DFT calculations on structural and electronic properties of Bi2MO6 (M = Cr, Mo, W)

Lai, Kangrong; Wei, Wei; Dai, Ying; Zhang, Rui‐Qin; Huang, Baibiao

doi:10.1007/s12598-011-0262-0

Cited by 61 publications

(22 citation statements)

References 48 publications

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“…The BiVO 4 , Bi 2 MoO 6 , and Bi 2 WO 6 photocatalysts possess a direct band gap. According to density functional theory (DFT) calculations, the O 2p and Bi 6s levels form the valence band while M nd (V 3d, Mo 4d, W 5d) levels form the conduction band, which demonstrates that the charge in O 2p + Bi 6s hybrid orbitals would transfer to the empty M nd orbitals during photoexcitation 104‐108 . In addition, the Bi 6s 2 lone pair with spatial activity reduced the oxidation band gap and improved the hole conductivity, because the Bi 6s orbital was located in the O 2p orbital and dispersed the top of the valence band to a large extent 106 .…”

Section: Structural Of Bismuth‐based Photocatalytic Materialsmentioning

confidence: 99%

Bi‐based photocatalysts for light‐driven environmental and energy applications: Structural tuning, reaction mechanisms, and challenges

Chen

Liu

Cui

et al. 2020

EcoMat

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Environmental pollution and energy crisis have become major challenges to sustainable development of human society. Solar-driven photocatalytic technology is regarded as an extremely attractive solution to environmental remediation and energy conversion. Unfortunately, practical applications of traditional photocatalysts are restricted owing to the poor absorption of visible light, insufficient charge separation and undefined reaction mechanism. Therefore, developing novel visible light photocatalysts and exploring their modification strategies are significant in the area of photocatalysis. Bi-based photocatalysts have attracted wide attention due to unique geometric structures, tunable electronic structure and decent photocatalytic activity under visible light. At present, Bi-based photocatalysts can be mainly classified as bismuth metal, binary oxides, bismuth oxyhalogen, multicomponent oxides and binary sulfides, and so forth. Although they can be used as independent photocatalysts for environmental purification and energy development, their efficiency is not ideal. Therefore, many efforts have been made to enhance their photocatalytic performance in the past few decades. Significant progresses in determining the fundamental properties of photocatalysts, improving the photocatalytic performance and understanding the photocatalytic mechanism in important reactions have been made benefited from the various new developed concepts and approaches. This review introduces the structural properties of Bi-based photocatalysts in detail and summarizes the design and modification strategy for improving the photocatalytic performance, including metal/ Peng Chen and Hongjing Liu contributed equally to this work.

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Section: Structural Of Bismuth‐based Photocatalytic Materialsmentioning

confidence: 99%

Bi‐based photocatalysts for light‐driven environmental and energy applications: Structural tuning, reaction mechanisms, and challenges

Chen

Liu

Cui

et al. 2020

EcoMat

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“…The (Bi 2 O 2 ) 2+ layers are sandwiched between (WO 6 ) octahedral layers. From an electronic point of view, BWO presents hybridized valence bands occupied by the Bi 6 s and O 2p states that shift the absorption band edge towards the visible region, with the concomitant appearance of a narrow absorption region [38][39][40][41][42] . Therefore, an interesting feature of the BWO orthorhombic structure is the innate presence of both crystal distortion and Bi 6 s lone pair electrons, which are associated with structural and electronic order/disorder effects, respectively, that are the driving force behind and responsible for the properties and functions of BWO.The chemical and physical properties of BWO-based materials are closely related to their structures, morphologies and photoluminescence emissions, which are an outcome of the synthetic pathway.…”

mentioning

confidence: 99%

Femtosecond-laser-irradiation-induced structural organization and crystallinity of Bi2WO6

