可见光响应氮掺杂TiO_2制备与性能表征  

Preparation and Properties Characterization of Visible-light-driven N-doped TiO_2

作　　者：王勇[1,2] 陈桂华[1] 李李泉[2] 杨辉[3] 

机构地区：[1]台州学院医药化工学院,临海317000 [2]南京工业大学材料科学与工程学院,南京210009 [3]浙江大学纳米科学与技术中心,杭州310027

出　　处：《人工晶体学报》2012年第4期1053-1058,1065,共7页Journal of Synthetic Crystals

基　　金：浙江省教育厅项目(Y200906690)

摘　　要：采用水热法制备了可见光响应的氮掺杂TiO2光催化剂,利用XRD、SEM、XPS、UV-vis对样品结构、形貌和光谱等性质进行表征。研究结果表明:氮掺杂抑制晶粒长大,促进晶格畸变;氮进入TiO2晶格中,引起TiO2光催化剂的激发,吸收光谱向低能方向移动。以降解甲基橙为模型反应,研究样品的光催化性能;以对苯二甲酸作为·OH自由基捕获剂,利用化学荧光技术研究光催化反应体系中·OH自由基生成量。结果表明:与纯TiO2相比,氮掺杂样品具有较高的光催化活性。这与下列因素有关:氮掺杂样品具有较小的晶粒尺寸,有利于促进光生电荷的分离与相界面上电荷转移效率,降低TiO2能隙并使吸收光谱红移。在实验条件下,光催化性能随n(N/Ti)比值的增大而增强;羟基自由基的生成速率与光催化活性规律一致,即·OH的生成速率越大,光催化活性越高。Nitrogen doped visible-light-driven TiO2 photocatalyst was successfully synthesized by hydrothermal method. The structure, morphology and spectral properties of the photoeatalyst were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, X-ray photoelectron spectroscopy （XPS）, and UV-vis diffuse reflectance spectra （DRS）. The XRD results showed that nitrogen doping inhibited the increase of crystallite size. XPS spectroscopy indicated nitrogen dopants were incorporated into TiO2 lattice. A shift of the absorption edge to the lower energy were observed using DRS spectroscopy. The photocatalytic activities of the samples were investigated by degradation of methyl orange （MO） under visible light irradiation. Using terephthalie acid as hydroxyl radicals （ · OH ） eapturer, the quantity of· OH formed in the photocatalytic reaction system were determined by fluorescence technique. It was found that all nitrogen doped samples showed higher photocatalytic activities than pure TiO2 sample. Which could be explained by the reason： the smaller crystallite size of nitrogen doped TiO2 sample improved the photogenerated charge separation and enhanced the efficiency ofinterfacial charge-transfer process; nitrogen doping narrowed the band gap of TiO2 and extended the absorption to visible light region. The results indicated that the photocatalytic performance of the photocatalyst increased with the molar ratio of N to Ti; the variation of the formation rate of·OH was consistent with the photocatalytic activity, namely the greater formation rate of · OH, the higher photocatalytic activity of sample.

关 键 词：氮掺杂 二氧化钛 可见光响应 甲基橙 羟基自由基 

分 类 号：TQ424.1[化学工程]