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Fourier-transform infrared spectroscopy (FTIR) spectrum of the Fe-Al2O3 NPs with different Fe dopants (in the range wavenumber of 400–4000 cm⁻¹)
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![Tauc plot of [F(R)hν]1/2 vs E (hv) energy of the Fe-Al2O3 NPs with...](publication/342863230/figure/fig5/AS:961851101810700@1606334581588/Tauc-plot-of-FRhn1-2-vs-E-hv-energy-of-the-Fe-Al2O3-NPs-with-different-Fe-dopants_Q320.jpg)
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 indi...
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In this research, we used a fast and simple method for synthesis of calcium titanate (CaTiO3) and calcium ferrite (CaFe2O4) nanostructures: microwave assisted co-precipitation method. The effect of time, microwave radiation power and type of solvent on the morphology of magnetic nanoparticles was studied. Calcium ferrite/calcium titanate (CaFe2O4/C...
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... Fig. 6 shows the absorption spectrum of synthesized nanoparticles and it was observed that the absorption peak was found at around 235 nm. The calculated band gap was 5.3 eV, which was greater than iron-doped alumina (Fe/Al 2 O 3 ) nanoparticles using the co-precipitation method [35].These findings affirm the superior advantages of the methodology employed in our current investigation compared to conventional methods. ...
Water pollution resulting from the discharge of dye-containing effluents poses a formidable challenge to environmental sustainability and human well-being. Thus, present work focuses on the innovative biogenic synthesis of Fe-doped Al 2 O 3 nanoparticles using Eichhornia crassipes leaf extract as a sustainable and eco-friendly approach towards the removal of Malachite Green dye from aqueous solutions. The synthesis process is characterized using various analytical techniques to confirm the successful formation of Fe-doped Al 2 O 3 nanoparticles. The synthesized nanoparticles crystallize in corundum structure with average particle size of 61.87 nm, confirmed through XRD and BET analysis. UV examination revealed an absorption peak at 235 nm, confirming alumina nanoparticle formation, while FESEM micrographs depicted a rock-like structure. The synthesized nanoparticles demonstrate promising potential for the remediation of the toxicant Malachite Green dye as 96.67% of the dye has been removed within 60 min. Batch experiments were conducted to study the adsorption kinetics, isotherms, and thermodynamics and the adsorption mechanism fitted well with Freundlich isotherm (R 2 =0.982) and pseudo-second order kinetics (R 2 =1.000). Comparative literature analysis suggests present study is the first to investigate, Fe-doped Al 2 O 3 through biogenic approach and its potential efficacy in degrading Malachite green dye. This biogenic approach to Fe-doped Al 2 O 3 synthesis provides valuable insights for industrial applications and aligning with sustainable development goals. The work also important considering circular economy objectives and commercial use. Abbreviations MG Malachite Green dye XRD X-ray diffraction FESEM Field emission scanning electron microscope EDS Energy-dispersive spectroscopy BET Brunauer, Emmett, and Teller method FTIR Fourier transform infrared spectroscopy q e Amount of adsorbate per unit mass of adsorbent at equilibrium (mg.g-1), q t Amount of adsorbate per unit mass of adsorbent at time t (mg.g-1), C 0 Initial concentration of MG dye (mg.L-1), C e Equilibrium concentration (mg.L-1), V Volume of dye solution (L), W Weight of nanoparticles adsorbent (g), k 1 Pseudo-first order rate constant (min-1), k 2 Pseudo second order rate constant (g.mg-1 .min-1), k int Intra-particule diffusion rate constant (mg.g-1 .min-0.5), C Constant indicating the thickness of the boundary layer, q m Monomolecular layer (maximum) adsorption capacity (mg.g-1) K L Langmuir adsorption equilibrium constant (L.mg-1) K F Freundlich isotherm constant (L.mg-1), K d Equilibrium constant (cm 3 .g-1)
... From the overall spectrum ( Figure S5a), the region at high wavenumbers (>3000 cm −1 ) can be assigned to O−H groups due to adsorbed moisture and the presence of bicarbonates, the peaks between roughly 1300 and 1700 cm −1 to surface adsorbed carbonate species and the large peak below 1000 cm −1 to vibration modes of the metal oxide. 15,38,61 Figure S5b focuses on the region of the carbonate peaks, where two main absorption peaks and a smaller broader one can be observed. ...
