In energy storage and conversion applications, high performance can be achieved by maximizing nanomaterial utilization—ideally approaching 100 %. This study comprehensively investigates the preparation of layered nanomaterials and the effects of nanoconfinement on the performance of energy storage and conversion devices. Specifically, KyIrOx and KyPtOx layered materials were successfully synthesized via solid-state reactions, thereby expanding the library of oxide-layered compounds. Additionally, a free-standing nanosheet structure (2.5D) was fabricated using a macroporous carbon template. Quinone-based aromatic compounds were adsorbed into activated carbon micropores smaller than 1 nm, yielding an adsorption-controlled system. A model electrode study employing reduced graphite oxide demonstrated that the redox reversibility of redox-active aromatic compounds was improved with decreasing interlayer distance. This finding suggests that the redox reversibility can be tuned effectively by controlling the nanoscale spacing in electrode materials.
Fe-based stents have been made a figure in biodegradable stents by their good mechanical capacity and biocompatibility, appropriate strength–ductility combination. Although the iron corrosion rate was not ideal, which had been optimized by iron alloy and polymer coating introduction. As a long-term implanted biodegradable material, the real concern about iron-based stents mainly laid in long-term biosafety. In this work, rats were used as an animal model to study the chronic toxicity and carcinogenicity of iron-based stents. Two years later, the changes in body weight and the physiological status during the experiment were monitored, and the blood routine and blood analysis combined with the health of major organs and histopathological tests were performed. The results demonstrated that there was no significant difference compared with the control group (316L SS) in body weight, blood routine index, blood biochemical index, and carcinogenic rate that further confirmed the biosafety of iron-based material.
Ignition delay times (IDT) for stoichiometric propane (C3H8) diluted with nitrogen were measured in a shock tube facility under reflected shock wave conditions at pressures ranging from 1 to 10 atm and temperatures between 850 and 1500 K. The experiments were limited to a maximum pressure of 10 atm due to the facility’s constraints. In addition, numerical simulations were conducted using several detailed kinetic mechanisms at pressures from 1 to 30 atm and three equivalence ratios (φ = 0.5, 1, and 2) to provide comparative insights. The results indicated that IDT decreases as pressure increases, with a more significant reduction observed between 1 and 10 atm compared to 10 to 30 atm. While most models exhibited similar trends and minimal discrepancies, the GRI Mech 3.0 mechanism demonstrated a slower prediction of ignition delay times at temperatures below 1250 K. In contrast, the POLIMI model exhibited a relatively faster prediction at temperatures above 1250 K, with the deviation between the two models becoming more pronounced as pressure increased. A comparative analysis revealed that the experimental predictions of propane autoignition behavior were in good agreement with the results obtained using the ARAMCO 3.0 mechanism. To further understand the chemistry governing the autoignition process of C3H8, a sensitivity analysis was performed for a stoichiometric mixture at three distinct temperatures (850 K, 1200 K, and 1550 K).
Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) are extremely ideal nanofillers for applications in damping polymer. This work explores the damping behavior of polymer nanocomposite beams made of epoxy resin reinforced with CNTs and GNPs experimentally. Beam specimens for the vibration tests together with dynamic mechanical analysis (DMA) are fabricated with different weight ratios of CNTs and GNPs, upon which DMA and free vibration tests are conducted. Scanning electron microscope images are also obtained to check the dispersion of nanofillers in microscale. It is found that the first-order loss factor of composite beam specimens shows a rise of 41.1% at 0.4 wt% CNT content compared with that of pure epoxy, while the first-order loss factor of composite beam specimens with 0.025 wt% GNP content increases up by 128.9%. The maximum value of the first-order loss factor of nanocomposite beams with GNP reinforcement is 62.2% higher than that with CNTs.
