Green synthesis of AgI-reduced graphene oxide nanocomposites: Toward enhanced visible-light photocatalytic activity for organic dye removal

Novel reduced graphene oxide (RGO) enwrapped AgI nanocomposites were successfully fabricated by a facile template-free ultrasound-assisted method at room temperature. The structural, morphological, and optical studies demonstrate that the obtained nanostructures have good crystallinity and that the graphene nanosheets are decorated densely with AgI nanostructures. The photocatalytic activity of the composite was evaluated by the degradation of an organic dye, Rhodamine B (RhB), under visible-light irradiation. The results indicate that AgI with incorporated graphene exhibited much higher photocatalytic activity than the pure AgI due to the improved separation efficiency of the photogenerated carriers and that it prolonged the lifetime of the electron-hole pairs due to the chemical bonding between AgI and graphene. AgI (0.4 mg mL ^-1 of graphene oxide) nanocomposites displayed the highest photocatalytic degradation efficiency and the corresponding catalytic efficiencies within 70 min were ∼96%. Moreover, with the assistance of H ₂ O ₂ the photocatalytic ability of the as-obtained AgI-RGO nanocomposites was enhanced. The corresponding catalytic efficiencies within 30 min were ∼96.8% (for 1 mL H ₂ O ₂ ) under the same irradiation conditions. The excellent visible-light photocatalytic efficiency and luminescence properties make the AgI-RGO nanocomposites promising candidates for the removal of organic dyes for water purification and enable their application in near-UV white LEDs.