卟啉敏化的钛酸盐纳米管的可见光催化活性

Photocatalytic Activity of Titanate Nanotubes Sensitized with Porphyrin

制备了四碘化5,10,15,20-四(对-N,N,N三甲基苯胺基)卟啉敏化的钛酸盐纳米管(TAPPI-TNTs),并利用甲基橙(MO)作为模型污染物考察了其可见光催化活性。结果表明,TAPPI-TNTs是一个高效的可见光催化剂,在其催化作用下,可见光照射1 h后,甲基橙的降解率为89%。与此相反,纯钛酸盐纳米管并不具有可见光催化活性。此外,TAPPI-TNTs的稳定性较高,可以多次循环使用,在第五次循环中,甲基橙的降解率仍可达到50%以上。这可能是由于带正电荷的卟啉与带负电荷的钛酸盐纳米管之间存在着较强的静电吸引作用,卟啉紧密地吸附在钛酸盐纳米管上,导致卟啉的光激发电子易于向钛酸盐纳米管转移,从而使钛酸盐纳米管得到了有效敏化。

Titanate nanotubes sensitized with 5,10,15,20-tetrakis（p-N,N,N-trimethylanilinium） porphyrin tetraiodide（TAPPI-TNTs） were prepared.Meanwhile,the photocatalytic activity was evaluated under visible light irradiation using methyl orange（MO） as a model contaminant.The results display that TAPPI-TNTs are an efficient photocatalyst with 89% degradation of MO after 1 h visible irradiation.In contrast,the pure titanate nanotubes do not show any photocatalytic activity.In addition,the TAPPI-TNTs are good at recycling photocatalytic activity.The degradation rate of MO is still up to 50% in the fifth cycle.One possible explanation is that the porphyrin molecules can be adsorbed closely on the titanate nanotubes due to the strong electrostatic attraction between the porphyrin molecules with positive charges and the titanate nanotubes with negative charges,which leads to an effective transfer of photo-excited electrons from the porphyrin molecules to the titanate nanotubes.Therefore,the titanate nanotubes are effectively sensitized by porphyrin.