SERS and the photo-catalytic performance of Ag/TiO2/graphene composites

Three kinds of reusable surface enhanced Raman scattering (SERS) substrates based on Ag-TiO2-G, Ag-G-TiO2 and G-Ag-TiO2 hybrid structures were prepared by a combination method of simple sol-gel self-assembly and annealing. The composites were confirmed by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Raman mapping spectra of the three hybrids were analyzed in order to study the difference of charge transfer between Ag, TiO2 and graphene. In addition, rhodamine 6G (R6G) was used as the probe analyte, and the SERS activity of the three structures decreased orderly in the sequence of Ag-G-TiO2, G-Ag-TiO2, and Ag-TiO2-G, with the enhancement factor of about 106, which was due to the high electromagnetic enhancement of the Ag nanoparticles (AgNPs). The photo-catalytic properties of the three kinds of composites were experimentally studied via Raman mapping measurements through UV irradiation. The photocatalytic ability decreased also orderly in the sequence of Ag-G-TiO2, G-Ag-TiO2, and Ag-TiO2-G, and the reason was discussed in details. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement