Crystalline Size Research Articles

COMPLEX OF Co(II) WITH LIGAND 2,2’-BIPYRIDINE AND ANIONIC TRIFLUOROACETATE: SYNTHESIS, PHYSICAL PROPERTY, STRUCTURAL ANALYSIS AND ITS ANTIBACTERIAL ACTIVITY

The complex containing Co(II), bipyridine (bipy), and trifluoroacetate (TFA) was prepared and characterized. The metal content, conductance, and TGA-DTG analysis estimate the formula of [Co(bipy)3](CF3COO)2.5,5H2O. The magnetic property shows the moment of 4.2-5.3 BM which should correspond to the three unpaired electrons with the typically strong orbital contribution in cobalt(II). The UV-VIS spectral profiles indicate the three possible spin-allowed transitions of the corresponding quartet states. The characteristic vibration modes of bipy and TFA confirm the complex formula. The SEM photographs support the crystalline particle size, and the corresponding EDX signifies the existence of all elemental contents. The powder XRD profile has been refined according to the Le Bail method of the Rietica program, and the result suggests being a structurally monoclinic system of space group C2/c. This complex exhibits a weak inhibition against S. aureus and E. coli bacterial activity.

Investigation of structural and optical properties of TM-doped CuO NPs: Correlation with their photocatalytic efficiency in sunlight-induced pollutant degradation

The presence of non-biodegradable, toxic, and harmful organic pollutants in various environmental mediums poses significant threats to ecosystems and human health. This study investigates the impact of transition metal (TM) doping on the photocatalytic performance of copper oxide nanoparticles (CuO NPs) in degrading methylene blue (MB) dye under sunlight irradiation. CuO NPs are synthesized using the co-precipitation method. X-ray diffraction (XRD) analysis revealed a monoclinic structure with space group C2/c for undoped and TM–doped CuONPs, with crystalline sizes ranging from 13 nm for undoped to 36 nm for Zn-doped CuO. Based on UV–Visible Spectroscopy data, the band gap energies and the nature of electronic band transitions are determined using a new simplified calculation method. Accordingly, direct band gap energy exhibits a slight red-shift as a result of doping with Ni, Mn or Fe, from 1.427 eV for undoped to 1.402 eV for Fe-doped CuO. While Co or Zn doping, induces a trivial blue-shift to 1.468 eV and 1.434 eV respectively. The CuO particles show a heterogenous distribution size and shape. The mean grain size raised from 34.3 nm for undoped to about 100 nm for TM-doped CuONPS, excluding the Co-doped CuO for which the mean grain size reached 154.532 nm with highest standard deviation heterogeneity of 125.737 nm. Furthermore, photocatalytic experiments demonstrated that TM-doping significantly enhanced the degradation rate of MB dye under sunlight irradiation. Co-doped CuO is the most efficient catalyst. This makes TM-doping a promising pathway for the use of CuO NPs in wastewater decontamination applications.

Effect of Hydrochloric Acid Hydrolysis under Sonication and Hydrothermal Process to Produce Cellulose Nanocrystals from Oil Palm Empty Fruit Bunch (OPEFB).

This paper presents an approach for hydrolyzing cellulose nanocrystals from oil palm empty fruit bunch (OPEFB) presented through hydrochloric acid hydrolysis under sonication-hydrothermal conditions. Differences in concentration, reaction time, and acid-to-cellulose ratio affect toward the yield, crystallinity, microstructure, and thermal stability were obtained. The highest yield of cellulose nanocrystals up to 74.82%, crystallinity up to 78.59%, and a maximum degradation temperature (Tmax) of 339.82 °C were achieved through hydrolysis using 3 M HCl at 110 °C during 1 h. X-ray diffraction analysis indicated a higher diffraction peak pattern at 2θ = 22.6° and a low diffraction peak pattern at 2θ = 18°. All cellulose nanocrystals showed a crystalline size of under 1 nm, and it was indicated that the sonication-hydrothermal process could reduce the crystalline size of cellulose. Infrared spectroscopy analysis showed that a deletion of lignin and hemicellulose was demonstrated in the spectrum. Cellulose nanocrystal morphology showed a more compact structure and well-ordered surface arrangement than cellulose. Cellulose nanocrystals also had good thermal stability, as a high maximum degradation temperature was indicated, where CNC-D1 began degrading at temperatures (T0) of 307.09 °C and decomposed (Tmax) at 340.56 °C.

