Photocatalytic oxidation reactivity of holes in the sulfur- and carbon-doped TiO2 powders studied by time-resolved diffuse reflectance spectroscopy
Photocatalytic oxidation reactivity of holes in the sulfur- and carbon-doped TiO2 powders studied by time-resolved diffuse reflectance spectroscopy
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DOI：
10.1021/jp0470593
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发表时间：
2004-12-16
影响因子：
3.3
通讯作者：
Majima, T
中科院分区：
文献类型：
--
作者：
Tachikawa, T;Tojo, S;Majima, T
利用时间分辨漫反射（TDR）光谱研究了纯TiO 2和硫、碳掺杂TiO 2粉末在紫外或可见激光闪光光解过程中光生空穴（h（+））的光催化氧化反应性。研究了H（+）在TiO 2表面对甲醇和4-甲硫基苯甲醇（MTPM）的单电子氧化过程。对载流子和MTPM自由基阳离子（MTPM.+）的TDR谱和时间轨迹进行了观测。结果表明，在355 nm激光光解TiO 2粉末过程中产生的H（+）对基质的氧化反应按纯TiO 2> S掺杂TiO 2> C掺杂TiO 2的顺序增加。在另一方面，没有观察到的基板的单电子氧化反应，在430 nm的激光光解的S-和C-掺杂的二氧化钛粉末，虽然电荷载流子被充分激发后产生。讨论了在TiO_2粉末的激光闪光光解过程中，掺杂位置上的H ~+的捕获和释放过程对氧化反应的影响。
The photocatalytic oxidation reactivities of the photogenerated holes (h(+)) during ultraviolet or visible laser flash photolysis of pure anatase and sulfur- and carbon-doped TiO2 powders were investigated using time-resolved diffuse reflectance (TDR) spectroscopy. The one-electron oxidation processes of substrates such as methanol and 4-(methylthio)phenyl methanol (MTPM) by h(+) at the TiO2 surface were examined. The TDR spectra and time traces observed for charge carriers and the MTPM radical cation (MTPM.+) revealed that the oxidation reactions of substrates by h(+) generated during the 355-nm laser photolysis of TiO2 powders increased in the order of pure TiO2 > S-doped TiO2 > C-doped TiO2. On the other hand, no one-electron oxidation reactions of the substrates were observed during the 430-nm laser photolysis of the S- and C-doped TiO2 powders, although the charge carriers were sufficiently generated upon excitation. The effects of the trapping and detrapping processes of h(+) at the doping sites on the oxidation reactions during the laser flash photolyses of the TiO2 powders are discussed.