Field Emission Scanning Electron Microscopy Analysis Research Articles

Cellulose Isolation and Characterization of Green Seaweed C. Lentillifera from Halmahera, Indonesia

Caulerpa lentillifera or known as sea grapes is a type of green seaweed which is rich of nutritional components and widespread in the tropical regions in Asia, including Indonesia. Moreover, C. lentillifera contains of polysaccharides, such as cellulose which has the potential to various applications. In this study, C. lentillifera collected from Halmahera, Indonesia was determined for its chemical compositions (moisture, ash, extractives, hemicellulose, α-cellulose contents) and was extracted to obtain cellulose. Isolation of cellulose from C. lentillifera was done by soxhlet extracted using ethanol-benzene solvent to remove extractives, boiling to increase the amount of cellulose extracted, H2O2 bleaching to eliminate any remaining pigments and other contaminants, and freeze drying to get coarse powder of cellulose. The moisture content, ash, extractives, hemicellulose, α-cellulose of C. lentillifera were 11.94%, 31.62%, 11.53%, 35.57%, and 7.95%, respectively. The yield of cellulose obtained was 31.13% based on seaweed dry weight. FE-SEM (Field Emission-Scanning Electron Microscopy) analysis of C. lentillifera showed colonies of diatoms in elliptical shapes. FTIR (Fourier Transform Infrared) measurements indicating cellulose purity after extraction process. X-Ray Diffraction (XRD) analysis resulted some peaks of salt crystals in C. lentillifera and cellulose of C. lentillifera in amorphous form. After extraction, the crystallinity index of cellulose obtained was 37.3%.

Rheological and nano-mechanical characteristics of bituminous mastics containing waste and ordinary filler at different temperatures

This study has focused on the effect of cement kiln dust (CKD) as a waste filler on the rheological and nano-mechanical properties of bituminous mastic in comparison with limestone powder (LSP) as an ordinary filler. Mastics were prepared using three filler to bitumen (F/B) ratios including, 0.4, 0.8 and 1.2. The strategic highway research program (SHRP) standard and multiple stress creep recovery (MSCR) test methods were used to evaluate the behavior at high performance temperatures. Also, SHRP standard and time sweep methods were performed to evaluate the fatigue behavior at medium performance temperatures. Low temperature properties were examined by bending beam rheometer. Field emission scanning electron microscopy (FESEM) was used to evaluate the quality of filler distribution in the mastic. Furthermore, the nano-mechanical properties of mastics were examined by atomic force microscopy (AFM) including topography roughness, elastic modulus and adhesion force. Fundamental evaluations with AFM indicated that, at a constant F/B ratio, CKD filler with a higher fineness and specific surface area showed higher elastic modulus and lower adhesion than LSP. Also, the FESEM analysis for filler distribution showed the highest homogeneity coefficient at F/B ratio of 0.8. A significant relationship was observed between SHRP rutting parameter and creep variables in MSCR method. Both methods indicated a superior rutting resistance for CKD than LSP. Although, there was no clear relationship between SHRP fatigue parameter and the time sweep outcomes.

Synthesis, characterization, and preliminary insights of ZnFe2O4 nanoparticles into potential applications, with a focus on gas sensing

