Iron-oxide-based nanoparticles produced by pulsed infrared laser pyrolysis of Fe(CO)5

The synthesis of nanosized (1-100 nm) particles is an active research field in chemical processing technologies. The process may be of particular relevance in the case of the widely used iron-based materials. In this paper, we report on the preparation and characterization of ultrafine powders produced by pulsed infrared laser pyrolysis of iron pentacarbonyl, Fe(CO)(5), in sensitized mixtures. The synthesis is performed in a flow reactor, at rather high pressure (400 mbar) and high laser fluence (similar to 5 J cm(-2)). The average diameter of the particles is 30 nm. Different characterization methods of the fine powder aged in atmosphere indicate the presence of a substantial oxidic portion, identified as the beta-Fe2O3 . H2O form. Some experimental observations suggest the possibility of iron-oxides formation during synthesis in the flow reactor. The relevant mechanisms for this reaction route are discussed. (C) 1998 Elsevier Science S.A. All rights reserved.