Ag/TiO2/freeze-dried graphene nanocomposite as a high performance photocatalyst under visible light irradiation

Ag/TiO2/freeze-dried graphene nanocomposites have been prepared via a facile one-step solvothermal method for the photocatalytic degradation of RhB under visible light irradiation. During the solvothermal process, reduction of graphene oxide and loading of Ag/TiO2 nanoparticles on graphene sheets were achieved. Investigation of chemical state of products showed that covering of Ag/TiO2 surface with higher weight ratio of graphene resulting in that Ag metals in Ag/TiO2 were oxidized to Ag2O in nanocomposite structure after solvothermal process. Degree of photocatalytic activity enhancement strongly depends on the coverage of Ag/TiO2 surface by porous graphene. The sample of 1 wt% porous graphene hybridized Ag/TiO2 showed the highest photocatalytic activity, which is related to high migration efficiency of photo-induced of electrons and reduction of electron–hole recombination rate due to high electrical conductivity of graphene. Expanding of absorption to visible light region was ascribed to surface plasmon resonance effect of Ag metals and presence of graphene. Investigation of photocatalytic performance of formic acid as a dye-less organic pollutant showed that dye sensitization effect of RhB molecules during evaluation of photocatalytic performance was negligible.

Due to visible light absorption by localized surface plasmonic resonance of Ag, decreasing of electron–hole recombination, and increasing of electron transport through Ag and graphene, incorporating of Ag and freeze-dried graphene with TiO2 can improve the photocatalytic performance.Figure optionsDownload as PowerPoint slide