The effect of Fe 3+ -doped on structure and optical properties of mesoporous Al 2 O 3 /SiO 2 composite

Ghasemifard, Mahdi; Fathi, Ehsan; Ghamari, Misagh

doi:10.1016/j.mssp.2015.11.001

Cited by 14 publications

(6 citation statements)

References 28 publications

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“…The dielectric functions for the real part ε 1 (ω) and imaginary part ε 2 (ω) were determined as follows 3, probably due to the nonuniformity of the lattice in the composite semiconductor Fe 2 O 3 −carbon, and consequently the less stable structure. 77,78 The details of determining the band gap from the low-loss region of the REELS spectra have been reported in some previous studies. 20,25,26,39,49,50,79,80 more vital interaction between the C 1s from AC with the Fe 3d and O 2p from Fe 2 O 3 makes the top of the valence bands become thin.…”

Section: Resultsmentioning

confidence: 99%

“…The FTIR spectra were used for determining the refractive index ( n ), extinction coefficient ( k ), and dielectric function based on the following equations. First, the pattern was converted from transmittance T (ω) to reflectance R (ω) − The reflectance pattern R (ω) is the input spectra used for determining n (ω) and k (ω) as follows , where the phase change φ(ω) is the reflection of the photon after traveling inside the sample The φ(ω) is made more simple for computation by applying the KK relation , where j is the series of the wavenumber; if j is an odd number, then the i values are 2, 4, 6, 8, ..., j – 1, j + 1 and if the wavenumber j is even, the i values are 1, 3, 5, 7, ..., j – 1, j + 1, ...; Δω = ω i +1 – ω i . The n (ω) and k (ω) values from the analysis of FTIR spectra are shown in Figure c.…”

Section: Resultsmentioning

confidence: 99%

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Enhanced Visible-Light Absorption of Fe₂O₃ Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

et al. 2021

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Visible-light absorption is a critical factor for photocatalyst activity and absorption of electromagnetic (EM) interference application. The band gap of Fe 2 O 3 is 2 eV, which can be increased by doping with a high-band-gap material such as carbon from activated carbon (AC) with a band gap of 4.5 eV for increased visible-light absorption. The porosity decreases from 88 to 81.6%, and the band gap increases from 2.14 to 2.64 eV by increasing the AC from 10 to 25%, respectively. The photocatalytic activity takes 120 min to produce a harmless product for 10− 20% AC, but 25% AC shows 89.5% degradation in only 90 min and the potential to attenuate the EM wave up to 99% due to the RL being below −20 dB. The secondand third-cycle degradation achieved by the composite Fe 2 O 3 −AC having 25% AC is 88.2 and 86.5% in 90 min, respectively. The pore of the surface state of AC contains a trapped charge, and interaction occurs between the charge (electron/hole) and O 2 or H 2 O to produce OH and superoxide (O 2 − ) radicals. These radicals move inside the molecule of the pollutant (methylene blue (MB)) to break up the bond, with the final products being H 2 O and CO 2 . The X-ray photoelectron (XPS) spectra show that oxygen plays a key role in the interatomic bonding with Fe, C, and MB atoms. The best absorption of EM interference is −21.43 dB, with degradation reaching 89.51% in only 90 min for 25% AC due to its higher band gap and anisotropy constant. Fe 2 O 3 −carbon is a multifunctional material for the green environment because of its electromagnetic interference absorption and photodegradation of wastewater.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Enhanced Visible-Light Absorption of Fe₂O₃ Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

et al. 2021

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“…Heat treatment of as-prepared dark and white powder at 850 • C results in crystalline structure formation. [20][21][22] B: Urea metal cation ratio (U:MC = 0.8 and 0.7): The cations of titanium and silicon were added to urea and distilled water as the base solution. The heating process accompanied with bubbles formation due to the removal of volatile species.…”

Section: Methodsmentioning

confidence: 99%

Frequency dependence and fuel effect on optical properties of nano TiO₂-based structures

