Search

The phase formation behavior of β′-SiAlON with the general formula Si6-zAlzOzN8-z was studied comprehensively for z values from 1 to 3 using spark plasma sintering (SPS) as the consolidation technique at synthesis temperatures from 1400 to 1700 °C. The samples were prepared close to the β′-SiAlON composition line: Si3N4 − 4/3(AlN·Al2O3) in the phase diagram using (A) nano-sized amorphous Si3N4 and (B) micro-sized β-Si3N4 precursors. Field-emission scanning electron microscopy (FESEM) was used for microstructural analysis. Most compositions reached almost full density at all SPS temperatures. Compared with the micro-sized β-Si3N4 precursor, the nano-sized amorphous Si3N4 precursor accelerated the reaction kinetics, promoting the formation of dense β′-SiAlON + O′-SiAlON composites after SPS at synthesis temperatures of 1400–1500 °C. This resulted in very high values of Vickers hardness (Hv10) = 18.2–19.2 GPa for the z = 1 composition related to the hardness of the O′-SiAlON component phase. In general, for samples synthesized from nano-sized amorphous Si3N4, which were almost fully dense, containing >95% β′-SiAlON, the hardness values were 13.4–13.8 GPa with a fracture toughness of 3.5–4.6 MPa m1/2. For equivalent samples synthesized from micro-sized β-Si3N4, hardness was in the range 13.9–14.4 GPa with a fracture toughness of 4.3–4.5 MPa.m1/2. These values are comparable with fully dense β′-SiAlONs, usually containing intergranular glass phase which has been sintered by HIP and other processes at much higher temperatures for longer times.

Corrosion is the primary cause of failure of heat exchangers in industry, especially in the oil and petrochemical sector. The modes of failure related to corrosion include erosion corrosion, pitting corrosion, crevice corrosion, grain boundary corrosion, dealloying, galvanic corrosion, stress corrosion cracking, waterside corrosion, uniform corrosion, and microbially induced corrosion. Primary causes of corrosion-related failures were found to be fabrication and welding defects, presence of residual stresses, inappropriate materials selection and design, improper water chemistry/flow and poor choice of filters, presence of corrosive species such Cl−, Sx−, O2, NH4 + in water, nonadherence to recommended operating conditions, and noncompliance with standard practices during the shutdown. This article is a review covering only corrosion-related failures in heat exchangers.

Novel Au and cellulose nanocrystals (CNC)-doped SrO nanocomposites have been fabricated using simple and cost-effective chemical co-precipitation technique. Various concentrations of Au were doped into fixed amounts of CNC and SrO nanocomposites. The objective of this triplex nanocomposite was to examine the effect of incorporating dopants in SrO on the efficient elimination of organic contaminants from water and their antibacterial potential with molecular docking study. Adequate experimental conditions such as temperature, suitable volume ratio of reactants and pH were generated during the synthesis. For comparative studies, nanocomposites were evaluated through a number of characterization tools. The structural and morphological analysis through XRD and HR-TEM revealed the cubic crystalline structure of aggregated SrO quantum dots (QDs). Furthermore, an interconnected chain-like structure of nanoclusters was observed upon CNC and Au incorporation in SrO lattice. The size of nanoclusters/nanoparticles was calculated to be approximately 30 nm which matched well with the reported literature. Reduction in crystallinity and bandgap from 4.12 eV (for pristine SrO) to 3.8 eV was observed upon co-doping with CNC and Au in SrO lattice. Furthermore, pH-based catalytic analysis of prepared nanocomposites revealed 98% dye degradation (in acidic media) against methylene blue ciprofloxacin (MBCF) dye along with good bactericidal activities against Gram-positive/negative bacteria, respectively. In silico molecular docking analysis for enzyme targets belonging to cell wall synthesis (penicillin-binding protein 4) and fatty acid synthesis (enoyl-[acyl-carrier-protein] reductase) suggested Au–CNC and Au/CNC-doped SrO nanostructures as possible inhibitors of these enzymes owing to their good binding scores and binding interactions with active site residues. (a) Preparation of cellulose nanocrystals (CNC) by acid hydrolysis. (b) Schematic synthesis route to fabricate Au/CNC–SrO nanocomposites.

Graphene oxide (GO)-doped MnO2 nanorods loaded with 2, 4, and 6% GO were synthesized via the chemical precipitation route at room temperature. The aim of this work was to determine the catalytic and bactericidal activities of prepared nanocomposites. Structural, optical, and morphological properties as well as elemental composition of samples were investigated with advanced techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible (vis) spectroscopy, photoluminescence (PL), energy-dispersive spectrometry (EDS), and high-resolution transmission electron microscopy (HR-TEM). XRD measurements confirmed the monoclinic structure of MnO2. Vibrational mode and rotational mode of functional groups (O–H, C=C, C–O, and Mn–O) were evaluated using FTIR results. Band gap energy and blueshift in the absorption spectra of MnO2 and GO-doped MnO2 were identified with UV–vis spectroscopy. Emission spectra were attained using PL spectroscopy, whereas elemental composition of prepared materials was recorded with scanning electron microscopy (SEM)-EDS. Moreover, HR-TEM micrographs of doped and undoped MnO2 revealed elongated nanorod-like structure. Efficient degradation of methylene blue enhanced the catalytic activity in the presence of a reducing agent (NaBH4); this was attributed to the implantation of GO on MnO2 nanorods. Furthermore, substantial inhibition areas were measured for Escherichia coli (EC) ranging 2.10–2.85 mm and 2.50–3.15 mm at decreased and increased levels for doped MnO2 nanorods and 3.05–4.25 mm and 4.20–5.15 mm for both attentions against SA, respectively. In silico molecular docking studies suggested the inhibition of FabH and DNA gyrase of E. coli and Staphylococcus aureus as a possible mechanism behind the bactericidal activity of MnO2 and MnO2-doped GO nanoparticles (NPs).

Heterocyclic azo dyes are an important class of azo dyes well known due to their widespread applications as colorants and functional materials as well. In the present investigation, synthesis of a new series of heterocyclic azo dyes (6a-i) based on pyrazole core is portrayed. The synthetic strategy involves the diazotization of 4-aminoacetanilide (1) followed by coupling with different active methylene compounds in alkaline medium to afford intermediates (4a-d). The latter, on condensation, with separately synthesized substituted hydrazines (5a-d) afforded the target dyes (6a-i). The structures of newly synthesized dyes were established by 1H and 13C nuclear magnetic resonance spectroscopy, infrared spectroscopy, and elemental analysis. UV-Visible absorption study of synthesized dyes was conducted and λmax was found in the range of 388–401 nm. Furthermore, these dyes were applied on leather as a topcoat and found to exhibit moderate to high values of the application parameters such as light fastness, wash fastness, and rubbing fastness.

In the present work, boron nitride (BN) nanosheets were prepared through bulk BN liquid phase exfoliation while various wt. ratios (2.5, 5, 7.5 and 10) of bismuth (Bi) were incorporated as dopant using hydrothermal technique. Our findings exhibit that the optical investigation showed absorption spectra in near UV region. Density functional theory calculations indicate that Bi doping has led to various modifications in the electronic structures of BN nanosheet by inducing new localized gap states around the Fermi level. It was found that bandgap energy decrease with the increase of Bi dopant concentrations. Therefore, in analysis of the calculated absorption spectra, a redshift has been observed in the absorption edges, which is consistent with the experimental observation. Additionally, host and Bi-doped BN nanosheets were assessed for their catalytic and antibacterial potential. Catalytic activity of doped free and doped BN nanosheets was evaluated by assessing their performance in dye reduction/degradation process. Bactericidal activity of Bi-doped BN nanosheets resulted in enhanced efficiency measured at 0–33.8% and 43.4–60% against S. aureus and 0–38.8% and 50.5–85.8% against E. coli, respectively. Furthermore, In silico molecular docking predictions were in good agreement with in-vitro bactericidal activity. Bi-doped BN nanosheets showed good binding score against DHFR of E. coli (− 11.971 kcal/mol) and S. aureus (− 8.526 kcal/mol) while binding score for DNA gyrase from E. coli (− 6.782 kcal/mol) and S. aureus (− 7.819 kcal/mol) suggested these selected enzymes as possible target.

Various concentrations (0.01, 0.03 and 0.05 wt ratios) of graphene oxide (GO) nanosheets were doped into magnesium oxide (MgO) nanostructures using chemical precipitation technique. The objective was to study the effect of GO dopant concentrations on the catalytic and antibacterial behavior of fixed amount of MgO. XRD technique revealed cubic phase of MgO, while its crystalline nature was confirmed through SAED profiles. Functional groups presence and Mg-O (443 cm−1) in fingerprint region was evident with FTIR spectroscopy. Optical properties were recorded via UV–visible spectroscopy with redshift pointing to a decrease in band gap energy from 5.0 to 4.8 eV upon doping. Electron–hole recombination behavior was examined through photoluminescence (PL) spectroscopy. Raman spectra exhibited D band (1338 cm−1) and G band (1598 cm−1) evident to GO doping. Formation of nanostructure with cubic and hexagon morphology was confirmed with TEM, whereas interlayer average d-spacing of 0.23 nm was assessed using HR-TEM. Dopants existence and evaluation of elemental constitution Mg, O were corroborated using EDS technique. Catalytic activity against methyl blue ciprofloxacin (MBCF) was significantly reduced (45%) for higher GO dopant concentration (0.05), whereas bactericidal activity of MgO against E. coli was improved significantly (4.85 mm inhibition zone) upon doping with higher concentration (0.05) of GO, owing to the formation of nanorods.

Various concentrations (2.5, 5, 7.5, 10 wt%) of zirconium were doped onto MoS2 using hydrothermal method. X-ray diffraction affirmed existence of hexagonal phase and increased crystallite size upon doping. Synthesized nanosheets appeared agglomerated after doping. Raman analysis provided evidence about defect density, layered structure of S-Mo-S planes as well as electronic band configuration of Zr-doped MoS2. Furthermore, Zr-doped MoS2 nanosheets were applied on a glassy carbon electrode as a layer of sensor film using nafion adhesive to fabricate the working electrode of the proposed phenylhydrazine (PHyd) electrochemical sensor probe. A calibration curve based on concentration of PHyd versus current plot was recorded to be linear over the full concentration range of 0.1 nM to 1.0 mM. The concentration linear range (0.1 nM–0.1 mM) was denoted as the large dynamic range (LDR) for PHyd detection based on the measurement of calibration plot. The slope of LDR with active surface area (0.0316 cm2) of GCE was used to determine analytical parameters of the sensor such as sensitivity (13.4652 µA µM−1 cm−2), linearity, and detection limit (91.54 ± 4.58 pM). Besides these, the PHyd sensor performance was investigated in terms of reproducibility, long-term stability, response time, and validity with regard to its capability for effective analysis of real environmental samples in this field. All parameters exhibited satisfactory and acceptable results.

Graphical abstract, Introduction Hard coatings are primarily based on carbides, nitrides and carbonitrides of transition metal elements such as W, Ti, Zr, etc. Zr-based hard coatings show good resistance to wear, erosion, and corrosion as well as exhibit high hardness, high temperature stability, and biocompatibility, making them suitable candidates for tribological, biomedical, and electrical applications. Objectives The present study aims to synthesize uniform and adherent hard Zr-based coatings that demonstrate sound mechanical integrity. Methods Stainless steel (SS316) samples were coated with single layers of Zr, Zr-nitride, and Zr-carbonitride using magnetron sputter deposition technique. Deposition conditions were controlled to produce each coating with two different thickness i.e., 2 and 3 μm. Calotest was employed to confirm coatings thickness. Scanning electron microscope fitted with energy dispersive x-ray spectrometer was used to ascertain the morphology and elemental constitution of coatings. Cross-sectional samples were examined to ascertain coatings thickness and adhesion. X-ray diffractometer was employed for structural analysis. Instrumented nanoindentation hardness and elastic modulus were determined with nanoindenter. Ratio of nanohardness to elastic modulus was evaluated to observe the effect of coatings thickness on tribological behavior. Results Three coating compositions were produced namely hcp-Zr, fcc-ZrN and fcc-Zr2CN. The highest hardness and elastic modulus were shown by ZrN coatings while pure Zr coatings showed the lowest values. Conclusion All coating compositions were found to be relatively uniform, continuous and adherent with no evidence of decohesion at the coating-substrate interface. Coatings produced in this study are thought to be suitable for tribological applications.

Films created by poly (e-caprolactone) (PCL) have made a lot of consideration in biomedical applications because of their biodegradability, biocompatibility, incredible flexibility, and nontoxic degradation by-products. In this study, switching behavior of surface morphology of linear and star-shaped PCL as a function of polarity of the substrate, molecular weight of the polymer, solvent vapor annealing, solvent annealing, and thermal annealing were investigated. Films of PCL were prepared by drop casting method and their morphology was visualized through atomic force microscopy (AFM). Although, the whole study is based on AFM imaging, some of the basic morphologies of PCL films as obtained by AFM are also compared with SEM and TEM analysis. The substantial difference in polarity and roughness of mica and silicon wafers leads to different chain orientation of the polymer chains. Morphology transition strongly depends on the molecular weight of the polymer, low molar mass PCL presented larger surface domains compared to their higher molar mass analogs. Annealing of polymer with THF and ethanol vapors has improved the long-range ordering of PCL chains, while hexane and water vapors led to swelling of the films. The morphology of the film has also shown selectivity for the casting solvent. Thermal annealing around the melting temperature of the PCL made polymeric chains more extended and uniformly oriented.

MoS2 nanosheets were developed by undertaking the liquid-phase exfoliation of bulk counterparts. In order to enhance its photocatalytic properties, the host material was doped with p-type transition metals (i.e., Ag, Co, Bi, and Zr). The hydrothermal technique was used to produce samples doped with 7.5 wt% transition metals (TM). X-ray diffraction detected the existence of 2H-phase by mirroring its reflection at 2θ ∼ 14°, while the peak distribution revealed the degree of exfoliation in samples. Low PL intensities indicated a lower recombination of electron-hole pairs, as corroborated by a high degree of photocatalytic action. Raman analysis was undertaken to identify molecular vibrations. The A1g mode in Raman spectra consistently showed a blueshift in all samples and the E12g mode was only slightly affected, which is evidence of the p-type doping in the MoS2 nanosheets. In the XPS spectrum, two characteristic peaks of Mo 3d appeared at 229.87 and 233.03 eV assigned to Mo-3d5/2 and Mo-3d3/2, respectively. Furthermore, a microstructural examination with HR-TEM and FESEM divulged a thin-layered structure of MoS2 consisting of flat, gently curved or twisted nanosheets. Diverse morphologies were observed with a non-uniform distribution of the dopant. Photocatalytic action of the TM-doped products effectively degraded methylene blue (MB) concentrations of up to 94 percent (for Ag-MoS2). The synergistic effect of doped MoS2 nanosheets against S. aureus in comparison to E. coli bacteria was also evaluated. The efficacy % age improved from (0-31.7%) and (23.5-55.2%) against E. coli, and (0-34.2%) and (8.3-69.23%) against S. aureus. Moreover, results from first principles calculations indicate that substitutional doping of TM atoms is indeed advantageous. Theoretical calculations confirmed that doping with Ag, Co, Bi, and Zr leads to a decrease in the band gap to a certain degree, in which the conduction band edge shifts toward lower energy, while the valence band shifts closer to the high energy end. It can be concluded that Ag, Co, and Bi impurities can lead to beneficial p-type doping in MoS2 monolayered structures. With regards to doping with Zr, the acceptor levels are formed above the edge of the valence band, revealing an introduction of the p-type character.

