Fabrication and photocatalytic properties of a visible-light responsive nanohybrid based on self-assembly of carboxyl graphene and ZnAl layered double hydroxides

The synthesis of a layer-by-layer ordered nanohybrid with a sandwich structure was based on electrostatically driven self-assembly between the negatively charged carboxyl graphene monolayer and the positively charged ZnAl-layered double hydroxide nanosheets. The characteristics of the layer-by-layer ordered nanohybrid were investigated by SEM, TEM, AFM and XRD. The enhanced photocatalytic activity of the calcined product was determined by the photocatalytic degradation of the cationic dye methylene blue (MB) and anionic dye orange G (OG) under visible light. The enhanced photocatalytic efficiency was mainly attributed to the effective electronic coupling between graphene and calcined ZnAl-LDH. Additionally, the chemical stability of the calcined ZnAl-LDH is significantly improved by hybridization of graphene and this is attributed to the protection provided by the close contacted graphene with highly stability. This work also establishes a simple method for fabricating graphene-based nanohybrids with a sandwich structure.