Dinitrogen Fixation Using Conducting Polymer/Titanium Oxide Junction

研究了在温和条件下白光驱动的固氮系统。典型的体系由二氧化钛(TiOx)和聚(3-甲基噻吩基)(P3MeT)组成，它们的异质结在20℃和40%RH的白光照射下会生成铵盐晶体(NH4ClO4)。本研究的目的是对固氮产物进行鉴定，并获得有关固氮机理的信息。X射线光电子能谱分析表明，光照射前后的结也形成了氨的固定产物之一。此外，产物的定量和X-射线的电子色散分析相结合表明，该反应是由在TiOx/P3MeT界面形成的氨气引发的，然后在P3MeT块体中部分转化为NH4ClO_4。进一步的研究表明，P3MeT薄膜中的水分子和极化子/双孔分子物种对固定反应有贡献。这些结果导致了材料/器件的结构，并提高了光能到化学能量的转换效率。

Nitrogen fixation systems driven by white light under mild conditions was investigated. The typical system consists of titanium oxide (TiO_x) and poly(3-methylthiophene)(P3MeT), and their heterojunction is previously shown to produce ammonium salt crystals (NH_4ClO_4) when exposed to white light in air at 20℃ and 40%RH. The purpose of this study is to identify the nitrogen-fixation products and to obtain the information on the fixation mechanism. X-ray photoelectron spectroscopic analyzes of the junctions before and after the photoirradiation revealed that ammonia is also formed as one of the fixation products. Additionaly, the combination of quantification of the products and electron-dispersive analysis of X-rays revealed that the reaction is initiated by annmonia formation (at the TiO_x/P3MeT interface) and followed by its partial conversion into NH_4ClO_4 in the P3MeT bulk. Further investigations showed the contribution of water molecules and polaron/biporaron species in the P3MeT film to the fixation reaction. These results led to the materials/device structures and increasing the efficiency of the light-to-chemical energy conversion.