UV Vis Diffuse Reflectance Research Articles

Photocatalytic reduction of nitroarene derivatives by impressive visible-light active Co3O4-QDs/Mn3O4 nanocomposite

A visible light active Co3O4-quantum dots (QDs)/Mn3O4 nanocomposite was successfully synthesized by a straightforward precipitation approach. Notably, the formation of Mn3O4 nanosheets in composite structure was evidenced by different physicochemical techniques especially transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and N2 sorption analyses, which indicated the uniform distribution of Co3O4-QDs with small size of around 5 nm on the surface of Mn3O4 nanosheets along with the enhancement of specific surface area for final composite. Also, the persistence of Co3O4-QDs during nanocomposite synthesis was analyzed by X-ray diffraction (XRD), FT-IR and TEM techniques. The diffuse reflectance UV–Vis and electrochemical impedance spectroscopies revealed the reduction of band gap energy and enhanced charge separation efficiency for Co3O4-QDs/Mn3O4 nanocomposite, respectively, which consequently led to improved photocatalytic response in comparison with bare Co3O4-QDs and Mn3O4 nanosheets. The as-prepared nanocomposite exhibited excellent photocatalytic activity in the reduction of a wide range of substituted nitroarenes with the yields of higher than 80 % relative to the corresponding arylamines, using N2H4·H2O as the hydrogen source and ethanol as green solvent at 25 °C and ambient pressure under visible light illumination. The synergistic effect could improve the production of active hydrogen atoms, therefore, the reasons for this transformation over the prepared nanocomposite under benign conditions are fully discussed. Furthermore, the nanocomposite could be easily recycled without decay in photocatalytic activity for at least five successive cycles.

Ag QDs modified BiOCl/UiO-66-NH2 Z-scheme heterojunction for accelerated visible light-driven photocatalytic degradation of ciprofloxacin

Ag quantum dots (QDs) anchored on the surface of BiOCl/UiO-66-NH2 Z-scheme heterojunctions were synthesized and characterized by various techniques such as X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (UV–vis DRS), electrochemical impedance spectroscopy (EIS), and photoluminescence (PL). The effects of Ag QDs loading, pH values and co-existing anions on the photocatalytic performance were comprehensively analyzed. The results concluded that the Ag QDs modified catalysts exhibited excellent photocatalytic performance for the degradation of ciprofloxacin (CIP), especially, the catalyst with 5 % Ag QDs loading (referred to as ABU-5) achieved a degradation efficiency of 72 % within 120 min and the apparent reaction rate constant was 0.00538 min−1. The outstanding performance of the ABU-5 catalyst is attributed to the introduction of Ag QDs as electron transfer bridges, improving visible light absorption and enhancing charge transfer between BiOCl and UiO-66-NH2. Free radical trapping experiments and leaching tests were carried out to determine the contribution rates of reactive species to the degradation efficiency and the concentration of Ag+ in solution after the reaction. The possible degradation pathways of CIP by ABU-5 were investigated by gas chromatography-mass spectrometry (GC-MS).

Nanocasting synthesis of mesoporous CeO2 particle abrasives from mesoporous SiO2 hard templates for enhanced chemical mechanical polishing performance

Mesoporous abrasive particles exhibit superior chemical mechanical polishing/planarization (CMP) performance, as compared with the corresponding bulk materials. Nevertheless, the lack of control over the shape and particle size or distribution extremely restricts the development of mesoporous abrasives and their potential applications. To overwhelm these drawbacks, pure and ytterbium-doped mesoporous ceria (mCeO2 and mCeYbO2) spheres with well-defined morphology and good uniformity were synthesized via a straightforward nanocasting strategy using high-quality mesoporous silica spheres as hard templates and metal nitrates as precursors. The resulting samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, UV–vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, Zeta potential, and N2 adsorption-desorption measurements. The as-prepared mCeO2 and mCeYbO2 products exhibited enriched surface defects (trivalent Ce, vacancy oxygen, hydroxyls) and polycrystalline porous frameworks with a surface area of up to 160 m2/g and pore size of 4–7 nm. Benefiting from these synergistic attributes, the flexible and defective particle abrasives enabled significant improvements in both surface quality and removal efficiency during oxide-CMP, as compared to commercial CeO2. A possible CMP mechanism was proposed on the basis of the physical contact state, adsorption and adhesion behavior, as well as tribochemical interaction occurred at CeO2–SiO2 interfaces. This work demonstrates highly promising abrasive materials advancement combining architecture and defect engineering towards high-performance oxide-CMP.

