Low Concentration Iron-Doped Alumina (Fe/Al 2 O 3 ) Nanoparticles Using Co-Precipitation Method
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ORIGINAL PAPER
Low Concentration Iron-Doped Alumina (Fe/Al2O3) Nanoparticles Using Co-Precipitation Method Majid Farahmandjou 1
&
Abolfazl Khodadadi 2 & Mojtaba Yaghoubi 3
Received: 20 January 2020 / Accepted: 6 June 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Pure aluminum oxide (Al2O3) and iron-doped alumina Fe-doped Al2O3 with different percentages of Fe dopant nanoparticles (NPs) were synthesized by co-precipitation method. The XRD analysis indicated that the samples have γ, δ, θ, and α phases and the crystal structure became more stable with increasing Fe dopant. The results of the TEM analysis indicated that the particle size of the 4%-doped sample is about 45 nm. The results of FTIR analysis indicated an increase in the intensity of the Al-OH absorption with increasing of the Fe dopant. The UV-DRS optical analysis demonstrated that the band gap energy of the pure Al2O3 sample decreased from 4.1 to 3.51 eV for the sample with a 6% impurity. Finally, the VSM magnetic analysis showed the paramagnetic behavior of the Fe-doped alumina. Keywords Fe-Al2O3 nanoparticle . Co-precipitation . XRD . Magnetic properties
1 Introduction In recent years, metal oxide nanomaterials have been broadly considered in the fields of industry and medicine [1–9]. More specifically, the aluminum oxide (alumina) nanoparticles (NPs) have been extensively applied in electronics, optoelectronics, medicine, and petrochemical industries [10–16]. The properties of these nanomaterials are considerably changed by increasing the surface-to-volume ratio. Alumina has different phases including γ, η, κ, δ, θ, and α. The γ phase has a cubic structure formed at 700 to 1000 °C and is used generally as a catalyst, whereas the α phase has a hexagonal (hcp) structure and is formed when the temperature reaches 1200 °C. This structure is applied in the drilling and cutting subtle stones due to its high stiffness. The other phases are thermodynamically unstable whose structure eventually changes to the α-alumina phase
* Majid Farahmandjou [email protected] 1
Department of Chemistry, Faculty of Pharmaceutical Sciences, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
2
Department of Physics, Islamis Azad University, Tehran North Branch, Tehran, Iran
3
Departments of Physics, Islamic Azad University, Ayatollah Amoli Branch, Amol, Iran
when adding the dopant [17–22]. The α-Al2O3 unit cell has a hexagonal cell structure, having a rhombohedral primitive cell. Each Al3+ center is in an octagonal structure in which Al3+ ions occupy two-thirds of the octagonal empty spaces in terms of crystallographic [23, 24]. An increase in alumina temperature results in the loss of the hydroxyl group and the formation of Al4+ aluminum alpha cations in tetrahedral and Al6+ in octahedral, which in turn leads to phase transformation, porosity reduction, decrease in surface area, and an increase in size [25–29]. The addition of a small amount of transition metal dopants such as Cu, Zn, and Fe to the alumina l
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