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 photoinduced 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.