Microstructure and properties of WC-reinforced AlCoCrFeNiSi high entropy alloy coatings prepared via high-velocity arc spraying

In this research, (AlCoCrFeNiSi)100-x(WC)x (x=0, 20 and 40 wt%) high entropy alloy (HEA) coatings were successfully deposited on the surface of Q235 steel substrate using high-velocity arc spraying method. The study investigated the presence of WC particles on the phase composition, microstructure, tensile bonding strength, and corrosion behavior of the HEA coatings. X-ray diffraction analysis revealed that without WC particles, the predominant phase in the coating was a face-centered cubic (FCC). However, when 20 wt% and 40 wt% of WC particles were added, the phase composition shifted to include FCC, body-centered cubic (BCC), W3C, Cr7C3, and other carbides. The WC particles also reduced the crystalline grain size of the coatings from 14.75 nm to 10.34 nm. The microhardness value increased from 252.5 HV0.1 to a peak of 529.9 HV0.1, as the content of WC increased representing a microhardness improvement factor ranging from 1.4 to 3 times that of the substrate. The tensile bonding strength of the coatings was also enhanced with WC content. The coating with 40 wt% WC particles demonstrated the highest tensile bonding strength of 40.23 MPa. The cohesion, adhesion, and glue failures occurred after the tensile test, with adhesion failure being more prominent in the coatings without WC particles and glue failure being more prominent in the WC-reinforced coatings. Compared to the Q235 steel substrate, the coated samples showed enhanced resistance against corrosion due to the formation of the passive oxide layers. The effective resistance against corrosion was attained when the proportion of WC particles was 20 wt%, displaying the least values for corrosion current density and corrosion rate in 3.5 wt% NaCl solution. Examination through SEM and XPS analysis indicated that the coatings’ structures and the formation of protective passive layers enhanced the corrosion resistance.

A facile route to synthesis NixFe1−xFe2O4 ferrofluids with optimal rheological and magneto‐optical properties

AbstractThis study presents an easy method for synthesizing ultrafine NixFe1–xFe2O4 nanoparticles with adjustable composition (x = 0–.8), followed by their stabilization into ferrofluids. Structural identification of the crystalline structure, lattice points, and grain boundaries from the broadened diffraction peaks reveal an average crystalline size of the nanoparticles as 10–16.5 nm. Transmission electron microscopy images reveal spherical magnetite nanoparticles with a particle size ranging from 6 to 13 nm, consistent with diffraction studies. In ferrofluids, the NixFe1–xFe2O4 nanoparticles are stabilized in kerosene with oleic acid, a surfactant. Absorbance data of the ferrofluids is seen in the 200–400 nm wavelength region of UV–vis spectra. The magnetic properties of the samples are probed using a Superconducting Quantum Interference Device. The synthesized samples exhibit superparamagnetic behavior at room temperature (300 K). The saturation magnetization of the samples decreases with an increase in Ni composition (x = 0–.8), ranging from 54 to 28 emu/g. This study explores the magnetic and magneto‐optical properties of NixFe1–xFe2O4 ferrofluids. Magneto‐viscosity of ferrofluids is also studied, and the final application of such ferrofluids in data storage, catalysis, and biomedical applications is discussed.

20.2% Efficiency Organic Photovoltaics Employing a π-Extension Quinoxaline-Based Acceptor with Ordered Arrangement.

Organic solar cells, as a cutting-edge sustainable renewable energy technology, possess a myriad of potential applications, while the bottleneck problem of less than 20% efficiency limits the further development. Simultaneously achieving an ordered molecular arrangement, appropriate crystalline domain size, and reduced nonradiative recombination poses a significant challenge and is pivotal for overcoming efficiency limitations. This study employs a dual strategy involving the development of a novel acceptor and ternary blending to address this challenge. A novel non-fullerene acceptor, SMA, characterized by a highly ordered arrangement and high lowest unoccupied molecular orbital energy level, is synthesized. By incorporating SMA as a guest acceptor in the PM6:BTP-eC9 system, it is observed that SMA staggered the liquid-solid transition of donor and acceptor, facilitating acceptor crystallization and ordering while maintaining a suitable domain size. Furthermore, SMA optimized the vertical morphology and reduced bimolecular recombination. As a result, the ternary device achieved a champion efficiency of 20.22%, accompanied by increased voltage, short-circuit current density, and fill factor. Notably, a stabilized efficiency of 18.42% is attained for flexible devices. This study underscores the significant potential of a synergistic approach integrating acceptor material innovation and ternary blending techniques for optimizing bulk heterojunction morphology and photovoltaic performance.

