Facile assembly of silica gel/reduced graphene oxide/Ag nanoparticle composite with a core-shell structure and its excellent catalytic properties

A ternary assembly of silica gel (SG)/reduced graphene oxide (RGO)/Ag nanoparticles (Ag NPs) with a core-shell structure was prepared in aqueous solution by electrostatic self-assembly combined with a one-step reduction process. The composition and structure of the assembly (SG/RGO/Ag) were characterized by powder X-ray diffraction, transmission electron microscopy and Raman spectroscopy. The catalytic activity of the assembly was investigated for the degradation of rhodamine B (RhB) in the presence of NaBH4. The results showed that the degradation efficiency of the ternary assembly was the highest when compared with those of pure SG, SG/RGO and SG/Ag. When the loading amount of RGO and Ag NPs was 0.50% and 0.78% respectively, the degradation efficiency of the SG/RGO/Ag assembly can reach 100% within 8 min at 13 degrees C, and 1.2 min at 25 degrees C. This was about nine times the degradation efficiency of SG/RGO, and three times that of SG/Ag. The remarkably enhanced activity for the ternary assembly can be attributed to the synergy interaction between the RGO and Ag NPs. Importantly, the assembly has low a cost, convenient separability, and long-term stability for the degradation of RhB.