CO2 adsorbents comprising various alkaline sorption active phases supported on mesoporous Al2O3 were prepared. The materials were tested regarding their CO2 adsorption behavior in the mid-temperature range, i.e., around 300 °C, as well as characterized via XRD, N2 physisorption, CO2-TPD and TEM. It was found that the Na2O sorption active phase supported on Al2O3 (originated following NaNO3 impregnation) led to the highest CO2 adsorption capacity due to the presence of CO2-philic interfacial Al–O––Na⁺ sites, and the optimum active phase load was shown to be 12 wt % (0.22 Na/Al molar ratio). Additional adsorbents were prepared by dispersing Na2O over different metal oxide supports (ZrO2, TiO2, CeO2 and SiO2), showing an inferior performance than that of Na2O/Al2O3. The kinetics and thermodynamics of CO2 adsorption were also investigated at various temperatures, showing that CO2 adsorption over the best-performing Na2O/Al2O3 material is exothermic and follows the Avrami model, while tests under varying CO2 partial pressures revealed that the Langmuir isotherm best fits the adsorption data. Lastly, Na2O/Al2O3 was tested under multiple CO2 adsorption–desorption cycles at 300 and 500 °C, respectively. The material was found to maintain its CO2 adsorption capacity with no detrimental effects on its nanostructure, porosity and surface basic sites, thereby rendering it suitable as a reversible CO2 chemisorbent or as a support for the preparation of dual-function materials.
... The discrepancy between the ionic radii of rare earth elements and Al 3+ , leading to an extremely low equilibrium solubility limit of rare earth elements ∼ 10 −3 % [57], makes it possible to exclude the introduction of cerium ions into the Al 2 O 3 matrix. Therefore, the most probable is the substitution of Al 3+ by Fe 3+ [58]. ...
This study presents Ce-Fe-O systems supported on γ-Al2O3 or SiO2 to enhance the reactivity of an oxygen-deficient CeFeO3 perovskite phase, which are promising catalysts for the production of fuels and chemicals from CO2 as feedstock. The synthesis was carried out by the glycine-nitrate solution combustion method at various fuel-to-oxidizer ratios, and with or without the addition of ammonium nitrate. The obtained composites were characterized by XRD, SEM, EDX, N2-physisorption, H2-TPR, and CO2-TPD to study the relationship of physicochemical properties with catalytic CO2 hydrogenation (rWGS) activity. γ-Al2O3 was found to be a more suitable support than SiO2 due to its ability to form a higher content of the perovskite phase, significantly reduce the size of CeFeO3 crystallites, and increase oxygen defectiveness and CO2 adsorption capacity. Combustion in the presence of silica results in the binding of most of cerium into a silicate phase, which is inactive for rWGS.
... This study obtained Fe and Al materials from the leaching and recovery process (Co-precipitation). The advantages of the Co-precipitation method compared to other methods such as sol-gel, solid state, hydrothermal synthesis, and spray pyrolysis are the relatively inexpensive price, easy manufacturing method, environmentally friendly, and the most advantageous because it can produce a homogeneous material composition and shape [10][11][12]. Fe/Al precursors, Ni/Co precursors, and Li sources were mixed and reacted using a solid-state high-temperature method to become NCAF batteries. The physical, chemical, and electrochemical properties of the NCAF samples were analyzed using X-ray diffractometer (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), Differential Thermal Analysis/Thermal Gravimetry (DTA/TG), and battery capacity tests. ...
... The peak at wavenumber 3270/cm is associated with the hydroxyl group bonds and describes the -OH group of water molecules still trapped in the precipitate. Another absorption peak is at wave number 2400/cm, which is a C-O group; besides that, the absorption peak at 1644/cm is a C=O vibrational bond [10]. The wave number 1000/cm is assigned to the Al-O group, and anything below 700/cm is defined as the stretching of the Fe-O group [13]. ...
Fly ashes often become an environmental problem and are difficult to process. Utilizing coal fly ash as a product is a promising approach to overcoming it. In response to this problem, the metal content in fly ash waste in the form of Al2O3 and Fe2O3 can be utilized by applying them as dopants on the nickel-rich cathode material to achieve LiNixCoyAlzFe(1-x-y-z)O2 (NCAF) which is a modified form of nickel-based cathode material or NCA. In this study, NCAF material was made in 3 stages: (i) Recovery of valuable metals Al and Fe from fly ash by leaching and precipitation processes to obtain Aluminum-iron (AF) precursor; (ii) Nickel-cobalt (NC) containing precursors were prepared by mixing nickel and cobalt salts using the coprecipitation method. This NC precursor and AF were mixed at a mass ratio of 90:10; (iii) Lithiation through heat treatments under an O2 atmosphere to form NCAF cathode material. The results of the NCAF material characterization are: (i) The XRD test showed the same diffraction pattern as the JCPDS 87-1562 reference; (ii) FTIR test of NCAF material showed that the storage condition affects the surface of NCAF powder; (iii) SEM-EDX test showed that the NCAF material has an agglomerated morphology and crystal-shape with a primary particle size of around 140 nm; (iv) Electrochemical test of Li-ion battery with NCAF cathode using graphite as anode showed charge and discharge capacity of 172 mAh/g and 144 mAh/g, respectively. Based on the results, implementing Al and Fe from fly ash as materials for Li-ion batteries should be considered for future energy storage technology developments.
