Synthesis and characterization of nanowires formed by self-assembled iron particles

The formation of iron particles without and with carbon coating was studied in a hot wall flow reactor. The precursors ironpentacarbonyl (IPC, Fe(CO)(5)) and ethylene (C2H4) both diluted in N-2 were used in a concentric tubular flow arrangement and were heated to temperatures between 570 and 1170 K at pressures between 50 and 500 mbar. In experiments without C2H4, either individual iron particles in the size range of 8 nm less than or equal to d(p) less than or equal to 15 nm or long iron chains composed of several hundreds of individual iron particles were found depending on the reaction conditions. In experiments with C2H4 addition, these particles or particle chains were covered by a thin carbon/carbide layer. The size of the primary particles was measured in situ by time-resolved laser-induced incandescence (TR-LII) and ex situ by rapid thermophoretic particle probing and TEM imaging.