Pinatti

Gouveia

Doñate‐Buendía

et al. 2020

Sci Rep

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controlling the structural organization and crystallinity of functional oxides is key to enhancing their performance in technological applications. in this work, we report a strong enhancement of the structural organization and crystallinity of Bi 2 Wo 6 samples synthetized by a microwave-assisted hydrothermal method after exposing them to femtosecond laser irradiation. X-ray diffraction, UVvis and Raman spectroscopies, photoluminescence emissions, energy dispersive spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy were employed to characterize the as-synthetized samples. To complement and rationalize the experimental results, firstprinciples calculations were employed to study the effects of femtosecond laser irradiation. Structural and electronic effects induced by femtosecond laser irradiation enhance the long-range crystallinity while decreasing the free carrier density, as it takes place in the amorphous and liquid states. these effects can be considered a clear cut case of surface-enhanced Raman scattering.Bismuth tungstate, Bi 2 WO 6 (BWO), is an important n-type semiconductor with a narrowband gap energy (E gap ) of 2.8 eV that allows efficient absorption of visible light (λ > 400 nm) and has been widely studied due to its wide range of properties, such as ferroelectricity, piezoelectricity, pyroelectricity, nonlinear dielectric susceptibility, and photoluminescent emissions 1,2 . The multifunctionality of this material has been demonstrated on its photocatalytic activity 3-22 , photocatalytic degradation of drugs 23 , dyes 24-26 alcohols 27 , and phenol 28 , environmental purification, energy conversion 29 , and production of sustainable and combustible compounds 3 . Recently, some works attested this material to be efficient in water splitting for hydrogen generation 30-32 , for shielding against low-energy gamma rays 33 and for CT/IR imaging and photothermal/photodynamic therapy of tumours 34,35 .BWO has an orthorhombic structure and belongs to the Aurivillius family. It is formed by alternating (Bi 2 O 2 ) n 2n+ and perovskite (WO 4 ) n 2n layers 36 , which are composed of (WO 6 ) octahedral layers and (Bi-O-Bi) layers. Their crystal structure can also be described by alternating [Bi 2 O 2 ] 2+ slabs and [WO 4 ] 2− slabs, with oxygen atoms shared between the slabs to create chemical bonds. An important characteristic of this structure is that local environments of both W and Bi cations are highly distorted 37 . The off-centre octahedral distortions are a general feature of the structural chemistry of d 0 metal cations. Each W cation is coordinated with six O atoms to form [WO 6 ] octahedral clusters that are connected to each other by corner-sharing O atoms. The (Bi 2 O 2 ) 2+ layers are sandwiched between (WO 6 ) octahedral layers. From an electronic point of view, BWO presents hybridized valence bands occupied by the Bi 6 s and O 2p states that shift the absorption band edge towards the visible region, with the concomitant appearance of a narrow absorpt...

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“…A similar result was also reported. [39] Although calculated bandgap value could underdetermine the real value, it is still reliable and reasonable to qualitatively analyze the characteristics of the band structure.…”

Section: Optical Propertiesmentioning

confidence: 99%

Acetic Acid Assisted to Prepare Bi2MoO6 with Visible-Light-Induced Activity

Meng¹,

Zhang²

2017

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Photocatalysis has been extensively studied and developed. To overcome the visible-light irresponsive hindrance, developing novel materials has become a significant promise. Bismuth-based semiconductors were promising candidates with suitable band gaps, and various bismuth-based semiconductors can be prepared via facile methods. Herein, we report a modified hydrothermal method assisted by adding acetic acid in the precursor to prepare Bi2MoO6 with enhanced photocatalytic activity in the degradation of RhB under visible light irradiation. This work provides a new approach to improve photocatalytic activity via adding chemicals in the precursors during the preparation.

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DFT calculations on structural and electronic properties of Bi2MO6 (M = Cr, Mo, W)

Cited by 61 publications

References 48 publications

Bi‐based photocatalysts for light‐driven environmental and energy applications: Structural tuning, reaction mechanisms, and challenges

Bi‐based photocatalysts for light‐driven environmental and energy applications: Structural tuning, reaction mechanisms, and challenges

Femtosecond-laser-irradiation-induced structural organization and crystallinity of Bi2WO6

Acetic Acid Assisted to Prepare Bi2MoO6 with Visible-Light-Induced Activity

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