高等学校化学学报

高等学校化学学报

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浓度梯度分布的镍和氮共掺杂TiO2光催化剂的制备和表征

柏源, 孙红旗, 刘会景, 金万勤   

  1. 南京工业大学材料化学工程国家重点实验室, 南京 210009
  • 收稿日期:2008-04-23 修回日期:1900-01-01 出版日期:2008-11-10 发布日期:2008-11-10
  • 通讯作者: 金万勤

Preparation and Characterization of TiO2 Photocatalyst Co-doped by Nitrogen and Nickel with Concentration Gradient Distribution

BAI Yuan, SUN Hong-Qi, LIU Hui-Jing, JIN Wan-Qin*   

  1. State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
  • Received:2008-04-23 Revised:1900-01-01 Online:2008-11-10 Published:2008-11-10
  • Contact: JIN Wan-Qin

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摘要： 以TiCl4为钛前驱体, 氨水和氯化镍为掺杂离子给体, 采用沉淀和层层浸渍相结合的方法制备了氮、镍共掺杂TiO2光催化剂. 采用X射线衍射(XRD)、氮气吸附-脱附、X射线光电子能谱(XPS)、紫外-可见漫反射吸收光谱(UV-Vis)等现代表征方法对催化剂的晶体结构、微结构、掺杂基团和光谱性质进行了表征. XRD和氮吸附-脱附分析结果表明, 氮、镍共掺杂TiO2为单一锐钛矿相, 具有介孔结构. XPS谱证实掺杂的氮和镍分别以NOx和Ni2O3及NiO的形式存在, 且镍在共掺杂表面的浓度高于体相中的浓度, 在扩散方向上存在浓度梯度分布. 4-氯酚的降解实验结果表明, 浓度梯度分布镍和氮共掺杂TiO2的紫外光-可见光催化活性均高于均相共掺杂TiO2、单掺杂和未掺杂TiO2的催化活性. 其原因是掺杂的氮以NOx形式存在, 使催化剂的感光范围拓展至可见光区; 而掺杂的镍维持了半导体体系的电荷平衡, 有效抑制了Ti3+的产生. 同时掺杂的镍在催化剂中存在浓度梯度分布, 减少了光生电子和空穴的复合几率, 提高了催化剂的光催化活性.

关键词: 光催化, TiO2, 氮/镍共掺杂, 可见光, 浸渍法

Abstract: Nitrogen and nickel co-doped TiO2 photocatalyst was synthesized by the combination of precipita-tion with layer-by-layer impregnation, in which titanium tetrachloride was used as Ti-precursor and ammonia, nickel chloride as doping-ion donors. The samples were characterized by means of X-ray diffraction(XRD), nitrogen adsorption-desorption, X-ray photoelectron spectroscopy(XPS) and UV-Vis spectroscopy(UV-Vis). The as-prepared photocatalyst was dominantly in anatase phase and a mesoporous structure. The doped nitrogen and nickel impurities were found to be NOx and Ni2O3, NiO species, which were confirmed by XPS. The photocatalytic activity of co-doped TiO2 was higher than that of both pure and single doped one. Visible light response was due to NOx and the doped nickel maintains the charge balance at the same time. Simul-taneously, the special concentration gradient distribution of Ni in this work reduced the possibility of recom-bination of photogenerated holes and electrons, which seemed to contribute to the enhancement of the photo-catalytic activity of nitrogen and nickel co-doped TiO2.

Key words: Photocatalysis, Titanium dioxide, Nitrogen and nickel co-doping, Visible light, Impregnation method

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