Oxide Halides Research Articles

Hydrophilicity and Pore Structure Enhancement in Polyurethane/Silk Protein-Bismuth Halide Oxide Composite Films for Photocatalytic Degradation of Dye.

Polyurethane/silk protein-bismuth halide oxide composite films were fabricated using a blending-wet phase transformationin situsynthesis method. The crystal structure, micromorphology, and optical properties were conducted using XRD, SEM, and UV-Vis DRS characterize techniques. The results indicated that loaded silk protein enhanced the hydrophilicity and pore structure of the polyurethane composite films. The active species BiOX were observed to grow as nanosheets with high dispersion on the internal skeleton and silk protein surface of the polyurethane-silk protein film. The photocatalytic efficiency of BiOX/PU-SF composite films was assessed through the degradation of Rhodamine B under visible light irradiation. Among the tested films, the BiOBr/PU-SF composite exhibited the highest removal rate of RhB at 98.9%, surpassing the removal rates of 93.7% for the BiOCl/PU-SF composite and 85.6% for the BiOI/PU-SF composite. Furthermore, an active species capture test indicated that superoxide radical (•O2-) and hole (h+) species played a predominant role in the photodegradation process.

Construction of functionalized In-based metal organic framework/BiOCl1−xIx Z-scheme heterojunction for efficient photocatalytic degradation of tetracycline: Performance and mechanism

The environmental implications of antibiotics have drawn widespread attention. Numerous monomer-based bismuth oxide halide catalysts have been extensively studied to remove tetracycline (TC) from aquatic environments. Integrating bismuth oxide halide composites with In-based metal organic framework (NH2-MIL-68(In)) might potentially serve as a novel strategy. By meticulously adjusting Cl and I within the composite bismuth halide oxide (B-x), a suite of purpose built heterojunctions (NMB-x) were synthesized, which were engineered to facilitate the efficient photodegradation of TC in simulated and actual aquatic environments. The incorporation of Z-scheme heterojunctions yielded a significant enhancement in photocatalytic responsiveness and charge carrier separation. Notably, NMB-0.3 demonstrated remarkable TC removal efficiency of 88.52 ± 3.05%, which is 3.74 times of B-0.3 within 90 min. The apparent quantum yield was also increased from 8.97% (B-0.3) to 19.68% (NMB-0.3). The removal of TC from natural water bodies was also assessed. Moreover, the photocatalyst concentration, assessed using response surface method, was found to show influential factors on TC removal. In addition, density functional theory (DFT) simulations were employed to identify vulnerable sites within TC. Intermediates and pathways in the photodegradation of TC have also been inferred. Furthermore, a comprehensive environmental toxicity assessment of representative intermediates demonstrated that these intermediates exhibited significantly reduced environmental toxicity compared to TC. This study provides a new approach to the design strategy of efficient and environmentally friendly MOF-based photocatalysts.

Fabrication of porous and defect-rich BiOI/MWCNTs photocatalyst by Ar plasma-etching for emerging pollutants degradation

Carbon material modification and defect engineering are indispensable for bolstering the photocatalytic effectiveness of bismuth halide oxide (BiOX). In this study, a novel porous and defect-rich Ar-CB-2 photocatalyst was synthesized for emerging pollutants degradation. Leveraging the interfacial coupling effect of multi-walled carbon nanotubes (MWCNTs), we expanded the absorption spectrum of BiOI nanosheets and significantly suppressed the recombination of charge carriers. Introducing defects via Argon (Ar) plasma-etching further bolstered the adsorption efficacy and electron transfer properties of photocatalyst. In comparison to the pristine BiOI and CB-2, the Ar-CB-2 photocatalyst demonstrated superior photodegradation efficiency, with the first-order reaction rates for the photodegradation of tetracycline (TC) and bisphenol A (BPA) increasing by 2.83 and 4.53 times, respectively. Further probe experiments revealed that the steady-state concentrations of ·O2− and 1O2 in the Ar-CB-2/light system were enhanced by a factor of 1.67 and 1.28 compared to CB-2/light system. This result confirmed that the porous and defect-rich structure of Ar-CB-2 inhibited electron-hole recombination and boosted photocatalyst-oxygen interaction, swiftly transforming O2 into active oxygen species, thus accelerating their production. Furthermore, the possible degradation pathways for TC and BPA in the Ar-CB-2/light system were predicted. Overall, these findings offered a groundbreaking approach to the development of highly effective photocatalysts, capable of swiftly breaking down emerging pollutants.

