A wet‐chemical preparation of a Fe ₃ O ₄ ‐CuO composite powder in core‐shell structure

Abstract

We developed a process for coating CuO powder with magnetite film from an aqueous solution. Reaction solution contained 0.12 M of FeCl 2 and 0.03 M of CuCl 2 . The Cu 2+ ions promoted the oxidation of Fe(OH) 2 to form Fe 3 O 4 . The solution was maintained at pH ~6 using CH 3 COONH 4 of 0.2 M as a buffer to prevent the formation of hematite. The CuO grains of a spherical shape and ~50 µm in size were mechanically suspended in the solution, on which magnetite particles were directly deposited. The mole ratio of Cu 2+ / Fe 2+ strongly influenced the coverage of the magnetite film as well as the morphology of the constituent grains. When the Fe 2+ / Cu 2+ mole ratio was 1: 0.5, the spherical magnetite particles of ~60 nm in diameter coated well each CuO grain with the thickness of ~3 µm. The prepared powder exhibited that the saturation magnetization and the coercivity reached to ~5.4 emu/g and ~575 Oe, respectively. On heating up to 450 o C, the powder experienced two oxidations below 400 o C, indicating the formation of γ-Fe 2 O 3 . The magnetic composite powder appeared to be stable up to 400 o C.

Preyssler‐based nanocomposite as a magnetic photocatalyst: synthesis, characterisation and its photocatalytic activity for decolourisation of rhodamine B

“…Therefore a lot of researchers have focused on the preparation of magnetic nanoparticle composites [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] to obtain novel properties. Compared with organic analogues [7,8], inorganic composites of magnetic nanoparticles [13][14][15] are considered to be easier to prepare and more safe in use. Among various used nanoparticles in inorganic composites, silver nanoparticles have attracted a great deal of interest because they can be applied for electronics [25], optics [26][27][28][29], and catalysis [30].…”

“…One type of important magnetic nanoparticles is Fe 3 O 4 that has been extensively studied because of their unique magnetic properties. Therefore a lot of researchers have focused on the preparation of magnetic nanoparticle composites [7–24] to obtain novel properties. Compared with organic analogues [7, 8], inorganic composites of magnetic nanoparticles [13–15] are considered to be easier to prepare and more safe in use.…”

Impregnated Copper(II) Oxide on Magnetite as Catalyst for the Synthesis of Benzo[b]furans from 2‐Hydroxyarylcarbonyl Derivatives and Alkynes

“…An alternative route has been designed, which avoids the high cost of ortho ‐functionalized arylalkynes, by starting from the corresponding N ‐tosylhydrazone and using terminal alkynes, acetonitrile as the solvent, and CuBr (10 mol‐%) as the homogeneous catalyst . Herein, we report the first example of the use of the heterogeneous catalyst CuO‐Fe 3 O 4 for the coupling‐allenylation‐cyclization of o ‐hydroxybenzaldehydes with terminal alkynes to yield benzo[ b ]furan derivatives.…”

Preparation and Characterization of Graphene Nanoplatelet/Magnetite Compound Powders

“…Recently, Allen et al [8] have used the ferritin-like protein cage to synthesize homogeneous magnetic nanoparticles. Hyun and co-workers [9] coated Fe3O4 on the surface of CuO in the buffer solution contained FeCl2, CuCl2, CH3COONH4 and CuO powder by the wet-chemical method. Huang et al [10] fabricated the core-shell structure particles comprising nearly monodisperse polystyrene (PS) spheres as cores and the magnetite as shell by seeded growth from the reaction of FeCl2 with diethylene glycol (DEG) in aqueous solutions.…”