resumo
This work presents for the first time one-step ultrafast (precursor-free) synthesis of 1D MnFe 2 O 4 (MFO) nanorods and soft magnetic colloidal nanoparticles (NPs) using microwave-assisted hydrothermal (MAH) methods, with or without citric acid (CA) as a surfactant ( in situ synthesis), respectively. The mechanism of growth of spinel MFO nanostructures during the MAH synthesis was studied by varying synthesis duration (3 - 6 h) and temperature (180 - 200 degrees C). An increase in both the duration and temperature improved the purity of the samples, up to 97%. On the other hand, a temperature increase by 20 degrees C notably shortened the formation time of MFO nanorods, which have an average diameter and length of less than 20 nm and 350 nm, respectively, as observed at 200 degrees C after 6 h. All the fabricated MFO NPs with spherical and rod-like morphologies manifested high saturation magnetization in the range of 54 - 64 emu/g. The chelation of lattice metal ions by CA resulted in the formation of a stable colloid comprising 100% pure spinel MFO NPs with a size of <= 32 +/- 10 nm (mean +/- SD) and featuring very soft magnetic properties. This colloid was generated by the MAH synthesis at 175 degrees C within 30 min. Notably, an increase in synthesis duration from 30 min to 3 h diminished MFO phase purity from 100% to 52% and saturation magnetization from 43.4 +/- 0.7 to 33.9 +/- 2.0 emu/g for CA-functionalized MFO NPs owing to CA degradation increasing during the in situ MAH synthesis with longer duration. This study indicates good potential of ultrafast MAH synthesis for the development of 1D magnetic spinel nanostructures with controllable morphology, size, magnetic properties, and colloidal stability, thereby offering a wide range of applications within the fields of adsorption, catalysis, electronics, and biomedicine.
palavras-chave
IRON-OXIDE NANOPARTICLES; COMPUTER-SIMULATION; MAGHEMITE; HEMATITE; REMOVAL; NANOCRYSTALS; SPECTROSCOPY; GAMMA-FE2O3; CURVE; IONS
categoria
Materials Science
autores
Chernozem, PV; Urakova, A; Koptsev, DA; Surmeneva, MA; Wagner, DV; Gerasimov, EY; Romanyuk, KN; Kholkin, AL; Chernozem, RV; Surmenev, RA
nossos autores
Andrei Kholkin
Investigador Jubilado
Konstantin Nikolaevich Romanyuk
Investigador JúniorProjectos
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
agradecimentos
This work was financially supported by the Russian Science Foundation (project No. 23-23-00511) . HRTEM experiments were performed using facilities of the shared research centre "National centre of investigation of catalysts" at the Boreskov Institute of Catalysis. The VCM/HRTEM/SPM studies were supported by the Ministry of Science and Higher Education (grant agreement #075-15-2021-588 from 1 June 2021) . This work related to PFM and MFM was done within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020) , UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) , financed by national funds through the FCT/MCTES (PIDDAC) . It is also funded by national funds (OE) , through FCT - Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. The authors thank the central laboratories of TPU (Analytical Centre) for the XPS measurements. The English language was corrected and certified by shevchuk-editing.com.