Solar photoactivity of nano-N-TiO₂ from tertiary amine: role of defects and paramagnetic species

详细信息    查看全文

• 作者：Francesca Spadavecchia ; Giuseppe Cappelletti ; Silvia Ardizzone ; Claudia L. Bianchi ; Serena Cappelli ; Cesare Oliva ; Paolo Scardi ; Matteo Leoni ; Paola Fermo
• 关键词：N-doped nanotitania ; Synchrotron radiation X-ray diffraction ; NO_x degradation ; Unconventional methylene blue removal ; Paramagnetic sites
• 刊名：Applied Catalysis B: Environmental
• 出版年：2010
• 出版时间：7 June 2010
• 年：2010
• 卷：96
• 期：3-4
• 页码：314-322
• 全文大小：1132 K

文摘

N-doped TiO₂ nanocrystals were successfully synthesized by a controlled sol–gel reaction at pH 9 followed by calcinations at 400 °C. Triethylamine was used to modulate the N content of the samples. The photocatalytic activity was tested using a solar irradiation source with regard to two different pollutants: NO_x (in the gas phase) and methylene blue (MB), deposited onto the oxide film. In the case of MB degradation the disappearance of the (MB) blue colour was measured directly onto the solid, by means of UV–vis-NIR diffuse reflectance spectroscopy. The final mineralization of the organic molecule was assessed by COD determinations. All N-doped samples produce a better removal of both pollutants than the undoped and commercial samples. By coupling structural (by X-ray synchrotron radiation) and morphological (HRTEM, BET, granulometry) characterizations with spectroscopic analyses (EPR and XPS), the presence of paramagnetic centers, defects, edge dislocations and surface states is appreciated and found to affect the material photocatalytic behaviour.