Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Environ Sci Technol. 2010 Sep 15;44(18):6992-7. doi: 10.1021/es101343c.
Titanium dioxide nanoparticles codoped with nitrogen and silver (Ag(2)O/TiON) were synthesized by the sol-gel process and found to be an effective visible light driven photocatalyst. The catalyst showed strong bactericidal activity against Escherichia coli (E. coli) under visible light irradiation (λ > 400 nm). In X-ray photoelectron spectroscopy and X-ray diffraction characterization of the samples, the as-added Ag species mainly exist as Ag(2)O. Spin trapping EPR study showed Ag addition greatly enhanced the production of hydroxyl radicals (•OH) under visible light irradiation. The results indicate that the Ag(2)O species trapped e(CB)(-) in the process of Ag(2)O/TiON photocatalytic reaction, thus inhibiting the recombination of e(CB)(-) and h(VB)(+) in agreement with the stronger photocatalytic bactericidal activity of Ag(2)O/TiON. The killing mechanism of Ag(2)O/TiON under visible light irradiation is shown to be related to oxidative damages in the forms of cell wall thinning and cell disconfiguration.
氮和银共掺杂二氧化钛纳米粒子（Ag(2)O/TiON）通过溶胶-凝胶法合成，被发现是一种有效的可见光驱动光催化剂。该催化剂在可见光照射下（λ>400nm）对大肠杆菌（E. coli）表现出很强的杀菌活性。在对样品的 X 射线光电子能谱和 X 射线衍射表征中，添加的 Ag 物质主要以 Ag(2)O 的形式存在。自旋捕获 EPR 研究表明，Ag 的添加在可见光照射下大大增强了羟基自由基（•OH）的生成。结果表明，Ag(2)O 物种在 Ag(2)O/TiON 光催化反应过程中捕获了 e(CB)(-)，从而抑制了 e(CB)(-)和 h(VB)(+)的复合，这与 Ag(2)O/TiON 更强的光催化杀菌活性一致。Ag(2)O/TiON 在可见光照射下的杀菌机制被证明与细胞壁变薄和细胞变形等氧化损伤形式有关。
