Photo-Chemical Synthesis of Iron Oxide Nanowires Induced by Pulsed Laser Ablation of Iron Powder in Liquid Media

Iron oxide nanowires are synthesized by photochemical method through nanosecond pulsed laser ablation of iron powder in liquid media. The synthesis is tried using various wavelengths (248 and 532 nm) of pulsed laser at different liquids (water, ethanol, methanol, isopropanol and glycol). The solution of iron oxide nanowires is obtained only in methanol when the iron powder (size < 60 μm) is irradiated at 248 nm. Ablation with 532 nm in methanol resulted in solutions of iron oxide nanoparticles. It is very interesting to note that irradiating solutions of the nanoparticles, obtained via 532 nm ablation, with laser pulses at 248 nm laser gives rise to the solution of iron oxide nanowires again. It is to be recorded that only nanoparticles are obtained in water, ethanol, isopropanol and glycol when ablated with any of the said two lasers. Chemical and structural characterization suggest that the as-synthesized products are mainly amorphous goethite [FeO(OH)]. Annealing above 400°C, converts it into crystalline hematite (α-Fe2O3). The formation mechanism of the nanowires from extended 2D nanosheets is discussed.