Photocatalytic activity evaluation of polyvinylpyrrolidone K30 assisted synthesis of 1D oxygen-vacancy-rich Bi5O7BrxI1-x nanorod solid solution

The unique layered structure of bismuth halide oxide has led to an extensive application in the degradation of refractory antibiotics from water environments. With the aid of regulating the energy band structure of photocatalytic materials and equilibrating the response towards visible light and redox ability, a novel oxygen-vacancy-rich Bi5O7BrxI1−x nanorod solid solution was synthesized by polyvinylpyrrolidone K30 assisted solvothermal method, and its photocatalytic behavior was investigated for the degradation of antibiotic levofloxacin under visible light. The degradation rate of the optimal Bi5O7Br0.5I0.5 to levofloxacin can reach 82.7% within 30 min, which is 9.22 and 4.74 times higher than those of the monomers Bi5O7Br and Bi5O7I. The catalyst of Bi5O7Br0.5I0.5 shows 99.88% antibacterial activity against Escherichia coli. The efficient photocatalytic ability of the Bi5O7Br0.5I0.5 is resulted from the alteration of energy band structure and suppression of charge recombination due to benign changes in the electronic and crystal structures. Furthermore, both various characterizations and Density Functional Theory calculations reveal that a multitude of oxygen vacancies exist in the Bi5O7Br0.5I0.5. The photocatalytic degradation pathways were explored and the toxicity of the intermediates was also appraised. The present work provides a mild and feasible construction of solid solutions and introduction of oxygen vacancies to eliminate environmentally refractory organic pollutants with photocatalytic technology.

Uniform incorporation of two-dimensional BiOBr into perovskite crystals and films to enhance photoluminescence

The all-inorganic perovskite nanocrystals are promising luminescent materials for optoelectronic devices. However, it is still a challenge to prepare perovskite nanocrystals with high luminescence. Herein, a synthesis method was developed for the uniform incorporation of ultra-thin BiOBr nanosheets into perovskite crystals at both body-embedding and surface-passivating positions. The micron-scale green-emitting phosphors composed of Cs4PbBr6 nanocrystals and BiOBr nanosheets are prepared. The crystal structure of Cs4PbBr6 nanocrystals can remain almost unchanged although prepared from different PbBr2 concentrations. The luminescence mechanism of Cs4PbBr6 is discussed. The Cs4PbBr6@BiOBr submicron phosphors can be dispersed in DMSO solvent without disintegration and dissolution, which are used as seeds of the CsPbBr3 film growth. The CsPbBr3 films with Cs4PbBr6@BiOBr doped exhibit pure optical characteristics of CsPbBr3, indicating that Cs4PbBr6 is converted to CsPbBr3 during the film preparation process. Furthermore, these Cs4PbBr6@BiOBr phosphors are mixed with CaAlSiN3: Eu red-emitting commercial phosphors to make white LEDs (WLEDs). Overall, this study provides a revealing insight into a kind of composite material constructed with halide perovskite and bismuth halide oxide.

Hybrid Lead‐Free Metal Antimony Oxide Chlorides with Highly Efficient Blue Light Emissions

AbstractHerein, we report two hybrid zero‐dimensional (0D) lead‐free metal oxide halides of [PPip]Sb2Cl6O (1) ([PPip]=1‐(2‐Pyridyl)piperazine) and [PmPip]Sb2Cl6O (2) ([PmPip]=1‐(2‐Pyrimidyl)piperazine). Compounds 1 and 2 are able to exhibit narrow blue light emissions excited by UV light with photo‐luminescence quantum yields (PLQYs) of 25.49 % and 24.71 %, respectively. Through systematical characterizations, these blue light emissions can be attributed to the radiative transition in conjugated organic cations. Benefiting from the highly efficient intrinsic blue emissions, compound 2 can be used as blue fluorophor to fabricate liquid crystal display. This work provides a new to assembly blue emitter through by virtue of the optical active organic cations in hybrid materials.

