Abstract
In the present article, the synthesis of TiO2/diazonium/graphene oxide and its photocatalytic activity for methylene blue (MB) degradation have been demonstrated. The functionalization of graphene oxide (GO) with diazonium salt (diazonium-GO) was conducted for enhancing the dispersibility of GO in distilled water. TiO2 was highly dispersed in diazonium-GO to form TiO2/diazonium/graphene. The obtained specimens were characterized by X-ray diffraction, FT-IR spectroscopy, Raman spectroscopy, UV-Vis spectroscopy, scanning electron microscope, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the TiO2 phase in TiO2/diazonium/GO composites can be controlled by adjusting the amount of ethanol or titanium oxide in the reactant mixture. The obtained composites exhibited photocatalytic activities for methylene blue degradation (MB). The composite with ac. 70% anatase can provide the highest MB degradation efficiency. The studying of some intermediates for MB photocatalytic degradation using LC-MS showed that structure of MB by the cleavage and oxidation of one or more of the methyl group substituent on the amine groups lead to form compounds with low molecular masses. Total organic carbon studies confirmed a complete mineralization of MB. The present catalyst was stable and recyclable after three times with a negligible loss of catalytic activity. In addition, the TiO2/diazonium/GO can also photocatalyze for the degradation of some other dyes (phenol, methyl red, and Congo red).
Highlights
Titanium oxide-based materials in several types and forms have exhibited excellent potential as powerful photocatalysts for various reactions thanks to their chemical stability, nontoxicity, and high reactivity and interesting materials with nonline optical properties for applications in ultrafast optical information processing, optical switching, and optical limiting for protection against strong laser radiation [1]
The photocatalytic activity of the TiO2/diazonium/graphene oxide (GO) composite material was evaluated by the degradation of methylene blue (MB) in the visible light region
The results show that the photocatalytic activity of TiO2/diazonium/GO was relatively high compared with previous reports
Summary
Titanium oxide-based materials in several types and forms have exhibited excellent potential as powerful photocatalysts for various reactions thanks to their chemical stability, nontoxicity, and high reactivity and interesting materials with nonline optical properties for applications in ultrafast optical information processing, optical switching, and optical limiting for protection against strong laser radiation [1]. In order to overcome this experimental hinderance, several GO derivatives have been prepared by grafting new functional groups such as ethylenediamine [25], EDTA [26], and diazonium of sulfanilic acid [27] through a GO backbone to form the water soluble GO; as a result, nanooxide particles are effectively dispersed in a GO matrix Continuing this idea, in the present paper, GO was modified by the diazonium salt of sulfanilic acid prior to dispersion of TiO2 on GO with an idea to enhancing the possibility of inserting active oxygen-containing polarization groups between graphite layer in graphene oxide, which adjusts the semiconductivity of graphene oxide in the obtained composite. The photocatalytic activity of the TiO2/diazonium/GO composite material was evaluated by the degradation of methylene blue (MB) in the visible light region
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