Dependency of the optical properties of heterogeneous calcium bismuthate–bismuth oxide particles on the order of layers alternation

Shtarev, Dmitry S.; Doronin, Ivan; Blokh, Artem I.; Shtareva, Anna V.

doi:10.1007/s11082-016-0633-8

Cited by 6 publications

(3 citation statements)

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“…The higher photocatalytic activity of the calcium bismuthate over Bi 2 O 3 is also mentioned in other studies wherein the catalytic properties of CBO materials have been studied [53][54][55].…”

Section: Discussionmentioning

confidence: 56%

Preparing a Ca-Bi-O System by the Precipitation Method and Studying Its Intermediate Structural Properties for Applications in Water Treatment

et al. 2023

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This study focuses on the development of a Ca-Bi-O system (CBO) with efficiency in the degradation of Rhodamine B, which is extremely toxic to many organisms and can have long-term negative consequences if not safely removed from the water. The conventional precipitation method was used to create a stable phase of Ca2Bi2O5 with a stoichiometric 1:1 molar ratio of Ca:Bi. Before obtaining the pure phase, the details of the reaction processes were investigated and the various intermediate products were identified using X-ray diffraction followed by Fourier transform infrared, UV-Vis, and Raman spectroscopy. An ab initio calculation evaluated with the HSE06 functional yields a band gap of 3.5 eV, similar to the band gap obtained by diffuse reflectance recorded on Ca2Bi2O5. This newly synthesized compound is addressed to the environmental application by investigating the photocatalytic properties of CBO materials obtained at different calcination temperatures. The investigation of pure Ca2Bi2O5, with characterization techniques and complemented by new first-principles calculations to investigate the photocatalysis provide valuable new insights for this scarcely studied yet potentially interesting compound.

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Section: Discussionmentioning

confidence: 56%

Preparing a Ca-Bi-O System by the Precipitation Method and Studying Its Intermediate Structural Properties for Applications in Water Treatment

et al. 2023

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“…The strontium bismuthates were synthesized and their photocatalytic activity investigated in earlier studies by Shtarev et al . in such reactions as the degradation of phenol and the oxidation of acetaldehyde as part of systematic studies into the photocatalytic properties of bismuth‐containing solids . That said, however, neither their application toward the photocatalytic water splitting process nor the photoreduction of CO 2 was the objective of the present study, although future studies should examine the behavior of these bismuthates in such processes.…”

Section: The Resolutionmentioning

confidence: 99%

Considerations of Trends in Heterogeneous Photocatalysis. Correlations between Conduction and Valence Band Energies with Bandgap Energies of Various Photocatalysts

et al. 2019

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A principal objective of our work was to illustrate the existence of unknown trends in the E CB = f(E bg ) and the E VB = f(E bg ) behavior for certain classes of compounds that also included a set of bismuthate photocatalysts; new trends may easily be hidden within more general trends. Indeed, when the data for the bismuthates are added to data related to novel visible-lightactive (VLA) photocatalysts, the trend remains the same with high significance levels for the E VB = f(E bg ) linear correlation. Using well-known data for complex (ternary) oxides, the search for new trends in the behavior of the E CB = f(E bg ) and the E VB = f (E bg ) dependences opens up the potential to develop new VLA photocatalysts. The feasibility of new desired trends can be estimated a priori using a modern theoretical analysis of the electronic structure of targeted semiconductors; note that new trends in the behavior of E CB and E VB versus bandgap energy E BG have been established for CaBi 6 O 10 , Sr 2 Bi 2 O 5 , Sr 3 Bi 2 O 6 , and Sr 6 Bi 2 O 11 . We also re-examined earlier symmetric-type plots for a set consisting of a large number of simple (binary) and a set consisting of complex (ternary) metal oxides and find some significant differences. We herein report a novel trend in the empirical dependence of the energy positions of conduction bands (E CB ) and valence bands (E VB ) on bandgap energies (E bg ) for alkali earth metal bismuthate semiconductor photocatalysts for which we show that their dependences follow the linear functions E CB = A + BE bg and E VB = a + bE bg . However, contrary to earlier symmetric relationships of some metal oxides for which A = a = 1.23 eV, B = À 0.5, and b = 0.5 toward water splitting, the relationships found for the bismuthates show them to be asymmetric with negative slopes (B < 0, b < 0) and a converging point A = a = 4.5 eV. Also re-examined are the earlier symmetric-type plots for a set consisting of a large number of simple (binary) and a set consisting of complex (ternary) metal oxides and find some significant differences. Variations in both slopes (B < 0 and b > 0) and the converging point (1.4 eV < A = a < 2.0 eV) is demonstrated. The photoactivity of some strontium bismuthates is predicted toward the photoelectrochemical reduction of CO 2 from the novel trend in behavior of their bands' energy positions relative to their bandgap energies.

