Growth mechanism and photocatalytic properties of SrWO4 microcrystals synthesized by injection of ions into a hot aqueous solution

New spacious SrWO4/PEDOT-PPy nanohybrids and their electrochemical and photocatalytic activities

A novel SrWO4-poly(3,4-ethylene dioxythiophene) (PEDOT)-polypyrrole (PPy) nanocomposite was synthesized via chemically oxidative polymerization and considered by using numerous method of the techniques. The resulting SrWO4/PEDOT-PPy nanocomposite demonstrated remarkable electrochemical sensing capabilities for sulfadiazine (SFA). As a modified glassy carbon electrode (SrWO4/PEDOT-PPy/GCE) revealed for superior catalytic activity in the electrochemical oxidation of sulfadiazine, enabling sensitive detection with quantification and detection limits of 1.0936 × 10-9 M µA-1 and 2.2104 × 10-9 M µA-1, respectively. This technique effectively determined SFA content in real samples. Additionally, SrWO4/PEDOT-PPy demonstrated extraordinary photocatalytic ability, achieving a Methylene Blue (MB) degradation rate of up to 99.1% under halogen light irradiation within 80 min. Hybrid photocatalyst has exhibited to strong reusability and photocatalytic stability under frequent light exposure. A contrivance for the photocatalytic deprivation of MB by SrWO4/PEDOT-PPy is proposed. These results underscore the crucial role of SrWO4/PEDOT-PPy in practical environmental remediation analysis. The fluorescence investigations have betrothed to terephthalic acid radical formations of SrWO4/PEDOT-PPy hybrids, which were modulated by different approaches, and its mainly driven for higher illumination aptitudes. Meanwhile, this was more supporting for physio-chemical properties of the phenomenon, at this consequential with significantly well improved to the photocatalytic performances. Because of this, SrWO4/PEDOT-PPy hybrid materials were comprehended to deliver excellent kinetics, and better recyclable activities.

Alkaline metal tungstate anchored on functionalized-MWCNT: A co-active electrocatalyst for the detection of levofloxacin

The widespread usage of levofloxacin (LVF) intake is executed for several urinary and respiratory systems infections in human. But, its over intake leads to severe damage to humans and the environment by its exposure. Hence the detection of LVF is concerned and we herein developed an electrocatalyst, strontium tungsten oxide nanospheres and later decorated onto the functionalized multiwall carbon nanotubes (SrWO4/f-MWCNT) to perform effective electrochemical recognition of LVF in aquatic and biological samples. Binary metal oxide with carbon composite SrWO4/f-MWCNT was developed due to its specific features as nanostructures. Various methods of investigation have been examined to identify the physiochemical characteristics like X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and morphological characteristics including field emission scanning electron microscopy, and transmission electron microscopy. The synthesized SrWO4/f-MWCNT sample crystalline size was around 32.9 nm. The SrWO4/f-MWCNT modified glassy carbon electrode (GCE) has been subjected to electrochemical investigation with a wide linear range of 0.049 μM-574.73 μM with good sensitivity 2.86 μA μM-1 cm2, the limit of detection at 14.9 nM for LVF sensing. Furthermore, the designed LVF detection exhibited excellent anti-interference, stability, reproducibility, and repeatability. The as-developed sensor's electrochemical outcomes indicate the superior performance inherent in the developed composite.

The Intrinsic Relationship between Photoluminescence and Photocatalysis of MMoO4/MWO4 (M = Mg, Ca, Sr and Ba) Heterojunctions: Heterojunction Construction, Mechanism Insight and Development Tendency

The migration behavior of electron and hole pairs determines both photoluminescence and photocatalytic activity, which are two distinct properties of semiconductor materials. The photoluminescence and photocatalytic activity of semiconductor materials also exhibit strong method-dependent behavior under the influence of synthesis methods. In this review, the synthesis methods of MMoO4, MWO4 and MMoO4/MWO4 (M = Mg, Ca, Sr and Ba) heterojunction composites and their photoluminescence and photocatalytic activities are reviewed for the first time. The effects of different M ions on the photoluminescence and photocatalytic activity of MMoO4/MWO4 heterojunction composites are also reviewed. There is also a discussion about the intrinsic correlation mechanism between photoluminescence and photocatalytic activity. Different M ions result in different coordination environments in MMoO4/MWO4 heterojunction composites, which leads to different photoluminescence and photocatalytic mechanisms of different MMoO4/MWO4 heterojunction composites. This review provides theoretical reference and technical guidance for future research on MMoO4/MWO4 heterojunction composites.

