Study On The Synthesis Of Ag/Graphene/TiO₂ Nanocomposite And Its Photocatalytic And Antibacterial Properties

Objective:A novel one-dimensional Ag/graphene/TiO2 nanofibers (TGA) nanocomposite photocatalyst with UV-Vis response properties has been fabricated via electronspinning method, thermal reduction process, photo-reduced method, and its photocatalytic and antibacterial activities have been evaluated.Materials and methods:TiO2 nanofibers were prepared by electronspinning, and TiO2/G nanocomposite was successfully synthesized via wrapping of rGO sheets assembled from strong electrostatic interaction between negatively charged GO and positively charged TiO2 nanofibers following thermal reduction, then loading Ag nanoparticles by adding TiO2/G composite to AgNO3 aqueous solution through photo-reduced. SEM, HRTEM, XRD, XPS, Raman spectroscopy, FTIR and DRS have been used to characterize the sample. The photocatalytic activity of sample was evaluated by photocatalytic degradation of RhB aqueous solution under UV-Vis light irradiation. And the antibacterial activity of TGA was investigated by inhibition zone method and the plate-counting method.Results and Conclusions:(1) Preparation and characterization:SEM and HRTEM showed that TGA nanocomposite has been successfully prepared by wrapping rGO sheets around TiO2 nanofibers and then loading Ag nanoparticles onto the surface of the TG.XRD showed that TiO2 nanofibers have existed in the form of anatase. XPS showed that Ti, O, C, Ag elements existed and the oxide graphene has been reduced to graphene containing a small part of oxygenate groups, and most of Ag+has been reduced to Ag nanoparticles. FTIR further confirmed that the oxide graphene has been reduced to graphene. Raman showed lower defects in graphite comprising sp2 hybridization. DRS showed that the absorption spectrum has extended from uv region to visible region by introducing graphene and Ag nanoparticles.(2) Photocatalytic experiment:RhB solution can be completely degraded in the 50 min of irradiation by TGA, and the reaction rate kinetic constant of TGA reaches 0.0682 min-1. Moreover, after three successive cycles, the TGA composite structure shows almost no change and the photocatalytic activity of TGA composite has no obvious decrease.(3) Antibacterial experiments:The nutrient agar method, the inhibition zone diameter of the S. aureus is 8.9nm, and the inhibition zone diameter of the E. coli is 7.9nm. The colony counting method, both of the the viability of S. aureus and E. coli reach 0% after UV-Vis light irradiation for 2h.