This work presents a hydrothermal-based facile method for synthesizing ZnFe2O4, whose size can be controlled with the concentration of sodium acetate used as a fuel and its physical changes at nanoscales when exposed to two different gases. The structural, morphological, compositional, and electronic properties of the synthesized samples are also presented in this paper. The crystal structure of the synthesized samples was determined using an X-ray Diffractometer (XRD). The results revealed fluctuations in the size, lattice parameter, and strain in the nanoparticles with increasing the concentration of sodium acetate. Field-Emission Scanning Electron Microscopy (FESEM) was used to determine synthesized materials’ morphology and particle size. It revealed that the particles possessed approximately spherical morphology whose size decreased significantly with the increasing amount of sodium acetate. Transmission Electron Microscopy (TEM) was utilized to determine the structure, morphology, and elemental distributions in particles at the nanoscale, and it confirmed the findings of XRD and FESEM analyses. The high-resolution TEM (HRTEM) imaging analysis of the nanoparticles in our studied samples revealed that the particles predominantly possessed (001) type facets. X-ray photoelectron spectroscopy (XPS) and core-loss electron energy loss spectroscopy (EELS) showed an increasing fraction of Fe2+ with the decreasing size of the particles in samples. The Brunauer, Emmett, and Tellers (BET) analysis of samples revealed a higher surface area as the particle size decreases. In addition, the determined surface area and pore size values are compared with the literature, and it was found that the synthesized materials are promising for gas-sensing applications. The ab initio calculations of the Density of States (DOS) and Band structure of (001) surface terminating ZnFe2O4 were carried out using Quantum Espresso software to determine the bandgap of the synthesized samples. They were compared to their corresponding experimentally determined bandgap values and showed close agreement. Finally, in-situ TEM measurement was carried out on one of the four studied samples with robust properties using Ar and CO2 as reference and target gases, respectively. It is concluded from the presented study that the size reduction of the ZnFe2O4 nanoparticles (NPs) tunes the bandgap and provides more active sites due to a higher concentration of oxygen vacancies. The in-situ TEM showed us a nanoscale observation of the change in one of the crystal structure parameters. The d spacing of ZnFe2O4 NPs showed a noticeable fluctuation, reaching more than 5% upon exposure to CO2 and Ar gases.

Synthesis, characterization of Ca (OH)2: TiO2 nanocomposite and evaluation of its antimicrobial efficacy

Introduction and Aim: Root canal treatment is a dental operation that entails the extraction of the compromised tooth pulp tissue, sterilization of the root canal system, and subsequent filling with an inert substance. To mitigate the potential for bacterial infections and subsequent difficulties, it is customary for patients to receive a prescription for antibiotics prior to undergoing a root canal procedure. The objective of this study was to assess the effectiveness of Ca(OH)2: TiO2 nanoparticles as a potential substitute for antibiotics in root canal therapies, while also investigating their antibacterial properties against specific infections. Materials and Methods: Ca (OH)2: TiO2 nanoparticles were synthesized chemically using calcium hydroxide and varying concentrations of titanium oxide powder by a sol-gel process. The Ca (OH)2: TiO2 nanoparticles synthesized was characterized using Field Emission Scanning Electron Microscope (FE-SEM), energy dispersive X-ray (EDX), Fourier Transform Infrared Spectrometer (FT-IR), and UV-Vis spectrophotometry. The antibacterial activity of the synthesized nanoparticles was evaluated against pathogens Escherichia coli, Staphylococcus aureus, and Candida albicans spp.) by gel diffusion method. Results: FE-SEM analysis indicated that the Ca (OH)2: TiO2 composite material exhibited an amorphous structure, characterized by a particle size measuring 25.88 nm. But FTIR was focused on the spectral region between 4000 and 450 cm-1. The absorption spectra of nanoparticles composed of titanium dioxide consistently displayed a prominent peak at a wavelength of 300 nm. The results of the experiment pertaining to the biological effects of composites suggest that the inclusion of TiO2 nanoparticles at concentrations of 25%, 50%, and 75% in the composite material led to a notably wider inhibitory zone in comparison to the use of Ca(OH)2 alone, with a statistically significant p-value of 0.05. Conclusion: The use of varying concentrations of Ca (OH)2TiO2 improves microbial activity against Escherichia coli, Staphylococcus, and Candida.

Hard acid soft base (HSAB) guided morphology engineered copper oxides for efficient photocatalytic degradation of textile effluent under visible light

This study demonstrates the synthesis of morphology guided copper oxide nanostructures (CuO) based on Hard Acid and Soft Base concept (HSAB) and their influence on photocatalytic activity under visible light. Herein, we adopted simple chemical bath approach for the synthesis of CuO nanomaterial with different morphologies by using various precursors of copper such as copper nitrate, copper sulfate and copper chloride. The as-synthesized samples were characterized by means of various analytical techniques namely X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV–Visible absorption spectroscopy (UV–VIS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and Brunauer-Emmett-Teller surface area analysis (BET). FE-SEM analysis revealed that the as-synthesized CuO, displayed precursor depended morphologies, including horse mane, honeycomb, and aggregated cubic shaped morphologies. Notably, horse mane like copper oxide (henceforth referred to as CuO-1) produced using copper nitrate as a precursor, showed 92.18% towards methylene blue (MB) dye degradation within a span of 180 min under visible light illumination. Thus this study opens the door for the synthesis of other metal oxides with distinct morphologies that could be used for potential photocatalytic applications.

