Synthesis, structure, and photo-Fenton activity of PrFeO3-TiO2 mesoporous nanocomposites

Porous nanocomposites based on PrFeO3-TiO2 were synthesized using the glycine-nitrate combustion method with different values of mass content of TiO2 (0–7.5 %) and subsequent heat treatment in air. The results of X-ray phase analysis and Raman spectroscopy confirmed the presence of ultradispersed TiO2, structurally close to that of anatase. The morphology, specific surface area, and porous structure of the obtained powders were characterized by scanning electron microscopy and adsorption-structural analysis, the results of which showed that the samples had a foam-like mesoporous structure.The specific surface area and the average pore size were in the ranges of 7.6–17.8 m2/g and 7.2–15.2 nm, respectively, and varied depending on the TiO2 content. The optical properties of the nanocomposites were studied by UV-visible diffuse reflection spectroscopy, the energy of the band gap was calculated as 2.11–2.26 eV. The photocatalytic activity of PrFeO3‑TiO2 nanocomposites was investigated in the process of photo-Fenton-like degradation of methyl violet under the action of visible light. It was shown that the maximum reaction rate constant was 0.095 min-1, which is ten times higher than the value for the known orthoferrite-based analogs. The obtained photocatalysts were also characterized by their high cyclic stability. Based on the studies carried out, the obtained porous PrFeO3-TiO2 nanocomposites can be considered to be apromising basis for photocatalysts applied in advanced oxidative processes of aqueous media purification from organic pollutants.

Facile thermal synthesis of g-C3N4/ZnO nanocomposite with antibacterial properties for photodegradation of Methylene blue

Semiconductors as photocatalysts are ideal materials for wastewater remediation. A nanocomposite of g-C3N4 and ZnO was produced using a two-step in-situ synthesis technique to achieve a better photocatalyst. The samples were assessed via UV-vis diffuse reflection spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, Fourier transform infrared analysis, and X-ray diffraction. The photodegradation of methylene blue as an organic dye model was assessed to examine the photocatalytic properties of the synthesized samples. The antibacterial characteristics of synthesized samples were also investigated. The findings revealed that the photodegradation efficiency of the binary g-C3N4/ZnO systems was greater than that of pristine g-C3N4. Under irradiation, the photodegradation yield of g-C3N4/ZnO with a 15 wt.% of ZnO was up to 3.5 times better than that of pristine g-C3N4. The feature of enhanced separation of photoinduced holes and electrons resulting from heterojunction formation between g-C3N4 and ZnO surfaces might be attributed to this photocatalytic activity enhancement. The synthesized binary nanocomposites showed good antibacterial properties against Escherichia coli and Staphylococcus aureus bacteria.

Preparation of BiOCl/Bi2WO6 Photocatalyst for Efficient Fixation on Cotton Fabric: Applications in UV Shielding and Self-Cleaning Performances

In this work, a visible-light-driven BiOCl/Bi2WO6 photocatalyst was obtained via a facile hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), ultraviolet/visible light diffuse reflection spectroscopy (UV/Vis), and photocurrent (PC). BiOCl/Bi2WO6 was modified with (3-chloro-2-hydroxypropyl) trimethyl ammonium chloride to obtain the cationized BiOCl/Bi2WO6. Cotton fabric was pretreated with sodium hydroxide (NaOH) and sodium chloroacetate solution to obtain carboxymethylated cotton fabric, which was further reacted with cationized BiOCl/Bi2WO6 to achieve finished cotton fabric. The cotton fabrics were characterized by Fourier-transform infrared spectroscopy (FT-IR), XRD, SEM, and EDS. The photocatalytic activity of the BiOCl/Bi2WO6 photocatalyst and cotton fabrics was assessed by photocatalytic degradation of MB (methylene blue) solution under simulated visible light. The self-cleaning property of cotton fabrics was evaluated by removing MB solution and red-wine stains. Results revealed that the coated cotton fabrics exhibited appreciable photocatalytic and self-cleaning performance. In addition, anti-UV studies showed that the finished cotton fabrics had remarkable UV blocking properties in the UVA and UVB regions. Therefore, the finished cotton fabric with BiOCl/Bi2WO6 can provide a framework for the development of multifunctional textiles.