Novel prism shaped C3N4-doped Fe@Co3O4 nanocomposites were fabricated via a co-precipitation route for effective removal of organic pollutants from water and for bactericidal applications. Doping of C3N4 in the heterojunction significantly enhanced the photocatalytic and sonocatalytic activity against methylene blue ciprofloxacin (MBCF) dye. The main purpose of doping Fe atoms in the cobalt lattice was to generate crystal and surface defects. Moreover, the optimum doping amount of C3N4 for maximum degradation performance was evaluated. A detailed examination of the prepared nanocomposites was carried out systematically using various characterization tools for better understanding. HR-TEM images revealed the formation of novel prism shaped structures that exhibited outstanding degradation of the organic dye in water. Significant bactericidal potential was also observed for the synthesized nanocomposites against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. In silico, molecular docking studies against β-lactamase, DHFR and FabI enzymes served to elucidate the mechanism governing the bactericidal activity of the as-synthesized nanoparticles (NPs). Furthermore, a scavenging study by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and COD (chemical oxygen demand) analysis was performed in order to evaluate active species and the anti-oxidant potential of prepared composites.

This paper explores the possible role of defect states in charge transport in a type II heterointerface formed by ZnO/SnO2 composite nanostructures (CNs) grown using VLS technique. XRD and high-resolution TEM analysis revealed the granular growth of SnO2 in a matrix of ZnO. Raman spectra obtained from CNs were marked by the presence of oxygen vacancies as Raman modes were broadened and shifted. XPS results confirmed the presence of oxygen vacancies in ZnO and SnO2 and Zn interstitials in ZnO, which showed dependence on growth temperature. Photoluminescence (PL) spectra acquired from CNs were marked by the presence of a very broad PL band in the visible region centered around 2.4 eV, while a very weak near-band-edge emission was observed. The PL band in the visible region showed contributions from Zn interstitials (2.4–2.6 eV) and oxygen vacancies (1.9–2.1 eV) in ZnO, and the PL band of SnO2 consisted of primarily oxygen vacancies (1.9–2.1 eV). The PL bands obtained from CNs showed the absence of Sn interstitials in SnO2. The photoluminescence excitation (PLE) spectrum taken from CNs clearly showed absorption in the band gap due to defects. The role of defect states in the charge transfer process in type II heterostructures was further studied by electrical measurements on SnO2/ZnO bilayer thin films. Temperature-dependent I–V characterization showed significant accumulation of charges at the interface, which was released by thermal excitation. It is, therefore, concluded that defects can play a positive role in photocatalytic devices, where excess charge is needed at the interface for catalytic reaction.

Super duplex stainless steels (SDSS) are used in offshore applications and oil/gas plants operating under severe service conditions due to their superior mechanical and electrochemical properties. Fracture toughness, wear and corrosion resistance of a material depends largely on its microstructure and can be improved by refining the latter. Friction stir processing (FSP) can be employed to refine the microstructure of the material, resulting in superior fracture toughness, wear, and corrosion resistance. In the present research, SAF 2507 SDSS was subjected to FSP with optimized processing parameters to study the influence of FSP on fracture toughness, wear, and corrosion resistance of the material. It was observed that FSP refined alloy grains by decreasing the grain size from an average of 160 µm in the base metal to 2-30 µm in the stir zone. Refinement of grains increased the hardness of the material, which enhanced its wear resistance by more than 15%. Wear track and debris analysis revealed the change in wear mechanism of the processed material. FSP also modified the surface composition of processed material, which served to improve its corrosion resistance by more than 80%. Morphology of the corroded surfaces of base and processed material showed that the processed material was more resistant to corrosive attacks than base material. FSP enhanced the grain boundaries in the processed region which improved the fracture toughness after exposure to accelerated corrosion by about 26%. Fractographic study revealed that processed material had brittle fracture behavior while base material had ductile fracture behavior.

Sol–gel method was used to synthesize pure and doped (Ni, Co, and Fe) Cr2O3 nanoparticles (NixCr2-xO3, CoxCr2-xO3, and FexCr2-xO3, where x = 0.00, 0.01, 0.03, 0.05, and 0.07). The structural properties of the prepared samples were determined using x-ray powder diffraction (XRD) with an aim to investigate the influence of doping concentration on the behavior of pure and doped Cr2O3 nanoparticles (NPs). The average crystallite size was estimated with Debye Scherrer’s formula. Morphology of pure and doped (Ni, Co, and Fe) Cr2O3 nanoparticles was examined using field emission scanning electron microscope (FESEM). Fourier transform infrared spectroscopy (FT-IR) was employed to ascertain surface group species of the samples. UV–Vis spectroscopy was used to determine the energy band gap of samples through optical absorption spectrum. Photoluminescence spectroscopy was undertaken to acquire emission and absorption spectra and determine defects in the structures of all synthesized nanopowder samples. Antibacterial activity of pure and doped (Ni, Co, and Fe) Cr2O3 nanoparticles was investigated against Gram-negative bacteria such as Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus) using paper disc diffusion method and pour plate procedure. Enhanced anti-bactericidal activity was shown against Gram-negative bacteria compared to Gram-positive bacteria. The minimum and maximum inhibition of E. coli and S. aureus was recorded with 40 and 100 μg/ml of nanoparticles, respectively. Furthermore, iron-doped Cr2O3 was more effective in restricting growth of bacterial cell compared to cobalt- and nickel-doped Cr2O3. Superior activity observed against E. coli and S. aureus in terms of inhibition make these samples suitable and potential candidates in medical and paint industries.

Boron nitride (BN) nanosheets were prepared by chemical exfoliation method and incorporation of Cu as a dopant was achieved using hydrothermal route. Hexagonal phase of BN (h-BN) was detected using x-ray difractometer (XRD). Functional group analysis with fourier transform infrared spectroscope (FTIR) was employed to identify the chemicals used in the process, which was then further confirmed with energy dispersive x-ray spectroscopy (EDS) coupled with FESEM. Optical analysis undertaken with UV–vis. spectroscopy indicated absorption at UV region. Raman spectroscopy was used to acquire molecular fingerprints of BN molecules. Photoluminescence (PL) spectroscopy was carried out to study the exciton behaviour of samples in order to elucidate the electron migration and transfer rate. Field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM) were employed to examine the morphology and structure of materials. The experimental results indicate that Cu-doped BN nanosheets possess excellent catalytic potential and superior antibacterial activity.

This article reports the isolation and characterization of microcrystalline cellulose from date seeds of the date palm tree. The raw ground date seeds (RG-DS) are composed of cellulose matrix wrapped by lignin and hemicellulose as amorphous components. Cellulose was isolated from RG-DS through the following sequence: dewaxing, delignification/(bleaching) and acid hydrolysis. FTIR and Raman analysis for the bleached date seeds (B-DS) revealed the successful removal of the amorphous components from the polymer matrix. The X-ray diffractogram of the obtained (B-DS) exhibited the characteristic peaks of native cellulose (type I), with a crystallinity index (CrI = 62%). An additional acid hydrolysis step was used to convert native cellulose into microcrystalline cellulose (MCC-DS) with higher crystallinity (CrI = 70%). SEM analysis showed that the obtained microcrystals exhibit agglomerated and irregular elongated or semi-spherical shaped morphology. TEM analysis confirmed the semicrystalline nature of the MCC-DS. Thermal analysis showed enhanced thermal stability of MCC-DS. The current study shows the feasibility of using date seeds as a low-price source for obtaining MCC which is envisaged for applications in pharmaceutical and food industries as well as for preparing bionanocomposites with enhanced thermal properties.