PREPARATION, CHARACTERISATION, EVALUATION AND DFT ANALYSIS OF CILNIDIPINE-L-PHENYLALANINE COCRYSTAL

Objective: The objective of this study was to prepare, characterise and evaluate pharmaceutical cocrystals of Cilnidipine using L-phenylalanine as the coformer to enhance the aqueous solubility of Cilnidipine. It was also proposed to study the mechanism of cocrystal formation based on Density Functional Theory (DFT) using Gaussian software. Methods: To overcome the limitation of poor aqueous solubility of Cilnidipine, a 1:1 pharmaceutical cocrystal of Cilnidipine was prepared using L-phenylalanine as the coformer by liquid assisted grinding (LAG) technique. The resultant cocrystals were characterised by Fourier transform-infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and field emission scanning electron microscopy (FE-SEM). They were evaluated for their saturation solubility in water. The mechanism of cocrystal formation was studied at the DFT level of theory. Results: The band broadening of the–NH and–NO peaks in FTIR spectra of Cilnidipine indicated the formation of hydrogen bonds in the prepared cocrystals. A single sharp melting endotherm at 218.40 °C in the DSC curve confirmed the formation of cocrystals. The appearance of new peaks in the PXRD pattern of the prepared cocrystals showed the formation of a new crystalline phase. FE-SEM analysis also confirmed the above findings. The prepared cocrystals exhibited 3.31 folds enhancement in saturation solubility. The DFT analysis showed the formation of intrmolecular hydrogen bonding between the–NO of Cilnidipine and–NH of L-phenylalanine. Conclusion: The present study demonstrated a successful approach for enhancing the solubility of poorly water-soluble drug Cilnidipine by cocrystallisation technique using L-phenylalanine as the coformer.

Fabrication and characterization of PANI-based sandwiched photodetector devices on n-Si and ZnO nanorods: Performance evaluation

This study focuses on the fabrication and characterization of simple sandwiched photodetector devices based on polyaniline (PANI) with various configurations: ITO/PANI/n-silicon, and ITO/PANI/ZnO nanorods (NRs)/n-silicon. The PANI polymer was synthesized from the polymerization of aniline, and the ZnO NRs were grown via hydrothermal method. The fabricated devices were analyzed via field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and current-voltage (I-V) measurements. FESEM analysis revealed distinct PANI structures at the center and edge of the samples, with dendrites forming at the edge and mesh-like structure at the center due to solvent effect during deposition. The addition of PANI as an interlayer in the nSi/ITO junction enhanced the contact and improved carrier separation. However, the performance of the PANI-ZnO NRs devices was mixed, whereby performing better than ITO/ZnO NRs/nSi at zero bias voltage but otherwise at higher bias voltages. The thick PANI layer improved light absorption and reduced dark current but allowed increased hole-electron recombination, reducing overall performance. ITO/PANI/nSi recorded the highest normalized photocurrent-to-dark current ratio (NPDR) at 0 V bias of 50870 W−1 under 385 nm illumination. ITO/ZnO NRs/nSi sandwiched device obtained the highest responsivity value at 0.253 A W−1 at − 8 V bias under 385 nm illumination.

Pore Structure Alteration of Shale with Exposure to Different Fluids: The Longmaxi Formation Shale in the Sichuan Basin, China

