Reproducibility of the Synthesis of Iron Oxide Nanoparticles Produced by Laser Pyrolysis (original) (raw)

Laser Pyrolysis of Iron Oxide Nanoparticles and the Influence of Laser Power

Molecules

The purpose of this study was to investigate the synthesis of iron oxide nanoparticles under two different conditions, namely high and low gas flow rates, using laser pyrolysis and to examine the influence of laser power. The attained nanoparticles have been characterised regarding their stability and hydrodynamic dimensions by dispersive light scattering analysis (DLS), structure–X-ray diffraction (XRD), elemental composition–energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), and morpho-structural characterisation achieved by transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). For a better understanding of the laser power influence, the residence time was also calculated.

Laser-driven synthesis and magnetic properties of iron nanoparticles

Journal of Nanoparticle Research, 2006

Nanoparticles of iron have been prepared by laser-driven decomposition of iron pentacarbonyl vapor. In this method, an infrared laser rapidly heats a dilute mixture of precursor vapors to decompose the precursor and initiate particle nucleation. It was found that when using SF 6 as a photosensitizer during the synthesis, ferrous fluoride (FeF 2 ) was produced as an undesired byproduct in the product powder. The particle size, composition, and crystalline structure have been characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS). Results of magnetization measurements for small iron nanoparticles (about 5 nm diameter) are also presented, showing superparamagnetic behavior at room temperature, and a blocking temperature near 125 K.

Iron Oxide Materials Produced by Laser Pyrolysis

2010

The laser pyrolysis technique was employed in the production of magnetic iron oxide nanometric powders due to its capability of producing highly homogeneous nanoparticles in continuous form. This technique consists of the laser-driven rapid heating of an iron precursor in vapor phase in presence of oxygen. Different samples were prepared by changing the experimental conditions of synthesis. We found that high crystallinities and good magnetic properties are attained at high density of the laser power and strong oxidation. By the contrary, softer conditions using low laser densities and soft oxidation conditions give in general smaller and poorly ordered nanoparticles. The particles obtained were in the range of 2 to 9 nm in diameter (TEM). All of them were superparamagnetic at room temperature with saturation magnetization values in the interval of 4-38 emu/g-sample. The samples consist in Fe 2 O 3 maghemite with carbon as the main impurity present on the surface in the form of C=O bonds.

MAGNETIC PROPERTIES OF IRON OXIDE NANOPARTICLES OBTAINED BY LASER EVAPORATION

The paper concentrates on a synthesis of spherical magnetic particles obtained by laser evaporation under various process conditions. Depending on the process conditions, which include the pressure in a process chamber, laser pulse duration, mean laser power, and the type of power gas, the stoichiometry of the material ranges from Fe 2.70 O 4 to Fe 2.84 O 4 , while the average diameter of nanoparticles ranges between 10–23 nm. The nanoparticles have an inverse spinel structure. In terms of the magnetic properties, the samples are a superparamagnetic ensemble. The spherical shape of the majority of nanoparticles as well as the existence of merely one magnetic phase are verified by the characteristics of microwave absorption. A relatively high saturation magnetization and a narrow size distribution of small nanoparticles obtained at 700 mmHg working pressure, 100 ms pulse duration, and 200 W laser power allow the authors to consider these conditions to be the most optimum for the nanopowder synthesis and recommend them for biological applications.

Production of iron-oxide nanoparticles by laser-induced pyrolysis of gaseous precursors

Applied Surface Science, 2000

Laser-assisted pyrolysis in a continuous flow reactor has been applied to synthesise iron-oxide nanoparticles. The scope of the present contribution was to investigate the possibility of increasing the reaction yield in order to obtain powder Ž . amounts suitable for practical applications. To this aim, a gas mixture containing Fe CO and N O has been submitted to 5 2 CO c.w. laser pyrolysis. As a reaction sensitiser gas, SF has been preferred to C H to avoid ethylene fragmentation in 2 6 2 4