The Complex of Cr(III) with Ligand of 2,6-Bis(pyrazol-3-yl)pyridine and Anionic Trifluoromethanesulfonate: Synthesis, Characterization and Antibacterial Activity

The complex containing chromium(III), 2,6-bis(pyrazol-3-yl)pyridine (3-bpp), and CF3SO3– (trifluoromethanesulfonate (triflate)) has been prepared and characterized. The conductance, metal content, and thermogravimetric and differential thermal analysis (TGA-DTA) analysis suggest the complex to be [Cr(3-bpp)2](CF3SO3)3.2H2O. The paramagnetic moment corresponds to the three unpaired electrons being consistent with the electronic configuration of chromium(III). The electronic spectral bands are not well resolved attributed to the spin-allowed transitions of quartet ground state to quartet excited states. The IR spectral data signify the mode of vibrations typical for 3-bpp as well as the triflate. While the images of scanning electron microscope-energy dispersive X-ray (SEM) photographs confirm the crystalline particle size and the energy dispersive X-ray (EDX) signifies the existence of all elemental content. The analysis of powder-X-ray diffraction (powder-XRD) following the Rietica program of Le Bail suggests being a structurally orthorhombic crystal system, and Pbca space group, with Z = 16, Rp = 4.30, Rwp = 5.14, Rexp = 12.17, R-FBragg = 0.04, and goodness of fitting (GOF) = 0.1783. The complex shows a weak inhibition of bacterial activity against S. aureus and E. coli.

Characterization of Calotropis gigantiea plant leaves biomass-based bioplasticizers for biofilm applications

The present surge in environmental consciousness has pushed for the use of biodegradable plasticizers, which are sustainable and abundant in plant resources. As a result of their biocompatibility and biodegradability, Calotropis gigantiea leaf plasticizers (CLP) serve as viable alternatives to chemical plasticizers. First time, the natural plasticizers from the Calotropis leaves were extracted for this study using a suitable chemical approach that was also environmentally friendly. The XRD results showed a reduced crystallinity index of 20.2 % and a crystalline size of 5.3 nm, respectively. TGA study revealed that the CLP has good thermal stability (244 °C). Through FT-IR study, the existence of organic compounds in CLP can be investigated by key functional groups such as alcohol, amine, amide, hydrocarbon, alkene, aromatic, etc. Further the presence of alcoholic, amino, and carboxyl constituents was confirmed by UV investigation. SEM, EDAX analysis, and AFM are used to examine the surface morphology of the isolated plasticizer. SEM pictures reveal rough surfaces on the CLP surface pores, which makes them suitable for plasticizing new bioplastics with improved mechanical properties. Poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer matrix, was used to investigate the plasticization impact after the macromolecules were characterised. The biofilm PBAT/CLP had a thickness of 0.8 mm. In addition, the reinforcement interface was examined using scanning electron microscopy. When CLP is loaded differently in PBAT, the tensile strength and young modulus change from 15.30 to 24.60 MPa and from 137 to 168 MPa, respectively. CLP-reinforced films demonstrated better surface compatibility and enhanced flexibility at a loading of 2 % when compared to pure PBAT films. Considering several documented characteristics, CLP may prove to be an excellent plasticizer for resolving environmental issues in the future.