A new era in the development of advanced functional materials was partly sparked by the discovery of 2D materials. In this respect, graphene is believed to have marked the origin of 2D materials. The ability to fabricate a vast majority of such advanced nanomaterials hinges upon the strength of interplanar interactions realized in their respective bulk counterparts. The present study undertakes the comparative analysis of oft-explored 2D materials such as Dirac 2D materials (GO, rGO), TMDCs (MoS2) and 2D insulators (BN) in the context of their structural, optical, thermal and morphological parameters. Despite implementing several methodologies including a combination of physical, chemical and biological techniques, aquatic and microbial pollution remains a challenge to this day. More recently, nanomaterials have attracted considerable attention as these are believed to hold an extraordinary prospective for utilization toward environmental remediation. Among several probable candidates, 2D materials hold immense appeal due to its useful properties including high absorptivity and large surface area, which enable them to be employed for multifaceted applications. In the present study, a wide range of experimental results extracted from numerous characterization techniques (i.e., XRD, UV–Vis, FTIR, HR-TEM, XPS, DSC-TGA, and Raman) is included. For instance, optical data obtained from these materials point toward a narrow bandgap, while HR-TEM images show large surface area, which suggests that these materials hold promising prospect for use in applications that require strong catalytic activity. Further experimental results indicate that photocatalytic and sonophotocatalytic potential is significantly enhanced by 2D materials. In this respect, rGO showed 60% degradation of synthetic pollutant in 100 min and MoS2 realized 55% degradation during the same duration. The present study suggests that rGO may be used as a superior photocatalyst in wastewater treatment and related environmental applications. Moreover, the sonophotocatalytic behavior exhibited by these materials showed consistently higher efficiency compared to the respective individual processes which is attributed to the formation of larger amounts of electron–hole pairs.

Development of resilient and efficient composite materials that exhibit substantial antimicrobial activity, ample photocatalytic ability and considerable capacity for drug delivery is highly desirable. The present study demonstrates the incorporation of selenium (Se) in transition metals (vanadium-V, niobium-Nb, and tantalum-Ta) via standard solid-state hydrothermal reaction method. Generated nanostructures (V:Se, Nb:Se, Ta:Se) were characterized using various techniques. XRD analysis confirmed the presence of monoclinic phase compounds while crystallite size (~ 13.5–26.2 nm) was calculated using Debye–Scherrer equation. FESEM was used to examine surface morphologies of V:Se (rod-like and disc-shaped) and of Nb and Ta selenides (irregular agglomerated nanospheres). Compositional and functional group analysis was undertaken through FTIR spectroscopy and EDS coupled with SEM, respectively. Raman spectroscopy was carried out to ascertain the bending and stretching vibrational modes in samples. Optical properties were investigated through UV–Vis spectroscopy and the PL emission spectra were acquired to evaluate the charge separation and recombination behavior of compounds. Thermal stability of designed composites was measured using TGA/DSC. Potential uses of the prepared nanoparticles were explored in multiple fields including photocatalysis, antimicrobial and drug delivery systems. Methylene blue dye was degraded under 400–700 nm wavelength in the presence of synthesized wide band gap composites as photocatalysts. The selenium–metal particles were subjected as antimicrobial agents against gram (−ve) and gram (+ve) bacteria and experimental results suggested this material to be an effective antibiotic. Furthermore, synthesized nanocomposites were examined as carrier of anticancer drug (DOX) and their drug delivery profile was also investigated.

Inorganic semiconducting ZnS doped with Cr nanoparticles was fabricated using chemical co-precipitation method with monothioethylene glycol as capping agent. This study is an effort to investigate as to how various concentration ratios of systematically doped Cr (1, 3, 5, and 7 wt%) to ZnS affect structural, optical, and morphological properties at room temperature. Powder X-ray diffraction (XRD) studies revealed that crystallinity improved upon doping and the synthesized material has cubic structure without secondary phase. XRD and Raman spectra showed successful incorporation of Cr3+ particles into ZnS host lattice. The functional groups and chemical species associated with vibration of molecules were determined with Fourier transform infrared spectroscopy (FTIR). Field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HR-TEM) images showed nanoscale particles with cubic and spherical morphology. Elemental composition of Cr-ZnS particles was determined using energy-dispersive X-ray (EDX) spectroscopy. Kinetics of degradation of methylene blue (MB) catalyzed via synthesized nanoparticles was recorded under UV–Vis irradiation. The antimicrobial evaluation of Cr-doped ZnS nanocomposites against MDR S. aureus showed significant (p

Carbon nanotubes (CNTs) have enormous application in various fields such as sensors, aerospace, super capacitors and photovoltaic devices, etc., and they are extensively exploited for number of other energy and environmental applications nowadays. With the rapid development and evolution in the field of aerospace industry, the existing developed technologies do not have adequate potential to overpower the requirements and demands of the new era. Nanocomposites based on CNT have procured significant attention in recent years for their applications in aircrafts, military crafts, missile and spacecraft due to advanced properties such as thermal stability, chemical stability, huge surface area, etc. In this review, the fundamentals in the field on CNT nanocomposites with reference to nanoparticles and conducting polymers such as DGEBA, polyaniline, polythiophene and polypyrrole are discussed. The main objective of the review is to study the advancement in aerospace applications of polymer/CNT nanocomposites.

Nanostructured materials incorporated with biological reducing agents have shown significant potential for use in bactericidal applications. Such materials have also demonstrated considerable efficacy to counter effects of chemical toxicity. In this study, nanostructured molybdenum disulfide (MoS2) was doped with various concentrations (2.5, 5, 7.5, 10 wt%) of zirconium (Zr) using a hydrothermal route in order to assess its antimicrobial and catalytic potential. Doped and control samples were characterized with various techniques. X-ray diffraction (XRD) analysis confirmed the presence of the hexagonal phase of MoS2 and identification of various functional groups and characteristic peaks (Mo bonding) was carried out using FTIR spectra. Micrographs obtained from FESEM and HR-TEM showed a sheet-like surface morphology, while agglomeration of nanosheets was observed upon doping with nanoparticles. To seek further clarity regarding the layered features of S–Mo–S planes, the defect densities and electronic band structure of pure MoS2 and doped MoS2 samples were investigated through Raman analysis. Optical properties of Zr-doped MoS2 nanosheets were assessed using a UV-vis spectrophotometer and the results indicated a red-shift, i.e., movement of peaks towards longer wavelengths, of the material. Dynamics of migration and recombination of excited electron–hole pairs were investigated using PL spectroscopy, which was also used to confirm the presence of exfoliated nanosheets. In addition, the synthetic dye degradation potential of pure and doped samples was investigated in the presence of a reducing agent (NaBH4). It was noted that doped MoS2 showed superior catalytic activity compared to undoped MoS2. The nanocatalyst synthesized in this study exhibited enhanced antibacterial activity against E. coli and S. aureus at high concentrations (0.5, 1.0 mg/50 μl). The present study suggests a cost-effective and environmentally friendly material that can be used to remove toxins such as synthetic dyes and tannery pollutants from industrial wastewater.

