Nanocomposite of TiO2 with functionalized graphene oxide nanosheets with PDI as efficient photocatalyst in visible light region

Research into graphene oxide (GO) has been prospering in diverse areas due to their unique structural, optical, and electronic properties [1]. Functionalization of GO is the best way to obtain the desirable performance and improve its efficiency [2]. Herein an effective and facile approach for introducing photoactive and stable hybrid of graphene oxide (GO) and perylenediimide (PDI) was presented. For this purpose, we used three different methods such as (i) the amidation of GO and reaction between the amidated GO and perylene-3, 4, 9, 10-tetracarboxylic dianhydride (GNP-1), (ii) the conversion of carboxylic acid group of GO to acyl chlorides and the reaction between acylated GO and symmetric PDI (GNP-2), and (iii) amidation of GO and the reaction between amidated GO and asymmetric PDI (GNP-3). The studies on the stability and on the dispersibility of these hybrids showed that the GNP-3 hybrid is more stable and dispersible than other hybrids. Also, non-using of hazardous materials such as thionyl chloride in third method (GNP-3) make it as a superior method. This hybrid considers as a sensitizer for photocatalytic process due to its stability in aqueous solution and visible light absorption. Then a series of GNP/TiO2 nanocomposites with different percentage of GNP-3 were prepared, and the structure, morphology, and photocatalytic activity of these new materials were systematically investigated. This strategy can be extended to many other organic and inorganic semiconductors, which opens new possibilities for high-efficiency graphene-based solar energy conversion.