Rational Design and Synthesis of ZnWO4 Nanorods Decorated with SnS Nanodots with Enhanced Visible-Light Photocatalytic Performance

Aiming to construct a direct Z-scheme binary heterostructure for efficient degradation of the organic dye Rhodamine B (RhB), ZnWO4 nanorods decorated with SnS nanodots were rationally designed and prepared via a facile two-step route. Morphological observation and structural study showed that ultra-fine SnS nanodots were anchored on the surface of ZnWO4 nanorods to form an intimate contact between the two components. Such a special structure provided SnS/ZnWO4 nanocomposites with significantly enhanced light harvesting capacity, revealed by the results of UV-vis diffuse reflection spectroscopy (DRS). Photoluminescence (PL) analysis in combination with electrochemical measurements demonstrated that the recombination of photoactivated charge carriers was efficiently inhibited and the transfer of photoactivated charge carriers was successfully achieved due to the introduction of SnS. The degradation rate over SnS/ZnWO4 nanocomposites reached a maximum value at SnS content of 9 wt%. The significantly enhanced photoactivity of SnS/ZnWO4 nanocomposites was imputed to the synergistic effect of the promoted light absorption ability and effective photogenerated charge carriers’ transfer and separation.

Fabrication of clay soil/CuFe2O4 nanocomposite toward improving energy and shielding efficiency of buildings

In this research, the energy and shielding efficiency of brick, fabricated by clay soil, as a practical building material was reinforced using CuFe2O4 nanoparticles. Initially, the nanoparticles were fabricated using the sol–gel method and then loaded in the brick matrix as a guest. The architected samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), diffuse reflection spectroscopy (DRS), field emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HRTEM), vibrating-sample magnetometer (VSM), differential scanning calorimetry (DSC) thermograms, and vector network analyzer (VNA) analyses. IR absorption of the tailored samples was monitored under an IR source using an IR thermometer. IR absorption and energy band gap attested that inserting the nanoparticles in brick medium led to the acceleration of a warming brick, desirable for energy efficiency in cold climates. It is worth noting that the brick/CuFe2O4 nanocomposite achieved a strong reflection loss (RL) of 58.54 dB and gained an efficient bandwidth as wide as 4.22 GHz (RL > 10 dB) with a thickness of 2.50 mm, meanwhile it shielded more than 58% of the electromagnetic waves at X-band by only a filler loading of 10 wt%. The microwave absorbing and shielding characteristics of the composite are mainly originated from conductive loss, electron hopping, natural and exchange resonance, relaxation loss, secondary fields, as well as eddy current loss. Interestingly, the shielding property of the nanocomposite was significantly generated from its absorbing features, reducing the secondary electromagnetic pollutions produced by the shielding materials applying the impedance mismatching mechanism.

g-C3N4/MoS2 Heterojunction for Photocatalytic Removal of Phenol and Cr(VI)

In this study, molybdenum disulfide (MoS2) decorated on graphitic carbon nitride (g-C3N4) heterostructure catalysts at various weight ratios (0.5%, 1%, 3%, 10%, w/w) were successfully prepared via a two-step hydrothermal synthesis preparation method. The properties of the synthesized materials were studied by X-ray diffraction (XRD), attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FT-IR), UV–Vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM) and N2 porosimetry. MoS2 was successfully loaded on the g-C3N4 forming heterojunction composite materials. N2 porosimetry results showed mesoporous materials, with surface areas up to 93.7 m2g−1, while determined band gaps ranging between 1.31 and 2.66 eV showed absorption over a wide band of solar light. The photocatalytic performance was evaluated towards phenol oxidation and of Cr (VI) reduction in single and binary systems under simulated sunlight irradiation. The optimum mass loading ratio of MoS2 in g-C3N4 was 1%, showing higher photocatalytic activity under simulated solar light in comparison with bare g-C3N4 and MoS2 for both oxidation and reduction processes. Based on scavenging experiments a type-II photocatalytic mechanism is proposed. Finally, the catalysts presented satisfactory stability (7.8% loss) within three catalytic cycles. Such composite materials can receive further applications as well as energy conversion.