Copper-doped TiO2 was prepared with a sol–gel chemical method. Various concentrations (3, 6, and 9 wt%) of Cu dopant were employed. Several techniques were implemented to assess the structural, optical, morphological and chemical properties of the synthesized samples. Evaluation of elemental composition using SEM-EDS and XRF techniques showed the presence of dopant element in the prepared samples. XRD analysis confirmed the presence of anatase (TiO2) phase with interstitial doping. Incorporation of dopant was observed to enhance the crystallinity and increase the crystallite size of the synthesized products. SAED profiles revealed a high degree of crystallinity in the prepared specimens, which was also evident in the XRD spectra. Optical properties studied using UV-vis spectroscopy depicted a shift of the maximum absorption to the visible region (redshift) that signified a reduction in the band gap energy of Cu-doped TiO2 samples. Examination of morphological features with scanning and high-resolution transmission electron microscopes revealed the formation of spherical nanoparticles with a tendency to agglomerate with increasing dopant concentration. Molecular vibrations and the formation of Ti–O–Ti bonds were revealed through FTIR spectra. PL spectroscopy recorded the trapping efficiency and migration of charge carriers, which exhibited electron–hole recombination behavior. Doped nanostructures showed enhanced bactericidal performance and synergism against S. aureus and E. coli. In summary, Cu-doped TiO2 nanostructures were observed to impede bacteria effectively, which is deemed beneficial in overcoming ailments caused by pathogens such as microbial etiologies. Furthermore, molecular docking analysis was conducted to study the interaction of Cu-doped TiO2 nanoparticles with multiple proteins namely β-lactamase (binding score: −4.91 kcal mol−1), ddlB (binding score: −5.67 kcal mol−1) and FabI (binding score: −6.13 kcal mol−1) as possible targets with active site residues. Dye degradation/reduction of control and Cu-doped samples were studied through absorption spectroscopy. The obtained outcomes of the performed experiment indicated that the photocatalytic activity of Cu-TiO2 enhanced with increasing dopant concentration, which is thought to be due to a decreased rate of electron–hole pair recombination. Consequently, it is suggested that Cu-TiO2 can be exploited as an effective candidate for antibacterial and dye degradation applications.

Zirconium-based coatings exhibit a range of useful properties such as high hardness, high temperature stability, biocompatibility, and good resistance to wear, erosion, corrosion and oxidation, making them suitable candidates for use in tribological, biomedical, corrosion-resistant, nuclear fuel, electrical and decorative applications. Common deposition methods reported for Zr-based coatings include cathodic vapor deposition, plasma enhanced chemical vapor deposition, magnetron sputtering, reactive sputtering, reactive melt infiltration, laser pulse deposition, etc. Both single and multilayered coatings are produced. This paper presents a review of the effects of deposition methods and operational conditions on the properties of zirconium carbide, zirconium nitride and zirconium carbonitride hard coatings. It describes the role of various process parameters used during the deposition of advanced functional coatings. The present study will contribute to the understanding of hard coatings in general.

Despite implementing several methodologies including a combination of physical, chemical and biological techniques, aquatic and microbial pollution remains a challenge to this day. Recently, nanomaterials have attracted considerable attention due to their extraordinary prospective for utilization toward environmental remediation. Among several probable candidates, TiO2 stands out due to its potential for use in multifaceted applications. One way to improve the catalytic and antimicrobial potential of TiO2 is to dope it with certain elements. In this study, Zr-doped TiO2 was synthesized through a sol–gel chemical method using various dopant concentrations (2, 4, 6, and 8 wt%). Surface morphological, microstructural and elemental analysis was carried out using FESEM and HR-TEM along with EDS to confirm the formation of Zr–TiO2. XRD spectra showed a linear shift of the (101) anatase peak to lower diffraction angles (from 25.4° to 25.08°) with increasing Zr4+ concentration. Functional groups were examined via FTIR, an ample absorption band appearing between 400 and 700 cm−1 in the acquired spectrum was attributed to the vibration modes of the Ti–O–Ti linkage present within TiO2 nanoparticles, which denotes the formation of TiO2. Experimental results indicated that with increasing dopant concentrations, photocatalytic potential was enhanced significantly. In this respect, TiO2 doped with 8 wt% Zr (sample 0.08 : 1) exhibited outstanding performance by realizing 98% elimination of synthetic MB in 100 minutes. This is thought to be due to a decreased rate of electron–hole pair recombination that transpires upon doping. Therefore, it is proposed that Zr-doped TiO2 can be used as an effective photocatalyst material for various environmental and wastewater treatment applications. The good docking scores and binding confirmation of Zr-doped TiO2 suggested doped nanoparticles as a potential inhibitor against selected targets of both E. coli and S. aureus. Hence, enzyme inhibition studies of Zr-doped TiO2 NPs are suggested for further confirmation of these in silico predictions.

Zirconium-based coatings have found important uses ranging from functional deposits on carbon fibers, field emitters, nuclear fuel particles, and dental and body implants to protective layers on tool bits, roller contacts, integrated circuits, and components exposed to high temperatures as well as aesthetically pleasing decorative coatings on common household fixtures. These applications are made possible by the remarkable properties of zirconium such as its high temperature ionic conductivity, corrosion resistivity, good wear resistance, elevated fracture toughness, and high hardness and strength. Zirconium has thermal expansion and modulus of elasticity close to those of iron and steel, respectively. This paper presents a review of the microstructure, properties and applications of Zr-carbide, Zr-nitride and Zr-carbonitride hard coatings synthesized using various processing techniques. The discussion presented in this article is deemed to be relevant to hard coatings in general.

Cobalt concentrations of 7.5 and 10 wt% were incorporated in chemically exfoliated molybdenum disulfide (MoS2) nanosheets using hydrothermal route. Various characterization techniques were employed to evaluate the Co-doped MoS2 for structural, physiochemical, optical, and morphological properties. X-ray diffraction (XRD) technique confirmed the increase in crystallinity and crystallite size with doping ratios. The presence of functional groups and vibrational characteristic peak of Mo–O was determined using Fourier-transform infrared spectroscopy (FTIR). Field emission scanning electron microscope (FESEM) and high-resolution transmission electron microscope (HR-TEM) micrographs showed surface morphology and interlayer spacing. Absorption spectra and bandgap energy decreased with conjugation of Co ascribed to quantum confinement and edge effects as investigated using UV–visible spectroscopy. Thermal properties of prepared samples depicted weight and thermal stability as confirmed by differential scanning calorimeter and thermogravimetric analysis (DSC-TGA). Photoluminescence (PL) spectra confirmed the presence of doped species and revealed the growth of MoS2 monolayer. Dye degradation of doped and undoped MoS2 was tested in the presence of catalyst sodium borohydride (NaBH4) and it was observed that the methylene blue (MB) removal process increased with doping concentration. These nanocatalysts may prove useful in the removal of industrial contaminants, especially leather, and tanneries pollutants.

The development of resistance against antibiotics used to treat bacterial infections along with the prevalence of medication residues presents significant public health problems globally. Antibiotic-resistant germs result in infections that are difficult or impossible to treat. Decreasing antibiotic effectiveness calls for rapid development of alternative antimicrobials. In this respect, nanoparticles (NPs) of copper oxide (CuO) manifest a latent and flexible inorganic nanostructure with noteworthy antimicrobial impact. Green synthesis of CuO NPs was performed in the current study, which was then doped with varying amounts of ginger (Zingiber officinale, ZO) and garlic (Allium sativum, AS) extracts. In low and high doses, the synthesized compound was used to measure the antimicrobial effectiveness against pathogenic Escherichia coli. The present research successfully demonstrated a renewable, eco-friendly synthesis technique with natural materials that is equally applicable to other green metal oxide NPs.

Combination of bioactive material such as hydroxyapatite (HAp) with antibacterial agents would have great potential to be used as bone implant materials to avert possible bacterial infection that can lead to implant-associated diseases. The present study aimed to develop an antibacterial silver nanoparticle-decorated hydroxyapatite (HAp/AgNPs) nanocomposite using chemical reduction and thermal calcination approaches. In this work, natural HAp that was extracted from chicken bone wastes is used as support matrix for the deposition of silver nanoparticles (AgNPs) to produce HAp/AgNPs nanocomposite. XRD, FESEM-EDX, HRTEM, and XPS analyses confirmed that spherical AgNPs were successfully synthesized and deposited on the surface of HAp particles, and the amount of AgNPs adhered on the HAp surface increased with increasing AgNO3 concentration used. The synthesized HAp/AgNPs nanocomposites demonstrated strong antibacterial activity against Staphylococcus aureus bacteria, where the antibacterial efficiency is relied on the amount and size of deposited AgNPs. In addition, the in vitro bioactivity examination in Hank’s balanced salt solution showed that more apatite were grown on the surface of HAp/AgNPs nanocomposite when AgNO3 concentration used >1 wt.%. Such nanocomposite with enhanced bioactivity and antibacterial properties emerged as a promising biomaterial to be applied for dentistry and orthopedic implantology.

