Preparation of iron nanoparticles by reduction of acicular β-FeOOH particles

Acicular beta-FeOOH nanoparticles were prepared either by oxidation of ferrous chloride in a lamellar liquid crystal phase at 60 degrees C, or by forced hydrolysis of ferric chloride at 80 degrees C. The particles prepared in the liquid crystal phase were rod-shaped, with an average length of 85 nm and an aspect ratio of 12. Sodium borohydride reduction of these particles gave needle-shaped iron particles with lengths of about 80 nm. beta-FeOOH particles prepared by forced hydrolysis of ferric chloride were ellipsoid-shaped with and average length of 7 0 nm and an aspect ratio of 7. Unfortunately, when these particles were reduced the iron particles did not maintain the shape and size. They were-large chains of spheres or clusters of small particles with a distribution of sizes and shapes.