Production of iron-oxide nanoparticles by laser-induced pyrolysis of gaseous precursors

Laser-assisted pyrolysis in a continuous flow reactor has been applied to s ynthesise iron-oxide nanoparticles. The scope of the present contribution w as to investigate the possibility of increasing the reaction yield in order to obtain powder amounts suitable for practical applications. To this aim, a gas mixture containing Fe(CO)(5) and N2O has been submitted to CO2 c.w. laser pyrolysis. As a reaction sensitiser gas, SF6 has been preferred to C2 H4 to avoid ethylene fragmentation in N2O presence and the formation of iro n carbides. Due to unexpected SF, dissociation, the synthesis process led t o the preferential formation of iron fluoride compounds. Powder samples, su bmitted to calcining treatment (400 degrees C, 3 h), showed an almost compl ete transformation to alpha- and gamma-iron oxides retaining the nanostruct ure feature of the powder. (C) 2000 Elsevier Science B.V. All rights reserv ed.