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Design and Development of Unique Photocatalytic Systems for the Decomposition of NOx

设计和开发用于分解氮氧化物的独特光催化系统

基本信息

批准号：
10044170
负责人：
ANPO Masakazu
金额：
$ 2.05万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044170/
关键词：
Metal ion-implantation method TiOィイD22ィエD2 photocatalyst NOx decomposition Utilization of solar beam Cr ion-implanted TiOィイD22ィエD2 Utilization of visible light Ag ZSM-5 酸化チタン太陽光イオン注入法 NO光触媒分解反応ゼオライト ESR

项目摘要

Until now, photocatalytic reactions involving TiO2 photocatalysts for the decomposition of NOx were known to proceed only under UV light irradiation. In this research project, by the application of advanced metal ion-implantation with various transition metal ions such as V and Cr, it was found that novel TiO2 photocatalysts which absorb and operate efficiently under visible light irradiation for the decomposition of NOx could be developed. In-situ ESR and XAFS investigations revealed that the implanted V ions which exist as VィイD14+ィエD1 at the lattice position in place of TiィイD14+ィエD1 ion play a significant role in the shift in the absorption bands of TiO2 toward visible light regions. On the other hand, highly dispersed TiO2 catalysts anchored within the pore structure of the Y-zeolite by an ion-exchange method (Ti-Y zeolite) exhibited higher photocatalytic activity as compared to powdered TiO2. V or Cr ion-implantation on the Ti-Y zeolite also leads to a shift in the absorption band of the catalyst toward visible light regions and it was found that these V or Cr ion-implanted Ti-Y zeolites successfully decompose NOx under irradiation with visible light longer than 450nm, while maintaining just as a high photocatalytic activity as observed before applying ion-implantation. Furthermore, in-situ ESR and FT-IR investigations *lucidated the electron transfer from the photo-excited active site of the photocatalyst into the p anti-bonding molecular orbital of NO which led to a weakening of the N-O bond and initiated the decomposition of the NO molecule. It can be said that the present research has opened the way to many innovative possibilities, significantly to address urgent environmental problem and also as an important breakthrough in the utilization of solar energy.

到目前为止，利用TiO2光催化剂降解NOx的光催化反应仅在紫外光照射下进行。在本研究项目中，通过应用先进的金属离子注入各种过渡金属离子，如V和Cr，可以开发出新型的TiO2光催化剂，该催化剂在可见光照射下能够高效地吸收和运行于分解NOx。原位电子自旋共振和X射线光电子能谱研究表明，V离子以VィイD14+ィエD1形式存在于晶格位置，取代了TiィイD14+ィエD1离子，对TiO2光吸收谱带向可见光方向移动起着重要的作用。另一方面，通过离子交换方法固定在Y型沸石孔结构中的高分散TiO2光催化剂表现出比粉状TiO2光催化活性更高的光催化活性。V或Cr离子注入到Ti-Y分子筛上后，催化剂的吸收带向可见光方向移动，在450 nm以上的可见光照射下，这些分子筛成功地分解了NOx，同时保持了与注入前一样高的光催化活性。此外，现场ESR和FT-IR研究表明，电子从光催化剂的光激发活性中心转移到NO的p反键分子轨道上，导致N-O键减弱，启动了NO分子的分解。可以说，本研究为许多创新的可能性开辟了道路，对解决紧迫的环境问题意义重大，也是太阳能利用的重要突破。