A graph-based genetic algorithm (GA) is used to identify molecules (ligands) with high absolute docking scores as estimated by the Glide software package, starting from randomly chosen molecules from the ZINC database, for four different targets: Bacillus subtilis chorismate mutase (CM), human β2-adrenergic G protein-coupled receptor (β2AR), the DDR1 kinase domain (DDR1), and β-cyclodextrin (BCD). By the combined use of functional group filters and a score modifier based on a heuristic synthetic accessibility (SA) score our approach identifies between ca 500 and 6,000 structurally diverse molecules with scores better than known binders by screening a total of 400,000 molecules starting from 8,000 randomly selected molecules from the ZINC database. Screening 250,000 molecules from the ZINC database identifies significantly more molecules with better docking scores than known binders, with the exception of CM, where the conventional screening approach only identifies 60 compounds compared to 511 with GA+Filter+SA. In the case of β2AR and DDR1, the GA+Filter+SA approach finds significantly more molecules with docking scores lower than −9.0 and −10.0. The GA+Filters+SA docking methodology is thus effective in generating a large and diverse set of synthetically accessible molecules with very good docking scores for a particular target. An early incarnation of the GA+Filter+SA approach was used to identify potential binders to the COVID-19 main protease and submitted to the early stages of the COVID Moonshot project, a crowd-sourced initiative to accelerate the development of a COVID antiviral.
A laser selective metallization on polycarbonate/acrylonitrile butadiene styrene (PC/ABS) substrates has been developed to fabricate copper patterns in this research. A laser curable Pd complex consists of 4-Vinylpridine (4VP), trimethylolpropanetriacrylate (TMPTA), tert-butyl peroxybenzoate (TBPB) and Pd(OAc)2, is utilized. First, liquid-phase palladium complex deposited on flexible substrates is irradiated by the laser beam. This produced a cured Pd complex with an effective catalytic activity. Then, a copper layer can be selectively deposited in the laser activation area on the PC/ABS substrate to form a copper pattern with excellent adhesion by electroless deposition (ELD). Various laser curing parameters, including laser mode (continuous or pulsed), laser energy and laser wavelength, are investigated to elucidate their effects on the morphology of copper pattern and the adhesion between the copper layer and PC/ABS substrate. The copper coating plated in this way shows low resistivity, which can make the bulb bright and not peel off after testing the adhesion with 3M 600 tape. Moreover, we also demonstrate that the copper patterns can be prepared easily by laser-curing catalyst pattern, with electroless copper deposition, which is a fast and effective strategy for fabricating circuit patterns on the PC/ABS substrate.
Industrial electrochemistry, Physical and theoretical chemistry
Mahmoud F. Mubarak, Mohamed A. Zayed, Ayman Nafady
et al.
Hybrid nanostructure materials derived from activated metakaolinite are of growing importance due to their intriguing structural/functional properties and promising biomedical/environmental applications, especially designing desalination membranes. Herein, we report procedures to design and fabricate membranes based on waste polyethylene/porous activated-metakaolinite thin film nanocomposites (WPE/PAMK-TFN). It has been devoted to improving water desalination processes, where efficient removal of trace level (~250 ppm) of toxic heavy metals such as Cd(II), Pb(II), and Cu(II) ions from synthetic wastewater solutions was highly accomplished. Physicochemical techniques such as X-ray diffraction (XRD), surface analysis (BET), and Fourier transform infrared spectroscopy (FTIR) have been extensively employed to elucidate the structure/composition of the prepared nanomaterials. The effect of concentration (0–0.5 wt%) of porous activated-metakaolinite (PAMK) on water permeation was investigated. The results obtained revealed that 0.5 wt% of PAMK clay particles produced the highest dispersion, as evident by SEM images of the nanocomposite membranes. Significantly, the constructed membrane showed marked improvements in porosity, hydrophilicity, and hydraulic resistance. Moreover, elemental mapping studies have confirmed the intercalation of activated bentonite clay within the polymer matrix. The obtained results demonstrated that increased flux and rejection capability of membranes occurred at high clay dosage. In contrast, the low rejection capability was observed at either lower pH and higher initial feed concentrations. Ultimately, for 250 ppm of Cd(II), Pb(II), and Cu(II) ions, the constructed membranes showed maximum removal capability of 69.3%, 76.2%, and 82.5% of toxic cations, respectively.