Theoretical investigations of structural, electronic, optical and thermoelectric properties of oxide halide perovskite ACoO3 (A=Nd, Pr or La)

Perovskite oxides have emerged as promising alternatives for photovoltaic devices due to their astonishing optoelectronic properties. Nevertheless, a density functional theory study was performed on the electronic, optical, and thermoelectric properties of ACoO3 (A = Nd, Pr, and La) by TB-mBJ potentials. Based on the optimized structures, the observed results show that studied compounds display p-type semiconductor behavior with a bandgap of 1.95 eV, 1.08 eV, and 1.57 eV respectively. Hence, spherical charge density contours illustrate the ionic character of Nd/Pr/La/Co and O. The optical spectra are reported and discussed, the maximum absorption intensity for the LaCoO3 is ∼20 × 104 cm around 400 nm. Furthermore, the figure of merit, the electrical and thermal conductivity of each compound are investigated by applying Boltzmann transport theory, the high mobility of carriers enhances the Seebeck coefficient and electrical conductivity of ACoO3 (A = Nd, Pr, and La) materials. Our finding results make these materials favorable candidates for photovoltaic applications.

Perovskite Oxide-Halide Solid Solutions: A Platform for Electrocatalysts.

The successful integration or hybridization of perovskite oxides with their halide cousins would enable the formation of both multi-anionic and multi-cationic solid solutions with unique metal-ion sites and synergistic properties that could potentially surpass the performance of classic perovskites. However, such solid solutions had not been produced previously owing to their distinct formation energies and different synthesis conditions. Solid solutions combining perovskite oxides with fluorides were produced in this study by mechanochemical synthesis. The obtained perovskite oxide-halide solid solutions had highly mixed elements and valences, uniform element distributions, and single-phase crystalline structures. The solid solution with an optimized combination of oxides and fluorides exhibited enhanced catalytic performance in the oxygen evolution reaction.

Perovskite Oxide–Halide Solid Solutions: A Platform for Electrocatalysts

AbstractThe successful integration or hybridization of perovskite oxides with their halide cousins would enable the formation of both multi‐anionic and multi‐cationic solid solutions with unique metal‐ion sites and synergistic properties that could potentially surpass the performance of classic perovskites. However, such solid solutions had not been produced previously owing to their distinct formation energies and different synthesis conditions. Solid solutions combining perovskite oxides with fluorides were produced in this study by mechanochemical synthesis. The obtained perovskite oxide–halide solid solutions had highly mixed elements and valences, uniform element distributions, and single‐phase crystalline structures. The solid solution with an optimized combination of oxides and fluorides exhibited enhanced catalytic performance in the oxygen evolution reaction.

Synthesis, Structure and Electronic Properties of Three Tin Oxide Halides

AbstractThree tin oxide halides, Sn7O4Cl6, Sn7O4Br6, and Sn4OI6, were synthesized by solid‐state reactions of SnO and SnX2 (X=Cl, Br, I) at 300 °C. Crystal structures were solved and refined from single crystal X‐ray diffraction data, revealing the presence of cubane‐like [Sn4O4] units in the structures of Sn7O4Cl6 and Sn7O4Br6. The electronic structure of Sn7O4Cl6 was analyzed by DFT band structure calculations and the electron localization function (ELF).

Facile precipitation synthesis of extraordinary visible‐light‐driven BiOXs photocatalyst

Bismuth halide oxide with three halogen elements (P-BiOXs) catalyst was prepared by a facile precipitation method at room temperature only for 30 min. Several measurement technologies were employed to characterise the structures and morphologies of the obtained samples. Coloured Rhodamine B (RhB), methyl orange (MO), methylene blue (MB) and colourless bisphenol A (BPA) were selected to evaluate the photocatalytic activity of the samples. The experimental results showed the P-BiOXs thin nanoplates exhibited the most excellent photocatalytic activity among the prepared samples for the degradation of MO under visible light illumination. More importantly, the catalyst P-BiOXs could effectively degradate RhB, MB and BPA. The P-BiOXs catalyst displayed good photocatalytic stability by the recycling tests. The highly efficient visible light catalytic properties of P-BiOXs could be due to the high specific surface area, enhanced light-harvesting ability, the suitable bandgap energy and the lower recombination rate of the photogenerated electrons and holes.

