Center for Nanoscale Materials, and Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
J Am Chem Soc. 2009 Mar 4;131(8):2893-9. doi: 10.1021/ja807654k.
Modification of TiO(2) nanoparticles with dopamine enables harvesting of visible light and promotes spatial separation of charges. The formation of reactive oxygen species (OH, (1)O(2), O(2)(-), HO(2), H(2)O(2)) upon illumination of TiO(2)/dopamine was studied using complementary spin-trap EPR and radical-induced fluorescence techniques. The localization of holes on dopamine suppresses oxidation of adsorbed water molecules at the surface of nanoparticles, and thus formation of OH radicals. At the same time, dopamine does not affect electronic properties of photogenerated electrons and their reaction with dissolved oxygen to produce superoxide anions. Superoxide anions are proposed to generate singlet oxygen through dismutation reaction, resulting in a low yield of (1)O(2) detected.
多巴胺修饰的 TiO(2) 纳米颗粒能够捕获可见光并促进电荷的空间分离。采用互补的自旋捕获 EPR 和自由基诱导荧光技术研究了 TiO(2)/多巴胺在光照下形成的活性氧物种（OH、(1)O(2)、O(2)(-)、HO(2)、H(2)O(2)）。多巴胺上的空穴定位抑制了纳米颗粒表面吸附水分子的氧化，从而抑制了 OH 自由基的形成。同时，多巴胺不影响光生电子的电子性质及其与溶解氧反应生成超氧阴离子。超氧阴离子通过歧化反应产生单线态氧，导致检测到的(1)O(2)产率较低。
