Biogenic synthesis of a Ag-graphene nanocomposite with efficient photocatalytic degradation, electrical conductivity and photoelectrochemical performance

This paper reports an environmentally benign, simple, cost efficient, one-step, surfactant free, and biogenic synthesis of a silver-graphene (Ag-graphene) nanocomposite using an electrochemically active biofilm (EAB). The EAB was used for the reduction of Ag+ to Ag-0 onto the graphene sheets. The morphology, structure, composition, and optical properties and contact angle of the Ag-graphene were obtained using a range of techniques which confirmed the anchoring/presence of silver nanoparticles (AgNPs) onto the graphene sheets. The photocatalytic activity of Ag-graphene was evaluated by the degradation of methylene blue and Congo red dye in aqueous solution at an ambient temperature in the dark and under visible-light irradiation. The results showed that the photocatalytic activity of the Ag-graphene nanocomposite was enhanced significantly by the loading of AgNPs in the graphene sheets. Contact angle measurements confirm the hydrophilic nature of the Ag-graphene nanocomposite which is very helpful in photocatalysis. The electrical conductivity and photocurrent measurements of the Ag-graphene nanocomposite exhibited a much better performance than P-graphene. This study highlights the design of a novel facile synthetic route for a new photocatalyst using the SPR of Ag and graphene as a support. The as-synthesized Ag-graphene nanocomposite has potential applications in photocatalytic degradation, photoelectrodes and optoelectronic devices.