Facile Microwave Process in Water for the Fabrication of Magnetic Nanorods

Abstract

1 - ArticleMagnetic nanorods were successfully prepared in water by a simple and fast method through microwave (MW) assisted reduction using akaganeite beta-FeOOH nanorods and hydrazine as precursors and reductor, respectively. Elongated paramagnetic akaganeite precursors are synthesized for the first time using dopamine as green chemical shape-control agent. The nature and the growth mechanism are identified by XRD, Raman spectroscopy and HRTEM analysis. Fast MW reduction process induces a structural and magnetic change depending on MW irradiation cycles. After 2 min, MW reduction leads to iron oxide nanorods with aspect ratio 3.2. XRD and Raman spectroscopy indicate a heterogeneous composition with high proportion of maghemite. The FMR spectrum is characteristic of shape anisotropy and weak ferromagnetic behavior is observed from SQUID measurements

Silica-Coated and Bare Akaganeite Nanorods: Structural and Magnetic Properties

“…16 The assynthesized akaganeite nanorods were further coated with a 5-nm-thick silica shell. In brief, 20 mL of the suspension containing as-synthesized akaganeite nanorods (159 mM, Fe ions) were transferred into 50 mL of ethanol solution containing 0.8 mL of aqueous ammonia (25 %) and 150 mg of polyvinylpyrrolidone (PVP).…”

“…[22][23][24][25][26][27] Moreover, the β-FeOOH phase is important and widely used as a precursor in the 4 preparation of iron, hematite, maghemite and magnetite nanosized materials. 16,[28][29][30][31][32] Akaganeite is an antiferromagnetic material with a Néel temperature in the range of T N ≈ 240-299 K. 12,20,33 A substantial reduction of the Néel temperature, down to T N = 15 K, has been observed in amorphous β-FeOOH nanowires. 19 It has also been observed that the Curie-Weiss temperature varies within a wide range for differently synthesized β-FeOOH materials.…”

A facile green synthesis of spherical Fe3O4 magnetic nanoparticles and their effect on degradation of methylene blue in aqueous solution

“…Currently, iron oxide nanoparticles are highly inspiring nanoparticles from an essential research point of view, considering the dependence of the magnetic properties with shape, size, composition, surface and interaction. The iron nanoparticles have several potential applications in medical diagnosis and therapy [1], drug delivery [2], magnetic resonance imaging [3] and cancer hyperthermia treatment [4]. However, the synthesis of iron nanoparticles has been synthesized by various approaches such as hydrothermal [5], sonochemical [6], micro emulsion [7], electrochemical [8], co-precipitation [9], ammonia solutions [10], sol-gel [11], surfactants [12], solvothermal [13], solvents [14], mechano-chemical [15] and emulsion techniques [16].…”

Shape matters: synthesis and biomedical applications of high aspect ratio magnetic nanomaterials

“…Motte and co-workers synthesized magnetic nanorods by a two-step one-pot procedure involving the microwave reduction of precursor nanorods obtained in the first step. 25 In this case, the shape control is achieved during the synthesis of the precursor (akaganeite β-FeOOH) using dopamine, which is known for its strong affinity for Fe(III). In the absence of dopamine ligands, mainly hexagonal nanoparticles were obtained, while its presence promoted the growth of rodshaped nanoparticles whose aspect ratio was inversely proportional to the reaction times, decreasing from 5.8 after 2 h reaction time to 4.6 after 4 h. Dopamine plays here a similar role to that of phosphate ions in the above-discussed examples, 23,24 favouring the growth of rod-like structures along the c-axis of the β-FeOOH crystal.…”