Deposition of colloidal metal nanoparticles on zinc oxide nanorods and their influence on visible photoluminescence

We examine the influence of colloidal Au and Ag nanoparticles (NP) on hydrothermally grown ZnO nanorods (NR). Individual 60 nm diameter NP and small NP assemblies without formation of large aggregates were deposited on poly-L-lysine covered NR films using the dip-coating method. The evaluation of morphological and optical properties of the obtained ZnO-metal hybrids was done using scanning electron microscopy, photoluminescence (PL) and diffuse reflection spectroscopy. The presence of Au NP selectively suppressed the PL components near 560 nm wavelength associated with ZnO surface defects, whereas equally sized Ag NP resulted in a much smaller change of PL signal, barely above the noise level. The presented results may be useful for tuning the optical properties of hybrid materials in development of sensor or photovoltaic devices.

Mixed anionic double sodium-cobalt(II) diorthodiphosphate: structure and growing of single-crystals

The solubility of cobalt oxide was determined in the melts of the system Na2O–P2O5–CoO–NaF in a wide range of molar ratios Na2O:P2O5 (0.5–2.0) and temperatures of 800–9000C at the sodium fluoride content of 10 wt.% and 20 wt.%. The region of existence and optimal conditions for growing monocrystals of complex phosphate Na4Со3(PO4)2P2O7 in the melts of the system Na2O–P2O5–CoO–NaF was found out. The synthesized compound was investigated using a number of physicochemical methods (IR spectroscopy, diffuse reflection spectroscopy, X-ray phase analysis, X-ray structure analysis and differential thermal analysis). The complete chemical analysis of the synthesized compound was performed and the melting temperature was determined 7650С, without decomposition). The X-ray diffraction analysis of Na4Со3(PO4)2P2O7 single crystals was carried out and the unit lattice parameters were determined. Phosphate crystals belong to the rhombic crystal system, sp. gr. Pna21; crystal lattice parameters are as follows: a=18.021(1) Å, b=10.389(2) Å, c=6.532(2) Å, V=1222.47(1) Å3, Z=4, сcalc=3.47 g cm–3. The following specific features of the structure of complex phosphate Na4Со3(PO4)2P2O7 have been established: the presence of conduction channels for the sodium ion along the oy axis and the presence of differently coordinated Na and Co polyhedra with an uncharacteristic coordination number. The optimal conditions for the growth of complex phosphate single crystals with a high weight yield were selected. The use of the synthesized compound Na4Со3(PO4)2P2O7 as a functional material with ion conductivity was suggested.

Photocatalytic Dye Degradation and Biological Activities of Cu-Doped ZnSe Nanoparticles and Their Insights

Environmental nanotechnology has received much attention owing to its implications on environmental ecosystem, and thus is promising for the elimination of toxic elements from the aquatic surface. This work focuses on Cu-doped ZnSe nanoparticles using the co-precipitation method. The synthesized Cu-doped ZnSe nanoparticles were examined for structural, optical, and morphological properties with the help of XRD, FTIR, UV/vis diffuse reflection spectroscopy (DRS), FESEM, TEM, and XPS. The synthesized Cu-doped ZnSe nanoparticles revealed the presence of Cu2+ in the ZnSe lattice, which has been shown to take a predominant role for enhanced catalysis in the Cu-doped ZnSe nanoparticles. The synthesized Cu-doped ZnSe nanoparticles were investigated for their catalytic and antibacterial activities. The 0.1 M copper-doped ZnSe nanoparticles exhibited the highest rate of degradation against the methyl orange dye, which was found to be 87%. A pseudo-first-order kinetics was followed by Cu-doped ZnSe nanoparticles with a rate constant of 0.1334 min−1. The gram-positive and gram-negative bacteria were used for investigating the anti-bacterial activity of the Cu-doped ZnSe nanoparticles. The Cu-doped ZnSe nanoparticles exhibited enhanced photocatalytic and antibacterial activity.

Structural and UV-Vis Diffuse Reflection Spectroscopy Studies of Nanosized Sr0.5Ba0.5Nb2O6 synthesized by Co-Precipitation method

The Sr0.5Ba0.5Nb2O6 (SBN-50) is Synthesis by coprecipitation method in nanoscale. TG/DTA shows the reaction and tetragonal phase formation occur at low temperatures, due to which the good homogeneity and morphology of the particles is observed. The average size of the particles was found to be ~ 45 nm. The lattice parameters is found very close to the reported values of single crystals despite method of synthesis and size of the particles. A reflectance spectrum in UV and visible regions shows less reflectance for 337nm and 519nm respectively.