2016

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TiO 2 -(Ti 0.5 Si 0.5 )O 2 nanopowders (TS-NPs) with average particle size around 90 nm were successfully synthesized by controlled auto-combustion method by using citric acid/nitric acid (AC:NA) and urea/metal cation (U:MC). The structure of powders was studied based on their X-ray diffraction (XRD) patterns. The XRD of TS-NPs shows that rutile and anatase are the main phases of TS-NPs for AC:NA and U:MC, respectively. Particle size and histogram of nanopowders were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Optical properties of TS-NPs were calculated by Fourier transform infrared spectroscopy (FTIR) and Kramers-Kroning (KK) relation. Plasma frequencies of TS-NPs obtained from energy loss functions depend on fuels as a result of changes in crystal structure, particle size distribution, and morphology.

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“…In this study, the highest distance between the two optical phonon vibration mode ((LO-TO)) for ZnO/TiO2 (5 g) at 800 o C may due to some H2O loses in the lattice consequently increase optical bandgap [64,69]. The (LO-TO) was increased with the increasing the TiO2 concentration at the same calcination temperature but not for 700 o C may due to the number of defect (dislocation density) increase consequently the atomic bonding unstable and rearrange to form new atomic cluster in the lattice structure [70,71]. The real part (ε 1 ) and imaginary part (ε 2 ) of dielectric function functions were calculated from the relation between n and k as follows [66]:…”

Section: Optical Propertiesmentioning

confidence: 97%

“…[65,66,72] from the quantitative analysis of electron spectroscopy [66,73]. The (LO-TO) is important parameters to identified stability of the covalent bond and the lattice match in the ZnO/TiO2 composite [70].…”

Section: Optical Propertiesmentioning

confidence: 99%

Green Synthesis ZnO/TiO2 for High Recyclability Rapid Sunlight Photodegradation Textile Dyes Applications

Rusman

Heryanto

et al. 2021

Preprint

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Composite ZnO/TiO2 have been successfully synthesized by green synthesis method with various calcination temperature 500oC, 600oC, 700oC, and 800oC (TiO2 concentrations: 2.5 g and 5 g) for photocatalyst application. In this study, Calopogonium mucunoides leaf extract was used as reducing and stabilizing agent. The synthesized composites were characterized by using Fourier Transform Infra-Red (FTIR), X-Ray Diffraction (XRD), and UV-Visible spectroscopy. The XRD spectra shows the hexagonal phase with wurtzite structure of ZnO and anatase for TiO2. The best degradation performance is 98.26% (only 10 min) for ZnO/TiO2 (5 g) with calcination temperature is 800oC. This is due to the highest distance between two optical phonon mode Δ(LO-TO) and lowest attenuating and propagating constant. The composite ZnO/TiO2 shows high potentials photodegradation of organic dyes with the high stable recyclability up to 5 cycles (> 95%) only for every 15 minutes. High potentials for applicability with the concept environmentally friendly principles and stability for circular chemistry, and efficiency of use the energy and chemicals.

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The effect of Fe 3+ -doped on structure and optical properties of mesoporous Al 2 O 3 /SiO 2 composite

Cited by 14 publications

References 28 publications

Enhanced Visible-Light Absorption of Fe₂O₃ Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Enhanced Visible-Light Absorption of Fe₂O₃ Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Frequency dependence and fuel effect on optical properties of nano TiO₂-based structures

Green Synthesis ZnO/TiO2 for High Recyclability Rapid Sunlight Photodegradation Textile Dyes Applications

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The effect of Fe 3+ -doped on structure and optical properties of mesoporous Al 2 O 3 /SiO 2 composite

Cited by 14 publications

References 28 publications

Enhanced Visible-Light Absorption of Fe2O3 Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Enhanced Visible-Light Absorption of Fe2O3 Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Frequency dependence and fuel effect on optical properties of nano TiO2-based structures

Green Synthesis ZnO/TiO2 for High Recyclability Rapid Sunlight Photodegradation Textile Dyes Applications

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Product

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Enhanced Visible-Light Absorption of Fe₂O₃ Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Enhanced Visible-Light Absorption of Fe₂O₃ Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Frequency dependence and fuel effect on optical properties of nano TiO₂-based structures