Low-crystalline urchin-like CuCo2O4/rGO composite for high-performance supercapacitor

Abstract To meet the excellent capacity, power density and long lifespan for supercapacitors, developing advanced transition-metal oxide electrode materials is an important topic. Herein, we explored the effect of alkali source hydrolysis on the structural feature of CuCo2O4 during the growing process. It is found that urea with stronger hydrolysis ability leads to better morphology but larger crystalline grain size. Further, the grain size is decreased by introducing reduced graphene oxide (rGO). Consequently, the urea-derived CuCo2O4/rGO composite with urchin-like hierarchy configuration and small crystalline grain size provides a specific capacity of 1664 C g−1 at current density of 1 A g−1, and remains 65.3% of initial capacity when the current density increases to 30 A g−1. The symmetric supercapacitor achieves a high energy density (16 Wh kg−1 at 7200 W kg−1) and cycle stability (93.2% capacity retention after 10 000 cycles at 10 A g−1). This study highlights the inherent relation between the structural feature and synthesis condition.

High photocatalytic degradation of methylene blue and enhancing the magnetization, AC conductivity of Dy3+ and Ce3+ doped CdCoFe2O4 nano ferrites

Photocatalysts that combine with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. A series of Cd0.4Co0.6DyXCeXFe2-2XO4 spinel nano ferrites (nFs) were synthesized by using a highly efficient low-temperature method of citrate sol-gel auto-combustion for Methylene Blue (MB) dye degradation photocatalysts under visible light irradiation that combines with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. The recycled MB is one of the hazardous textile dyes that is used extensively but causes risks for both humans and the environment. The prepared Dy3+ and Ce3+ doped Cd–Co nFs were polycrystalline with cubic structure, and crystalline size was increased from 15.78 to 21.02 nm with higher crystallinity, and the surface morphology changes from a spherical shape to a hexagonal shape with higher doping concentrations. The direct optical band gap values are increased. FTIR spectra reveal the stretching vibrations along the [M↔O] bond tetrahedral (A) and octahedral (B) sites. HRTEM results revealed that the prepared Cd–Co nFs have higher crystalline nature and high porosity. VSM indicates the sample's soft magnetic action and hysteresis loops showed the highest saturation magnetization (Ms) is 12.243 emu/g, and retentivity increases around 6.038 emu/g, decreasing the dielectric tangent loss, dielectric constant and dielectric loss. The AC conductivity raised with applied frequency. The PL gives a blue emission, and photocatalytic has the highest degradation activity 40.93 % of MB would be successful after 120 min irradiation of X = 0.07 Dy3+ and Ce3+ doped Cd–Co nFs.

Harnessing the synergistic effects of graphene oxide based Sn/Fe codoped Bi2O3 nanocomposites for superior supercapacitor performance

Pure Bi2O3, 5 % Sn/Fe codoped Bi2O3, Graphene Oxide (GO) based Pure, and 5 % Sn/Fe codoped Bi2O3 nanocomposite are synthesized using a hydrothermal method. The synthesized material is comprehensively characterized to investigate its crystallographic, morphological, magnetic, and surface properties. Our findings reveal that the GO-based 5 % Sn/Fe co-doped Bi2O3 exhibits an exceptional capacitance of 1302.5 F/g. This remarkable capacitance enhancement can be attributed to a combination of factors, including changes in crystalline size, enhanced magnetization properties, an increase in surface area (170.86 m2/g), the introduction of defects in the material's structure, as well as low value of charge transfer resistance (0.3817 Ω) which indicates exceptional conductivity of the material. GO-based 5 % Sn/Fe co-doped Bi2O3 illustrates remarkable cycle stability with a retention rate of 81 % after 2000 cycles. The findings from this research provide evidence that GO-based Sn/Fe co-doped Bi2O3 is a material with outstanding prospects for high-performance energy storage applications, especially in supercapacitors. The combined effects of GO inclusion and co-doping provide new opportunities for the development of novel electrode materials with improved electrochemical characteristics.

Optimizing carboxylated nanocellulose preparation: A kinetic and mechanistic study on the enhancement of TEMPO-mediated oxidation via swelling treatment

This study explored the application of swelling pretreatment as a solution to the high cost and contamination associated with the process of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation for nanocellulose preparation. The results demonstrated that swelling significantly expanded the fibers while preserving the degree of polymerization (DP) of cellulose (approximately 95 %). The native crystal structure and hydrogen bonding of cellulose were disrupted after swelling, leading to a reduction in crystallinity and crystallite size, and the decrease of bonding energy and content of intermolecular O6-H⋯O3′. The TEMPO-mediated oxidation processes of cellulose fibers with or without swelling were successfully fitted using a consecutive first-order reaction kinetic model. The fitting results indicated that swelling significantly reduced the activation energy of TEMPO-mediated oxidation and enhanced the reaction rate. Among three swelling systems, the NaOH/thiourea/water system exhibited the optimal promotion effect. Consequently, the swelling treatment enables a significant reduction of 30 % in the catalyst dose for the TEMPO-mediated oxidation while preserving a competitive reaction rate, yield, and product performance. Lower catalyst dosage helps to reduce cost and environmental impact, facilitating the industrial application of the TEMPO-mediated oxidation process.

