Insight into the Effects of Fe Addition on the Local Structure and Electronic Properties of SrTiO<sub>3</sub>

Silva, Luís F.; M’Peko, Jean-Claude; Andrés, Juán; Beltrán, Armando; Bernardi, Maria Inês Basso; Mesquita, Alexandre; Antonelli, Eduardo; Moreira, Mário L.; Mastelaro, Valmor Roberto

doi:10.1021/jp408839q

Cited by 50 publications

(74 citation statements)

References 81 publications

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“…However, modeling the structure of excited electronic states and their properties using the firstprinciples electronic structure methods is still a huge challenge. To overcome this difficulty, numerous efforts by our research group have been made to understand the mechanism of PL emissions in SrTiO3, SrTiO3:Sm, CaWO4, BaZrO3, and BaZr1-xHfxO3 solid solutions based on the characterization of excited electronic states [31][32][33][34][35][36][37] respectively, as the constituent building blocks of this material [49]. There are several reports on the electronic structure calculations performed to study CZO in the ground state [50][51][52][53][54][55].…”

Section: Octahedral Rotations Provoke Changes In the B-o And A-o Bondmentioning

confidence: 99%

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

Oliveira

Gracia

Assis

et al. 2017

Journal of Alloys and Compounds

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CaZrO3 (CZO) powders were synthesized at different temperatures (400, 600, 800, and 1000 °C) and characterized by X-ray diffraction, Raman and ultraviolet-visible spectroscopic methods, along with photoluminescence (PL) emissions. First principle calculations based on the density functional theory (DFT), using a periodic cell models, provide a theoretical framework for understanding the PL spectra based on the localization and characterization of the ground and electronic excited states.Fundamental (singlet, s) and excited (singlet, s*, and triplet, t*) electronic states were localized and characterized using the ideal and distorted structures of CZO. Their corresponding geometries, electronic structures, and vibrational frequencies were obtained. A relationship between the different morphologies and structural behavior has also been established. Polarized structures were identified by the redistribution of the 4dz2, 4dyz, and 4dxy (Zr) orbitals at the conduction band and the 2pz (O) orbital in the valence band for s, s* and t*. Analysis of the vibrational eigenvector modes of these electronic states reveals a relationship between them via asymmetric bending and stretching modes that arise from Zr atom displacements due to polyhedral [ZrO6] distortion. Furthermore, the results provided an insight into the PL emissions of the as-synthesized CaZrO3 and led to the conclusion that the presence of electronically excited states is strongly related to the structural order-disorder effects (polyhedral distortion) at short range for both [ZrO6] and [CaO8] clusters.

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Section: Octahedral Rotations Provoke Changes In the B-o And A-o Bondmentioning

confidence: 99%

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

Oliveira

Gracia

Assis

et al. 2017

Journal of Alloys and Compounds

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“…Several techniques such as activated carbon adsorption, microbial degradation, UV/H 2 O 2 processes, biodegradation and electrolysis have been applied in past to tackle this problem. 8,9 Recently, semiconductor based photocatalytic degradation have attracted much attention as green, highly efficient technology for the removal of antibiotics and other pollutants from water. [10][11][12][13] Among various semiconductors, TiO 2 and ZnO are mostly explored materials for various environmental remediation applications.…”

Section: Introductionmentioning

confidence: 99%

N-doped ZnO–MoS₂ binary heterojunctions: the dual role of 2D MoS₂ in the enhancement of photostability and photocatalytic activity under visible light irradiation for tetracycline degradation

Kumar

Sharma

Bhattacharyya

et al. 2017

Mater. Chem. Front.

