Unveiling point defects in titania mesocrystals: a combined EPR and XPS study

Константинова, Е. А.; Миннеханов, А. А.; Бельтюков, А. Н.; Ivanov, V. K.; Sutherland, Andrew J.; Boytsova, O. V.

doi:10.1039/c8nj03196g

Cited by 13 publications

(7 citation statements)

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“…Mesocrystals are a quite new and fascinating nanostructure, which is composed of aligned nanocrystals [204][205][206]. The mesocrystal structure might be synthesized from the primary nanocrystals by self-assembly-based crystallization (non-classical crystallization, as shown in Figure 16 [204]) and a template method (e.g., polyethylene template [207]). For example, Wu et al confirmed that rutile titania mesocrystals have been formed by the rapid crystallization by particle attachment (CPA), i.e., non-classical crystallization [208].…”

Section: Titania Mesocrystalsmentioning

confidence: 99%

Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

et al. 2019

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Titania photocatalysts have been intensively examined for both mechanism study and possible commercial applications for more than 30 years. Although various reports have already been published on titania, including comprehensive review papers, the morphology-governed activity, especially for novel nanostructures, has not been reviewed recently. Therefore, this paper presents novel, attractive, and prospective titania photocatalysts, including zero-, one-, two-, and three-dimensional titania structures. The 1D, 2D, and 3D titania structures have been mainly designed for possible applications, e.g., (i) continuous use without the necessity of particulate titania separation, (ii) efficient light harvesting (e.g., inverse opals), (iii) enhanced activity (fast charge carriers' separation, e.g., 1D nanoplates and 2D nanotubes). It should be pointed out that these structures might be also useful for mechanism investigation, e.g., (i) 3D titania aerogels with gold either incorporated inside the 3D network or supported in the porosity, and (ii) titania mesocrystals with gold deposited either on basal or lateral surfaces, for the clarification of plasmonic photocatalysis. Moreover, 0D nanostructures of special composition and morphology, e.g., magnetic(core)-titania(shell), mixed-phase titania (anatase/rutile/brookite), and faceted titania NPs have been presented, due to their exceptional properties, including easy separation in the magnetic field, high activity, and mechanism clarification, respectively. Although anatase has been usually thought as the most active phase of titania, the co-existence of other crystalline phases accelerates the photocatalytic activity significantly, and thus mixed-phase titania (e.g., famous P25) exhibits high photocatalytic activity for both oxidation and reduction reactions. It is believed that this review might be useful for the architecture design of novel nanomaterials for broad and diverse applications, including environmental purification, energy conversion, synthesis and preparation of "intelligent" surfaces with self-cleaning, antifogging, and antiseptic properties.

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Section: Titania Mesocrystalsmentioning

confidence: 99%

Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

et al. 2019

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“…51,53 However, the Ti was found in 4+ oxidation state in Ce 0.5 Ti 0.5 -UiO-66-NH 2 as observed from the Ti2p 3/2 , 2p 1/2 , and the satellite peak positions at binding energies of 458.31, 463.99, and 470.10 eV, respectively, in Figure 3c. 54,55 After calcination, the core-level spectra of Ce3d of CeO 2 and the phase-pure Ce 0.75 Ti 0.25 O 2 in Figure 3d,e exhibited as many as 10 peaks, wherein five doublets correspond to 3d 5/2 (assigned as x) and 3d 3/2 (assigned as y). The peaks labeled as x − y (886.3 and 902.4 eV), x″ − y″ (892.6 and 910.8 eV), and x‴ − y‴ (898.3 and 916.8 eV) are assigned to primary photoionization of Ce 4+ arising from Ce 3d 9 4f 2 O2p 4 , Ce 3d 9 4f 1 O2p 5 , and Ce 3d 9 4f 0 O2p 6 final states, respectively.…”