Joint Electroreduction of Chromium and Boron Ions and Electrochemical Synthesis of Chromium Borides in Halide–Oxide Melts

The electroreduction of oxygen-containing chromium ions $${\text{CrO}}_{{\text{4}}}^{{{\text{2}}-}}$$ and $${\text{C}}{{{\text{r}}}_{{\text{2}}}}{\text{O}}_{{\text{7}}}^{{{\text{2}}-}}$$ and their joint electroreduction with fluoroborate ion $${\text{BF}}_{{\text{4}}}^{ - }$$ in the equimolar KCl–NaCl melt at 1073 K are studied by cyclic voltammetry. The electroreduction of $${\text{CrO}}_{{\text{4}}}^{{{\text{2}}-}}$$ and $${\text{C}}{{{\text{r}}}_{{\text{2}}}}{\text{O}}_{{\text{7}}}^{{{\text{2}}-}}$$ proceeds via two steps to form chromium oxide Cr2O3 in the first step. In the second step, Cr2O3 also precipitates in the case of the electroreduction of $${\text{CrO}}_{{\text{4}}}^{{{\text{2}}-}}$$ , and a mixture of Cr2O3 and metallic chromium is formed due to the electroreduction of $${\text{C}}{{{\text{r}}}_{{\text{2}}}}{\text{O}}_{{\text{7}}}^{{{\text{2}}-}}$$ . Against the background of the KCl–NaCl melt, fluoroborate ion can interact with the $${\text{C}}{{{\text{r}}}_{{\text{2}}}}{\text{O}}_{{\text{7}}}^{{{\text{2}}-}}$$ ion to form chromium ( $${\text{Cr}}{{{\text{O}}}_{{\text{2}}}}{\text{F}}_{{\text{4}}}^{{{\text{2}}-}}$$ ) and boron ( $${\text{BOF}}_{{\text{2}}}^{-},$$ BOF) oxyfluoride complexes. The possibility that electrochemical synthesis of chromium boride phases occurs in a halide–oxide melt is shown by the joint electroreduction of chromium and boron oxyfluoride complexes.

Die Europium(II)-Oxidhalogenide Eu2OBr2 und Eu2OI2

Abstract The syntheses and crystal structures of the two isotypic europium(II) oxide halides Eu2OBr2 and Eu2OI2 are reported. They crystallize orthorhombically in the space group Ibam (Z=4; Eu2OBr2: a=709.86(5), b=1200.34(9), c=628.71(4) pm; Eu2OI2: a=739.78(5), b=1295.13(9), c=644.82(4) pm). The unit cell parameters presented here, and thus the interatomic distances of Eu2OI2, are significantly smaller than the ones reported in the literature, which is explained by the substitution of europium with larger barium cations due to the synthesis route described in the early study. Central building blocks of both crystal structures are trans-edge-connected [OEu4]6+ tetrahedra forming straight ∞ 1 { [ OEu 4/2 e ] 2 + } $_\infty ^1\{ {[{\text{OEu}}_{{\text{4/2}}}^{\text{e}}]^{2 + }}\} $ chains running parallel to the [001] direction. Bundled like a hexagonal rod packing, their interaction is achieved by Br− or I− anions for charge compensation.

Cs7Sm11[TeO3]12Cl16 and Rb7Nd11[TeO3]12Br16, the new tellurite halides of the tetragonal Rb6LiNd11[SeO3]12Cl16 structure type

Two new rare-earth – alkali – tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs7Sm11[TeO3]12Cl16 (I) and Rb7Nd11[TeO3]12Br16 (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn11(TeO3)12] and [M6X16] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted.

