Photodriven Disproportionation of Nitrogen and Its Change to Reductive Nitrogen Photofixation.

Nitrogen fixation is an essential process for sustaining life. Tremendous efforts have been made on the photodriven fixation of nitrogen into ammonia. However, the disproportionation of dinitrogen to ammonia and nitrate under ambient conditions has remained a grand challenge. In this work, the photodriven disproportionation of nitrogen is realized in water under visible light and ambient conditions using Fe-doped TiO microspheres. The oxygen vacancies associated with the Fe dopants activate chemisorbed N molecules, which can then be fixed into NH with H O as the oxidation product. The generated H O thereafter oxidizes NH into nitrate. This disproportionation reaction can be turned to the reductive one by loading plasmonic Au nanoparticles in the doped TiO microspheres. The generated H O can be effectively decomposed by the Au nanoparticles, resulting in the transformation of the disproportionation reaction to the completely reductive nitrogen photofixation.