Naturally formed oxide film on the surface of aluminum reduces corrosion rate to significant extent. Anodizing of aluminum is done to enhance this feature by increasing film thickness deliberately to desired level. In the current work, anodizing of Al-2024 alloy was carried out in sulfuric-acetic acid anodizing bath of different concentrations along with gradually increased applied potential. The structure and morphology of the developed anodized film was investigated with and without the addition of acetic acid. Structural and surface analysis results revealed the difference in the anodized layer formation with the presence of acetic acid in sulfuric acid bath. Electrochemical investigation was carried out to evaluate the surface protective performance of the formed anodized film in 3.5% NaCl solution. Potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) revealed that lowest corrosion rate with highest polarization resistance was achieved due to the presence of CH3COOH in the anodizing bath. Non-adsorptive and less porous anodized film noticed to be formed with the presence of CH3COOH in bath solution.

Supercritical water is uniquely a green medium for diverse applications because of its changing nature from polar to non-polar. Owing to this property, it is being considered for heavy oil upgradation since it dissolves both organics (oil) and hydrogen while inorganics behave conversely. However, because of the high pressure and temperature (22.1 MPa, 374 °C), corrosive environment (chlorides, sulfides and salt deposition) and stresses involved, there are serious concerns encountered while utilizing supercritical water in reactors. These include change in the component-material microstructure due to hydrogen ingress, sulfide stress corrosion cracking and salt deposition leading to pitting and de-alloying. Various alloys such as ferritic–martensitic steels, austenitic stainless steels, Ti-, Ni- and Zr-based alloys have been used, while new alloys and materials are continuously being investigated to considerably help abate these problems and ultimately improve the life of reactors. Despite significant past efforts in material development, reactors still suffer from these problems and challenges. This review assesses materials selection, the current progress in material development as well as their potentials in ameliorating reactors resistance to oxidation, pitting, embrittlement, etc. This study aims to improve understanding of material selection for supercritical water reactors based on the corrosive environment of the reactor and hence help engineers to make insightful decisions in selecting material for the specific corrosive environment. Schematic illustration of materials susceptibility in supercritical water reactor

The demand of high anodic potential for oxygen evolution reaction (OER) because of its sluggish kinetics limits the overall efficiency and practical applications of electrochemical water splitting ...

Dopamine (DA) is a neurotransmitter that plays a pivotal role in the brain's proper functioning and several other physiological processes. Herein, we demonstrate the miniaturized electrochemical sensor for detecting DA using hafnium metal‐organic framework (Hf‐MOF) derived new nanocomposite of hafnium and cobalt oxides (HfO2‐CoO). Calcination of Hf‐MOF coated with cobalt acetylacetonate complex [(Co(acac)2] yield HfO2‐CoO nanoparticles supported over in situ generated graphitic carbon. The excellent adsorption capabilities of HfO2 and highly catalytic CoO activity make this bimetallic HfO2‐CoO nanocomposite to display a stable response over a wide linear concentration range when used as electrode material in the electrochemical DA sensing process. Moreover, the computational study also proves that CoO improves the chemisorption properties of HfO2 for DA. Electrochemical studies are performed through cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV). For the case of LSV, the HfO2‐CoO nanocomposite modified glassy carbon electrode (HfO2‐CoO/GCE) exhibit a linear response to DA concentration ranging from 0.25 to 3.15 mM. However, with DPV HfO2‐CoO/GCE electrode has displayed a linear range of 10–190 μM and a detection limit of 1.8 μM is achieved. The electrode has also shown excellent stability, and only 19 % loss in its initial current response is observed over 150 days of specific interval testing. The HfO2‐CoO/GCE nanocomposite electrode, due to its unique feature of stability, selectivity, and sensitivity, has a good potential for use as an analytical tool for non‐enzymatic sensing of DA and other neurotransmitters in the human fluid.

In this work, size-controlled synthesis of nickel ferrite nanoparticles was achieved by the calcination of a bimetallic (Fe/Ni) metal-organic framework (MOF). The bimetallic MOF (Fe2Ni-MIL-88B) itself was prepared by a two-step route. The first step involved synthesis of the secondary building unit (SBU) by reacting stoichiometric amounts of Ni and Fe precursors with acetic acid. A ligand substitution reaction (terephthalate replaces acetate) in the SBU leads to the formation of the MOF, which was characterized by PXRD, FTIR, SEM and TEM. Afterwards, the MOF was calcined under air atmosphere to obtain nickel ferrite nanorods. PXRD analysis confirmed the spinel structure of the nickel ferrites while electron microscopic analysis (SEM, TEM) revealed their nanorod-like morphology. By increasing the calcination temperature from 600 to 1000 °C, particle size increased from 16 to 32 nm. Oxidation of benzyl alcohol was used as a model test reaction to probe the applicability of spinel nickel ferrite nanorods for catalysis. Interestingly, the largest nanorods exhibited the highest activity (86% conversion), thus demonstrating the potential of spinel ferrites in catalyzing oxidation reactions.

Various concentrations of Mg-doped ZnO nanorods (NRs) were prepared using co-precipitation technique. The objective of this study was to improve the photocatalytic properties of ZnO. The effect of Mg doping on the structure, phase constitution, functional groups presence, optical properties, elemental composition, surface morphology and microstructure of ZnO was evaluated with XRD, FTIR, UV–Vis spectrophotometer, EDS, and HR-TEM, respectively. Optical absorption spectra obtained from the prepared samples showed evidence of blueshift upon doping. XRD results revealed hexagonal wurtzite phase of nanocomposite with a gradual decrease in crystallite size with Mg addition. PL spectroscopy showed trapping efficiency and migration of charge carriers with electron–hole recombination behavior, while HR-TEM estimated interlayer d-spacing. The presence of chemical bonding, vibration modes and functional groups at the interface of ZnO was revealed by FTIR and Raman spectra. In this study, photocatalytic, sonocatalytic and sonophotocatalytic performance of prepared NRs was systematically investigated by degrading a mixture of methylene blue and ciprofloxacin (MBCF). Experimental results suggested that improved degradation performance was shown by Mg-doped ZnO NRs. We believe that the product synthesized in this study will prove to be a beneficial and promising photocatalyst for wastewater treatment. Conclusively, Mg-doped ZnO exhibited substantial (p E. coli predicted inhibition of given enzymes as possible mechanism behind their bactericidal activity.

Nanosized tin oxide was fabricated with a simple and cost-effective precipitation technique and was analyzed by performing x-ray powder diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, high-resolution transmission electron (HR-TEM) microscopy, energy-dispersive x-ray (EDX) and UV–Vis spectroscopy. The XRD results revealed that tin oxide particles possessed typical orthorhombic structure and exhibited improved crystallinity with annealing. Calcination at 250 °C produced predominantly orthorhombic SnO which transformed to SnO2 at higher temperatures of 500 and 750 °C. HRTEM and FESEM images showed existence of agglomeration within the particles of tin oxide. The absorption was found to increase up to a certain annealing temperature followed by a decrease, which was recorded via UV–Vis spectroscopy. The effect of annealing temperature on dye decomposition behavior of synthesized photocatalysts was studied. It was noted that annealing temperature affects the size of synthesized particles, band gap width and photoactivity of tin oxide. The sample prepared at 500 °C followed first-order kinetics and exhibited maximum photocatalytic reactivity toward methylene blue. The experimental results obtained from the present study indicate that SnO2 is a promising and beneficial catalyst to remove contaminants from wastewater and environment. The antimicrobial evaluation of SnO annealed at 500 °C against selected targets such as E. coli and S. aureus depicted significant inhibition zones in comparison with 250 and 750 °C samples. Furthermore, molecular docking predictions of SnO2 nanoparticles (NPs) were performed against active pocket of β-lactamase and DNA gyrase enzyme belonging to cell wall and nucleic acid biosynthetic pathway, respectively. The fabricated NPs showed good binding score against β-lactamase of both E. coli (− 5.71 kcal/mol) and S. aureus (− 11.83 kcal/mol) alongside DNA gyrase (− 9.57 kcal/mol; E. coli and − 8.61 kcal/mol; S. aureus). These in silico predictions suggested SnO2 NPs as potential inhibitors for selected protein targets and will facilitate to have a clear understanding of their mechanism of action that may contribute toward new antibiotics discovery.

