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Costly and time-consuming recovery of photocatalysts from treated water is one of the main challenges for the photocatalysis process. In this regard, an Ag-functionalized Bi 2 W(Mo)O 6 photocatalyst was successfully synthesized via a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method, immobilized on a polyvinylidene fluoride (PVDF) membrane and subsequently used for photocatalytic water treatment. The flower-like Ag-decorated Bi 2 W(Mo)O 6 photocatalyst revealed a significant enhancement (62%) in the photocatalytic degradation efficiency compared to the unmodified pure Bi 2 WO 6 (19%) due to the synergic contribution of the flower-like morphology with higher surface area, decrease in band gap by Mo doping and Ag-induced surface plasmon resonance (SPR) effects. In order to immobilize the photocatalyst, the Ag-decorated Bi 2 W(Mo)O 6 nanoparticles were distributed uniformly on the surface of the PVDF membrane. The results illustrate that the as-prepared Ag-loaded Bi 2 W(Mo)O 6 /PVDF composite membrane effectively degrades the organic molecules (51%) without any additional process for the photocatalyst separation, confirming its potential as a beneficial environmental-friendly material for water treatment applications. Graphical abstract

Costly and time-consuming recovery of photocatalysts from treated water is one of the main challenges for the photocatalysis process. In this regard, an Ag-functionalized Bi.sub.2W(Mo)O.sub.6 photocatalyst was successfully synthesized via a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method, immobilized on a polyvinylidene fluoride (PVDF) membrane and subsequently used for photocatalytic water treatment. The flower-like Ag-decorated Bi.sub.2W(Mo)O.sub.6 photocatalyst revealed a significant enhancement (62%) in the photocatalytic degradation efficiency compared to the unmodified pure Bi.sub.2WO.sub.6 (19%) due to the synergic contribution of the flower-like morphology with higher surface area, decrease in band gap by Mo doping and Ag-induced surface plasmon resonance (SPR) effects. In order to immobilize the photocatalyst, the Ag-decorated Bi.sub.2W(Mo)O.sub.6 nanoparticles were distributed uniformly on the surface of the PVDF membrane. The results illustrate that the as-prepared Ag-loaded Bi.sub.2W(Mo)O.sub.6/PVDF composite membrane effectively degrades the organic molecules (51%) without any additional process for the photocatalyst separation, confirming its potential as a beneficial environmental-friendly material for water treatment applications.

In the present study, the ZnS semiconductor quantum dots were successfully synthesized via an aqueous method utilizing glutathione (GSH), thioglycolic acid (TGA) and polyvinyl pyrrolidone (PVP) as capping agents. The structural, morphological and photo-physical properties and biocompatibility were investigated using comprehensive characterization techniques such as x-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), dynamic light scattering (DLS), Fourier transform infrared spectrometry (FT-IR), UV-Vis optical absorption, photoluminescence (PL) spectrometer and MTT assay. The XRD patterns showed a cubic zinc blende crystal structure and a crystallite size of about 2–3 nm using Scherrer’s equation confirmed by the electron micrographs and Effective Mass Approximation (EMA). The DLS and zeta-potential results revealed that GSH capped ZnS nanoparticles have the narrowest size distribution with an average size of 27 nm and relatively good colloidal stability. Also, the FT-IR spectrum confirmed the interaction of the capping agent groups with ZnS nanoparticles. According to the UV-Vis absorption results, optical bandgap of the spherical capped nanoparticles is higher compared to the uncapped sample and could be wider than 3.67 eV (corresponding to the bulk ZnS), which is due to the quantum confinement effect. From photoluminescence spectra, it was found that the emission becomes more intensive and shifts towards the shorter wavelengths in the presence of the capping agent. Moreover, the emission mechanism of uncapped and capped ZnS was discussed in detail. Finally, the MTT results revealed the satisfactory (>94%) biocompatibility of GSH capped ZnS quantum dots which would be a promising candidate applicable in fluorescent biological labels.

Ce-doped FeVO 4 nanocomposites were successfully synthesized using reverse micro-emulsion route. Thermal and microstructural characteristics were comprehensively investigated by simultaneous thermal analysis, X-ray diffraction (XRD), scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and laser particle size analyzer. Moreover, as the anode material of lithium-ion batteries, the electrochemical properties were studied by galvanostatic charge and discharge tests and electrochemical impedance spectroscopy. The thermal analysis illustrated that the triclinic crystal structure of FeVO 4 nanoparticles is formed at about 520 °C, which is confirmed by XRD and FT-IR results. Furthermore, the microstructural analyses revealed more regular particles and high specific surface area for wet-chemical derived FeVO 4 :Ce, which decreases the diffusion pathway of the lithium ions during the insertion/extraction process. The electrochemical measurements indicated that the electrode cycling performance and rate retention ability of Ce-doped FeVO 4 are better than those of pure FeVO 4 due to the expansion of the crystal lattice, which provided more lattice space for lithium intercalation and de-intercalation. Consequently, the as-prepared Ce-doped FeVO 4 with relatively high specific and reversible capacity, thermal stability and satisfactory cycling performance is a promising candidate for use as a lithium batteries anode material.

The most effective process parameters were determined to synthesize spherical LaF 3 nanoparticles with controllable size based on ethylenediaminetetraacetic acid (EDTA) via co-precipitation technique. Thermogravimetricdifferential thermal analysis, X-ray diffraction, scanning electron microscopy, dynamic light scattering and FT-IR spectroscopy were used to characterize the resulting powders. Detailed investigations revealed that the optimal LaF 3 host nano-material was obtained when NH 4 F was used as a fluoride source in the presence of EDTA at pH = 5. Furthermore, photoluminescence spectra showed an intense double emission peak at 289 and 302 nm for cerium-doped LaF 3 nanocrystals excited at 253 nm, which was assigned to the well-known 5d→4f ( 2 F 5/2 and 2 F 7/2 ) transitions of Ce 3+ levels due to luminescence center mechanism. The experimental results indicate that the synthesized LaF 3 :0.05Ce powders with a band gap of 5.3 eV are promising phosphors for high density scintillators.

