In situ g-C3N4@ZnO nanocomposites (with 0, 1, 3, 5, and 7 wt.% of g-C3N4 in nanocomposite) were synthesized via a one-pot hydrothermal method using precursors of urea, zinc nitrate hexahydrate, and hexamethylenetetramine. The g-C3N4@ZnO nanocomposites were characterized by X-ray diffraction, scanning electron microscope, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The photocatalyst activity of g-C3N4@ZnO nanocomposites was evaluated via methylene blue degradation experiment under visible light irradiation. The g-C3N4@ZnO nanocomposites showed an enhancement in photocatalytic activity in comparison to pure ZnO which increased with the g-C3N4 content (1, 3, 5, and 7 wt.%) in nanocomposites. The photocatalytic activity reached the highest efficiency of 96.8% when the content of g-C3N4 was 7.0 wt.%. Nanocomposite having 7.0 wt.% of g-C3N4 also showed good recyclability with degradation efficiency higher than 90% even in the 4th use. The improvement of photocatalytic activity could be attributed to the adsorption ability and effective separation of electron-hole pairs between g-C3N4 and ZnO. This work implies a simple method to in situ prepare the nanocomposite material of g-C3N4 and semiconductors oxide for photocatalyst applications with high efficiency and good recyclability.
Cuprous oxide nanoparticles (Cu 2 O-NPs) were fabricated by a simple solution-phase reduction route with a one-step reduction method. The used original chemicals were the copper sulfate and the sodium sulfite. The physicochemical properties of Cu 2 O-NPs were investigated by different methods such as XRD, Raman, SEM, and UV-Vis spectra. The results show that the molar ratio of precursors ([CuSO 4 ]/[Na 2 SO 3 ]) not only affects crystal structure and morphology but also affects the crystallinity of crystals and optical characteristics of Cu 2 O-NPs samples. The photocatalytic activity of Cu 2 O-NPs was evaluated by the removal of methylene blue (MB) aqueous solution under visible light irradiation. The result shows that good photocatalytic activity with the MB degradation is higher than 98% under visible light irradiation for 40 minutes and the rate constant of 0.11281 min ¹1 .
In-Situ composite materials of graphene (Gr) and ZnO microspindle with different Gr contents (1, 2 and 5 wt.%) were prepared via a facile one-step hydrothermal route with the assistance of hexamethylenetetramine. Graphene does not affect the hexagonal wurtzite crystal structure
of composite materials but strongly affects the morphological, structural, optical and photocatalytic properties of composite materials. In detail, Gr causes a decrease in both the dimensions of ZnO microspindle and photoluminescence efficiency. The average crystalline size and microstrain
first increase from 28.9 nm and 0.00394 to 49.5 nm and 0.00524 when Gr content increases from 0 to 1 wt.%, respectively; then decrease to 39.6 nm and 0.00404 when Gr content increase from 1 to 5 wt.%, respectively. Both pristine and composite materials show high photocatalytic activity with
high methylene blue degradation efficiency?more than 90%-just after 40 min under UV irradiation. Composite material having a Gr content of 5 wt.% shows the highest degradation efficiency of 96.5% which confirms the role of Gr in enhancing the photocatalytic activity of ZnO.
Nanocrystalline titania (TiO2) thin films prepared by spray pyrolysis deposition on to the heated glass in a temperature range of TS = 350 ÷ 450oC. Analysis of optical transmission spectral of films reveals an optical band gap of about 3.2÷3.4 eV and the transmittance above 80% for TiO2 films with thickness of 0.8÷1.6 µm. X-ray diffraction (XRD) analysis demonstrates that the films are found of anatase phase in crystal structure. The AFM photographs show the nano-size of the constituents. The crystallize size and crystalline of the samples is discussed with respect to the film thickness and deposition temperature.
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