Crystal structure and thermodynamic properties of cesium tantalum tungsten oxide

Knyazev, A. V.; Черноруков, Н. Г.; Смирнова, Н. Н.; Kuznetsova, N. Yu.; Markin, A. V.

doi:10.1016/j.tca.2008.01.017

Cited by 20 publications

(17 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This large jump is sharply in contrast with what is observed for the fully d 0 analogue CsTaWO6 (inset to Fig. 1c) which does not exhibit a phase transition [15]. The difference between them clearly indicates that the phase transition in CsW2O6 is driven by an electronic instability due to the presence of 1 electron per two W sites.…”

mentioning

confidence: 57%

Spontaneous Formation of Zigzag Chains at the Metal-Insulator Transition in theβ-PyrochloreCsW2O6

et al. 2013

View full text Add to dashboard Cite

A paramagnetic metal to nonmagnetic insulator transition at T(MIT)=210 K is reported for the β-pyrochlore oxide CsW(2)O(6), accompanied by a first order structural transition that creates <110> oriented chains in the pyrochlore lattice. Comparison of CsW(2)O(6), which has 1 electron per 2 W sites, to the fully d(0) analog CsTaWO(6) shows that the transitions are electronically driven. Corefinement of high resolution synchrotron x-ray and neutron diffraction data shows that the structural distortion that creates the W chains cannot be attributed to simple charge or orbital ordering. Density functional theory calculations suggest that the phase transition is driven by a sharply peaked electronic density of states near the Fermi energy in the cubic β-pyrochlore phase. A further electronic instability is required to create the insulating ground state.

show abstract

mentioning

confidence: 57%

Spontaneous Formation of Zigzag Chains at the Metal-Insulator Transition in theβ-PyrochloreCsW2O6

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The Ta/W cations are located in the 16 c Wyckoff sites (0,0,0) and the O or N atoms are in the 48 f sites ( x , 1/8, 1/8). The location of the Cs cations is in the 8 b sites (3/8, 3/8, 3/8) 28…”

Section: Resultsmentioning

confidence: 99%

N‐Doped CsTaWO₆ as a New Photocatalyst for Hydrogen Production from Water Splitting Under Solar Irradiation

Mukherji¹,

Marschall²,

Tanksale³

et al. 2010

Adv Funct Materials

140

View full text Add to dashboard Cite

Photocatalysts for efficient solar hydrogen production are highly sought after. Here a new type of nitrogen‐doped tantalum tungstenate (CsTaWO6) material, which demonstrates excellent visible light absorption and improved photocatalytic activity, is demonstrated. X‐ray diffraction (XRD) patterns reveal that the defect pyrochlore‐type structure of CsTaWO6 remained intact upon nitrogen doping. UV‐vis spectra indicate that nitrogen doping in the compound results in a red‐shift of the absorption edge from 358 nm to 580 nm, thus offering significantly increased visible light absorption. X‐ray photoelectron spectroscopy (XPS) further indicates that [Ta/W]–N bonds were formed by inducing nitrogen to replace a small amount of oxygen in the material, resulting in a compound of CsTaWO6‐xNx. The explanation of the experimental results is supported by density functional theory calculations. The density of states (DOS) and the projected DOS after substitutional doping of nitrogen in CsTaWO6 indicated that N‐doping reduces the bandgap significantly from 3.8 to 2.3 eV due to N 2p and O 2p orbital mixing. The role of the new N 2p states is also investigated by studying the production of the •OH radicals in the visible light region (>420 nm). In CsTaWO6‐xNx, the N 2p orbitals are the main contributors to the top of the valence band, causing bandgap narrowing while the bottom of conduction band, due to Ta 4d orbitals, remains almost unchanged. Compared with its undoped counterpart, nitrogen‐doped CsTaWO6‐xNx exhibits a nearly 100% increase in solar hydrogen production efficiency.

show abstract

“…[28] The optimised lattice parameter a is 10.367 ,s urprisinglys imilart o that of CsTaWO 6 (10.379 ). The structure parameters of KTaWO 6 and Sn 0.5 TaWO 6 (as idealised model compound representing full K/Snexchange) were fully optimised.…”

Section: Resultsmentioning

confidence: 68%

“…For KTaWO 6 ac ubic unit cell was assumed similar to CsTaWO 6 . [28] The optimised lattice parameter a is 10.367 ,s urprisinglys imilart o that of CsTaWO 6 (10.379 ). In the Sn 0.5 Ta WO 6 unit cell two K atoms were replaced by one Sn, initially located at an 8b Wyckoff site.…”

Section: Resultsmentioning

confidence: 68%

The Influence of Tin(II) Incorporation on Visible Light Absorption and Photocatalytic Activity in Defect‐Pyrochlores

Weiß

Bredow²,

Marschall

2018

Chemistry A European J

View full text Add to dashboard Cite

Thed efect pyrochlore KTaWO 6 has been used to systematicallyi nvestigate the effect of Sn II incorporation conditions on theb and structure and subsequentp hotocatalytic properties.D ifferent tin precursors show varying influ-ence on the resultingb and gap. While the optimum conditions diminish the band gap by up to 1.4 eV,t he increasei n visible light absorption does not correlate with an increase of photocatalytic activity.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

show abstract

Crystal structure and thermodynamic properties of cesium tantalum tungsten oxide

Cited by 20 publications

References 12 publications

Spontaneous Formation of Zigzag Chains at the Metal-Insulator Transition in theβ-PyrochloreCsW2O6

Spontaneous Formation of Zigzag Chains at the Metal-Insulator Transition in theβ-PyrochloreCsW2O6

N‐Doped CsTaWO₆ as a New Photocatalyst for Hydrogen Production from Water Splitting Under Solar Irradiation

The Influence of Tin(II) Incorporation on Visible Light Absorption and Photocatalytic Activity in Defect‐Pyrochlores

Contact Info

Product

Resources

About

Crystal structure and thermodynamic properties of cesium tantalum tungsten oxide

Cited by 20 publications

References 12 publications

Spontaneous Formation of Zigzag Chains at the Metal-Insulator Transition in theβ-PyrochloreCsW2O6

Spontaneous Formation of Zigzag Chains at the Metal-Insulator Transition in theβ-PyrochloreCsW2O6

N‐Doped CsTaWO6 as a New Photocatalyst for Hydrogen Production from Water Splitting Under Solar Irradiation

The Influence of Tin(II) Incorporation on Visible Light Absorption and Photocatalytic Activity in Defect‐Pyrochlores

Contact Info

Product

Resources

About

N‐Doped CsTaWO₆ as a New Photocatalyst for Hydrogen Production from Water Splitting Under Solar Irradiation