Degradation of reactive blue dye under UV irradation using iron based nanocomposites

Abstract The textile industry contributes significantly to environmental pollution through the discharge of non-biodegradable colored dye effluents, emphasizing the need for effective wastewater treatment methods. Traditional approaches, including physical and biological treatments, face limitations, necessitating exploration into advanced oxidation processes (AOPs). Iron-based photocatalysts, particularly those synthesized through green methods, have shown promise in degrading organic pollutants. In this study, iron nanocomposites, including CSINCs, ASINCs, and ACINCs, are synthesized by mixing two different plant extract mixtures with an Iron precursor solution. XRD analysis confirms cubic structures for the prepared nanocomposites, with crystalline sizes of 14.21, 15.79, and 28.74 nm, respectively. UV–vis spectrophotometer shows characteristic absorption peaks in the 380–400 nm range. FESEM imaging reveals spherical particles, and EDX analysis detects typical signals of Fe, O, and C. FTIR spectra indicate various functional groups present in the nanocomposites. The study further focuses on optimizing the degradation of Reactive Blue 171 (RB 171) dye, considering factors such as pH, concentration of RB 171, and photocatalyst concentration. The results demonstrate that ACINCs, specifically at a concentration of 10 mg/100 mL in a mixture with Reactive Blue dye at a concentration of 50 ppm, exhibit enhanced degradation under UV irradiation. This detailed investigation contributes to the understanding of the structural and functional characteristics of Iron nanocomposites and their potential application in the efficient degradation of textile dyes, emphasizing the importance of optimizing key parameters for enhanced photocatalytic performance.

Synthesis and Characterization of Sol-Gelled Barium Zirconate as Novel MTA Radiopacifiers.

Barium zirconate (BaZrO3, BZO), which exhibits superior mechanical, thermal, and chemical stability, has been widely used in many applications. In dentistry, BZO is used as a radiopacifier in mineral trioxide aggregates (MTAs) for endodontic filling applications. In the present study, BZO was prepared using the sol-gel process, followed by calcination at 700-1000 °C. The calcined BZO powders were investigated using X-ray diffraction and scanning electron microscopy. Thereafter, MTA-like cements with the addition of calcined BZO powder were evaluated to determine the optimal composition based on radiopacity, diametral tensile strength (DTS), and setting times. The experimental results showed that calcined BZO exhibited a majority BZO phase with minor zirconia crystals. The crystallinity, the percentage, and the average crystalline size of BZO increased with the increasing calcination temperature. The optimal MTA-like cement was obtained by adding 20% of the 700 °C-calcined BZO powder. The initial and final setting times were 25 and 32 min, respectively. They were significantly shorter than those (70 and 56 min, respectively) prepared with commercial BZO powder. It exhibited a radiopacity of 3.60 ± 0.22 mmAl and a DTS of 3.02 ± 0.18 MPa. After 28 days of simulated oral environment storage, the radiopacity and DTS decreased to 3.36 ± 0.53 mmAl and 2.84 ± 0.27 MPa, respectively. This suggests that 700 °C-calcined BZO powder has potential as a novel radiopacifier for MTAs.

Rice powder template for hausmannite Mn3O4 nanoparticles and its application to aqueous zinc ion battery.