The interaction between shale and various fluids is crucial as it modifies pore structures, which govern the effective development of shale gas and the geological storage of carbon dioxide in shale formations. In this study, samples from the Longmaxi Formation shale in Sichuan Basin of China were exposed to different fluids, including 6 MPa CO2, 12 MPa CO2, 6 MPa CO2+brine, and 12 MPa CO2+brine, at 45 °C for 100 days. Various methods, including X-ray diffraction (XRD), X-ray fluorescence (XRF), field-emission scanning electron microscopy (FESEM), and the low-pressure gas adsorption (N2) test, were adopted to evaluate chemical and structural changes during the exposure process. After being treated with supercritical CO2+brine and subcritical CO2+brine, the shale underwent significant changes in its major element composition. The content of Ca, Al, and K in shale saturated with supercritical CO2+brine decreased from 13.00% to 10.34%, from 3.65% to 3.36%, and from 1.56% to 1.37%, respectively. Meanwhile, the content of Si and Na in the same shale increased slightly after saturation. The amount of quartz and dolomite increased, while the levels of clay and calcite slightly decreased. The surface of the shale sample became rougher and small bumps and cracks appeared after saturation with different fluids, as shown by the FESEM analysis results. Furthermore, the changes in both the total pore volume and pore size followed a similar pattern to the alterations in the specific surface areas. The highest level of variation occurred with the shale that was saturated with 12 MPa of CO2, indicating that gas pressure and CO2 phase state have a significant influence on the shale’s pore structure. In addition, the distribution of pore sizes showed a bias towards larger sizes across all diameters; this suggests that the reaction resulted in a decrease in the number of micropores. This also highlights that the impact of varying fluid saturation was primarily focused on micropores and macropores. The results of this study provided experimental evidence to further test the mechanisms and permeability of geological storage of CO2 in organic-rich self-sourced shale.

Occurrence Characteristics of Chang 7 Shale Oil from the Longdong Area in the Ordos Basin: Insights from Petrology and Pore Structure

Organic geochemistry experiments, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N2 adsorption, CO2 adsorption, and two-dimensional nuclear magnetic resonance (2D NMR) were performed on ten Chang 7 shale samples (Longdong area, Ordos Basin) to elucidate their pore structure and the characteristics of oil occurrence. Moreover, the factors influencing free oil were discussed, and an occurrence model was established. FE-SEM analysis reveals that the pore types include interparticle pores, intraplatelet pores within clay aggregates, rare fracture pores, and organic matter (OM) pores. The pores are predominantly slit-shaped. The development of micropores was mainly contributed to by OM. Quartz and clay minerals influence the development of macropores and mesopores, feldspar mainly controls macropore development, and pyrite most strongly affects micropore development. Micropores and mesopores constitute the main total pore specific surface area, while mesopores and macropores are the main contributors to the total pore volume. Pores > 2 nm are the main storage spaces for shale oil, and free oil mainly occurs in pores > 20 nm. Adsorbed oil and free oil were assessed by NMR T1–T2 mapping. The adsorbed oil signal intensities range from 7.5–23.4 a.u. per g of rock, and the free oil signal intensities range from 4.4–23.2 a.u. per g of rock. The free oil proportions are 15.9–70.6% (average of 44.2%). The free oil proportion is negatively correlated with the clay mineral content and total organic carbon (TOC) content but positively correlated with the saturated hydrocarbon content and volume of pores > 20 nm. The results of this study could help optimize favorable shale oil target areas.

Influence of ultraviolet irradiation on the optical properties and biological activity of copper nanoparticles prepared by pulsed laser ablation

In this study, we synthesized colloidal copper nanoparticles (CuNPs) utilizing Q-switched Nd:YAG laser ablation on a copper plate immersed in double-distilled water at energies of 200 and 400 mJ, respectively, with 100, 200, 300, 400, and 500 pulses. The size and optical properties of nanoparticles were determined using a UV–Vis spectrophotometer, a transmission electron microscope (TEM), and a field emission scanning electron microscope (FE-SEM). The absorption spectra exhibited two surface plasmon resonance peaks (λSPR), one at 217 nm for copper oxide nanoparticles (CuONPs) and the other at 636 nm for CuNPs, with the increase in laser pulses. Consequently, the optical bandgap increased by roughly 3 eV. The TEM and FE-SEM analyses showed nearly spherical Cu nanoparticles with average diameters of 33 and 38 nm for laser energies of 200 and 400 mJ, respectively. An analysis of x-ray diffraction patterns revealed that CuONPs contained the crystallographic planes of a monoclinic and an orthorhombic crystal system. Additionally, the mean crystallite size of laser-ablated nanoparticles increased with increasing pulse energy. Furthermore, the absorption and optical bandgap of CuNPs increased slightly with an increase in ultraviolet irradiation exposure. The results of our study showed an increased inhibitory effect against both Staphylococcus aureus bacteria and Escherichia coli bacteria when CuNPs were irradiated by ultraviolet type C.

