resumo
Nanoparticles of zinc-cobalt spinel ferrite Co0.5Zn0.5Fe2O4 (CZFO) were prepared by co-precipitation route, and the effect of the addition of various surfactants (ethanol, PEG, CTAB and acetic acid; surfactant:metals = 0.5:1) on their magnetic and optical properties were investigated. Such surfactant additives have shown great potency in controlling and improving nucleation and growth stages, leading to an optimisation of crystallite size, porosity and specific surface area (SSA). The addition of ethanol in particular helped to optimise the physicochemical properties of the material, giving the lowest crystallite size of 11.7 nm, and highest porosity and SSA values of 0.65 cm(3)/g and 32.37 m(2)/g, respectively. The sample made with ethanol also had a small grain size of 50-100 nm. The CZFO made with ethanol surfactant also had greater coercivity (H-c) and saturation magnetisation (M-s) values compared with the other surfactants, of 22 kA m(-1) and 81.19 A m(2) kg(-1). UV-vis diffuse reflectance spectra (DRS) showed all samples made with surfactant additives had two distinct absorption edges in the visible region, around 550 nm and 700 nm. Two optical band gap (E-g) values were obtained for direct allowed transitions for these CZFO samples, with E-g1 values in the range of 1.99-2.06 eV, equivalent to that expected for ZnFe2O4, and E-g2 in the range of 1.60-1.66 eV, as expected for CoFe2O4. The CZFO made with ethanol also had the highest E-g values in both cases. (C) 2018 Elsevier B.V. All rights reserved.
palavras-chave
CO1-XZNXFE2O4 NANOPARTICLES; SIZE; DEGRADATION; TEMPERATURE; EVOLUTION; REMOVAL
categoria
Chemistry; Materials Science; Metallurgy & Metallurgical Engineering
autores
El Foulani, AH; Aamouche, A; Mohseni, F; Amaral, JS; Tobaldi, DM; Pullar, RC
nossos autores
David Maria Tobaldi
Investigador
Farzin Mohseni
Estudante de doutoramento
João Cunha de Sequeira Amaral
Investigador Auxiliar
Rob Pullar
ColaboradorGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G4 - Materiais Renováveis e Economia Circular
Projectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Projeto de Investigação Exploratória: João Amaral (IF/01089/2015)
agradecimentos
This work was supported by Fundacao para Ciencia e Tecnologia (FCT, Portugal) via the Portugal-Morocco bilateral collaboration grant FCT/CNRST-2015/2016 Proc. No 441.00. This work was partly carried out at CICECO- Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013) financed by national funds through the FCT/MEC, and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. RCP thanks FCT Grant IF/00681/2015, and JSA thanks FCT Grant IF/01089/2015, for supporting this work.