Section: Characterization Resultsmentioning

confidence: 99%

Photo- and Electrocatalytic Reduction of CO₂ over Metal–Organic Frameworks and Their Derived Oxides: A Correlation of the Reaction Mechanism with the Electronic Structure

et al. 2022

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A Ce/Ti-based bimetallic 2-aminoterephthalate metal–organic framework (MOF) was synthesized and evaluated for photocatalytic reduction of CO2 in comparison with an isoreticular pristine monometallic Ce-terephthalate MOF. Owing to highly selective CO2 adsorption capability, optimized band gaps, higher flux of photogenerated electron–hole pairs, and a lower rate of recombination, this material exhibited better photocatalytic reduction of CO2 and lower hydrogen evolution compared to Ce-terephthalate. Thorough probing of the surface and electronic structure inferred that the reducibility of Ce4+ to Ce3+ was due to the introduction of an amine functional group into the linker, and low-lying Ti(3d) orbitals in Ce/Ti-2-aminoterephthalate facilitated the photoreduction reaction. Both the MOFs were calcined to their respective oxides of Ce1–x Ti x O2 and CeO2, and the electrocatalytic reduction of CO2 was performed over the oxidic materials. In contrast to the photocatalytic reaction mechanism, the lattice substitution of Ti in the CeO2 fluorite cubic structure showed a better hydrogen evolution reaction and consequently, poorer electroreduction of CO2 compared to pristine CeO2. Density functional theory calculations of the competitive hydrogen evolution reaction on the MOF and the oxide surfaces corroborated the experimental findings.

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“…Meanwhile, NiS occupying the S defect results in the shift of binding energy. 42,43 The binding energy of Cd in 17%-NiS/ Cd 0.5 Zn 0.5 S was changed, indicating the formation of the heterojunction between NiS and Cd 0.5 Zn 0.5 S. In the Zn 2p spectrum (Fig. 3c), two peaks at 1021.2 eV (Zn 2p 3/2 ) and 1044.3 eV (Zn 2p 1/2 ) are assigned to the Zn (+2) chemical state of Cd 0.5 Zn 0.5 S. 44 The Ni 2p spectra of NiS and 17%-NiS/Cd 0.5 Zn 0.5 S are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

α-NiS–β-NiS growth on Cd_0.5Zn_0.5S formed Schottky heterojunctions for enhanced photocatalytic hydrogen production

Shen

Jin³

et al. 2022

New J. Chem.

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Unveiling point defects in titania mesocrystals: a combined EPR and XPS study

Abstract: Titania mesocrystals, prepared using a polyethylene template, were studied by a combination of electron microscopy, XPS and EPR techniques.

Cited by 13 publications

References 35 publications

Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

Photo- and Electrocatalytic Reduction of CO₂ over Metal–Organic Frameworks and Their Derived Oxides: A Correlation of the Reaction Mechanism with the Electronic Structure

α-NiS–β-NiS growth on Cd_0.5Zn_0.5S formed Schottky heterojunctions for enhanced photocatalytic hydrogen production

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Unveiling point defects in titania mesocrystals: a combined EPR and XPS study

Abstract: Titania mesocrystals, prepared using a polyethylene template, were studied by a combination of electron microscopy, XPS and EPR techniques.

Cited by 13 publications

References 35 publications

Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

Photo- and Electrocatalytic Reduction of CO2 over Metal–Organic Frameworks and Their Derived Oxides: A Correlation of the Reaction Mechanism with the Electronic Structure

α-NiS–β-NiS growth on Cd0.5Zn0.5S formed Schottky heterojunctions for enhanced photocatalytic hydrogen production

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Product

Resources

About

Photo- and Electrocatalytic Reduction of CO₂ over Metal–Organic Frameworks and Their Derived Oxides: A Correlation of the Reaction Mechanism with the Electronic Structure

α-NiS–β-NiS growth on Cd_0.5Zn_0.5S formed Schottky heterojunctions for enhanced photocatalytic hydrogen production