Immobilization of plasmonic Ag-Au NPs on the TiO2 nanofibers as an efficient visible-light photocatalyst

A heterostructure photocatalyst including metallic silver (Ag), gold (Au) in the form of nanoparticles (NPs) and titanium oxide (TiO2) nanofibers were fabricated using a combination of photodeposition and electrospinning techniques. In this procedure, electrospun TiO2 nanofibers were decorated by plasmonic Ag and Au NPs on the surface of nanofibers which were generated via photochemical reduction process. The synthesized Ag-Au/TiO2 nanocomposites which were considered as a favorable candidate for enabling the more access to visible-light in photocatalytic performance were subsequently characterized by field emission scanning electron spectroscopy (FESEM), transmission electron spectroscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and ultra-violet-visible (UV-vis) spectroscopy. UV-vis studies indicate the extension in the absorption region of composite toward the visible-light range have been occurred through the loading metallic nanoparticles into the TiO2 structure. Microscopic assessments in addition to EDS revealed that metallic NPs deposited on the surface of the fibers through photochemical reduction process. It was found that, the ratio of utilized Ag/Au in the final composite can significantly enhance the photocatalytic efficiency. It was suggested that introduction of the proper amount of noble metal NPs into the TiO2 matrix leads to the notable enhancement of visible-light decomposition of rhodamine B (Rh. B) as a model dye.