Iron ultrafine nanoparticles prepared by aerosol laser pyrolysis

Materials Letters, 2003

a-Fe nanoparticles have been prepared by a continuous process based on the CO 2 laser-induced pyrolysis of an iron pentacarbonyl aerosol. Uniform spherical nanoparticles of diameters between 13 and 24 nm consisting of an iron core and an oxide layer were obtained by this technique. It has been found that the mean particle size and the proportion of iron oxide vary with the laser power. Structural characteristics of the samples were determined by TEM and X-ray diffraction (XRD). Size distributions, determined both from TEM measurements and from X-ray diffraction by fitting the Fe(110) diffraction peak profile, are compared and discussed. Finally, the magnetic characterisation of the iron powders was carried out by attending to the hysteresis loop characteristics at room temperature.

Laser synthesis of magnetic iron oxide nanopowders

Technical Physics, 2012

Magnetic iron oxide nanopowders are synthesized by the laser ablation of a target made of a coarse Fe 2 O 3 powder. The geometric characteristics of the nanopowders and their yield are studied over a wide air pressure range ((1-34) × 10 4 Pa) in an evaporation chamber. The phase compositions of the nanopowders and the conditions under which their chemical composition is closest to magnetite Fe 3 O 4 are determined. The specific saturation magnetization and the coercive force of some iron oxide nanoparticles are measured.

Magnetic properties of nanometric Fe-based particles obtained by laser-driven pyrolysis

Journal of Physics and Chemistry of Solids, 2007

Fe-based nanoparticles were prepared by laser pyrolysis method using a cross-flow reactor in which the CO 2 laser radiation orthogonally crosses with the stream of Fe(CO) 5 , C 2 H 2 , and C 2 H 4 gases. The as-synthesised powder was characterised by HRTEM, XRD, Mo¨ssbauer spectroscopy, and low-and high-temperature magnetic measurements. The as-synthesised powder consisted of a-Fe and Fe 3 O 4 /g-Fe 2 O 3 nanoparticles embedded in a pyrolytic carbon matrix. The XRD pattern of the sample exhibited broad peaks. The crystallite size d XRD was estimated using the Scherrer formula and it was 1.8 nm for a-Fe and 1.6 nm for pyrolytic carbon. The assynthesised nanopowder was superparamagnetic. The blocking temperature was determined from the maximum of the ZFC curve and it was 32 K. After the sample had been cooled down to 4 K, the Mo¨ssbauer-Lamb factor f strongly increased. r

Iron-oxide-based nanoparticles produced by pulsed infrared laser pyrolysis of Fe(CO) 5

Materials Chemistry and Physics, 1998

The synthesis of nanosized ( 1–100 nm) particles is an active research field in chemical processing technologies. The process may be of particular relevance in the case of the widely used iron-based materials. In this paper, we report on the preparation and characterization of ultrafine powders produced by pulsed infrared laser pyrolysis of iron pentacarbonyl, Fe(CO)5, in sensitized mixtures. The synthesis is performed in a flow reactor, at rather high pressure (400 mbar) and high laser fluence ( ~ 5 J cm−2). The average diameter of the particles is 30 nm. Different characterization methods of the fine powder aged in atmosphere indicate the presence of a substantial oxidic portion, identified as the β-Fe2O3 · H2O form. Some experimental observations suggest the possibility of iron-oxides formation during synthesis in the

Impact of Laser Energy on Synthesis of Iron Oxide Nano-particles in Liquid Medium

World Journal of Nano Science and Engineering, 2011

We present echofriendly laser ablation technique of Synthesizing iron oxide nanoparticle in pure water and discuss the impact of laser energy on the size, shape and morphology of the nanoparticle. The synthesized nanoparticle was characterized by UV/Visible absorption spectroscopy and morphological study was performed by scanning electron microscope (SEM). Intensity and wave length of the absorption peak of the colloidal nanoparticle prepared in water are dependent on the laser energy. Red-shift in the absorption band was observed at increasing laser energy. The intensity of absorption peak also changed when ablating laser energy was increased. The spherical natures of the nanoparticle is lost as the laser energy gradually increases and finally triangular shaped structures is observed as the laser energy increases from 9.3 mJ to 75 mJ.