Effects of Temperature and Precursor Concentration on the Morphological and Optical Properties of Iron Oxide Nanoparticles

Abstract

AbstractIron oxide nanoparticles are inexpensive materials that are environmentally friendly and have properties that render them suitable for wide range of applications. A facile and time-effective coprecipitation method was used to prepare iron oxide nanoparticles in a 1:1 molar ratio of Fe2+ and Fe3+ ions in solution. Iron oxide nanoparticles obtained at 18 and 60 °C yielded spherical magnetite nanoparticles with particle sizes of 7.63 and 8.5 nm respectively while comprising a mixture of magnetite and hematite nanorods, with a mean width of 9.5 nm and a mean length of 75 nm were obtained at 90 °C. Iron oxide nanoparticles synthesized at 18 °C have energy band gap of 4.16 eV while those synthesized at 60 and 90 °C have the same band gap of 4.66 eV. Precursor concentrations of 0.042, 0.08 and 0.0126 M yielded spherical magnetite nanoparticles with particle sizes of 7.94, 8.5 and 8.5 nm respectively and the particle size range increased with increasing concentration. Magnetite nanoparticles synthesized with concentrations of 0.042, 0.08 and 0.126 M have optical band gaps of 4.65, 4.88 and 5.19 eV respectively. The magnetite crystalline phase was produced regardless of concentration at temperatures of 18 and 60 °C while a temperature of 90 °C yielded a mixture of magnetite and hematite phases. The band optical band gap showed direct proportionality with temperature and concentration in an inert environment.