Sustainable Solutions for Industrial Wastewater Remediation by KBiFe2O5 Under Visible‐Light Irradiation

AbstractIndustrial wastewater poses a serious threat to human health and the environment. The rising demand for an easy, efficient, environment‐friendly, and cost‐effective method for wastewater treatment has paved the way for the photocatalytic degradation of wastewater. Organic dyes, which comprise a major portion of organic pollutants in industrial wastewater, are highly toxic and carcinogenic. The hydrothermal method, being economical, easily available, and environmentally friendly, is used to prepare the time‐varying KBiFe2O5 samples. KBiFe2O5 is a lead‐free (nonhazardous), low‐bandgap brownmillerite‐structured crystalline material that can use a wide range of solar spectrum. Their phase purity is also confirmed by powder X‐ray diffraction (XRD), UV–Vis diffuse reflectance spectrophotometer (UV–Vis DRS) is done to confirm the bandgap value and Fourier transform infrared (FTIR) spectroscopy is performed to identify the chemical bonds in the material. Degrading textile organic effluent methylene blue (MB) dye under visible light and comparing its photodegradation performance are conducted to investigate the synthesized samples’ photocatalytic properties. The photocatalytic activity is relatively enhanced by adding H2O2 in a precise amount. So, the synthesized samples effectively demonstrate photocatalytic behavior, which has been used for wastewater remediation purposes.

Exploring the structural, morphology, optical and magnetic properties of ZnCoxMn(2-x)O4 prepared using hydrothermal method

Here we report the structural and physical property of ZnCoxMn(2-x)O4 (x = 0, 0.1 and 0.2) materials. The hierarchical ZnCoxMn2-xO4 (x = 0, 0.1 and 0.2) have been successfully synthesized by hydrothermal method. The surface of the ZnCoxMn(2-x)O4 varies according to its composition which is investigated. The absorption and band gap of the material were measured by UV-Vis diffuse reflectance spectroscopy (DRS) in the range of 200 – 800 nm. It was observed that the band gap gets decreased from the parent compound. The room temperature photoluminescence emission spectra of ZnCoxMn(2-x)O4 (x = 0,0.1 and 0.2) has been investigated. The magnetic property of material shows an antiferromagnetic nature. Further, X-ray photoelectron spectroscopy analysis confirms the substitution of Co on Mn site.

Understanding of the effect of concentration of green polysaccharide-based TiO2 for photoelectrochemical, photocatalytic, and antibacterial properties

Composites formed by TiO2/babassu mesocarp were synthesized by the sol-gel method with a percentage variation of 3 % and 5 % (w/v) called 3BBT and 5BBT, respectively. The materials were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), UV–Vis Diffuse Reflectance Spectroscopy, and surface area was calculated by the Brunauer–Emmett–Teller method (BET). Electrochemical studies were carried out, and photocurrent data was obtained as a function of the variation in gallic acid concentration and applied potential. The photocatalytic efficiency of the material was investigated by the degradation of the Methylene Blue (MB) dye under light. The antimicrobial activity of the materials was tested on Gram-positive and Gram-negative strains. XRD showed that the composites obtained are in the anatase crystallographic phase, and the increase in the percentage of babassu mesocarp influenced the reduction of peak intensity and crystallite size. The microscopy showed a more porous aspect of the 3BBT material and a denser aspect of the 5BBT material. It was confirmed by textural characterizations, which showed reduced pore volume and specific surface area of 5BBT compared to 3BBT. Increasing the percentage of polysaccharides caused a reduction in the band gap energy of TiO2 (Eg = 2.90 eV and Eg = 2.47 eV for 3BBT and 5BBT, respectively). The electrochemical study showed that the composites could detect gallic acid, providing increased sensitivity according to the increased applied photocurrent. They also showed good precision for the photoelectrochemical measurements, as verified in the repeatability test (2.66 % and 3.68 % RPD for 3BBT and 5BBT, respectively). The 3BBT showed greater photocatalytic capacity, discoloring 63.4 % of the MB dye in 120 min under light and electrons are the main species involved in photocatalytic activity demonstrated by 3BBT. Antibacterial tests indicated that the 5BBT material exhibits a greater capacity to inhibit E. coli and S. aureus bacteria.