... These peaks are consistent with the complex formation or chemisorption of oleic acid on the surface of air-dried AlO x NPs. The vibrational peaks at 531 cm -1 ( Figure S5C) and 870 cm -1 ( Figure S5E) correspond to the octahedral (Al-O 6 ) and tetrahedral (Al-O 4 ) groups of Al 2 O 3 [63]. Unlike the air-dried AlO x NPs, no spectral bands were observed for the annealed Al 2 O 3 NPs (Figure S5D, S5E). ...
Aluminum oxide is an important ceramic material for coatings and catalyst support for high-temperature applications. In this work, spherical aluminum oxide (AlOx) nanoparticles (NPs) are synthesized via the thermal decomposition of aluminum oleate using oleic acid as a stabilizing agent. X-ray diffraction analysis confirms its crystallization to γ-Al2O3 and α-Al2O3 after annealing at 700 and 1100 °C, respectively, revealing their gradual phase transition. Morphological and crystallinity changes of spherical nanoparticles upon annealing were investigated by transmission electron microscopy. The chemical composition and phase transitions to Al2O3 NPs were supported by X-ray photoelectron spectroscopy as a function of temperature. Monolayer assembly of as-synthesized NPs onto quartz substrate was performed using organic linker molecules (11-phosphonoundecanoic acid), which was confirmed by atomic force microscopy imaging. The optical band gap of the monolayer assembly was evaluated after annealing at different temperatures along with transmittance properties to compare with the current literature by UV–visible spectroscopy.
... The sample oxidized by HCl solution immersion presents vibrational bands in the region marked as region III (1200-950 cm −1 ) and a halo ranging from region marked as II (950-680 cm −1 ) up to the end of region I (680-400 cm −1 ). Due to the multiple Me-O bonds, that are very close and are superposing partial or total, the bands are visible as two halos [31][32][33]. At a deeper analysis it can be observed that the region I consists in two subregions: the first one in 680-530 cm −1 domain and the second one in 530-400 cm −1 range. ...
... At a deeper analysis it can be observed that the region I consists in two subregions: the first one in 680-530 cm −1 domain and the second one in 530-400 cm −1 range. These subregions are the specific for Me-O bonds in cubic ferrite such as Fe-O or Ni-O and even Al-O [31][32][33]. Also, Fe-O vibrational bands characteristic for Fe 2 O 3 compound are presented in these subregions [30,31]. In the case of the other sample, the vibrational bands in the region III are not evident, but those from the region II and I are distinctive. ...
... In the case of the other sample, the vibrational bands in the region III are not evident, but those from the region II and I are distinctive. This is a very important aspect, because in this domain are found the vibrational bands of Al 2 O 3 [26,32,33]. It should be pointed out this is a clear indication of the presence of alumina on the particle surface using the thermal treatment. ...
... The presence of vibration bands at 1100-400 cm −1 corresponds to the vibration of O-Al-O bonds in Al2O3 [73][74][75][76] that was formed on the ALA surface during 24h immersion in ASW and probably served as a protective barrier from the corrosive environment. The strong sharp bands that appeared between 1000 and 1200 cm −1 for both examining samples were assigned to γ-Al2O3 [76][77][78] and α-Al2O3 [79,80]. The other intense peak appearing between 500 and 800 cm −1 in both samples was attributed to α-Al2O3 [81][82][83][84][85]. Two small sharp peaks that appeared at 1120 and 1200 cm −1 on the samples treated with the AAE could correspond to functional groups responsible for the adsorption of AAE molecules on the ALA surface during the 24h immersion test, which resulted in the improvement of the structural properties of the protective film formed on the ALA surface in the presence of AAE [86][87][88][89]. ...
Plant extracts are increasingly being examined in the corrosion inhibition of metal and alloys in various environments due to their potent antioxidant properties. The use of Artemisia annua L. aqueous extract (AAE) as an aluminium alloy 5083 (ALA) corrosion inhibitor in artificial seawater (ASW) was investigated using electrochemical tests and spectroscopy tools, while the active biocompounds found in AAE were analyzed using high-performance liquid chromatography (HPLC). Electrochemical results showed that AAE acts as an anodic inhibitor through the physisorption (ΔG ≈ –16.33 kJ mol−1) of extract molecules on the ALA surface, thus reducing the active sites for the dissolution of the alloy in ASW. Fourier-transform infrared spectra confirmed that phenolic acids found in AAE formed the surface layer that protects ALA against the corrosive marine environment, while HPLC analysis confirmed that the main phytoconstituents of AAE were chlorogenic acid and caffeic acid. The inhibition action of phenolic acids and their derivatives found in the AAE was based on the physisorption of caffeic acid on the ALA surface, which improved physicochemical properties of the barrier film and/or conversion of Al3+ to elemental aluminium by phenolic acids as reducens, which slowed down the diffusion rate of Al3+ to or from the ALA surfaces. The protective effect of the surface layer formed in the presence of AAE against ASW was also confirmed by inductively coupled plasma–optical emission spectrometry (ICP-OES) whereby the measured concentration of Al ions after 1h of immersion of ALA in the pure ASW was 15.30 μg L−1 cm−2, while after the addition of 1 g L−1 AAE, the concentration was 3.09 μg L−1 cm−2.
