Catalytic synthesis, characterization and magnetic properties of iron phosphide nanowires

摘要

[[abstract]]Nanostructured materials are attracting great research interest due to their application as catalysts of organic reactions, as gas sensors and as advanced materials in future optic, electronic and magnetic devices.1–3 Recently, the fabrication of Fe-containing magnetic nanomaterials including iron,4 iron oxides5 and alloys such as FePt6 and FeCo7 became a very important issue in the potential application of their magnetic characteristics. Iron phosphide, FeP, a low-band gap semiconductor material with special magnetic properties, has traditionally been prepared by high-temperature reactions.8 Recently, Lukehart and Brock groups reported the preparation of Fe2P and FeP nanoparticles, respectively.9 Herein, we present the first example of synthesis of iron phosphide FeP nanowires by thermal decomposition of (4-cyclohexadiene)iron tricarbonyl, (4-C6H8)Fe(CO)3 in the presence of tri-n-octylphosphine oxide (TOPO) and tri-n-octylphosphine (TOP) as the stabilizing surfactants. In addition, magnetic properties of these products have been investigated in this study.The preparative procedure summarized in Scheme 1 is modified from the method for generation of Fe nanorods previously reported by Hyeon et al.4m Heating a mixture of 200 mg of (4-C6H8)Fe(CO)3 and 5.0 g of TOPO at 340 °C under a nitrogen atmosphere for 30 min afforded a black solution. To this black mixture in TOPO, was added a set amount of (4-C6H8)Fe(CO)3 (0 mg, sample A; 10 mg, sample B; 25 mg, sample C) in 5.0 ml of TOP and the solution was continuously heated at 360 °C for 30 min. This step was repeated once. After the resulting black mixture was cooled to room temperature, excess acetone was added to produce a black precipitate. The black powder product was collected by centrifugation and can be re-dispersed in pyridine or n-hexane to form a homogeneous solution.