Preparation of pigmentary grade bismuth vanadate Bi4V2O11 via coprecipitation method

ABSTRACT In this study, Bi4V2O11 pigments were synthesized using a coprecipitation method, and the pH value and calcination temperature were optimized from the viewpoint of red colorant. The obtained samples were characterized by XRF, XRD, Rietveld refinement, TEM, UV–vis diffuse reflectance spectrometry, SEM, XPS and color measurements. It was found that Bi4V2O11 samples with single-phase monoclinic structure could be prepared, when the calcination temperatures were 973 and 1073 K. The obtained single-phase Bi4V2O11 samples exhibited reddish hue. For the sample, which was prepared at pH = 7.0 and calcined at 973 K, its color coordinates were L* = 46.41, a* = +27.41, b* = +26.09.

Tuning the local structure of (Sm, Co) Co-doped Al2O3 system for optical band gap and low dielectric loss

This study is about the qualitative description of the high dielectric constant (>103) and low dielectric loss in a two co-existing phases. According to earlier beliefs, a material with high dielectric constant will exhibit high dielectric loss. However, this study gives the opposite, where a material with high dielectric constant can exhibit low loss. Herein, we report on the effect of tetrahedral – octahedral interaction in a γ- Al2O3 and CoAl2O4 biphasic system. Phase identification was carried out using Synchrotron x-ray carrying a wavelength of 0.7 Å. The disorder caused by varying cobalt (Co) concentration results in a two co-existing phase system with varying local polarizability due to mixing of cations in a host matrix. In addition, a decreasing trend in the band gap energy has been observed for both the phases as a function of increasing Co concentration, which is attributed to the intra-gap localized density of states determined from the UV–Vis diffuse reflectance spectroscopy (DRS).

Extended Interfacial Charge Transference in CoFe2O4/WO3 Nanocomposites for the Photocatalytic Degradation of Tetracycline Antibiotics.

The large-scale utilization of antibiotics has opened a separate chapter of pollution with the generation of reactive drug-resistant bacteria. To deal with this, in this work, different mass ratios of CoFe2O4/WO3 nanocomposites were prepared following an in situ growth method using the precursors of WO3 and CoFe2O4. The structure, morphology, and optical properties of the nanocomposite photocatalysts were scrutinized by X-ray diffraction (XRD), UV-visible diffuse reflectance spectra (UV-Vis DRS), photoluminescence spectrum (PL), etc. The experimental data signified that the loading of CoFe2O4 obviously changed the optical properties of WO3. The photocatalytic performance of CoFe2O4/WO3 composites was investigated by considering tetracycline as a potential pollutant. The outcome of the analyzed data exposed that the CoFe2O4/WO3 composite with a mass ratio of 5% had the best degradation performance for tetracycline eradication under the solar light, and a degradation efficiency of 77% was achieved in 20 min. The monitored degradation efficiency of the optimized photocatalyst was 45% higher compared with the degradation efficiency of 32% for pure WO3. Capturing experiments and tests revealed that hydroxyl radical (·OH) and hole (h+) were the primary eradicators of the target pollutant. This study demonstrates that a proper mass of CoFe2O4 can significantly push WO3 for enhanced eradication of waterborne pollutants.

