On the mechanism of nitrogen photofixation at nanostructured iron titanate films.

The photofixation of dinitrogen to ammonia at a nanostructured iron titanate thin film, prepared from iron(III) chloride and titanium tetraisopropylate, was established by isotopic labeling employing (15,15)N(2). It is found that traces of iron chloride in the film are required to observe significant amounts of ammonia. It is therefore proposed that the photogenerated hole oxidizes chloride to an adsorbed chlorine atom and the latter subsequently oxidizes ethanol, the reducing agent necessary for ammonia formation.

Nitrogen photofixation on nanostructured iron titanate films.

A nanostructured iron titanate thin film has been prepared by a sol-gel method from iron(III) chloride and titanium tetraisopropylate. Energy-dispersive X-ray analysis and Mössbauer spectroscopy suggest the presence of a Fe(2)Ti(2)O(7) phase, which was previously obtained as an intermediary phase upon heating ilmenite. In the presence of ethanol or humic acids and traces of oxygen, the novel film photocatalyzes the fixation of dinitrogen to ammonia (17 microM) and nitrate (45 microM).