Investigation on Sb-doped SnO2 as an efficient sensor for the detection of formaldehyde

The applicability of antimony-doped tin dioxide (Sb-doped SnO2) as a very precise sensor for detecting formaldehyde (HCHO) gas is investigated in this study. The sol-gel method was used to prepare pure SnO2 and Sb-doped SnO2 nanostructures, which resulted in better structural and morphological properties. The prepared samples were analyzed using several characterization techniques, including X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS). A structural investigation indicated the presence of a tetragonal SnO2 phase with a clear preference for the (110) orientation. Furthermore, the crystallite size reduced as the quantity of Sb doping rose. According to FE-SEM analysis, both the undoped (SnO2) and Sb-doped SnO2 samples had polyhedral structures. FTIR analysis verified the presence of organic functional groups in the prepared powder samples. The optical band gap (Eg) values decreased with an increasing concentration of Sb doping in the SnO2 nanostructures. XPS was used to determine the chemical elements of the prepared powder samples. In the gas sensing study, those based on 8 wt% Sb-doped SnO2 (referred to as ATO-8) outperformed the others. At room temperature, the ATO-8 sample demonstrated stronger sensor response, faster response and recovery durations (98 s/74 s), and linear behavior. These enhancements can be attributable to an increase in adsorbed oxygen species caused by Sb doping, highlighting ATO-8's potential as a substance for detecting HCHO. This study emphasizes the potential of ATO-8 as a significant resource for practical use in the detection of HCHO, with benefits such as improved indoor air quality, increased industrial safety, and advancements in environmental monitoring.

Synthesis of silver nanoparticles for use in conductive inks by chemical reduction method

In this study, the chemical reduction method was applied to synthesize silver nanoparticles used to prepare conductive inks. The two variables of polyvinylpyrrolidone (PVP)-stabilized mole in the 0.01–0.03 mol range and hydrazine reducing mole in the 0.1–0.5 mol range, along with constants such as precursor mole (silver nitrate), complexing mole (ethylene diamine) and solvent mole (water), were used. Nine random samples proposed by the Design Expert software were examined and studied. X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) were then used to characterize and evaluate the synthesized nanoparticles. According to the results obtained by XRD, FE-SEM and TEM analyses, the sample with 0.025 mol and 0.3 mol PVP had the minimum size of silver nanoparticles, which was around 20 nm, so it was chosen as the optimal sample for further research. The conductive ink was also prepared with the optimal sample of silver nanoparticles in 40% by weight and then characterized and evaluated by applying ultraviolet–visible (UV–Vis), simultaneous thermal analysis (STA), FE-SEM and electrical conductivity analysis. Finally, conductive ink was applied to polyethylene terephthalate (PET) and acrylonitrile butadiene styrene (ABS) substrates. The surface electrical resistance of conductive ink on PET and ABS substrates was then measured at about 6.4 Ω and 2.2 Ω, respectively.

Enhanced photocatalytic degradation of crystal violet dye and high-performance electrochemical supercapacitor applications of hydrothermally synthesised magnetic bifunctional nanocomposite (Fe3O4/ZnO)

The present investigation employed a facile hydrothermal approach for the fabrication of Fe3O4/ZnO dual-functional magnetic nanocomposite. Supercapacitor and visible-light-driven photocatalytic applications of the material were explored. X-ray diffraction, Fourier transform infrared spectra, ultraviolet–visible diffuse reflectance spectra (UV–vis/DRS), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray spectroscopy, and vibrating sample magnetometer were used to analyse the nanocomposite’s structural, morphological, optical, and magnetic properties. The FE-SEM analysis demonstrated that the surface morphology of Fe3O4, ZnO, and the Fe3O4/ZnO nanocomposite consisted of nanoparticles, nanoflakes, and nanoparticles adhered to the nanoflakes, respectively. The maximum specific capacitance of the electrode based on the Fe3O4/ZnO nanocomposite was measured to be 736.36 Fg−1 at a scan rate of 5 mVs−1. The electrode also demonstrated remarkable cycling stability, retaining 86.5% of its capacitance even after 3000 cycles. The Fe3O4/ZnO nanocomposite was found to have an optical bandgap of 2.7 eV, an average particle size of 22.5 nm, and a saturation magnetization of 68.7 emu g−1. The photocatalysis experiment was conducted using the optimised settings, which included a pH of 7.0, a dye concentration of 30 mg l−1, a catalyst dose of 1 g l−1, and a contact time of 120 min. The Fe3O4/ZnO nanocomposite exhibited a notable degradation efficiency towards crystal violet dye upon exposure to visible light, achieving a degradation efficiency of 96.9%. This performance surpassed that of pure ZnO, which attained a degradation efficiency of 70.2%. The nanocomposite exhibited a rate constant of 2.80 × 10−2 min−1, which was found to be notably higher than that of pure ZnO (0.8 × 10−2 min−1), as determined through modelling (pseudo-first order linear fit). The radical scavenger experiments indicated that the superoxide radicals and hydroxyl radicals are the primary reactive species. The Fe3O4/ZnO photocatalyst can be effectively isolated using a bar magnet. Remarkably, the photocatalytic efficiency of the material remained almost entirely intact even after undergoing four cycles of recycling. In addition, this research opens up exciting new possibilities for use in fields like energy storage and pollution control.