A dye-sensitized visible light photocatalyst-Bi24O31Cl10

The p-block semiconductors are regarded as a new family of visible-light photocatalysts because of their dispersive and anisotropic band structures as well as high chemical stability. The bismuth oxide halides belong to this family and have band structures and dispersion relations that can be engineered by modulating the stoichiometry of the halogen elements. Herein, we have developed a new visible-light photocatalyst Bi24O31Cl10 by band engineering, which shows high dye-sensitized photocatalytic activity. Density functional theory calculations reveal that the p-block elements determine the nature of the dispersive electronic structures and narrow band gap in Bi24O31Cl10. Bi24O31Cl10 exhibits excellent visible-light photocatalytic activity towards the degradation of Rhodamine B, which is promoted by dye sensitization due to compatible energy levels and high electronic mobility. In addition, Bi24O31Cl10 is also a suitable photoanode material for dye-sensitized solar cells and shows power conversion efficiency of 1.5%.

Ordering in lead-antimony oxide halides upon variation of chemical composition

Ordering in lead-antimony oxide halides upon variation of chemical composition

Syntheses, Crystal Structures, and Optical Properties of Indium Arsenic(III) Oxide Halides: In2(As2O5)Cl2 and In4(As2O5)(As3O7)Br3

AbstractTwo new indium arsenic(III) oxide halides, In2(As2O5)Cl2 (1) and In4(As2O5)(As3O7)Br3 (2), have been prepared by solid‐state reaction. Both of the compounds feature layered structures, in which indium–oxide halide octahedral rings or indium–oxo chains are bridged by indium–oxide halide octahedral dimers or indium–oxo unicapped trigonal prisms, and the interlinkage between the rings or chains is also consolidated by (As2O5)4– anions for 1, or (As2O5)4– and (As3O7)5– anions for 2. Compound 2 is the first compound in which three different indium‐ion coordination geometries coexist with the In3+ cations coordinated by O2– and Br– to form [InO6], [InO7], and [InOBr3] units. The diffuse reflectance spectra and band‐structure calculations show that they are wide‐band‐gap semiconductors.

ChemInform Abstract: Chemical Transport of Bismuth Oxide Halides BiOX (X: Cl, Br, I) with X2, HX and H2O, and Determination of the Molar Enthalpies of BiOX.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis and structure of mononuclear molecular complexes of molybdenum(VI) and tungsten(VI) oxy- and dioxyhalides

Specific features of the synthesis and structure of mononuclear molecular halide oxide complexes of Group VI d 0 metals molybdenum(VI) and tungsten(VI) are surveyed. Various methods of synthesis of adducts based on MOX4 and MO2X2 (M = Mo, W; X = F, Cl, Br) are described, such as direct interaction, ligand exchange, and the method of nascent reagents. The principles of formation of a particular geometric isomer are discussed: according to the self-consistency rule, the coordination of a neutral donor ligand L trans to a multiply bonded oxo ligand is preferable to that of acido ligands X− (anions). Rare exceptions are mentioned.

Nanoparticles in dendrimers: From synthesis to application

Methods for synthesizing metal, metal oxide, and metal halide nanoparticles (NPs) in the presence of dendrimers and dendrons are discussed in this review. There are numerous reviews describing dendrimers and their properties and applications in various areas of nanotechnologies, which indicates the growing interest of researchers in this unique class of monodisperse and highly branched macromolecules with highly ordered and controlled structures. The special magnetic, optical, and electronic properties of dendrimer (dendron) nanocomposites with NPs determine their prospects for application in medicine [54–58], in catalysis [32, 58–60], as molecular sensors [61–65], etc. Dendrimers successfully stabilize NPs, playing the role of a template (i.e., NPs are formed inside the dendrimer) or surfactants. In the latter case, dendrimers are stabilizing molecules, so the NPs are formed between the dendrimers. Functional dendrons can be also used as stabilizing molecules (1) directly during NP formation or (2) upon the subsequent functionalization of NPs via the replacement of the initial surfactants with dendrons. The unique advantages of dendrimers are completely fulfilled in those cases when the dendrimer design or reaction conditions allow either (1) the formation of very small NP sizes (for example, functional nanoclusters of gold and silver) or (2) control of the NP sizes, when dendrimer generation or other conditions vary, allowing one to control the properties of nanocomposites. Because the dendrimer (dendron) structure strongly differs from the structure of traditional surfactants, this leads to an opportunity of the targeted variation of solubility, functionality, and morphology of the nanocomposites based on dendrimers (dendrons) even when a dendrimer (dendron) plays the role of a surfactant.