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“…One factor that enables such behavior is a recently established trend in the empirical dependence of valence and conduction band energy positions on the materials’ bandgaps . In contrast to calcium, − strontium, − and barium − bismuthates, which have been widely studied, little is known about magnesium bismuthates . The primary goal of our work is to elaborate a preparation route of monophase Bi 26– x Mg x O 40 samples that is followed by the study of their optical and photocatalytic properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of Composition on the Optical and Photocatalytic Properties of Visible Light Responsive Materials Bi_26–xMg_xO₄₀

et al. 2020

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We report the synthesis and the crystal and electronic structure as well as the optical and photocatalytic properties of novel photoactive materials of the general formula Bi 26−x Mg x O 40 . Two compounds with compositions of Bi 24.28(3) Mg 1.72(3) O 40 and Bi 24.05(3) Mg 1.95(3) O 40 are synthesized using the pyrolytic method. According to X-ray diffraction analysis, the materials are monocrystalline species. Their electronic bandgaps determined from Tauc plots are 2.41 eV [Bi 24.28(3) Mg 1.72(3) O 40 ] and 2.69 eV [Bi 24.05(3) Mg 1.95(3) O 40 ]. Keeping in mind that optical bandgaps are typically larger than their electronic counterparts, we find that the bismuthate bandgaps match well that of Bi 24 Mg 2 O 40 (2.26 eV) predicted by density functional theory. Apparently, the synthesized bismuthates are indirect bandgap semiconductors just like Bi 24 Mg 2 O 40 . Both materials demonstrate nearly identical luminescence spectra. Their luminescence emission at 620 nm is most efficiently excited by 365 nm light. The materials' photocatalytic properties are evaluated in a visible light-induced photocatalytic phenol degradation reaction. Rather low activity of both compounds is detected. However, Bi 24.05(3) Mg 1.95(3) O 40 is ∼2 times more photocatalytically active than Bi 24.28(3) Mg 1.72(3) O 40 , which is associated with a higher Bi 5+ content in the former.

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Dependency of the optical properties of heterogeneous calcium bismuthate–bismuth oxide particles on the order of layers alternation

Cited by 6 publications

References 5 publications

Preparing a Ca-Bi-O System by the Precipitation Method and Studying Its Intermediate Structural Properties for Applications in Water Treatment

Preparing a Ca-Bi-O System by the Precipitation Method and Studying Its Intermediate Structural Properties for Applications in Water Treatment

Considerations of Trends in Heterogeneous Photocatalysis. Correlations between Conduction and Valence Band Energies with Bandgap Energies of Various Photocatalysts

Effect of Composition on the Optical and Photocatalytic Properties of Visible Light Responsive Materials Bi_26–xMg_xO₄₀

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Dependency of the optical properties of heterogeneous calcium bismuthate–bismuth oxide particles on the order of layers alternation

Cited by 6 publications

References 5 publications

Preparing a Ca-Bi-O System by the Precipitation Method and Studying Its Intermediate Structural Properties for Applications in Water Treatment

Preparing a Ca-Bi-O System by the Precipitation Method and Studying Its Intermediate Structural Properties for Applications in Water Treatment

Considerations of Trends in Heterogeneous Photocatalysis. Correlations between Conduction and Valence Band Energies with Bandgap Energies of Various Photocatalysts

Effect of Composition on the Optical and Photocatalytic Properties of Visible Light Responsive Materials Bi26–xMgxO40

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Effect of Composition on the Optical and Photocatalytic Properties of Visible Light Responsive Materials Bi_26–xMg_xO₄₀