Continuous-flow laser synthesis of large quantities of iron oxide nanowires in solution

Abstract

Large quantities of iron oxide nanowires are rapidly synthesized at room temperature by pulsed-laser (248 nm) ablation of iron powder under methanol. By introducing a stream of methanol, a continuous flow of nanoscale products is collected. Through control of the flow rate, and hence the residence time of the products within the growth vessel, their morphology can be controlled. At high collection rates a lamellate `nanobelt' morphology is observed, whereas at low collection rates nanowires dominate. Chemical and structural characterization suggests that the as-synthesized products have the stoichiometry of the goethite [FeO(OH)] phase. Annealing at temperatures above 400 degrees C crystallizes the products as hematite (alpha-Fe2O3).