Strength retrieval and microstructural characterization of Bacillus subtilis and Bacillus megaterium incorporated plain and reinforced concrete

This study aims to develop a self-healing concrete by using Bacillus subtilis and Bacillus megaterium as self-healing agents and subsequently extend the application to structural elements. Bacillus subtilis and Bacillus megaterium were directly incorporated in concrete at 0.5%, 1.0%, and 1.5% by weight of cement. Compression test, flexural strength test, and split tensile test were performed to analyse the strength properties of self-healing concrete. The self-healing efficiency of plain concrete was determined in terms of regain in compressive strength by testing standard pre-cracked concrete cube specimens, while as for reinforced concrete beams, self-healing efficiency was determined by means of repeated four-point load test (4PLT) and non-destructive testing (NDT). In addition to regain in compressive strength of plain concrete specimens, a significant recovery in flexural strength and crack depth was observed in both the Bacillus subtilis incorporated reinforced concrete (BSRC) beam and Bacillus subtilis incorporated reinforced concrete (BMRC) beams after 56-days of curing. The effect of Bacillus subtilis and Bacillus megaterium on water absorption capacity of concrete was studied and a significant reduction in water absorption capacity was observed. Microstructural analysis in the form of X-Ray Diffraction and Field Emission-Scanning Electron Microscopy analysis was also conducted on concrete samples. The microstructural analysis confirms the calcite precipitation by bacteria in cracks which attributes to the strength retrieval of cracked concrete specimens.

Amplified Dielectric Properties of PVDF-HFP/SrTiO3 Nanocomposites for a Flexible Film Capacitor.

A simple solution casting technique was used to fabricate perovskite strontium titanate (SrTiO3)-loaded poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) nanocomposite films for efficient energy storage applications. Various microscopic and spectroscopic methods were used to study the characteristics of the polymer nanocomposite films, like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction technique (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible spectroscopy, thermogravimetric analysis, and mechanical tensile test (stress vs strain). The FTIR, XRD, and FESEM analyses confirmed the incorporation and proper dispersion of SrTiO3 nanoparticles in the PVDF-HFP polymer matrix. An improvement in the optical, thermal, and mechanical behavior of the nanocomposite film was observed compared to the pure polymer. The values of dielectric constant, loss tangent, and AC conductivity of pure PVDF-HFP polymer and PVDF-HFP/SrTiO3 nanocomposites (2, 6, and 10 wt % SrTiO3 loadings) were analyzed in a temperature and frequency span of 30-150 °C and 1-100 kHz, respectively. To better understand the electrical properties of the materials, Nyquist plots were generated, and their related circuit designs were fitted. The 2 wt % SrTiO3 loaded nanocomposite exhibited the highest dielectric enhancement and AC conductivity compared to higher filler-loaded nanocomposites. This exceptional dielectric enhancement at very small filler loading is beneficial for commercialization and economically viable for real-time applications.

