Synthesis and Characterization of Anatase‐Structured Titania Hollow Spheres Doped with Erbium (<scp>III</scp>)

Single‐phase multiferroic Ba(Fe0.67Ce0.33)0.01Ti0.99O3 (BFTO:Ce) and Ba(Fe0.67La0.33)0.01Ti0.99O3 (BFTO:La) nanostructures were synthesized by a hydrothermal method (180°C/48 h). Rietveld refinement of X‐ray diffraction could confirm crystalline phase and lattice deformation by Ce, La into BFTO. The Ce and La doping induce nanoaggregation‐type BFTO nanostructural product due to their ionic size effect and chemical behavior with OH− ions. Raman active modes show tetragonal phase and defects due to vacancies in the BFTO lattice. Photoluminescence spectrum involves multiple visible emissions due to defects/vacancies. The observed ferroelectric polarization is enhanced due to shape/size effect of nanoparticles, lattice distortion, and filling of d orbital in the perovskite BaTiO3. The room‐temperature magnetic behavior is described due to antiferromagnetic interactions that strengthen by Ce and La doping. The zero‐field cooling and field cooling magnetic measurement at 500 Oe indicates antiferromagnetic to ferromagnetic transition. Dynamic magnetoelectric coupling was investigated, and maximum longitudinal magnetoelectric coefficient is 62.65 and 49.79 mV/cmOe, respectively, measured for BFTO:Ce and BFTO:La. The magnetocapacitance measurements induce negative values that described in terms of magnetoresistance and magnetic phase transition effects. The influence of oxygen vacancy on multiferroicity is evaluated by valance states of O ions.

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“…. This type of the behavior may exist due to creation of defects or vacancies . These defects are again confirmed by PL emission (Fig.…”

Section: Resultssupporting

confidence: 65%

Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe_0.01Ti_0.99O₃ Nanostructures

Verma

Kotnala

2016

J. Am. Ceram. Soc.

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“…Figure b shows the E g3 mode at 641 cm –1 for TiO 2 shifted to lower wavenumbers (∼640 cm –1 ) for the Er 3+ -modified samples, and this is attributed to the decrease in particle sizes of Er:TiO 2 and Er:TiO 2 /MWCNT consistent with the XRD results . Furthermore, the Er:TiO 2 /MWCNT E g3 mode has a diminished intensity due to Er 3+ ions extant primarily on the surface and do not create sufficient deformities in the TiO 2 lattice by changing the Ti–O bond lengths as well as the presence of MWCNT weakens the intensity of Raman bands. − …”

Section: Resultssupporting

confidence: 59%

Structure–Activity Relationships of Er³⁺ and MWCNT-Modified TiO₂: Enhancing the Textural and Optoelectronic Properties of TiO₂

et al. 2019

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Photoactive erbium-modified titanium dioxide grafted onto multiwalled carbon nanotubes (Er:TiO2/MWCNT) nanopowders were synthesized via a facile sol–gel route. Studies showed that the photocatalysts were monophasic crystalline anatase TiO2, with crystallite sizes ranging from 13.93 nm for neat TiO2 and 5.6 nm for Er:TiO2/MWCNT. The incorporation of Er3+ and MWCNT into TiO2 enhanced the textural properties and formed a mesoporous nanocomposite, where Er:TiO2/MWCNT had the highest surface area (103.14m2/g) and pore volume (0.4464 cm3/g). The composite contained Er2O3 and Ti–O–C structural fragments coincident with Er2O3 on the nanocomposites’ surfaces forming Ti–O–Er and Ti–O–C bonds. Er3+ induced a blueshift in the TiO2 absorption edge. The Er:TiO2/MWCNT had the highest photoactivity for the decolorization of RR120 compared to Er:TiO2 and TiO2 with an apparent rate constant of 28.37 × 10–3 min–1, which was more than 3.5 times greater than that of the pure TiO2 (8.39 × 10–3 min–1) and a maximum color removal efficiency of 99.49% over 180 min of irradiation. The increased photocatalytic efficiency is due to a combination of adsorption of the dye by the composite and the enhanced optoelectronic properties where Er:TiO2/MWCNT exhibited a marked decrease in photoluminescence intensity compared to TiO2, evincing suppression of electron–hole recombination originating from the formation of Er 4f sub-band gap states beneath the TiO2 conduction band and thereby lowering the excitation energy (E g) of TiO2, while the MWCNT acted as a porous coadsorbent and photosensitizer by transferring electrons to the TiO2 CB, thus broadening the spectral photoresponse for a high-potential solar active photocatalyst.

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“…Although there is some controversy, it seems that a mixture of anatase/rutile phases is desirable to get enhanced photoactivity [2,3]. Other methods to improve photoactivity include enlargement of surface area, loading of noble metal clusters [4], doping with appropriate elements [5,6], or using special morphologies such as hollow spheres [7,8]. As a photocatalyst, TiO 2 can be used in the form of powder and thin films [9].…”

Section: Introductionmentioning

confidence: 99%

Dispersion of mixtures of submicrometer and nanometre sized titanias to obtain porous bodies

Vicent

Sánchez

Molina

et al. 2013

Ceramics International

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The stability and rheological behaviour of bimodal titania suspensions was studied.Bimodal mixtures were prepared by mixing nanosized TiO 2 powders with an average primary size of ~20-40 nm and surface area of ~50 m 2 /g and/or a colloidal titania suspension of the same nanopowders dispersed in water with a submicrometer sized titania. The dispersing conditions were studied as a function of pH, type and content of dispersant, and sonication time for a constant solids content of 30 vol.% (62 wt%). The mixtures were slip cast and presintered at low temperatures (800−1000 ºC) in order to obtain porous materials with anatase as the major phase. The pore size distribution, microstructure and phase composition were characterised using MIP, SEM and XRD techniques, respectively.

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Synthesis and Characterization of Anatase‐Structured Titania Hollow Spheres Doped with Erbium (III)

Cited by 19 publications

References 50 publications

Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe_0.01Ti_0.99O₃ Nanostructures

Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe_0.01Ti_0.99O₃ Nanostructures

Structure–Activity Relationships of Er³⁺ and MWCNT-Modified TiO₂: Enhancing the Textural and Optoelectronic Properties of TiO₂

Dispersion of mixtures of submicrometer and nanometre sized titanias to obtain porous bodies

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Synthesis and Characterization of Anatase‐Structured Titania Hollow Spheres Doped with Erbium (III)

Cited by 19 publications

References 50 publications

Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe0.01Ti0.99O3 Nanostructures

Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe0.01Ti0.99O3 Nanostructures

Structure–Activity Relationships of Er3+ and MWCNT-Modified TiO2: Enhancing the Textural and Optoelectronic Properties of TiO2

Dispersion of mixtures of submicrometer and nanometre sized titanias to obtain porous bodies

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Product

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Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe_0.01Ti_0.99O₃ Nanostructures

Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe_0.01Ti_0.99O₃ Nanostructures

Structure–Activity Relationships of Er³⁺ and MWCNT-Modified TiO₂: Enhancing the Textural and Optoelectronic Properties of TiO₂