Photocatalytic and antibacterial activities of silver and iron doped titania nanoparticles in solution and polyaspartic coatings

摘要

Visible region active photocatalytic coatings are of interest for antimicrobial activity in low light applications or those employing LED lights with limited UV content. This work examined Ag and Fe doped titania nanoparticles (nTiO(2)) with varying dopant ranges in polyaspartic polymer coatings for potential light and dark activity. First, the Ag and Fe doped nTiO(2) were synthesized by sol-gel chemistry with varying dopant concentrations, then characterized with respect to their size and aggregate size distribution, crystallinity, and surface and band gap features. The photocatalytic activity was then tested with methylene blue under both AM 1.5 G and visible light. From both sample sets (Ag and Fe doped nTiO(2)), the best photo catalytically active sample materials were chosen for antibacterial tests with gram-negative Escherichia coli (E. coli) and gram-positive Bacillus subtilis (B. subtilis) in (a) solution and (b) polyaspartic nanocomposites under UV and visible irradiation. The results showed that Ag doped nTiO(2) samples delivered the best and excellent antibacterial action, even in the dark, attributed to both an enhanced band gap and surface area, as well as a combination of photocatalytic activity and Ag being present at the nanoparticle's surface. No leaching of Ag at room temperature was observed from the nTiO(2) structure, giving potential for next generation coatings that are both light and dark active.