The spinel LiNi0.5Mn1.5O4 (LNMO) is a promising cathode material for lithium-ion batteries due to its high working voltage. However, the capacity fading is a major problem of LNMO, especially at elevated temperatures. Surface coating is an effective method to solve this problem. In this paper, a conducting polymer, the cyclized polyacrylonitrile (cPAN), is applied to coat on the surface of LNMO by a simple heat-treatment method in air. The cPAN coating layer can prohibit the electrode materials from direct contacting with the electrolyte therefore reduce the amount of transition metal ions dissolved into the electrolyte. In addition, the cPAN coating layer can increase the conductivity of cPAN-LNMO. Compared to pristine LNMO, the electrochemical properties of cPAN-LNMO are significantly improved, especially at elevated temperatures. After 100 cycles at 55°C, the discharge capacity of cPAN-LNMO is 112.9 mAh g-1 with the 95.2% retention, while that of pristine LNMO is only 104.7 mAh g-1 with the 87.8% retention. These results indicate that the cPAN-LNMO composite is a competitive cathode material for practical application in high-voltage lithium-ion batteries.
Industrial electrochemistry, Physical and theoretical chemistry
Here, we report on the novel green synthesis of metallic copper nanoparticles from copper sulfate solution by using the leaf extract of Heliconia psittacorum. The stability and gradual formation of copper nanoparticles during interaction with the extract were investigated using ultraviolet-visible spectroscopy. The pattern of X-ray diffraction revealed the crystallinity and different phases of the nanoparticles. High-resolution transmission electron microscopy was done to obtain information about the morphology and microstructure of the green nanoparticles. The infrared spectra detected organic bioactive molecules associated with capping and stabilization of the particle surface. The antibacterial properties of these bioengineered Cu nanoparticles were tested toward a Gram-positive bacteria – Staphylococcus aureus – and two strains of Gram-negative bacteria – Escherichia coli and Pseudomonas putida. The antibacterial study showed that these biogenic copper nanoparticles have potent bactericidal property toward the examined bacterial species.
The multi-walled carbon nanotubes (MWCNTs) modified Li3V2(PO4)3/carbon composites (MWCNTs-LVPCs) are synthesized through the rheological phase reaction method using MWCNTs as a highly conductive agent. MWCNTs-LVPCs are characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscope. Charge-discharge cycling performance is also used to characterize the electrochemical properties. X-ray diffraction result reveals that the added MWCNTs do not have a significant effect on the crystal structure of MWCNTs-LVPCs, however, crystal particles growth of MWCNTs-LVPCs are dramatically inhibited by MWCNTs in scanning electron microscopy test. The electrochemical measurements show that the 1.0 wt.%-MWCNTs-LVPC composite yields the highest discharge specific capacity of 182.38 and 163.93 mAh g−1 at current rate of 15 and 90 mA g–1 among all the MWCNTs-LVPCs, which are much higher than those of Li3V2(PO4)3/carbon composite. After 100 cycles, the 1.0 wt.%-MWCNTs-LVPC composite still maintains a stable capacity of 125.37 mAh g–1. Therefore, construction of MWCNTs modified Li3V2(PO4)3/carbon composites offers an effective and convenient technique to improve the conductivity and electrochemical performances of Li3V2(PO4)3/carbon composites.
Industrial electrochemistry, Physical and theoretical chemistry
Oscar E. Vázquez-Noriega, Javier Guzmán, Nohra V. Gallardo-Rivas
et al.
Conductive polymers such as polypyrrole, PPy, are materials capable of conducting electrical current. In this paper two techniques for the electrodeposition of PPy on carbon steel were used: Cyclic Voltammetry (CV) and Chronoamperometry (CA). The characteristics of film electrosynthesized on the carbon-steel substrate (CS-1018) using KNO3 as supporting electrolyte was studied. The results concluded that under experimental conditions used is possible make a PPy film with adequate characteristics. Important factors were the grip and electrochemical stability of the formed film on steel, which depends on the electrosynthesis technique and in some cases favored by a pretreatment with a 10% HNO3 solution applied to the steel prior to electropolymerization. The results showed that the polypyrrole deposited with pretreatment completely covered the steel surface and showed better stability and grip.