In this research, a new blue-emitting phosphor Eu2+-doped SrZn2Si2O7 was developed for white light-emitting diodes via the sol–gel process. Thermogravimetric-differential thermal analysis, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), and photoluminescence (PL) spectra were used to characterize the resulting phosphors. The obtained phosphor is efficiently excited in the wavelength range of 340–400 nm which matches to a near-UV-emitting InGaN chip and emits strong band blue light peaking at 481 nm because of 4f65d1(2D) → 4f7(8S7/2) transition of Eu2+ ions. The effects of the activator concentration and excess Si (y > 1) on the luminescence properties were evaluated. It was found that, when the Eu2+ content (x) and the Si concentration (2y) were 0.04 and 2.4, respectively, the optimum phosphor can be achieved. Also, the mechanism of concentration quenching was determined to be the dipole–dipole interaction using Dexter’s theory. Finally, the mean crystallite size of the products was estimated to be approximately 30 nm using Scherrer’s equation, which was confirmed by the TEM observations.

In this research, a new blue-emitting phosphor [Eu.sup.2+]-doped Sr[Zn.sub.2][Si.sub.2][O.sub.7] was developed for white light-emitting diodes via the sol-gel process. Thermogravimetric-differential thermal analysis, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), and photoluminescence (PL) spectra were used to characterize the resulting phosphors. The obtained phosphor is efficiently excited in the wavelength range of 340-400 nm which matches to a near-UV-emitting InGaN chip and emits strong band blue light peaking at 481 nm because of [4f.sup.6][5d.sup.1](²D) → [4f.sup.7] ([sup.8][S.sub.7/2]) transition of [Eu.sup.2+] ions. The effects of the activator concentration and excess Si (y > 1) on the luminescence properties were evaluated. It was found that, when the [Eu.sup.2+] content (x) and the Si concentration (2y) were 0.04 and 2.4, respectively, the optimum phosphor can be achieved. Also, the mechanism of concentration quenching was determined to be the dipole-dipole interaction using Dexter's theory. Finally, the mean crystallite size of the products was estimated to be approximately 30 nm using Scherrer's equation, which was confirmed by the TEM observations.

Costly and time-consuming recovery of photocatalysts from treated water is one of the main challenges for the photocatalysis process. In this regard, an Ag-functionalized Bi.sub.2W(Mo)O.sub.6 photocatalyst was successfully synthesized via a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method, immobilized on a polyvinylidene fluoride (PVDF) membrane and subsequently used for photocatalytic water treatment. The flower-like Ag-decorated Bi.sub.2W(Mo)O.sub.6 photocatalyst revealed a significant enhancement (62%) in the photocatalytic degradation efficiency compared to the unmodified pure Bi.sub.2WO.sub.6 (19%) due to the synergic contribution of the flower-like morphology with higher surface area, decrease in band gap by Mo doping and Ag-induced surface plasmon resonance (SPR) effects. In order to immobilize the photocatalyst, the Ag-decorated Bi.sub.2W(Mo)O.sub.6 nanoparticles were distributed uniformly on the surface of the PVDF membrane. The results illustrate that the as-prepared Ag-loaded Bi.sub.2W(Mo)O.sub.6/PVDF composite membrane effectively degrades the organic molecules (51%) without any additional process for the photocatalyst separation, confirming its potential as a beneficial environmental-friendly material for water treatment applications. Graphical abstract

The sol–gel preparative method was employed to synthesize SrZn 2 Si 2 O 7 :Eu nanostructure phosphors for white-light emitting diodes. The effects of calcination temperature and atmosphere as two important process parameters on the structural, morphological and optical properties were investigated using comprehensive characterization methods such as X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM) and photoluminescence spectra. The obtained phosphors are efficiently excited from 340 to 400 nm, which matches the near UV emitting InGaN chip and emits strong band peaking at 481 nm due to 4f 6 5d 1 ( 2 D )  →   4f 7 ( 8 S 7/2 ) transition of Eu 2+ ions. In this europium-doped host lattice, a partial reduction of Eu 3+ to Eu 2+ at high temperature during the synthesis in air according to the charge compensation model is perceived. Furthermore, for this sample forbidden f–f transitions of Eu 3+ are observed. Finally, using Scherrer’s equation the crystallite size of the optimum products with color coordination of x  = 0.176, y  = 0.193 is estimated at ~30 nm, which was consistent with TEM observations.

In this research, a new blue-emitting phosphor Eu2+-doped SrZn2Si2O7 was developed for white light-emitting diodes via the sol--gel process. Thermogravimetric-differential thermal analysis, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), and photoluminescence (PL) spectra were used to characterize the resulting phosphors. The obtained phosphor is efficiently excited in the wavelength range of 340--400 nm which matches to a near-UV-emitting InGaN chip and emits strong band blue light peaking at 481 nm because of 4f 65d 1(2 D) -> 4f 7(8 S 7/2) transition of Eu2+ ions. The effects of the activator concentration and excess Si (y > 1) on the luminescence properties were evaluated. It was found that, when the Eu2+ content (x) and the Si concentration (2y) were 0.04 and 2.4, respectively, the optimum phosphor can be achieved. Also, the mechanism of concentration quenching was determined to be the dipole--dipole interaction using Dexter's theory. Finally, the mean crystallite size of the products was estimated to be approximately 30 nm using Scherrer's equation, which was confirmed by the TEM observations.