Development of SrWO4:Ho3+/Yb3+ green phosphor for optical thermometry application

In recent years, the growth of luminescent materials for optical thermometry applications has gained substantial attention due to their non-invasive and contactless nature. This research article presents the synthesis, characterization, and potential application of SrWO4:Ho3+/Yb3+ phosphors as temperature-sensitive materials. The inspection of the structural properties is done by X-ray diffraction and Raman and FTIR spectroscopy. The X-ray diffraction signifies the single tetragonal phase of the materials without any impurity or secondary phase. Nine Raman active modes are detected in the Raman spectra of pure SrWO4 and 10 Raman active bands are present in the doped samples. The morphology and elemental composition are visualised by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy. The spectral properties of these phosphors are evaluated by down-conversion and up-conversion photoluminescence, signifying their suitability for solid state lighting and optical thermometry in various temperature regimes. The phosphors can generate green and yellow light under blue and near-infrared radiation, respectively. The sensitivity of 3.19 × 10-3 K-1 ensures the promising prospects of SrWO4:Ho3+/Yb3+ phosphors for precise and reliable temperature sensing in diverse fields.

Strontium tungstate-modified disposable strip for electrochemical detection of sulfadiazine in environmental samples

Rapid-monitoring of drugs has attracted tremendous consideration owing to robust global demand for cost-effective and high effectiveness. Binary metal oxides with various morphology have been reported as electrodes for electrochemical sensor to fulfilling the clinical and enviromental requirements. In this study, strontium tungstate (SrWO₄) nanoflakes have been successfully prepared via the facile sonochemical method for the first time. The characteristics of as-prepared SrWO₄ are systematically measured by various analytical and spectroscopic methods. The SrWO₄ nanoflakes are utilized to modify the electrochemical electrode for the sulfadiazine (SDZ) determination. The SrWO₄ modified electrode possesses excellent electrocatalytic activity and high recognition capability for the electrochemical detection of SDZ. Impressively, the as-fabricated SrWO₄ modified electrode attainted lowest oxidation peak at +0.93 V (vs Ag/AgCl₂) with the limit of detection of 0.009 μM, the sensitivity of 0.123 µA µM^-1 cm² and linear detection range of 0.05-235 μM. The enhanced performance of proposed SrWO₄-based sensors could be attributed to the catalytic effect, large surface area, good electrical conductivity and physicochemical nature. Notably, the electrocatalytic performances of the SDZ sensors are good as compared to the previous literature, indicating the significance of the newly designed SrWO₄ modified electrode. The real-sample diagnosis by the SDZ detection in environmental sample demonstrates the proposed SrWO₄-based sensors with good recovery range.

Multi-dimensional architecture of Ag/α-Ag2WO4 crystals: insights into microstructural, morphological, and photoluminescence properties

Varying the concentration of ethylenediamine resulted in hollow or solid Ag/α-Ag₂WO₄ microflowers that emit light in the red region or in the blue region, respectively.

Effect of morphology and temperature treatment control on the photocatalytic and photoluminescence properties of SrWO4 crystals

This work reports the combined effect of the morphology and crystallization degree of the strontium tungstate (SrWO₄) scheelite structure on its photocatalytic and photoluminescence properties.

The Enhancement of H2 Evolution over Sr1-1.5xTbxWO4 Solid Solution under Ultraviolet Light Irradiation

In this work, Sr_1-1.5xTb_xWO₄ (0 ≤ x ≤ 0.2) solid solutions were synthesized via a traditional high-temperature solid state method. Le Bail fitting on the powder X-ray diffraction (XRD) pattern showed that these solid solutions are pure phase. Scanning electron microscopy showed that the SrWO₄ and Sr_0.82Tb_0.12WO₄ samples are composed of micrometer particles and submicron crystallites, respectively. Ultraviolet-visible diffuse reflectance spectra suggested that the bandgaps of Sr_1-1.5xTb_xWO₄ are narrower than the undoped sample. The Sr_0.82Tb_0.12WO₄ sample, with the assistance of 1.5 wt % Ru-cocatalyst, exhibits the best performance for H₂ evolution in 5 vol % aqueous triethanolamine (TEOA), which results in about 6.1 and 2.8 times efficiency improvement compared with the intrinsic SrWO₄ in methanol and aqueous TEOA, respectively. All the photocatalysts recycled after the photocatalytic reactions showed no degradation when checked by powder XRD.

Morphological and structural investigation of SrWO4 microcrystals in relationship with the electrical impedance properties

Synthesis of SrWO₄ crystal with spindles and spheres morphologies at ambient temperature. A structuring in tetragonal scheelite favors mixed conduction properties based on order–disorder transition.

Synthesis and photo-/electro-catalytic properties of a 3D POMOF material based on an interpenetrated copper coordination polymer linked by in situ dual ligands and Dawson-type phosphotungstates

A 3D Keggin POMOF based on a unique Cu/pz/pzc MOF was prepared and employed to degradation of typical dyes.