Synthesis of corn straw based carbon doped Nb2O5 as photocatalysts for Rhodamine B degradation under visible light illumination

Developing efficient visible light photocatalytic materials has always been a challenge for researchers. We have successfully prepared a series of corn straw based carbon doped Nb2O5 with excellent photocatalytic performance under visible light. A series of characterizations were carried out on the synthesized materials, including power X-Ray diffraction (XRD), scan electron microscopy (SEM), nitrogen adsorption, UV–vis diffuse reflectance spectra, X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of the synthesized samples was investigated under visible light irradiation using Rhodamine B as the degradation target. Under visible light irradiation for 30 min, C/Nb2O5 can decompose Rhodamine B by 97.1 %, and the photocatalytic performance remains unchanged after 5 cycles. In the article, the contributions of three active substances involved in the photodegradation of Rhodamine B were studied through scavenger study, and the mechanism of C/Nb2O5 photodegradation of Rhodamine B was analyzed. This research is of great significance for the application of biomass materials and the improvement of environmental quality, and also provides new ideas for designing and synthesizing new composite functional materials.

Enhanced hypersensitive (5D0→7F2) transition characteristics of Eu3+ doped β-Ga2O3 microrods

Exploring and realizing the luminescence characteristics of rare earth metal (RE) ions doped gallium oxide (Ga2O3) is crucial for developing optoelectronic device applications. The current research used the solid-state reaction approach to synthesize Ga2O3 microrods doped with various europium (Eu3+) concentrations (0.1, 0.2, 0.3, 0.5, 0.75, and 1 mol). X-ray diffraction (XRD) and Raman spectral analyses confirm the monoclinic structure of β-Ga2O3. The intensity of the Raman phonon modes decreased and a peak shift was observed for Eu:β-Ga2O3. The electron microscopy (SEM, TEM) images depicted a nearly uniform distribution of microrods for undoped and Eu:β-Ga2O3 samples. The interplanar distance (d = 0.290 nm, 0.561 nm, and 0.433 nm), from HR-TEM images, corresponding to (0 0 4), (1 0 0), and (1 0 2) crystallographic orientations confirm the monoclinic structure of β-Ga2O3. The elemental mapping images showed a nearly homogeneous Ga, O, and Eu distribution. The UV–visible diffuse reflectance spectroscopy (UV-DRS) showed a notable reduction in the bandgap as the Eu3+ concentration increased. The emission spectra of Eu: β-Ga2O3 microrods showed a narrow red emission at 612 nm (5D0 → 7F2), which relates to the 5D0 → 7Fj (j = 0, 1, 2, 3) energy level arising from an intra-4f transition of Eu3+ ions upon 394 and 465 nm excitation. The red emission was found to increase with Eu content up to 0.5 mol.%. A quenching of emission due to the multipole–multipole interactions was obtained beyond 0.5 mol.% of Eu. The absolute quantum yield (η) calculated for Eu: β-Ga2O3 (0.5 mol.%) was 3.82 %. The luminescence decay curve using the bi-exponential fit and the average lifetime (τ) of the Eu: β-Ga2O3 (0.5 mol.%) was found to be ∼0.172 ms. CIE chromaticity and correlated color temperature analyses of Eu:β-Ga2O3 microrods yielded a red emission with a superior color purity (93 %). The obtained results suggest that Eu:β-Ga2O3 (0.5 wt.%) microrods could be one of the potential candidates for red light sources.

Bioinspired synthesis of calcium magnesium aluminate nanoparticles using aloe vera extract: A promising material for electrochemical sensors, antibacterial and environmental remediation applications

Aloe vera (Aloe barbadensis miller) leaf extract was used in green fuel-assisted microwave synthesis to prepare Calcium Magnesium Aluminate (CMA). The synthesized CMA was characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), Scanning electron microscope (SEM), Energy dispersion spectrometer (EDAX), and Transmission Electron Microscopy (TEM) analyses. X-ray diffraction confirmed the formation of Ca2Mg2Al28O46. The UV–Vis diffuse reflectance (DRS) technique was employed to investigate its absorbance spectrum, and the band gap of CMA was found to be 4.9 eV. The CMA nanoparticles were used to design a sensing electrode for creatinine, enabling the determination of its concentration in human samples and heavy metals. Acid Orange-88 dye was degraded using CMA nanoparticles as a photocatalyst under UV irradiation. After dye degradation, treated water was used to grow Vigna radiata plants to test their suitability for seedling growth. This report demonstrates that CMA photocatalysts are alternatives to semiconductor photocatalysts for the degradation of Acid Orange-88 dye under UV illumination. Escherichia coli (E. coli), Staphylococcus species, and Pseudomonas species were used as model organisms to assess the antibacterial activity of CMA NPs through a green route.