Synthesis and its characterisation of selenium/silver/chitosan and cellular toxicity against liver carcinoma cells studies

Liver cancer is one of the most common lethal malignancy in the world. To treat liver cancer, new cure options are crucial. The use of natural substances along nanosciences may provide healing with lower toxicity and a smaller amount of side properties. In this research, The three-component selenium-silver-chitosan nanocomposite (Se-Ag-CS NCs) were synthesised with the help of ultrasound in a stepwise manner. The as-synthesised Se-Ag-CS NCs were characterised accordingly by applying powder X-Ray diffraction (PXRD), Fourier transforms infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive x-ray analysis (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS) and potential. The PXRD demonstrated that the NCs were synthesised successfully and the grain sizes of 27.3 were obtained. The FESEM and TEM analyses have shown the NCs have a nano-sized structure with spherical and rod-like morphologies in a coating of CS. The DLS analysis also revealed that NCs were synthesised in nanoscale particles. The NCs’ surface charge was also positive due to the presence of chitosan. Different concentrations of NCs (0, 0.125, 0.250, 0.500, and 1 mg/ml) were tested at different times (24, 48, and 72 h) to measure cytotoxicity against liver cancer cells. The results showed at a concentration of 1 mg/mL in 72 h, the most toxicity effects were applied to liver cancer cells. Moreover, the results indicated NCs can inhibit the growth of cancer cells in a dose-dependent manner, while the toxicity of nanocomposite on normal cells was less. It is important to create nanocomposites derived from natural polymers as a new strategy in cancer treatment that can fight cancer cells while having low toxicity for normal cells. Therefore, the present results can be considered in improving cancer-fighting methods.

Enhancing Dye-Sensitized Solar Cell Performance with Different Sizes of ZnO Nanorods Grown Using Multi-Step Growth

In this study, we employed a chemical solution method to grow zinc oxide (ZnO) nanorods on SnO2:F (FTO) substrates as photoelectrodes for dye-sensitized solar cells (DSSCs). The influence of varying ZnO nanorod dimensions on cell performance was investigated. Specifically, we explored the effects of nanorod length and diameter on dye adsorption capacity and photovoltaic conversion efficiency. Characterization techniques such as electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM) were utilized to analyze the ZnO nanorods. Our results demonstrate that the sequential growth technique allows for control over the length and diameter of ZnO nanorods, thereby modulating their optoelectronic properties. XRD and FE-SEM analyses revealed that the surface morphology of the ZnO nanorods impacts dye adsorption capacity and photovoltaic conversion efficiency. EIS measurements further indicated a significant influence of dye adsorption on the electron lifetime of ZnO nanorods. Overall, this study highlights the potential of multi-step growth of ZnO nanorods to optimize the performance of dye-sensitized solar cells by tuning their morphology and surface properties.

Superior photocatalytic performance of Dy2O3/graphitic carbon nitride nanohybrid for the oxidation Rhodamine B dye under visible light irradiation: A superoxide free radicals approach

Organic-inorganic hybrid semiconductor nanomaterials have emerged as promising candidates for next-generation energy and environmental solutions. These materials combine organic and inorganic components to form a new class of hybrid nanomaterials with enhanced photocatalytic activity under visible-light irradiation. In this study, g-C3N4 was integrated with different ratios of Dy2O3 using a hydrothermal process. The prepared hybrid composite materials were analysed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), UV–vis diffuse reflectance spectroscopy (UV-DRS), Brunauer-Emmett-Teller (BET) surface area analysis, field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray analysis (EDAX) high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Photoluminescence Spectroscopy (PL) and Electron Paramagnetic Resonance spectroscopy (EPR). The synthesized Dy2O3/g-C3N4 (DYCN) nanohybrid composite has a bandgap energy and surface area of 2.63 eV and 51.8 m2/g respectively. FE-SEM analysis showed nanorods connected to the sheet-like morphology of the prepared DYCN nanohybrid composite material. When exposed to visible light, the organic dye rhodamine B was used as a model pollutant to assess the photocatalytic activity of the synthesized materials. The oxidation of organic molecules was initiated by superoxide (•O2−) free radicals rather than hydroxyl radicals generated during the reaction, which was confirmed by EPR analysis. Due to its narrow bandgap, larger surface area, and presence of f shells in Dy2O3, the synthesized 5 % Dy2O3/g-C3N4 (DYCN 5) nanohybrid composite material showed more visible-light photocatalytic activity than pure g-C3N4 and various ratios of synthesized nanomaterials.

