Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian, China.
Environ Sci Technol. 2012 Apr 3;46(7):4042-50. doi: 10.1021/es204079d. Epub 2012 Mar 13.
A ternary Ag/AgBr/TiO(2) nanotube array electrode with enhanced visible-light activity was synthesized by a two-step approach including electrochemical process of anodization and an in situ photoassisted deposition strategy. The dramatically enhanced photoelectrocatalytic activity of the composite electrode was evaluated via the inactivation of Escherichia coli under visible light irradiation (λ>420 nm), whose performance of complete sterilization was much superior to other reference photocatalysts. PL, ESR, and radicals trapping studies revealed hydroxyl radicals were involved as the main active oxygen species in the photoelectrocatalytic reaction. The process of the damage of the cell wall and the cell membrane was directly observed by ESEM, TEM, and FTIR, as well as further confirmed by determination of potassium ion leakage from the killed bacteria. The present results pointed to oxidative attack from the exterior to the interior of the Escherichia coli by OH(•), O(2)(•-), holes and Br(0), causing the cell to die as the primary mechanism of photoelectrocatalytic inactivation.
一种具有增强可见光活性的三元 Ag/AgBr/TiO(2) 纳米管阵列电极通过两步法合成，包括电化学阳极氧化和原位光辅助沉积策略。通过可见光照射（λ>420nm）下大肠杆菌的失活评估了复合电极的光催化活性，其完全杀菌性能优于其他参考光催化剂。PL、ESR 和自由基捕获研究表明，羟基自由基作为光催化反应中的主要活性氧物质参与其中。通过 ESEM、TEM 和 FTIR 直接观察到细胞壁和细胞膜的损伤过程，并通过测定被杀细菌中钾离子的泄漏进一步证实。这些结果表明，OH(•)、O(2)(•-)、空穴和 Br(0)从外部对大肠杆菌进行氧化攻击，导致细胞死亡，这是光催化失活动力学的主要机制。