In this study, a simple calcination route was adopted to prepare hausmannite Mn3O4 nanoparticles using rice powder as soft bio-template. Prepared Mn3O4 was characterized by Fourier Transform Infra-Red Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray microanalysis (EDX), Powder X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) and Solid state UV-Vis spectroscopic techniques. Mn-O stretching in tetrahedral site was confirmed by FTIR and Raman spectra. % of Mn and O content supported Mn3O4 formation. The crystallinity and grain size was found to be 68.76% and 16.43 nm, respectively; tetragonal crystal system was also cleared by XRD. TEM clarified the planes of crystal formed which supported the XRD results and BET demonstrated mesoporous nature of prepared Mn3O4 having low pore volume. Low optical band gap of 3.24 eV of prepared Mn3O4 nanoparticles indicated semiconductor property and was used as cathode material to fabricate CR-2032 coin cell of Aqueous Rechargeable Zinc Ion Battery (ARZIB). A reversible cyclic voltammogram (CV) showed good zinc ion storage performance. Low cell resistance was confirmed by Electrochemical Impedance Spectroscopy (EIS). The coin cell delivered high specific discharge capacity of 240.75 mAhg-1 at 0.1 Ag-1 current density. The coulombic efficiency was found to be 99.98%. It also delivered excellent capacity retention 94.45% and 64.81% after 300 and 1000 charge-discharge cycles, respectively. This work offers a facile and cost effective approach for preparing cathode material of ARZIBs.

Feasibility of using chemical co-precipitation and a high-gravity reactor with blade packings for continuous production of magnetite nanoparticles

BackgroundMagnetite nanoparticles (Higee-magnetite) were continuously produced using chemical co-precipitation and a high-gravity reactor with blade packings. MethodsA novel process for continuously producing Higee-magnetite involved an Fe2+ concentration of 0.15 mol/L with an Fe2+/Fe3+/OH− molar ratio of 1/2/8, an aqueous Fe2+/Fe3+ flow rate of 0.5 L/min, an aqueous OH− flow rate of 0.5 L/min, and a rotation speed of the high-gravity reactor of 1800 rpm. Significant findingsThe mean crystalline size of Higee-magnetite was 11 nm. The average particle sizes of Higee-magnetite as determined using SEM and TEM were 23 nm and 9 nm, respectively. Higee-magnetite was superparamagnetic at 25 °C. The saturation magnetization of Higee-magnetite was 69 emu/g. The BET specific surface area, Langmuir specific surface area, and mean pore size of Higee-magnetite were 152 m2/g, 204 m2/g, and 10 nm, respectively. The rate of continuous production of Higee-magnetite was approximately 12 kg/day. Higee-magnetite had a much higher capacity for adsorbing Pb2+ than magnetite nanoparticles that had been produced in a batch reactor since it had a larger specific surface area. The Pb2+ adsorption isotherm of Higee-magnetite corresponded more closely to the Langmuir isotherm model than to the Freundlich isotherm model. Furthermore, consistent with the Langmuir isotherm model, Higee-magnetite had the maximum Pb2+ adsorption capacity of about 49 mg/g at 25 °C and pH 5. Therefore, Higee-magnetite is a favorable magnetic adsorbent for removing Pb2+ from water.

NiO/MnO2 nanocomposite in addition of layered Reduced Graphene oxide (RGO) electrode for accountable supercapacitor application

Reduced Graphene oxide/Nickel oxide/Magnesium dioxide) RGO/NiO/MnO2 nanocomposite electrode was successfully prepared by simple co-precipitation method. The synthesised nanocomposite was characterised by XRD, FESEM, EDAX, FTIR, UV, CV, GCD, EIS. The RGO/NiO/MnO2 nanocomposite was pretreated by ultrasonication, followed by thermal annealing at 350 oC. The crystalline face and size of nanocomposite were analysed by X-Ray Diffraction (XRD). The sandwich-like structure of RGO/NiO/MnO2 was analysed by Scanning Electron Microscope (SEM). This structure promoted an efficient contact between electrolyte and active materials, and the distinct architecture could offer fast transfer channels of ion and electrons. The nanocomposite exhibited high conductivity owing to the presence of RGO. The electrochemical performance of prepared nanocomposite was done by Cyclic Voltammetry (CV), Galvanostatic charge discharge (GCD), Electrical Impedance Spectroscopy (EIS). The synthesised RGO/NiO/MnO2 nanocomposite acquired high specific capacitance of 1167F/g at current density of 1 A/g. The low cost, low temperature RGO/NiO/MnO2 nanocomposite electrode could be the promising electrode for Energy storage devices.