Enhancement Study of the Photoactivity of TiO2 Photocatalysts during the Increase of the WO3 Ratio in the Presence of Ag Metal

Nanocomposites (NCs) consisting of 4%Ag/x%WO3/TiO2, with varied concentrations (x = 1, 3, 5, 7 wt.%) of WO3, were successfully synthesized using the sol-gel process to examine their photocatalytic performance. The synthesized 4%Ag/x%WO3/TiO2 nanopowder was characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (UV–vis DRS), photoluminescence (PL), and Brunauer–Emmett–Teller (BET) surface area analysis to elucidate its physicochemical properties. The photocatalytic evaluation revealed that the Ag/1%WO3/TiO2 nanocomposite exhibits 98% photoreduction efficiency for Cr(VI) after 2 h under visible light due to the impact of the plasmonic effect of Ag atoms. In addition, the Ag/4%WO3/TiO2 shows about 95% photooxidation efficiency for methylene blue (MB) dye after 4 h.

Boosting photocatalytic efficiency and nonlinear optical response of graphitic carbon nitride by infusing carbon nanotubes

Nanostructured materials are widely studied for their light-driven physical and chemical processes, which are key to their potential in photophysical applications. We introduce a one-pot solid-state pyrolysis technique for the synthesis of graphitic carbon nitride/carbon nanotube (g-C3N4/CNT) composites. The formation of the composite was characterized through X-ray diffraction, scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy. Notably, UV-vis diffuse reflectance spectroscopy indicated a reduction in the bandgap of pure g-C3N4 from 2.6 eV to 2.35 eV with the incorporation of 0.5 wt% CNT. The nonlinear optical transmission of the samples was analyzed at 532 nm using the open-aperture Z-scan technique employing 5 ns laser pulses, revealing a twelve-fold increase in the two-photon absorption coefficient (b) for g-C3N4/CNT0.5 compared to pristine g-C3N4. Remarkably, g-C3N4/CNT0.5 showed enhanced photocatalytic efficiency in degrading bisphenol A (BPA), with the kinetic constant (k) being ten times higher than that of pure g-C3N4. The improved photocatalytic performance of g-C3N4/CNT0.5 is attributed to the presence of CNTs, which act as effective electron acceptors and transfer channels, significantly enhancing the separation of photogenerated charge carriers in g-C3N4, as evidenced by the decreased intensity in the photoluminescence spectrum.

Shear strength and optical bandgap in As2Se3 glasses permanently compacted under GPa pressures

The application of GPa pressures on glassy As2Se3, at temperatures just below and above its glass transition, leads to permanently compacted glasses that exhibit increased densification. Also, melt-quenching of the same glass under a pressure of 7 GPa gives rise to the formation of its crystalline β-phase. The structure of these As2Se3 compacted solids have been explored by X-ray diffraction. Measurements of 10 MHz ultrasound velocities reveal that the density increase is associated with a substantial hardening of the elastic continuum as well as a growing shear strength of glassy solids: the shear modulus G increases by more than 35 % and the Poisson's ratio ν decreases by more than 13 %. The optical properties have been investigated by UV–VIS diffuse reflectance spectroscopy, which shows a well defined linear reduction of the optical bandgap Eg with increased density. All of these observations have been explained by considering a disordered layered structure of glassy As2Se3, where densification produced by compaction under GPa pressures gives rise to a progressive strengthening of the interlayer interactions.

