Characterization and material conditions of conducting polymer/titanium oxide hybrid systems used for dinitrogen fixation under ordinary pressure and temperature

Abstract

Nitrogen fixation systems driven by white light under mild conditions were investigated. A typical system consists of titanium oxide (TiO x ) and poly(3-methylthiophene) (P3MeT), and their heterojunction produced ammonium salt crystals (NH 4 +ClO 4 −) and ammonia when exposed to white light in air at ca. 20 °C and 40% relative humidity (RH). The production of the nitrogen compounds proceeded at a rate of 19 μmol m −2 h −1 under 486 W m −2 irradiation of white light. Visible-light activity for the photofixation of N 2 was exhibited by the spectral dependence of the fixation yield: the yields in the visible region were still in the range of 37–72% of that at 346 nm. The fixation yield was strongly dependent on the thickness of the P3MeT layer, the potential at which the TiO x layer was prepared, and the kind of the conducting polymer material.