The synergistic impact of graphene and copper on microstructure, corrosion behaviors and biocompatibility of a magnesium metal matrix composite in Hank's solution

BackgroundThis research aimed to explore the combined effects of graphene (Gr) and copper (Cu) in a magnesium metal composite (MMC) on its microstructure, biocompatibility, electrochemical, and immersion corrosion behaviors. MethodsThe MMCs were prepared using the mechanical stir-casting method. Alloys with a preset weight percentage of Gr (0.15 wt.%) and various weight percentages of Cu (0.5 and 1 wt.%) were produced with pure Mg as the matrix. Significant findingsThis study demonstrates that Gr and Cu enhance crystallinity and increase grain size in composite materials. The introduction of Gr into the magnesium matrix alone elevates the corrosion rate. However, there was a further addition of 0.5 wt.% Cu (0.5Cu) showed a slight reduction in grain size growth and corrosion rate. The addition of more copper (1 wt.% Cu (1Cu)) increases both grain size and the corrosion rate again. Cytotoxicity test results indicate that Gr and Cu enhance the cell viability of 3T3 fibroblasts in vitro. These findings shed light on the intricate interplay between Gr and Cu in the microstructure and corrosion resistance of Mg-based composites and inspire confidence in developing magnesium metal composites for clinical applications.

Optimizing phosphorene nanosheets for high performance all-solid asymmetric supercapacitors: A theoretical and experimental insight

This study probably for the first-time introduced a phase and morphology-tuned scalable, cost-effective method for large-scale production of Black Phosphorous/Phosphorene (BP), and investigated their in-depth electrochemical properties. Utilizing a one-pot mild wet chemical-assisted hydrothermal route in ethylenediamine, high-quality BP nanosheets were synthesized from amorphous red phosphorus (RP) with nearly 100 % conversion efficiency, yielding 7.1352 g for one batch at 130–170 °C. The resulting phosphorene nanosheets exhibited a small crystalline size (2.708 nm), hierarchically porous morphology, a 1.64 eV direct optical bandgap aligned with theoretically calculated bandgap using LDA approximation, and various structural defects, along with large specific surface area (50 m2g−1) and reduced number of layers (4–5) compared to prior literatures, suggesting electrochemical superiority. CV and GCD measurements in the potential window of −0.7 V to 0.1 V revealed its highest pseudo-capacitance response (84.91 %), reaching a maximum specific capacitance value of 759.748 Fg−1 at current density 2 Ag−1, surpassing all previous records. Moreover, BP displayed excellent cyclic stability of 89.8 % after 10,000 cycles, making it an excellent electrode material for supercapacitors. A solid-state asymmetric supercapacitor device (HASD), using BP, successfully lighted up 6 red LEDs for 10 s, achieving maximum specific energy density at 73.43 Wkg−1 at a power density of 1500 Wkg−1.

Fatigue crack growth study on rolled and cryogenically treated AZ31B Mg alloy plate

This paper investigates the fatigue crack growth rate (FCGR) of AZ31B Mg alloy after cryogenic treatments. Shallow and deep cryogenic treatments were carried out separately at −80οC and −196οC for 12 and 72 hrs, respectively. The microstructural characterization of the cryogenically treated AZ31B specimens was carried out by optical microscope (OM) and X-Ray diffraction (XRD). The small crystalline size structure generated in AZ31B alloy due to the cryogenic treatment further promoted the nucleation of Mg17Al12 phase. Accumulation of dislocation density was also observed in the cryogenically treated specimens. CT specimens were prepared for all three conditions to estimate the FCGR. The as-rolled specimen (R) had higher fatigue resistance than the cryogenically treated specimens. The R specimen’s threshold intensity factor (ΔKth) was higher than the cryogenically treated specimens. The exponent (m) value of the R specimen was lower than the shallow and deep cryogenic treated specimens. Hence, the crack growth resistance was marginally higher in the R specimen compared to the cryogenically treated specimens. However, the critical stress intensity factor (ΔKcr) of cryogenically treated specimens was slightly higher than the R specimen. The post-fracture characterization of the specimens was carried out at three different regions by SEM. The cleavage faces, tear ridges, and voids were noticed in all specimens. The fatigue failure of the R specimen was due to ductile and brittle mode, whereas the cryogenically treated specimen was dominated entirely by brittle fracture.