Li sensitized CdS/TiO2 nanocomposite photoanode for solar water splitting, hydrogen generation and photoelectrochemical (PEC) performance

Li–CdS/TiO2 nanocomposite with different composition 10Li–CdS/TiO2, 20Li–CdS/TiO2, 30Li–CdS/TiO2, 40Li–CdS/TiO2, 50Li–CdS/TiO2 were coated on FTO surface by using doctor blade followed by successive ionic layer adsorption and reaction (SILAR) method. As synthesized Li–CdS/TiO2 photoanode is characterized with field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), high resolution transmission electron microscopy (HR-TEM), diffuse reflectance spectroscopy (UV-DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). FE-SEM analysis suggests that, Li–CdS/TiO2 film is 10.2 μm thick, porous, spongy and uniformly covered on FTO surface. The HR-TEM images reveal that the CdS nanoparticles are in intimate contact with the TiO2 nanocrystal shells with the CdS/TiO2 interfaces and the particle size of CdS and Li2S lies in the range of 20 nm–50 nm. UV-DRS analysis shows that, as the loading of Li in CdS/TiO2 films increases, there is decrease in band gap energy. The XPS analysis supports the presence of Li+ in Li–CdS/TiO2 nanocomposite. The PL spectra suggest that, with the increase in extend of Li+ ions into Li–CdS/TiO2, intensity of green emission band increases and it is shifted to higher wavelength. This reflects the low recombination rate of photo generated charge carrier in Li–CdS/TiO2 which is responsible for higher photocatalytic H2 production. The visible light photoanodic performance of Li–CdS/TiO2 was investigated for H2 evolution using aqueous Na2SO3 and Na2S solution under natural sunlight. Among the all-synthesized nanocomposite material, the highest amount of hydrogen produced over 20Li–CdS/TiO2 was found to be 38.61 ml/g/h in natural sunlight. Photoelectrochemical (PEC) performance of Li–CdS/TiO2 was examined. A possible mechanism for photocatalytic hydrogen generation is also discussed.

Efficacy of high-volume fly ash and slag on the physicomechanical, durability, and analytical characteristics of high-strength mass concrete

In the last decade, the use of high-strength mass concrete has increased for the building of various high-impact infrastructure projects. Due to the larger size of sections and greater volume of Portland cement, the reduction of core strength and durability is often witnessed in these concrete sections. In this study, an attempt has been made to minimize the above issues by substituting ordinary Portland cement (OPC) with high-volume fly ash (FA) and ground granulated blast furnace slag (GGBFS). For this purpose, six types of samples viz. S1 (100% OPC), S2 (20% FA + 80% OPC), S3 (35% FA + 65% OPC), S4 (50% GGBFS + 50% OPC), S5 (70% GGBFS + 30% OPC), and S6 (33% FA + 33% GGBFS + 34% OPC) were prepared. The performances on the actual core concrete were evaluated by analyzing the peak temperature, compressive strength of cylindrical cores, rapid chloride migration test (RCMT), X-ray diffraction (XRD), thermogravimetry (TG), Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). Additionally, the bulk densities (wet and dry), water absorption, apparent porosity, and compressive strength of cube samples are also reported. Analyzing the results critically, it was observed that the use of high-volume FA and GGBFS (S5 and S6 samples) lowered the peak core temperature by 11–13 °C, increased the compressive strength of cores by 8–10 MPa, and lowered the RCMT values of cores by 12 × 10−12 - 13 × 10−12 m2/s as compared to the S1 (control) sample. Additionally, the increase in the ratio of the core-to-cube strength for the S5 and S6 samples is noted to be 24% and 29%, respectively, more than the control sample at 56 days of curing. The enhanced performance of the high-volume FA and GGBFS-based samples is due to the less core temperature rise due to less hydration reaction at the early ages and more secondary hydration reaction at the later ages, which has been justified by the XRD, FTIR, TG, and FESEM analyses. Finally, the sustainability and cost analysis revealed that the use of high-volume FA and GGBFS can significantly reduce embodied energy by 39–42%, embodied carbon by 53–58%, and production costs by 16–17%. The approach proposed in the article regarding the use of high-volume FA and GGBFS results in more green, durable, sustainable, and cost-effective high-strength mass concrete.