134

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In this work, we report the fabrication of binary semiconductor heterojunctions comprising of N-doped ZnO nanorods loaded with two-dimensional MoS 2 nanoflowers in varying amounts, using a facile hydrothermal synthesis method. These semiconductor heterojunctions have been demonstrated as highly efficient photocatalysts with enhanced performance under visible light irradiation for the degradation of a pharmaceutical pollutant, tetracycline. The superior photocatalytic activity of the heterojunctions can be attributed to the synergistic effect of Ndoping of ZnO and loading of MoS 2 leading to higher absorption of visible light, efficient separation of photo generated charge carriers and rapid charge transfer to reaction sites, as per the conduction band potentials of both N-doped ZnO and MoS 2 . In addition, the twodimensional nanoflower morphology of MoS 2 provides more reaction sites for the adsorption of pollutant, due to its large surface area. Furthermore, the transfer of holes from the valence band of N-doped ZnO to the valence band of MoS 2 prevents the photocorrosion of N-doped ZnO resulting in enhanced photostability of the catalyst during the reaction.

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“…Figure shows the XANES spectra of the SrTiO 3 samples, in which, four pre‐edge transitions labeled A, B, C1 and C2 are identified. The physical origin of peak A is a pure quadrupole transition from 1s → 3d ( t 2 g ), whereas B peak is due to the 1s → 4p, including some degree of 1s → 3d ( e g ) transition (.) The C1 and C2 peaks are attributed to a dipole excitation of 1s electrons to t 2 g and e g orbitals of the neighboring TiO 6 octahedra .…”

Section: Resultsmentioning

confidence: 99%

An Understanding of the Photocatalytic Properties and Pollutant Degradation Mechanism of SrTiO₃ Nanoparticles

Silva

Lopes

Mendonça

et al. 2016

Photochem & Photobiology

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Strontium titanate nanoparticles have attracted much attention due to their physical and chemical properties, especially as photocatalysts under ultraviolet irradiation. In this paper, we analyze the effect of heating rate during the crystallization process of SrTiO3 nanoparticles in the degradation of organic pollutants. The relationship between structural, morphological and photocatalytic properties of the SrTiO3 nanoparticles was investigated using different techniques. Transmission electron microscopy and N2 adsorption results show that particle size and surface properties are tuned by the heating rate of the SrTiO3 crystallization process. The SrTiO3 nanoparticles showed good photoactivity for the degradation of methylene blue, rhodamine B and methyl orange dyes, driven by a nonselective process. The SrTiO3 sample with the largest particle size exhibited higher photoactivity per unit area, independent of the molecule to be degraded. The results pointed out that the photodegradation of methylene blue dye catalyzed by SrTiO3 is caused by the action of valence band holes (direct pathway), and the indirect mechanism has a negligible effect, i.e. degradation by O2 (-•) and (•) OH radicals attack.

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Insight into the Effects of Fe Addition on the Local Structure and Electronic Properties of SrTiO₃

Cited by 50 publications

References 81 publications

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

N-doped ZnO–MoS₂ binary heterojunctions: the dual role of 2D MoS₂ in the enhancement of photostability and photocatalytic activity under visible light irradiation for tetracycline degradation

An Understanding of the Photocatalytic Properties and Pollutant Degradation Mechanism of SrTiO₃ Nanoparticles

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Insight into the Effects of Fe Addition on the Local Structure and Electronic Properties of SrTiO3

Cited by 50 publications

References 81 publications

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

N-doped ZnO–MoS2 binary heterojunctions: the dual role of 2D MoS2 in the enhancement of photostability and photocatalytic activity under visible light irradiation for tetracycline degradation

An Understanding of the Photocatalytic Properties and Pollutant Degradation Mechanism of SrTiO3 Nanoparticles

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Product

Resources

About

Insight into the Effects of Fe Addition on the Local Structure and Electronic Properties of SrTiO₃

N-doped ZnO–MoS₂ binary heterojunctions: the dual role of 2D MoS₂ in the enhancement of photostability and photocatalytic activity under visible light irradiation for tetracycline degradation

An Understanding of the Photocatalytic Properties and Pollutant Degradation Mechanism of SrTiO₃ Nanoparticles