BaWO4 Nanoparticles Research Articles

Modifications of structural and optical properties of nanophase BaWO4 phosphors: Dose dependent effect of high energy electron beam irradiation

The present work reports dose dependent influence of 8 MeV electron beam irradiation on the structural and optical properties of BaWO4 nanoparticles fabricated by chemical precipitation route. The synthesized materials were calcined at 400 °C for 3 h to get well defined nanocrystalline particles. The calcined materials were irradiated by 8 MeV electron beams of different doses and studied the influence of irradiation on the structural and optical properties of BaWO4 nanoparticles using various characterization tools. The structural studies revealed modifications of lattice parameters a and c, unit cell volume, d spacing, crystallite size, micro-strain, and peak shift for major peaks of X-ray diffraction patterns of the electron irradiated samples. The electron irradiation also results some defects in the crystal lattice of BaWO4 nanocrystals upon electron beam irradiation. Scanning electron microscopic images demonstrated mesoporous behaviour of the BaWO4 materials. The optical studies established that optical bandgap and intensity of photoluminescence emission can be modified by using electron irradiation technique for potential applications in electronics. Photoluminescence emission properties of BaWO4 phosphors suggest that they are useful for the construction of near ultraviolet light excited blue light emitting diodes. Results explored from the present work constitute the first report for the dose-dependent influence of electron beam irradiation on the structure, optical absorption and photoluminescence properties of BaWO4 nanoparticles.

Structural modifications and extended spectral response of nanocrystalline Ba1-xCuxWO4 samples

Ba1-xCuxWO4 nanoparticles were synthesized by chemical precipitation route. The structural properties of the Ba1-xCuxWO4 samples were characterized by X-ray diffraction, Fourier transformed infrared and Raman spectroscopic studies; morphological and microstructural characterizations were done by transmission electron microscopic and scanning electron microscopic measurements respectively. The optical characterization of the samples were performed by UV–Visible diffuse reflectance and photoluminescence spectroscopic studies, and the magnetic characterization were done by vibration sample magnetometer measurements. The structural characterization confirms the tetragonal scheelite structure for the samples. On doping with Cu atoms, the agglomeration and hence the size of the particles decreases appreciably. The optical bandgap of the samples decreases with increase in the amount of Cu atoms in the Ba1-xCuxWO4 sample, confirming the formation of intermediate energy levels. The absorption edge extends to visible region and the amount absorption increases with the amount of Cu atoms in the Ba1-xCuxWO4 sample. However, photoluminescent emission decreases with the increase in concentration of Cu atoms in the Ba1-xCuxWO4 sample, which also confirm the formation of intermediate energy levels. Vibrating sample magnetometer measurements of the Ba1-xCuxWO4 samples show large variations from the magnetic behaviour of the samples upon doping. The weak ferromagnetic behaviour of the Ba1-xCuxWO4 sample changes to superparamagnetic as the doping concentration increases. Moreover, the Cu doping resulted significant modifications on the structural, optical and magnetic properties of BaWO4 nanoparticles, which make them suitable for potential applications including optoelectronics, biomedical and photocatalytic applications.

Barium tungstate nanoparticles to enhance radiation therapy against cancer

High-Z nanoparticles have emerged as a novel type of radiosensitizers due to their relatively large X-ray cross-section and ability to enhance radical production under irradiation. Recently, CaWO4 nanoparticles have been prepared and their potential as a radiosensitizer has been demonstrated. Herein, we investigated BaWO4 nanoparticles as a novel type of alkaline-earth metal tungstate radiosensitizer for radiotherapy (RT). We synthesized BaWO4 nanoparticles using hydrothermal reaction and coated them with polyvinylpyrrolidone (PVP). We found that BaWO4 nanoparticles could more efficiently enhance hydroxyl radical production under irradiation than CaWO4 nanoparticles. When tested in vitro, BaWO4 nanoparticles showed lower toxicity than CaWO4 nanoparticles in the absence of irradiation, but induced more significant oxidative stress under irradiation. When tested in vivo, BaWO4 nanoparticles led to more efficient tumor inhibition without causing systemic toxicity. Overall, our results suggest that BaWO4 nanoparticles can efficiently enhance RT and hold great potential as a novel type of radiosensitizing agent.

Optimization and detailed stability study on coupling of CdMoO4 into BaWO4 for enhanced photodegradation and removal of organic contaminant

BaWO4 nanoparticles and BaWO4/CdMoO4 nanocomposites were synthesized by eco-friendly method at low temperature. The effects of various capping agents such as glucose, fructose, lactose, and starch on the morphology and particle size of BaWO4/CdMoO4 nanocomposites were investigated. The nanocluster was obtained with glucose and Ba2+ to capping agent molar ratio of (1:2). BaWO4/CdMoO4 nanocomposites were analyzed through techniques including, XRD, FT-IR, VSM, TEM, PL, FESEM, UV–vis, and EDX. According to the BET results, in the presence of glucose as the capping agent, surface area increased from 13.781 m2/g to 122.22 m2/g. Furthermore, adding CdMoO4 nanoparticles to BaWO4 causes optical properties and photocatalytic activity of BaWO4 to improve. Moreover, the effects of several factors such as BaWO4/CdMoO4 nanocomposites concentration and its particle size and difference dyes on the photocatalytic performance of BaWO4/CdMoO4 nanocomposites were studied under visible light.

