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Synthesis, characterization and photocatalytic properties of TiO2-rGO nanoparticles

Today, synthetic organic dyes are used in various industries. Wastewaters containing these dyes may be harmful to the environment, animals, and people. It is very important to degrade these dyes before discharging them into the environment. Heterogeneous photocatalysis could be effective in the degradation of organic dyes. A major advantage is the mineralization of organic dyes, which result in CO2, H2O, and corresponding mineral acids. TiO2 as a photocatalyst has of great interest due to its high activity, photochemical inertness, non- toxicity, efficiency, and low cost. The biggest drawbacks of TiO2 photocatalysis are the high bandgap energy (3.2 eV) and the easy recombination of photoinduced electron-hole pairs. That limits its feasibility for the photocatalytic application in a visible light region. The aim of this study was to synthesize the TiO2-rGO (titania-reduced graphene oxide) nanoparticles as photocatalysts in the visible light region. The graphene oxide was synthesized from natural graphite powder by Hummer's method. TiO2 sol was prepared by using titanium tetraisopropoxide as a precursor, i-propanol as a solvent, acetylacetone as a chelating agent and nitric acid as a catalyst. The TiO2-rGO nanoparticles with different amounts of GO were prepared on a borosilicate glass substrate by using the sol- gel dip-coating method. They were characterized by means of powder X-ray diffraction analysis, Fourier transform infrared spectroscopy and Scanning electron microscopy. The photocatalytic activities of the TiO2-rGO nanoparticles were evaluated by the degradation of the aqueous solution of methylene blue (MB) dye as a model pollutant. The irradiation was simulated with a light- emitting diode (LED) lamp with a radiation peak at 365 nm and a Solar-simulator lamp. The concentrations of MB were monitored by UV-Vis spectrophotometry. Obtained results indicated that photocatalytic properties of prepared TiO2-rGO nanoparticles depend on the amount of rGO and on the type of the irradiation source.

reduced graphene oxide, nanoparticles, photocatalysis

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