Synthesis and cation distribution in the new bismuth oxyhalides with the Sillén–Aurivillius intergrowth structures

Charkin, Dmitri O.; Akinfiev, V. S.; Alekseeva, Anastasia M.; Batuk, Maria; Abakumov, Artem M.; Kazakov, Sergey M.

doi:10.1039/c5dt02620b

Cited by 19 publications

(31 citation statements)

References 37 publications

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“…Ba 2 Bi 3 Nb 2 O 11 X (X = Cl, Br, I) compounds were synthesized based on reported literature (see X-ray diffraction (XRD) and scanning electron microscopy−energy dispersive X-ray spectroscopy (SEM-EDX)) in Figures S1 and S2). 19 The oxyiodide absorbs light with a quite long wavelength (Figure 1b), and its band gap is determined to be approximately 2.3 eV. We estimated the conduction band minimum (CBM) from the flat-band potential determined via the Mott−Schottky analysis (Figure S3).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…All oxyhalides were prepared via solid-state reactions. In the case of Ba 2 Bi 3 Nb 2 O 11 X (X = Cl, Br, I), the Silleń-type BaBiO 2 X and Aurivillius-type Bi 3 BaNb 2 O 9 were mixed in 1.05:1 composition and heated in air (X = Cl, Br) in an evacuated silica tube (X = I, and Cl for a certain case) at 800 °C for 20 h. 19 BaBiO 2 X precursors were prepared by calcining a stoichiometric mixture of BaCO 3 (FUJIFILM Wako Pure Chemical Corporation) and BiOX in air (X = Cl, Br) or in an evacuated silica tube (X = I) at 800 °C for 20 h. BiOCl was purchased from FUJIFILM Wako Pure Chemical Corporation, while BiOBr and BiOI were synthesized by a soft liquid deposition method; 43 5 mmol of Bi(NO 3 ) 3 •5H 2 O (FUJIFILM Wako Pure Chemical Corporation) was dispersed in 30 mL of ethanol and mixed with the solution of 5 mmol of KX (X = Br or I) (FUJIFILM Wako Pure Chemical Corporation) dissolved in 10 mL of pure water. After 5 h of stirring at room temperature, the precipitate was collected by centrifugation, washed several times with water and ethanol, and finally dried in air at 60 °C.…”

Section: ■ Methodsmentioning

confidence: 99%

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Layered Perovskite Oxyiodide with Narrow Band Gap and Long Lifetime Carriers for Water Splitting Photocatalysis

et al. 2021

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The development of semiconductors with narrow band gap and high stability is crucial for achieving solar to chemical energy conversion. Compounds with iodine, which has a high polarizability, have attracted attention because of their narrow band gap and long carrier lifetime, as typified by halide perovskite solar cells; however, they have been regarded as unsuitable for harsh photocatalytic water splitting because iodine is prone to self-oxidation. Here, we demonstrate that Ba2Bi3Nb2O11I, a layered Sillén–Aurivillius oxyiodide, not only has access to a wider range of visible light than its chloride and bromide counterparts, but also functions as a stable photocatalyst, efficiently oxidizing water. Density functional theory calculations reveal that the oxygen 2p orbitals in the perovskite block, rather than the fluorite Bi2O2 block as previously pointed out, anomalously push up the valence band maximum, which can be explained by a modified Madelung potential analysis that takes into account the high polarizability of iodine. In addition, the highly polarizable iodide contributes to longer carrier lifetime of Ba2Bi3Nb2O11I, allowing for a significantly higher quantum efficiency than its chloride and bromide counterparts. Visible-light-driven Z-scheme water splitting was achieved for the first time in an iodine-based system using Ba2Bi3Nb2O11I as an oxygen-evolution photocatalyst. The present study provides a novel approach for incorporating polarizable “soft” anions into building blocks of layered materials to manipulate the band structure and improve the carrier dynamics for visible-light responsive functions.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Methodsmentioning

confidence: 99%

Layered Perovskite Oxyiodide with Narrow Band Gap and Long Lifetime Carriers for Water Splitting Photocatalysis

et al. 2021

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“…The Madelung analysis is also a powerful tool when DFT computation is difficult to perform, for example, in a compound involving site deficiency, solid solution, and atomic displacement, which requires a large supercell for DFT and one often encounters convergence problems. As a proof-of-concept, we employed Bi 3 Sr 2 Nb 2 O 11 Cl reported by Charkin and co-workers . This compound belongs to n = 2 member of Sillén–Aurivillius-type perovskite with a general formula of (M 4 O 4 )X(A n –1 B n O 3 n –1 ).…”