Efficient photodegradation of methylthioninium chloride dye in aqueous using barium tungstate nanoparticles

BaWO4 nanoparticles were successfully used as the photocatalysts in the degradation of methylthioninium chloride (MTC) dye at different pH levels of aqueous solution. Pure phase of barium tungstate (BaWO4) nanoparticles was synthesized by modified molten salt process at 500 °C for 6 h. Structural and morphological characterizations of BaWO4 nanoparticles (average particle size of ~40 nm) were studied in details using powder x-ray diffraction (XRD), FTIR, Raman, energy-dispersive, electron microscopic, and x-ray photoelectron spectroscopy (XPS) techniques. Direct band gap energy of BaWO4 nanoparticles was found to be ~3.06 eV from the UV–visible absorption spectroscopy followed by Tauc’s model. Photocatalytic properties of the nanoparticles were also investigated systematically for the degradation of MTC dye solution in various mediums. BaWO4 nanoparticles claim the significant enhancement of the photocatalytic degradation of aqueous MTC dye to non-hazardous inorganic constitutes under alkaline, neutral, and acidic mediums.

Synthesis and characterization of BaWO4 nanoparticles with the aid of different surfactants and their photocatalyst properties

Nanoparticles sphere-like barium tungstate (BaWO4) have been successfully synthesized via the co-precipitation method process by using barium nitrate hexahydrate, Na2WO4·2H2O and of different surfactants like cetyl trimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and ethylene diamine tetraacetic acid (EDTA). The as-synthesized nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (UV–Vis), and energy dispersive X-ray microanalysis (EDX). According to the vibrating sample magnetometer, barium tungstate (BaWO4) nanoparticles indicated a ferromagnetic behavior at room temperature. Photo-catalytic property of barium tungstate was examined by degradation of methyl orange as organic pollutant in water under UV light irradiation. The results showed that methyl orange degradation was about 80% under for 70 min, so the synthesized product can be used as an effective photocatalyst.

Preparation and characterization of barium tungstate nanoparticles via a new simple surfactant-free route

In this paper BaWO4 nanoparticles were prepared via a sonochemical route based on the reaction between barium salt and Na2WO4·2H2O in water. Moreover, this method is free from any surfactant and organic solvents. The structural, morphological and optical properties of as-obtained products were characterized by techniques such as XRD, EDS, SEM, and UV–visible. The magnetic properties of as-prepared BaWO4 nanoparticles were also investigated with vibrating sample magnetometer. To evaluate the photocatalysts properties of nanocrystalline barium tungstate, the photocatalytic degradation of methyl orange under ultraviolet light irradiation was carried out. The new synthetic method presented in this paper has potential applications to fabricate other metal tungstates (BaWO4) materials.

Soft chemical synthesis and characterization of BaWO4 nanoparticles for photocatalytic removal of Rhodamine B present in water sample

In recent years, the use of metal oxides as photocatalysts for degradation of organic substances has attracted the attention of the scientific community. Metal oxide nanoparticles have been studied due to their novel optical, electronic, magnetic, thermal and potential applications as catalysts, gas sensors, photo-electronic devices, etc. In this research work, we report a simple, soft chemical route for synthesizing BaWO4 nanoparticles using cheap chemicals such as barium nitrate (precursor salt) and sodium tungstate (precipitating agent). The final product was dried at room temperature overnight and calcined at 400 °C and 800 °C for 2 h to get phase-pure product. The prepared nanoparticles (as prepared and heat-treated samples) were characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis and UV–Vis spectroscopy techniques. Photocatalytic degradation characteristics of Rhodamine B in water using BaWO4 nanoparticles were studied and reported.

Serendipitous discovery of super adsorbent properties of sonochemically synthesized nano BaWO4

The superior adsorbent properties of BaWO4 nanostructures have been reported for the first time. Flower shaped aggregates (∼250 nm) of BaWO4 nanoparticles, having an average size of ∼10–15 nm with a high surface area of ∼148.0 ± 0.2 m2 g−1, have been synthesized sonochemically and used for the adsorption of various cationic dyes from aqueous solutions. The sonochemically synthesized BaWO4 have been characterized by scanning electron microscopy (SEM), selected area electron diffraction (SAED), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR). The adsorbent capacity of this tungstate is much higher than that reported for other nanomaterials like Fe2O3, MnO2, WO3, etc. Complete removal of dyes like rhodamine B and methylene blue was possible within a short time span of 10–15 minutes. The adsorption process was followed using UV-Visible spectroscopy, while the material before and after adsorption has been characterized using physicochemical and spectroscopic techniques. Various isotherms have been used to fit the data, and kinetic parameters were evaluated. Moreover, the adsorbed dyes could be desorbed completely from nanoparticle surfaces by annealing at moderate temperature and were found to be efficient for multicyclic use. Thus this sonochemically synthesized nano BaWO4 has great significance in treatment of dye industry effluents as a promising adsorbent for cationic dyes from aqueous solution.

Precipitate synthesis of BaMoO4 and BaWO4 nanoparticles at room temperature and their photoluminescence properties

The uniform BaMoO4 and BaWO4 nanoparticles (NPs) have been successfully synthesized by solution route – the direct precipitation of Ba(NO3)2 and Na2MO4 (M=Mo and W) in ethylene glycol under 24h stirring. The XRD patterns and SEM images proved that the products were tetragonal structured BaMoO4 and BaWO4 with uniform round nanoparticles. Shape, average particle size and particle-size distribution of products were analyzed by TEM – showing the round nanoparticles with the average size of 31.52±4.65nm for BaMoO4, and 59.77±9.61nm for BaWO4. The room temperature photoluminescence (PL) indicated that the products have strong blue emission centered at 441nm – excited with 280nm wavelength for BaMoO4 NPs, and strong violet emission centered 378nm – excited with 344nm wavelength for BaWO4 NPs. These PL behaviors attributed the existence of intrinsic transitions in the [MO4]2- (M=Mo and W) tetrahedrons of their crystal lattices.