The role of surface and electronic structure features of the CsTeMoO6 β-pyrochlore compound during the photooxidation dyes process

Fukina, Diana G.; Koryagin, Andrey V.; Королева, А. В.; Жижин, Е. В.; Сулейманов, Е. В.; Волкова, Н. С.; Kirillova, N. I.

doi:10.1016/j.jssc.2022.122939

Cited by 26 publications

(11 citation statements)

References 42 publications

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“…At the same time, the composition of the compound changes and deviates from the stoichiometric one ‐ the amount of Rb and Nb atoms decreases (Table 2S, Figure 3S). As was shown in previous works, [4d,23] such a redistribution of the initial catalyst composition can be associated with the preferential sorption of the dye molecules and its decomposition products by these atoms, since the phase identity is retained after MB photooxidation. Moreover, Rb atoms are more likely to lead to chemical sorption, while Nb can act as the centers of physical adsorption.…”

Section: Resultssupporting

confidence: 62%

“…We have already presented a scheme for the formation of a partially negative surface of a powder with the β‐pyrochlore structure in previous works using RbTe 1.5 W 0.5 O 6 [4d] and CsTeMoO 6 , [23] as examples. It was emphasized that surface hydrolysis proceeds mainly due to the presence of alkaline elements in the composition.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the cubic crystal structure of the β-pyrochlore compound formed in the system Rb 2 OÀ Nb 2 O 5 À 2MoO 3 by specific synthesis method has been investigated. The possibility of the formation for only one composition with Nb : Mo = 13 : 3 using this method 0.0007 Visible light [23] RbTe 1.5 W 0.5 O 6 0.0004 Visible light [4d] TiO 2 (P25) 0.0106 UV light [32] SnO 2 0.0233 Visible light [33] α-Fe 2 O 3 0.0191 Visible light [33] has been emphasized. The range of differences between the compounds with same Nb : Mo ratio in octahedral framework and different symmetry prepared by solid state synthesis using stoichiometric reagents mixture and modified solid state synthesis has been obtained:…”

Section: Discussionmentioning

confidence: 99%

“…[4d] and CsTeMoO 6 , [23] as examples. It was emphasized that surface hydrolysis proceeds mainly due to the presence of alkaline elements in the composition.…”

Section: Dye Adsorption Process On the Catalyst Surfacementioning

confidence: 99%

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The Photocatalytic Oxidation Ability of Rb_0.9Nb_1.625Mo_0.375O_5.62 with Classic β‐Pyrochlore Structure

et al. 2022

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Previously the non-cubic β-pyrochlore polycrystalline compounds Rb 0.95 Nb x Mo 2-x O 6.475-0.5x (x = 1.31-1.663) have been obtained in the ternary system Rb 2 O-Nb 2 O 5 -2MoO 3 . However, using special synthesis condition leads to the formation of cubic Fd-3m β-pyrochlore Rb 0.9 Nb 1.625 Mo 0.375 O 5.62 with small size particles and surface area of 15 m 2 /g. The Rb 0.9 Nb 1.625 Mo 0.375 O 5.62 powder has been investigated by X-ray powder diffraction analysis and scanning electron microscopy with X-ray microanalysis. The crystal structure refinement has been performed using the Rietveld method. The electronic structure and optical band gap of Rb 0.9 Nb 1.625 Mo 0.375 O 5.62 have been studied in comparison to similar non-cubic composition Rb 0.95 Nb 1.625 Mo 0.375 O 5.66 . The photocatalytic properties of Rb 0.9 Nb 1.625 Mo 0.375 O 5.62 have been investigated on the example for dyes solution oxidation under UV irradiation. The dependence on the photocatalytic properties of dye type and catalyst mass has been studied. It has been observed that the main oxidative species for dye oxidation is hydroxyl radicals. The phase and composition stability of catalyst powder have been confirmed.

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Section: Resultssupporting

confidence: 62%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…[4d] and CsTeMoO 6 , [23] as examples. It was emphasized that surface hydrolysis proceeds mainly due to the presence of alkaline elements in the composition.…”

Section: Dye Adsorption Process On the Catalyst Surfacementioning

confidence: 99%

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The Photocatalytic Oxidation Ability of Rb_0.9Nb_1.625Mo_0.375O_5.62 with Classic β‐Pyrochlore Structure

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“…It is noticed, that β‐pyrochlores with polyvalent elements in an octahedral framework are likely to absorb the visible light [2b,c,11] . Therefore, the system of vanadium and tellurium oxides ((Rb/Cs) 2 O‐V 2 O 5 ‐2TeO 3 ) attracts the attention because both elements are capable of taking more than one oxidation state with octahedral coordination (V 4+ /V 5+ , Te 4+ /Te 6+ ).…”

