Understanding the adsorptive and photoactivity properties of Ag-graphene oxide nanocomposites

Nanocomposites of graphene oxide (GO) and silver nanoparticles (AgNPs) were synthesized using a practical photochemical silver functionalization. Their photocatalytic decomposition rates are governed by their large adsorption capacity, and the strong interaction with dye model contaminants such as Rhodamine B and Indigo Carmine. •The AgNPs-GO nanocomposites are easily produced by photo-impregnation of GO.•Defect domains of sp3 type of GO act as nucleation sites for anchoring AgNPs.•The cleavage of IC over the GO surface dominates the rate of degradation.•The AgNPs-GO nanocomposites present extensive Rhb and IC adsorptive capacity.•GO synthesis produces edge defects domains and functional groups for dye cleavage. Nanocomposites of graphene oxide (GO) and silver nanoparticles (AgNPs) were synthetized using a practical photochemical silver functionalization. Their photocatalytic activities were evaluated with two dyes, Rhodamine B and Indigo Carmine, under visible-light irradiation. The prepared nanocomposites were characterized by HRTEM, FESEM, XRD, Raman, FTIR and UV–vis absorption spectroscopy. These nanocomposites present new defect domains of sp3 type in combination with several graphitic functional groups that act as nucleation sites for anchoring AgNPs, while the sp2–sp3 edge defects domains of GO generate the photoactivity. Furthermore, their photocatalytic performances are governed by their large adsorption capacity, and strong interaction with dye chromophores. A comprehensive photocatalytic way underlying the importance of adsorption is suggested to explain the low visible-light responsive photoactivity of the AgNPs-GO nanocomposites and the possible binding-site saturation. Then, the usage of H2SO4 allows the production of ionic species and helps to confirm the strong adsorption of both dyes. The ability to synthesize AgNPs-GO nanocomposites with extensive adsorptive capacity is certainly of interest for the efficient removal of hazardous materials.