A biogenic protocol has been adopted for the formulation of zinc ferrite nanoparticles (ZFNPs) using an aqueous extract of Allium cepa (AC) as a reducing agent for the optimization of its properties. The various characterization results from XRD, SEM, DRS, Raman, and VSM clearly showed that the formulated ZFNP was a single phase with crystallite size in the range of 11–15 nm. A spherical morphology was observed for all the samples with particle size in the range of 34–52 nm. All the samples showed a superparamagnetic behavior with reduced saturation magnetization. The ZFNPs prepared were used for self-heating analysis in hyperthermia applications at 180 Oe applied field and 425 Hz. It produced enough heating within the therapeutic temperature to attain the Curie temperature. The ZFNP formulated is auspicious for hyperthermia applications with less side effect owing to their biocompatibility, moderate Curie temperature, and SAR value within the therapeutic range. The formulated nanoparticles have further broadened the horizon of hyperthermia therapeutic applications with an innocuous protocol within 300 s.

In this work, dolomite filler was introduced into thermoplastic starch (TPS) matrix to form TPS-dolomite (TPS-DOL) biocomposites. TPS-DOL biocomposites were prepared at different dolomite loadings (1 wt%, 2 wt%, 3 wt%, 4 wt% and 5 wt%) and by using two different forms of dolomite (pristine (DOL(P) and sonicated dolomite (DOL(U)) via the solvent casting technique. The effects of dolomite loading and sonication process on the mechanical properties of the TPS-DOL biocomposites were analyzed using tensile and tear tests. The chemistry aspect of the TPS-DOL biocomposites was analyzed using Fourier transform infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) analysis. According to the mechanical data, biocomposites with a high loading of dolomite (4 and 5 wt%) possess greater tensile and tear properties as compared to the biocomposites with a low loading of dolomite (1 and 2 wt%). Furthermore, it is also proved that the TPS-DOL(U) biocomposites have better mechanical properties when compared to the TPS-DOL(P) biocomposites. Reduction in the dolomite particle size upon the sonication process assisted in its dispersion and distribution throughout the TPS matrix. Thus, this led to the improvement of the tensile and tear properties of the biocomposite. Based on the findings, it is proven that the sonication process is a simple yet beneficial technique in the production of the TPS-dolomite biocomposites with improved tensile and tear properties for use as packaging film.

In this study, a novel, Co3O4 nanoparticle decorated MoS2 nanoflower (MoS2/Co3O4) has been fabricated via a facile hydrothermal method by taking different concentrations of Co3O4 (0, 1, 2, 4, and 6%). The FE-SEM images represent a three-dimensional flower-like structure for MoS2 and MoS2/Co3O4. The different structural parameters of the nanoflowers were estimated from the XRD analysis. TEM analysis revealed that the inter-planar spacing of the nanostructure varied with the concentration of the Co3O4 nanoparticles. The Raman spectroscopy of MoS2/Co3O4 nanoflower showed a distinct low-shift of the first-order Raman peaks suggesting n-type doping due to the incorporation of Co3O4. The specific capacitance as high as 220.72 mFcm-2 at 0.14 mAcm-2 together with high energy density and superior cycling stability (87% capacitance retention after 10,000 charge/discharge cycles) were obtained for the MoS2/Co3O4 (4%) nanocomposite from the electrochemical analysis. This improved specific capacitance of MoS2/Co3O4 can be attributed to the higher surface area, defect-rich structure, and lower charge transfer resistance of the prepared sample. The MoS2/Co3O4 nanostructure with improved specific capacitance and higher stability synthesized from a simple, low-cost process will pave the way to the production of efficient and economic energy storage devices.

Transparent and amorphous yttrium (Y)/Sialon thin films were successfully fabricated using pulsed laser deposition (PLD). The thin films were fabricated in three steps. First, Y/Sialon target was synthesized using spark plasma sintering technique at 1500 &deg, C in an inert atmosphere. Second, the surface of the fabricated target was cleaned by grinding and polishing to remove any contamination, such as graphite and characterized. Finally, thin films were grown using PLD in an inert atmosphere at various substrate temperatures (RT to 500 &deg, C). While the X-ray diffractometer (XRD) analysis revealed that the Y/Sialon target has &beta, phase, the XRD of the fabricated films showed no diffraction peaks and thus confirming the amorphous nature of fabricated thin films. XRD analysis displayed that the fabricated thin films were amorphous while the transparency, measured by UV-vis spectroscopy, of the films, decreased with increasing substrate temperature, which was attributed to a change in film thickness with deposition temperature. X-ray photoelectron spectroscopy (XPS) results suggested that the synthesized Y/Sialon thin films are nearly homogenous and contained all target&rsquo, s elements. A scratch test revealed that both 300 and 500 &deg, C coatings possess the tough and robust nature of the film, which can resist much harsh loads and shocks. These results pave the way to fabricate different Sialon doped materials for numerous applications.

In this paper, a production-type chemical vapour deposition (CVD) is utilized to deposit fluorine\ud doped tin oxide thin films of different thicknesses and dopant levels. Deposited films showed a\ud preferred orientation along the (200) plane of a tetragonal structure due to the formation of\ud halogen rich polar molecules during the process. A holistic approach studying elastic modulus\ud and hardness of resulting films by a high-throughput atmospheric-pressure CVD process is\ud described. The hardness values determined lie between 8 - 20 GPa. For a given load, the modulus\ud generally increased slightly with the thickness. The average elastic recovery for the coatings was\ud found to be between 45 – 50 %. Refractive index and thickness values derived from the fitted\ud ellipsometry data were in excellent agreement with independent calculations from transmission\ud and reflection data.

The present research is a comparative study that reports an economical and accessible method to synthesize niobium (Nb) and Tantalum (Ta) selenides and tellurides with useful application in the removal of pollutants in textile, paper, and dyeing industries as well as in medical field. In this study, solid-state process was used to generate nanocomposites and various characterization techniques were employed to compare two groups of materials under investigation. Structure, morphology, elemental constitution, and functional groups of synthesized materials were analyzed with XRD, FESEM coupled with EDS, FTIR, and Raman spectroscopy, respectively. HR-TEM images displayed nanoscale particles with tetragonal and monoclinic crystal structures. The optical properties were evaluated in terms of cut-off wavelength and optical band gap using UV-visible spectroscopy. A comparative behavior of both groups of compounds was assessed with regards to their catalytic and microcidal properties. Extracted nanocomposites when used as catalysts, though isomorphs of each other, showed markedly different behavior in catalytic degradation of MB dye in the presence of NaBH4 that was employed as a reducing agent. This peculiar deviation might be attributed to slight structural differences between them. Escherichia coli and Staphylococcus aureus (G –ve and + ve bacteria, respectively) were designated as model strains for in vitro antibacterial tests of both clusters by employing disk diffusion method. Superior antibacterial efficacy was observed for telluride system (significant inhibition zones of 26-35 mm) compared with selenide system (diameter of inhibition zone ranged from 0.8 mm to 1.9 mm). In addition, molecular docking study was undertaken to ascertain the binding interaction pattern between NPs and active sites in targeted cell protein. The findings were in agreement with antimicrobial test results suggesting NbTe4 to be the best inhibitor against FabH and FabI enzymes.

