Synthesis of Ag Doped TiO2 Nanofibers for Treatment of Environmental Pollutants
Authors:Michael Nalbandian, Joel Sanchez
Mentor:Nosang Myung, Professor and Chair of Chemical & Environmental Engineering, University of California Riverside
To develop sustainable water resources, diverse and scalable technologies are needed. As a motion towards this goal, we have synthesized titanium dioxide (TiO2) nanofibers by a simple electrospinning process. As opposed to other materials, titanium dioxide was proposed as a material for treatment due to its superior visible light photocatalysis properties for chemical oxidation towards harmful phenols. The degradation of phenols depends on the surface area of TiO2. As opposed to spherical TiO2 nanoparticles, nanofibers of the same volume as the nanoparticles have a greater surface area to volume ratio thus making them a suitable candidate. Electrospinning was chosen as a means to fabricate these fibers due to it being able to produce multi-functional nanostructured materials in a highly scalable and cost-effective manner. By means of electrospinning, nanofibers’ size will be optimized to produce the smallest diameter possible to increase surface interactions between pollutants and fibers. TiO2 nanofibers were synthesized from an organic precursor coupled with organic solvents. It has been observed that doping a metal oxide with a noble metal will alter the band gap energy of a material. Silver was dissolved in this solution at a 0-10% weight content. Nanofibers were synthesized in the 30-60 nm range. Pure TiO2 nanofibers were obtained by high temperature calcination of the inorganic-organic composite fibers. SEM, XRD, UV-Vis analysis were used as characterization methods and reactivity studies were performed for phenol degradation for pure/doped TiO2. Particularly, the most reactive silver doped TiO2 nanofibers synthesized thus far outperformed commercially available TiO2 Aeroxide ® P25, considered by many the gold standard in photocatalysis due to its high photoactivity. By doping TiO2 with silver we have decreased band gap as well as recombination kinetics thus increasing reactivity. Also, doping with the noble metal showed a significant increase in reactivity towards phenol.