Graphene/silver-based composites and coating on dead coral for degradation of organic pollution using the Z-scheme mechanism

A high-performance photocatalytic nanocomposite consisting of silver phosphate-based particles with GO and RGO was synthesized by co-precipitation and hydrothermal methods. Ag3PO4 was prepared by a co-precipitation method. The as-prepared Ag3PO4 nanocomposites were characterized by different analyses. The results demonstrated that the Ag3PO4 particles were well dispersed on the graphene-based surfaces. The photocatalytic performance of the GO/RGO/Ag3PO4 nanocomposite was evaluated for the photodegradation of methylene blue (MB) under exposure to visible light (xenon lamp lambda > 400 nm). The degradation rate was about 98% in 5 min. The enhancement in photocatalytic performance is attributed to the simultaneous presence of RGO and GO, which show significantly high absorption of organic molecules on the surface of GO/RGO, allowing the effective transfer and separation of photogenerated electrons. In addition, this modified structure can be in situ synthesized on dead coral structures that can be used in future real case-studies of the degradation of other organic pollutants. The ingredient of these composites, however, is about 93% Ag3PO4.