Section: Resultsmentioning

confidence: 99%

“…As a proof-of-concept, we employed Bi 3 Sr 2 Nb 2 O 11 Cl reported by Charkin and coworkers. 61 This compound belongs to n = 2 member of…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Valence Band Engineering of Layered Bismuth Oxyhalides toward Stable Visible-Light Water Splitting: Madelung Site Potential Analysis

et al. 2017

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A layered oxychloride BiNbOCl is a visible-light responsive catalyst for water splitting, with its remarkable stability ascribed to the highly dispersive O-2p orbitals in the valence band, the origin of which, however, remains unclear. Here, we systematically investigate four series of layered bismuth oxyhalides, BiOX (X = Cl, Br, I), BiNbOX (X = Cl, Br), BiGdOX (X = Cl, Br), and SrBiOX (X = Cl, Br, I), and found that Madelung site potentials of anions capture essential features of the valence band structures of these materials. The oxide anion in fluorite-like blocks (e.g., [BiO] slab in BiNbOCl) is responsible for the upward shift of the valence band, and the degree of electrostatic destabilization changes depending on building layers and their stacking sequence. This study suggests that the Madelung analysis enables a prediction and design of the valence band structures of bismuth and other layered oxyhalides and is applicable even to a compound where DFT calculation is difficult to perform.

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“…The present study aimed to extend the previous work by increasing the number of perovskite layers ( n ) in the S–A layered perovskite, with the general formula A 4 A n –1 ′ M n O 3 n +5 X having a staking sequence of [A 2 O 2 ]-X-[A 2 O 2 ]-[A n –1 ′ M n O 3 n +1 ]. Here, we focus on the double-layered ( n = 2) system A 4 A′M 2 O 11 Cl (Figure b). − The advantage of the n = 2 system over the previously studied n = 1 system (e.g., Bi 4 MO 8 X) is the compositional versatility of the cations (A, A′ and M) with different valences (e.g., A and A′ = Sr 2+ , Ba 2+ , Pb 2+ , and Bi 3+ ; M = Ti 4+ , Nb 5+ , and Ta 5+ ) and the presence and absence of lone-pair electrons. Given the further layer contribution of Madelung potentials, the n = 2 system could offer an opportunity to systematically tune the band levels and the resultant photocatalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Band Engineering of Double-Layered Sillén–Aurivillius Perovskite Oxychlorides for Visible-Light-Driven Water Splitting

et al. 2019

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Recently, Bi4MO8X (M = Nb and Ta; X = Cl and Br), Sillén–Aurivillius-type single-layered perovskite oxyhalides, have been shown to be promising visible-light-responsive photocatalysts with unique valence band structures. Here, we report on the synthesis, structures, and photocatalytic properties of a series of double-layered analogues A4A′M2O11Cl (A, A′ = Bi, Pb, Ba, and Sr; M = Ta, Nb, and Ti). Fourteen compounds including ten unreported compounds were successfully synthesized via a two-step method with various combinations of preliminary-prepared multimetal oxide and oxyhalide precursors. In a marked contrast to Bi4MO8X with an almost unvaried valence band maximum (VBM) and conduction band minimum (CBM), both VBM and CBM of A4A′M2O11X are variable to some degree, with a change of compositions. In Sr2Bi3M2O11Cl, for example, Sr-site replacement by Pb and Ba resulted in a shift of the valence and conduction band edges toward narrowing the band gaps. Structural characterizations and density functional theory/Madelung calculations revealed that the observed band edges are mainly understood in terms of the interaction between the Bi/Pb 6s2 lone pair and O 2p orbitals and Madelung site potentials of Bi3+ cations. Furthermore, compounds with a higher occupancy of Bi3+ in the fluorite layer showed improved conductivity of photoexcited electrons, leading to better photoelectrochemical performance for water oxidation under visible light.

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Synthesis and cation distribution in the new bismuth oxyhalides with the Sillén–Aurivillius intergrowth structures

Cited by 19 publications

References 37 publications

Layered Perovskite Oxyiodide with Narrow Band Gap and Long Lifetime Carriers for Water Splitting Photocatalysis

Layered Perovskite Oxyiodide with Narrow Band Gap and Long Lifetime Carriers for Water Splitting Photocatalysis

Valence Band Engineering of Layered Bismuth Oxyhalides toward Stable Visible-Light Water Splitting: Madelung Site Potential Analysis

Band Engineering of Double-Layered Sillén–Aurivillius Perovskite Oxychlorides for Visible-Light-Driven Water Splitting

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