Section: Introductionmentioning

confidence: 99%

Narrow Band Gap Compounds with β‐Pyrochlore Structure in the A₂O‐V₂O₅‐2TeO₃ (A=Rb, Cs) System

et al. 2023

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Two new isostructural compounds with composition of Rb + V 3 + 0.125 V 5 + 0.625 Te 6 + 1.25 O 6 and Cs + V 3 + 0.125 V 5 + 0.625 Te 6 + 1.25 O 6 have been synthesized by solid-state reaction. The crystal structure has been determined by X-ray diffraction analysis using Rietveld refinement. Both compounds possess β-pyrochlore structuretype with cubic space group Fd-3 m (Z = 8); the unit cell parameters: a = 10.04120(27) Å for RbV 0.75 Te 1.25 O 6 Å and a = 10.09119(23) Å for CsV 0.75 Te 1.25 O 6 . The oxidation states of vanadium and tellurium have been confirmed by X-ray photoelectron spectroscopy. The compounds contain vanadium in mixed valence state (3 + and 5 +). The compounds possess the unusual narrow band gap for oxide compounds -in the infrared (IR) range (~0.6 eV). The schematic electronic structure of the compounds has been estimated using XPS, UPS and electronic conductivity data; however, the shifts of the top of the valence edge and the bottom of the conduction band in the water conditions have been calculated using theoretical approximation. The thermal behavior of obtained compounds has been studied by differential thermal analysis. RbV 0.75 Te 1.25 O 6 and CsV 0.75 Te 1.25 O 6 melts at low temperatures (~500 °C) with decomposition and weight loss. The RbV 0.75 Te 1.25 O 6 powder decomposes to amorphous phase, whereas CsV 0.75 Te 1.25 O 6 transform into new β-pyrochlore compound with another composition.

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Crystal Structure and Photocatalytic Properties of the CsV_0.625Te_1.375O₆ Mixed‐Valence β‐Pyrochlore Compound

et al. 2023

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A new β‐pyrochlore compound with complex composition of Cs(V3+0.0625V5+0.5625Te4+0.34375Te6+1.03125)O6 has been synthesized by a solid‐state reaction and characterized by single‐crystal X‐ray diffraction and thermal analysis. The compound possesses the typical cubic symmetry with space group , however some of the oxygen atoms shift from the special position 48 f to the general crystallographic positions 32e, 96 g and 96 h. This shift is caused by complex B‐site composition with mixed‐valence vanadium and tellurium atoms, especially the presence of the large Te4+ ion. The locations of the valence band and conduction band edges were determined experimentally under vacuum conditions by X‐ray photoelectron spectroscopy, UV‐visible and impedance spectroscopy and evaluated theoretically for water solutions. The photocatalytic ability of the compound under visible light irradiation was determined using the methylene blue decomposition process as an example. The nature of the active radical species and possible dye degradation pathway were suggested according to experimental data.

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The role of surface and electronic structure features of the CsTeMoO6 β-pyrochlore compound during the photooxidation dyes process

Cited by 26 publications

References 42 publications

The Photocatalytic Oxidation Ability of Rb_0.9Nb_1.625Mo_0.375O_5.62 with Classic β‐Pyrochlore Structure

The Photocatalytic Oxidation Ability of Rb_0.9Nb_1.625Mo_0.375O_5.62 with Classic β‐Pyrochlore Structure

Narrow Band Gap Compounds with β‐Pyrochlore Structure in the A₂O‐V₂O₅‐2TeO₃ (A=Rb, Cs) System

Crystal Structure and Photocatalytic Properties of the CsV_0.625Te_1.375O₆ Mixed‐Valence β‐Pyrochlore Compound

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The role of surface and electronic structure features of the CsTeMoO6 β-pyrochlore compound during the photooxidation dyes process

Cited by 26 publications

References 42 publications

The Photocatalytic Oxidation Ability of Rb0.9Nb1.625Mo0.375O5.62 with Classic β‐Pyrochlore Structure

The Photocatalytic Oxidation Ability of Rb0.9Nb1.625Mo0.375O5.62 with Classic β‐Pyrochlore Structure

Narrow Band Gap Compounds with β‐Pyrochlore Structure in the A2O‐V2O5‐2TeO3 (A=Rb, Cs) System

Crystal Structure and Photocatalytic Properties of the CsV0.625Te1.375O6 Mixed‐Valence β‐Pyrochlore Compound

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The Photocatalytic Oxidation Ability of Rb_0.9Nb_1.625Mo_0.375O_5.62 with Classic β‐Pyrochlore Structure

The Photocatalytic Oxidation Ability of Rb_0.9Nb_1.625Mo_0.375O_5.62 with Classic β‐Pyrochlore Structure

Narrow Band Gap Compounds with β‐Pyrochlore Structure in the A₂O‐V₂O₅‐2TeO₃ (A=Rb, Cs) System

Crystal Structure and Photocatalytic Properties of the CsV_0.625Te_1.375O₆ Mixed‐Valence β‐Pyrochlore Compound