... The other important band of SiO2 is at about 511 cm −1 (bending vibration mode in O-Si-O) and is partially covered by other bands close to this value. The bands centered at 548 and 720 cm −1 are assigned to Al-O bands from Al2O3 to tetrahedral (Al-O4) and octahedral (Al-O6) groups[33][34][35].The bands of Me-O (Al-O and Fe-O) are all at around 500 cm −1 and therefore they are superposed, entirely or partially, giving a large band. The bands identified at 672 and 469 cm −1 are assigned to Fe-O vibrational mode in ferric oxide, Fe2O3. ...
Soft magnetic composites (SMCs) need a stable matrix to apply heat treatments for enhancing their magnetic characteristics. A stable matrix can be offered by alumina, but the densification of the ferromagnetic particles covered by this oxide (by sintering) can be very difficult. This paper proposes a feasible synthesis route for obtaining alumina matrix SMCs. An Fe-Si-Al alloy with nominal composition Fe85Si9Al6 was obtained by mechanical alloying of elemental Fe, Si, and Al powders, and further, the as-milled powders were superficially oxidized by immersion in HCl solution. The oxide layer was composed of iron, silicon, and aluminum oxides, as the Fourier-transform infrared spectroscopy technique revealed. The Fe-Si-Al@oxide powder was densified by the spark plasma sintering technique—SPS. Upon sintering, a continuous matrix of oxide (mainly alumina) was formed by the reaction of the Fe-Si-Al powder coreswith their oxide layer. The main part of the composite compacts after sintering consisted of an Fe3Si-ordered phase dispersed in an oxide matrix. The DC and AC tests of magnetic composite compacts showed that upon increasing the sintering temperature, the density, magnetic induction, and magnetic permeability increased. The initial magnetic permeability was constant in the entire range of testing frequencies and the magnetic losses increased linearly. The stability of the magnetic characteristics in frequency is promising for developing further such types of magnetic composite.
... [21][22][23] Alumina NPs has a wide range of applications in industry and research due to its high melting point and large surface area. [24][25][26] Also, due to its high porosity and high thermal resistance, alumina is used as a catalyst and catalyst base in the chemical industry. [27] Alumina has crystalline phases such as c, g, d, h, and j that each one has its own crystal properties and structure. ...
In this research, ceria (Ce)- doped alumina (Al2O3) nanoparticles (NPs) were fabricated in different level of cerium using coprecipitation method. To characterize the morphology, crystal structure and optical properties, the FESEM, XRD, TEM, UV-DRS and FTIR analyses were performed. The structure analysis of undoped samples showed the multiple phases of γ, δ and θ–alumina, and the structure remained unchanged when cerium atom was doped into the alumina. The morphology and structure studies were carried out to investigate the effect of Ce doping on the polycrystalline alumina nanoparticles. The optical analysis was also done to study of the bandgap energy of the Al2O3 NPs. The novelty of this work is the synthesis of Ce-doped Al2O3 NPs with new precursors and improving their optical properties.
... Figure 2(a) illustrates the as-prepared ZnO NPs prepared and Figure 2(b) and Figure 2(c) reveal the annealed samples at 450 • C and 1000 • C respectively. In fact, the NPs are closed to each other by increasing temperature due to increasing the intermolecular and interatomic forces [54][55][56][57][58][59][60][61][62][63][64] which lead to change the morphology of the NPs [65][66][67][68][69][70][71][72][73]. In addition, samples are less agglomerated because the EG stabilizers are removed from NPs by increasing treatment [74][75][76][77][78][79][80]. ...
In this study, zinc oxide (ZnO) nanoparticles (NPs) were first synthesized using co-precipitation method in the presence of Zn(NO3)2.6H2O precursor and calcined at different temperature of 450 oC and 1000 oC. Samples were then characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The XRD study revealed the hexagonal wurtzite structure for annealed samples. SEM images showed tthat he morphology of the ZnO NPs changed from sphere-like shape to polygon shape by increasing temperature. The exact size of NPs were measured by TEM analysis about 40 nm for as-prepared samples. The EDS analysis demonstrated an increasing level of Zn element from 28.5 wt% to 50.8 wt% for as-synthesized and annealed samples, respectively.