The first 3D host–guest structure based on a three-fold interpenetrated Ag-pz coordination polymer network and Keggin-type aluminum tungstates with photo/electro-catalytic properties

A 3-D POMOF host–guest structure based on {AlW₁₂} and Ag-pz MOF units was prepared, which exhibit good photo- and electrocatalytic behavior.

Photoluminescence and Photocatalytic Properties of Ag3 PO4 Microcrystals: An Experimental and Theoretical Investigation

The structural, morphological, and optical properties of Ag₃ PO₄ microcrystals were systematically characterized by using a combination of theoretical calculations and experimental techniques. These microcrystals were synthesized by the microwave-assisted hydrothermal (MAH) method. XRD, Rietveld refinements, and FTIR spectroscopy were employed to carry out a structural analysis; the morphologies of the microcrystals were examined by FEG-SEM. First-principles computational studies were used to calculate the geometries of bulk Ag₃ PO₄ and its (010), (100), (001), (110), (101), (011), and (111) surfaces. A continuous decrease in the energy of the (100) surface led to a good agreement between the experimental and theoretical morphologies. Optical properties were investigated by UV/Vis spectroscopy and photoluminescence (PL) measurements, which revealed a maximum PL emission at λ=444 nm. The MAH-synthesized sample exhibited good activity for the photocatalytic degradation of methyl orange dye under visible irradiation. The photocatalytic activity and PL behavior were correlated with the observed morphology.

Synthesis of BiVO4via oxidant peroxo-method: insights into the photocatalytic performance and degradation mechanism of pollutants

A new method was proposed to obtain monoclinic BiVO₄ with high photoactivity under visible light and its mechanism of photodegradation was investigated.

Facet-dependent photocatalytic and antibacterial properties of α-Ag2WO4crystals: combining experimental data and theoretical insights

We have combined experimental results and calculations with new paths to explain the photocatalytic and antibacterial activities of α-Ag₂WO₄crystals.

Construction of POMOFs with different degrees of interpenetration and the same topology

Three POMOFs with different degrees of interpenetration are reported and the influence of the organic molecules on the degree of interpenetration of the compounds is discussed.

Experimental and theoretical investigations of electronic structure and photoluminescence properties of β-Ag2MoO4 microcrystals

In this paper, we investigate a correlation between theoretical calculations and experimental data to explain the electronic structure and optical properties of silver molybdate (β-Ag2MoO4) microcrystals synthesized by the microwave-assisted hydrothermal method. X-ray diffraction, Rietveld refinement, and micro-Raman spectroscopy confirmed that these microcrystals crystallize in a spinel-type cubic structure. Field-emission scanning electron microscopy images revealed that the processing temperatures influence in the final shape of microcrystals. Optical properties were analyzed by ultraviolet-visible diffuse reflectance spectroscopy; the increase in the optical band gap energy (Egap) (from 3.24 to 3.31 eV) with processing temperature is associated with the reduction of intermediary energy levels. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level were conducted. The calculated band structure revealed an indirect Egap of approximately 4.00 and 3.34 eV for the β-Ag2MoO4 without and with the formation of defects, respectively. Theoretical calculations based on density of states and electron density maps were employed to understand the polarization phenomenon induced by structural defects in the β-Ag2MoO4 crystals. Finally, photoluminescence properties at room temperature of β-Ag2MoO4 microcrystals were explained by the charge-transfer mechanism involving tetrahedral [MoO4] clusters.

Rietveld refinement, morphology and optical properties of (Ba1−xSrx)MoO4crystals

In this article, the structural refinement, morphology and optical properties of barium strontium molybdate [(Ba1−xSrx)MoO4withx= 0, 0.25, 0.50, 0.75 and 1] crystals, synthesized by the co-precipitation (drop-by-drop) method, are reported. The crystals obtained were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, and Fourier transform–Raman (FT–Raman) and Fourier transform–infrared (FT–IR) spectroscopies. The shapes of the crystals were observed by means of field-emission scanning electron microscopy (FE-SEM). The optical properties were investigated using ultraviolet–visible (UV–Vis) absorption spectroscopy and photoluminescence (PL) measurements. XRD patterns, Rietveld refinement, and FT–Raman and FT–IR spectra showed that all of the crystals are monophasic with a scheelite-type tetragonal structure. The refined lattice parameters and atomic positions were employed to model the [BaO8], [SrO8] and [MoO4] clusters in the tetragonal lattices. The FE-SEM images indicate that increasedxcontent produces a decrease in the crystal size and modifications in the crystal shape. UV–Vis spectra indicated a decrease in the optical band gap with an increase inxin the (Ba1−xSrx)MoO4crystals. Finally, a decrease in the intensity of PL emission is apparent with an increase inxup to 0.75 in the (Ba1−xSrx)MoO4crystal lattice when excited by a wavelength of 350 nm, probably associated with the degree of structural order–disorder.