Exploring the defect formation and ionic migration in A2Zr2O7 (A = La, Ce, Nd, and Gd) Pyrochlore solid-state electrolytes

This study investigated the potential of A2Zr2O7 pyrochlore phase oxides (A = La, Ce, Nd, and Gd) as solid oxide fuel cell (SOFC) electrolyte materials. A2Zr2O7 ceramics were synthesized using the sol-gel process, and their disordered pyrochlore structure was confirmed by X-ray Diffraction and Rietveld refinement. Field Emission Scanning Electron Microscopy (FE-SEM) was used to examine the morphology of the materials, while X-Ray Photoelectron Spectroscopy (XPS) confirmed a high oxygen ion concentration. UV–Vis Diffuse Reflectance Spectroscopy (DRS) and density of states calculations consistently showed similar bandgap patterns in all zirconate pyrochlore. Density Functional Theory (DFT) simulations provided insights into the electronic structure and migration pathways. A two-probe conductivity study confirmed the relation between the ionic conductivity and ordering degree of pyrochlore. At 750 °C, LZO, CZO, and GZO exhibited ionic conductivity values of 5.44 × 10−3 S/cm, 3.00 × 10−3 S/cm, and 2.01 × 10−3 S/cm respectively, while NZO demonstrated a conductivity of 1.27 × 10−2 S/cm at 700 °C, which is higher than that of the other samples. This study favours the use of the sol-gel route for processing zirconate pyrochlore materials, highlighting its ability to achieve high densities at lower temperatures and exhibit enhanced ionic conductivity. A2Zr2O7 has emerged as a promising oxide-ion conducting solid electrolyte for intermediate temperature SOFC applications within the 600–750 °C temperature range.

Z-scheme heterojunction of TiO2/NH2-MIL-125(Ti) growing on carbon fibers cloth: Photocatalytic degradation of tetracycline and toxicity analysis

Photocatalysis stands out as a promising and eco-friendly method for antibiotics removal, yet traditional photocatalysts, mainly in powder form, are often prone to detachment and loss, making them difficult to recycle and reuse. In this work, we address this challenge by using carbon fiber (CF) cloth with a large area as a carrier for catalysts. To improve the photocatalytic efficiency, we synthesized TiO2 nanorods on the surfaces of CF cloth and incorporate NH2-MIL-125 (Ti) on them, thus the Z-scheme heterojunctions CF/TiO2/NH2-MIL-125(Ti) was obtained. In order to fully understand the structural properties and performance advantages of CF/TiO2/NH₂-MIL-125 (Ti) composites, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron spectroscopy (XPS), UV–visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), Brunauer-Emmett-Teller (BET), Mott-Schottky (M-S) and valence band X-ray photoelectron spectroscopy (VB-XPS). Due to the special electronic transmission path of the Z-scheme heterojunctions, the CF/TiO2/NH2-MIL-125(Ti) composite achieve 95.30 % degradation of tetracycline (TC) within 210 min. The composite also shows exceptional reusability, with a degradation rate of 93.55 % maintained even after four cycles. Finally, we proposed a pathway and catalytic process for the decomposition of TC by CF/TiO2/NH2-MIL-125(Ti) and performed toxicity assessments of TC and its precursors using T.E.S.T. software. This novel photocatalyst composite offers a green and efficient approach for treating antibiotic wastewater, presenting a significant advancement in environmental remediation strategies.

Green synthesis of TiO2@g-C3N4 nanocomposites for the photocatalytic degradation of pesticides and toxic organics present in water and wastewater

To address the environmental challenges caused by toxic organics in aquatic systems, photocatalytic degradation is a promising option. This study investigates the green synthesis of TiO2@g-C3N4 nanocomposites by coupling Titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) in different mass ratios through solvothermal technique due to their photocatalytic properties. Leaf extract from the Ziziphus jujube plant was utilized as a green template making the synthesis environmentally friendly, utilizing renewable resources, and employing facile and cost-effective methods. The nanocomposites were characterized using various analytical techniques including UV–Vis Diffuse reflectance spectroscopy (UV–Vis DRS), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS) to analyze the structural and morphological properties. The wavelength ranged from 385 to 454 nm and band gap energies ranged from 3.22 to 2.73 eV for the synthesized materials. The pure green TiO2 showed the highest band gap energy while pure g-C3N4 showed the lowest band gap energy among the synthesized materials. The photocatalytic activity of the synthesized nanocomposites was evaluated through the degradation of Bisphenol A and Malathion pesticide under UV light irradiation. The results indicated 71 % degradation of Bisphenol A with the 50 % TiO2@g-C3N4 nanocomposites exhibiting 1.422 x 10-2 min−1 rate constant and 74 % degradation of Malathion degraded over 20 % TiO2@g-C3N4 which depicted rate kinetics of 1.022 x 10-2 min−1. Moreover, both showcased higher performance than the individual TiO2 and g-C3N4 nanostructured materials.