Nanostructures of Cu-doped ZnO (Cu:ZnO) were prepared with the chemical precipitation technique with an aim to enhance the photocatalytic and antibacterial properties of ZnO. Phase constitution, the presence of functional groups, optical properties, elemental composition, surface morphology and microstructure were evaluated using an X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometer, energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HR-TEM), respectively. Emission spectra were obtained with a photoluminescence (PL) spectroscope whereas interlayer d-spacing was estimated through HR-TEM. ZnO consisted of a hexagonal wurtzite structure. The crystallinity of the sample was observed to increase with increasing doping concentration. The addition of Cu to ZnO served to transform nanoclusters into nanorods as revealed during SEM analysis. Catalytic activity enhanced due to the formation of nanorods, and UV-Vis absorption spectra showed that methylene blue (MB) degraded more efficiently with ZnO nanoclusters compared to the NaBH4 reagent. In addition, the doped NPs showed enhanced bacterial efficiency for G +ve. Finally, a molecular docking study was undertaken to highlight the importance of the binding interactions of the Cu-doped ZnO nanorods with β-lactamase and beta-ketoacyl-acyl carrier protein synthase III (FabH) as possible enzyme targets. This research indicates that Cu-doped Zn nanorods are a highly efficient photocatalyst and can be aptly employed for wastewater treatment and antibacterial applications.

Graphene oxide (GO) was obtained through modified hummers method and reduced graphene oxide (rGO) was acquired by employing heat treatment. Various concentrations (2.5, 5, 7.5 and 10 wt.%) of silver (Ag) were incorporated in GO nanosheets by adopting hydrothermal approach. Synthesized Ag decorated rGO photocatalyst Ag/rGO was characterized using X-ray diffraction (XRD) to determine phase purity and crystal structure. XRD patterns showed the formation of GO to Ag/rGO. Molecular vibration and functional groups were determined through Fourier Transform Infrared spectroscopy (FTIR). Optical properties and a decrease in bandgap with insertion of Ag were confirmed with UV-visible (Uv-vis.) spectrophotometer and Photoluminescence (PL). Electronic properties and disorders in carbon structures were investigated through Raman spectroscopy that revealed the existence of characteristic bands (D and G). Surface morphology of prepared samples was examined with Field Emission Scanning Electron Microscope (FESEM). Homogeneous distribution, size and spherical shape of Ag NPs over rGO sheets were further confirmed with the help of High-Resolution Transmission Electron Microscope (HR-TEM). Dye degradation of doped and undoped samples was examined through Uv-vis. spectra. Experimental results indicated that photocatalytic activity of Ag@rGO enhanced with increased doping ratio owing to diminished electron-hole pair recombination. Therefore, it is suggested that Ag@rGO can be used as a beneficial and superior photocatalyst to clean environment and wastewater.

In this work, boron nitride nanosheets (BNNS) were produced through chemical exfoliation of bulk boron nitride (BN). Furthermore, hydrothermal technique was used to incorporate various concentrations (2.5, 5, 7.5, and 10 wt%) of zirconium (Zr) as a dopant. The prepared undoped and doped BN samples were evaluated for its antimicrobial activity against E. coli and S. aureus. Structural analysis was undertaken using x-ray diffraction which identified the presence of hexagonal BN. FTIR and Raman spectroscopy were utilized to outline IR fingerprint and electronic properties of the synthesized material. Morphological information was obtained through micrographs extracted using field emission scanning electron spectroscope (FESEM) and high resolution transmission electron microscope (HRTEM), while d-spacing was also calculated through HRTEM analysis. Optical properties and emission spectra were examined by applying UV–vis and photoluminescence spectroscope (PL); whereas, band gap analysis was carried out via Tauc plot. Zr-doped BN nanosheets at increasing concentrations (0.5, 1.0 mg/50 μl) revealed enhanced antibacterial activity against E. coli compared to S. aureus (p

Two-dimensional layered materials doped with transition metals exhibit enhanced magnetization and improved catalytic stability during water treatment leading to potential environmental applications across several industrial sectors. In the present study, cobalt (Co)-doped boron nitride nanosheets (BN-NS) were explored for such an application. Chemical exfoliation process was used to exfoliate BN-NS and the hydrothermal route was adopted to incorporate Co dopant in various concentrations (e.g., 2.5, 5, 7.5, and 10 wt%). X-ray diffraction (XRD) study indicated that crystallinity improved upon doping with the formation of a hexagonal phase of the synthesized material. Selected area electron diffraction (SAED) confirmed enhanced crystallinity, which corroborates XRD results. Interlayer spacing was evaluated through a high-resolution transmission electron microscope (HR-TEM) equipped with Gatan digital micrograph software. Compositional and functional group analysis was undertaken with energy dispersive X-ray (EDS) and Fourier transform infrared (FTIR) spectroscopy, respectively. Field emission scanning electron microscope (FE-SEM) and HR-TEM were utilized to probe surface morphologies of prepared samples. Bonding modes in the sample were identified through Raman analysis. Optical properties were examined using UV-vis spectroscopy. Photoluminescence spectra were acquired to estimate the separation and recombination of excitons. Magnetic properties were studied by means of hysteresis loop acquired using VSM measurements. Methylene blue dye was degraded with as-prepared host and doped nanosheets used as catalysts and investigated through absorption spectra ranging from 250 to 800 nm. The experimental results of this study indicate that Co-doped BN-NS showed enhanced magnetic properties and can be used to degrade dyes present as an effluent in industrial wastewater.

We present the VLS synthesis and photoluminescence characteristics of In2 O3 nanopyramids at different growth temperatures in oxygen deficient environment. TEM images showed preferential growth of [2 2 2] planes. XPS results confirmed oxygen vacancies and metallic indium, which affected the Raman modes and reduced the correlation length. The PL spectrum consisted a very strong band in visible region was resolved in two sub-bands centered at 622 nm and 668 nm corresponding to oxygen vacancies and indium interstitials, respectively. Temperature dependent PL behavior was normal in nanostructures grown at 875 °C and 760 °C, with activation energies of 6.60 meV and 5.02 meV, 6.69 meV and 4.26 meV for the two bands, respectively. A Berthelot-like PL response was observed in nanostructures grown at 830 °C, with escape energy of 4.12 meV and 0.53 meV and activation energy of 2.09 meV and 5.33 meV for the two bands, respectively.

The production of an inexpensive, highly active electrocatalyst for a simple oxygen evolution reaction (OER) based on earth-abundant transition metals is still a major challenge. In addition, the ambiguity of the water splitting reaction (hydrogen evolution and OER) is a hurdle in the manufacture of suitable catalysts for the efficient water electrolysis process. Here, the synthesis of iron oxide/iron phosphide (Fe2O3/FeP) heterostructure and its counterparts Fe2O3 and FeP as cheap electrocatalysts for water electrolysis is presented. Characterization techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to analyze the structure of these electrocatalysts. Heterostructure Fe2O3/FeP has been shown to be a more active electrocatalyst than its counterparts. It initiates OER at a remarkably low potential of 1.49 V vs. reverse hydrogen electrode (RHE). For this electrocatalyst, a current density of 10 mA/cm2 is achieved at an overpotential of 264 mV for OER in 1.0 M potassium hydroxide solution and the value of the Tafel slope is 47 mV dec−1, outperforming its complements (Fe2O3 and FeP) under similar conditions. The results obtained are superior to those of previously reported Fe-based OER electrocatalysts. The Fe2O3/FeP electrocatalyst has proven its long-term stability by driving OER at 1.65 V (vs. RHE) for about 12.5 h.