance spectroscopy. The photocatalytic degradation ability was tested using methyl orange as a model pollutant. From the observed pseudo-first order reaction, it was clear that Cu 2 O@TiO 2 nanocomposites showed enhanced photocatalytic activity (rate = 0.223 s −1). The formation of demethylated methyl orange as an intermediate was identified from HPLC analysis at a retention time of 3.47 min. When doped with Cu 2 O, the TiO 2 preserved the integrity of its structural, revealing the morphology there is no significant changes have been made, favoring photoelectrochemical appliances. In presence of illumination , the photocurrent of Cu 2 O@TiO 2 was 4.5 folds greater than that of TiO 2 , involving that incorporating with Cu 2 O extensively enhanced mobility of electron via reducing the recombination rate of electron-hole pairs.
Catalysts, 2020
In the present work, copper nanoparticles were deposited onto the surface of two different commercial titanias (Evonik Aeroxide P25 and Aldrich anatase). During the synthesis, the concentration of copper was systematically varied (0.5%, 1.0%, 1.5%, 5.0%, and 10 wt.%) to optimize the composite-composition. The photocatalytic activity was evaluated under UV-light, using methyl orange and Rhodamine B as model and ketoprofen as real pollutant. For the hydrogen production capacity, oxalic acid was used as the sacrificial agent. The morpho-structural properties were investigated by using XRD (X-ray diffraction), TEM (Transmission Electron Microscopy) DRS (Diffuse Reflectance Spectroscopy), XPS (X-ray Photoelectron Spectroscopy), and SEM-EDX methods (Scanning Electron Microscopy-Energy Dispersive X-ray Analysis). Increasing the copper concentration enhanced the photocatalytic activity for methyl orange degradation in the case of Aldrich anatase-based composites. When the P25-based composites were considered, there was no correlation between the Cu concentration and the activity; but, independently of the base photocatalyst, the composites containing 10% Cu were the best performing materials. Contrarily, for the ketoprofen degradation, increasing the copper concentration deteriorated the photoactivity. For both Aldrich anatase and P25, the best photocatalytic activity was shown by the composites containing 0.5% Cu. For the degradation of Rhodamine B solution, 1.5% of copper nanoparticles was the most suitable. When the hydrogen production capacity was evaluated, the P25-based composites showed higher performance (produced more hydrogen) than the Aldrich anatase-based ones. It was found that Cu was present in four different forms, including belloite (Cu(OH)Cl), metallic Cu, and presumably amorphous Cu(I)-and Cu(II)-based compounds, which were easily convertible among themselves during the photocatalytic processes.
Synthesis of Cu2O nanocrystallites and their adsorption and photocatalysis behavior
Advanced Powder Technology, 2012
Cuprous oxide (Cu 2 O) nano-crystallites have been prepared via an electrochemical method by the anodic dissolution of copper in an alkaline solution of concentrated sodium chloride in a simple electrochemical cell. The effect of addition of glucose on the crystal size, structure and photocatalytic activity of Cu 2 O particles was studied. Photocatalytic decolorization of MeO in aqueous Cu 2 O suspensions was investigated. X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transformation infrared spectroscopy (FTIR) were used to characterize the samples. UV-vis Spectroscopy was employed to investigate the photocatalysis behavior of the Cu 2 O samples. The adsorption performance of the Cu 2 O samples showed that after adsorption of 2 h, the decolorization efficiencies of MO reached 11.81%, 95.24% and 56.53% for samples 1, 2 and 3, respectively, which proves that sample 2 has the highest adsorption capacity. The photocatalytic results showed that the as prepared Cu 2 O on the addition of 5 g/L glucose was the best sample since it was photostable and decolorized 98.7% of MeO solution in 30 min without any further decrease in the photocatalytic efficiency with increase in the irradiation time for 120 min. Higher concentrations of glucose lead to the decrease of photocatalytic efficiencies of the Cu 2 O particles.
University of Kashan, 2022
In this work, CuO/CeO 2 nancomposite was prepared via hydrothermal route. The product was prepared under 12 h and 150 o C. The shape, size, and crystalline structure have been investigated through using various techniques such as the scanning electron microscopy (SEM), with energy dispersive X-ray (EDX), the X-ray diffraction analysis (XRD), the Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The magnetic properties of prepared nanocomposites were studied via vibrating-sample magnetometer (VSM). Consequently, acid violet and rhodamine B dyes were applied for investigation the photocatalytic activity of prepared CuO/CeO 2 nanocomposite. Results showed that Acid violet and rhodamine B were photo-decolorization under UV irradiation after 120 minutes with 95.8 % and 88.2% respectively. This excellent performance was due to the suitable band structure of synthesized CuO/ CeO 2 nanocomposites which led to depress the recombination of photogenerated electrons and holes with increased the acidity of CeO 2 after incorporation it with CuO in the crystal lattice. This work introduces new nanocomposites for decolorization of organic pollutants from wastewater.