Investigation on luminescent characteristics of Tb3+/Dy3+co-doped boro-phosphate glass for cool white LED and radiation shielding applications

The Tb3+/Dy3+ co-doped Boro-Phosphate Glass (BPANZDyTb) was produced (40 B2O3 + 39P2O5 + 5 Al2O3 + 5 NaF + 10 ZnO + 0.5 Tb2O3 + 0.5 Dy2O3) using melt-quenching technique. X-ray diffraction measurements, Raman, and Fourier Transform Infrared were used to evaluate the structural behavior of the prepared glass. Powder-XRD spectra, in the 10–90° range showed that the prepared glass was amorphous. FTIR analysis reveals that the network contains a variety of structural groups, including B-O-B, BO4, BO, P-O, PO2, P-O-B, and PO4 units. The UV–visible diffuse reflectance spectroscopy was used to record and study the optical linear properties of Tb3+/Dy3+ co-doped Boro-Phosphate Glass (BPANZDyTb). The photoluminescence excitation peak was obtained at 348 nm. The emission peaks were located at 484 nm (4F9/2 → 6H15/2 → blue), 576 nm (4F9/2 → 6H13/2 → yellow), and 662 nm (4F9/2 → 6H11/2 → red). Tb3+ ions are located at 412 nm (5D3 → 7F5), 441 nm (5D3 → 7F4), 546 nm (5D4 → 7F5), and 625 nm (5D4 → 7F3). The result of CIE 1931 chromaticity coordinates indicate that the prepared glass is suitable material for cold white light emitting diode applications due to its color coordinates x = 0.3106 and y = 0.3240 and correlated color temperature (CCT) values about 6768 K. The gamma-ray parameters such as half-value layer (HVL), mass attenuation coefficient (μ/ρ), mean free path (MFP), and effective atomic number (Zeff) of the BPANZDyTb glass were studied using Phy-X software. The results of the gamma-ray parameter show that the Dy3+ ions and Tb3+ ions co-doped BoroPhosphate glass is an appropriate material for radiation shielding applications.

α-Bi2O3 tubular rods coated on Bi2O2CO3 nanosheets for high-performance asymmetric supercapacitor applications

Mixed phases of bismuth oxide nanostructures as an active electrode material in supercapacitor applications have recently gained huge research interest. In this study, the layered Bi2O2CO3 nanosheets and the secondary phase of α-Bi2O3 tubular rods named Bi2O2CO3/α-Bi2O3 heterostructure have been synthesized and utilized for supercapacitor applications. The crystal nature and microstructure of the Bi2O2CO3/α-Bi2O3 heterostructure were initially confirmed by powder X-ray diffraction (p-XRD), Raman, UV-Vis diffuse reflectance spectroscopy (UV-DRS, absorbance), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. X-ray photoelectron spectroscopy (XPS) measurements have investigated the oxidation states and chemical binding energies. Regarding the electrochemical performances, the Bi2O2CO3/α-Bi2O3 heterostructure as electro-active material delivered a maximum specific capacitance (Cs) value of 635 F g−1 at the given current density value of 1 A g−1 in a conventional three-electrode mode. A coin cell type electrode has been fabricated using Bi2O2CO3/α-Bi2O3 heterostructure, resulting in an asymmetric supercapacitor device cell (ASC), which has a Cs of 112 F g− 1 (at 1 A g− 1) and a power density and energy density values of 515 W kg−1 and 22.5 Wh kg−1 respectively. The two supercapacitor electrodes in sequence effectively ignite the red-light-emitting diode (LED). Moreover, in the ASC type Bi2O2CO3 /α-Bi2O3 heterostructure, the specific capacitance value was slightly reduced to 12.3 % by 2000 cycles, showing favourable cyclic performance and stability during the electrochemical process. Based on the above-mentioned characterization, the appropriate electrochemical performances of Bi2O2CO3/α-Bi2O3 tubular rod heterostructures make them a promising candidate for future energy storage devices.