Industrial electrochemistry, Physical and theoretical chemistry
Howida A. Fetouh, Tarek M. Abdel-Fattah, Mohamed S. El-Tantawy
The effect of aqueous extracts of Damsissa, Lupine and Halfa-bar on the corrosion of 7075-T6 aluminium alloy in an aqueous solution of 0.5M sodium chloride has been studied employing electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The impedance (Nyquist) plots manifested that the dissolution process is controlled by charge transfer from anodic to cathodic sites. The polarization curves showed that the three extracts act as cathodic inhibitors. Inhibitive mechanism was discussed assuming the adsorption of the three extracts on the electrode surface. Theoretical fitting of Langmuir, Flory-Huggins adsorption isotherms and the kinetic- thermodynamic model were tested to clarify the adsorption mechanism.
Industrial electrochemistry, Physical and theoretical chemistry
Sambhaji S. Bhande, Eun-kyung Kim, Dipak V. Shinde
et al.
Efficient charge separation in photoelectrochemical cell composed of solution-processed SnO2 nanosheets (NSs)-CdSe nanocrystallites (NCs), is investigated. The SnO2 NSs decorated with CdSe NCs, confirmed from the structural elucidation and morphological evolution studies, electrode exhibited 16.40 mA/cm2 and 2.70% short circuit current density and power conversion efficiency which were superior to pristine CdSe nanowires-based electrode (9.44 mA/cm2, 1.44%). This increment was caused by relatively smaller recombination losses followed by higher electron life time and was well-supported from the photoluminescence, incident photon-to-current efficiency and electrochemical impedance spectroscopy measurements.
Industrial electrochemistry, Physical and theoretical chemistry
A titanium plate with carbon films (TPCF) prepared by electrodeposition in a LiCl-KCl-K2CO3 melt is used as the electrode for vanadium redox flow battery. The electrochemical behavior of V2+/V3+ and VO2+/VO2+ redox couples on TPCF electrode is investigated by cyclic voltammetry, potentiodynamic polarization and impedance techniques. The results show that the V2+/V3+ redox couple performs a quasi-reversible process on TPCF electrode. However, VO2+/VO2+ redox couple presents an irreversible process. The carbon atoms on surface of TPCF electrode can be oxidized when the potential reaches 1.5 V, which means that the TPCF electrode has lower corrosion resistance than graphite electrode.
Industrial electrochemistry, Physical and theoretical chemistry
The cage compound CL-20 (a.k.a., 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, HNIW, or 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.03,11.05,9]dodecane) is a well-studied high-energy-density material (HEDM). The high positive gas- (ΔfHg°) and solid- (ΔfHs°) phase heat of formation values for CL-20 conformers have often been attributed to the strain energy of this cage compound and, by implication, to the conventional ring strain energy (CRSE) inherent in isowurtzitane which may be viewed as a “parent compound” (although not the synthetic precursor) of CL-20. ΔfHg° values and destabilization energies (DSEs), which include the contribution from CRSE, were determined by computation using a relatively new multilevel ab intio model chemistry. Compared to cubane, isowurtzitane does not have an exceptionally high CRSE. It is about the same as that of cyclopropane and cyclobutane. These investigations demonstrate that instead of the CRSE inherent in the isowurtzitane parent compound, the relatively high ΔfHg° and DSE values of CL-20 conformers must be due, primarily, to torsional strain (Pitzer strain), transannular strain (Prelog strain), and van der Waals interactions that occur due to the presence of the six >N–NO2 substituents that replace the six methylene (–CH2–) groups in the isowurtzitane parent compound. These conclusions are even more pronounced when 2,4,6,8,10,12-hexaazaisowurtzitane is viewed as the “parent compound.”
A new technique, which was developed to characterize the direct methanol fuel cell under work conditions, has been presented in this paper. The impedance measurements were made using dynamic electrochemical impedance spectroscopy research technique in the galvanostatic mode, using multiple sinusoidal excitation. Obtained results show, that together with an increase of the temperature and working load, the global impedance of the cell decreases. However the value of methanol flow rate does not have any influence on the impedance value. Current-voltage characteristics were also obtained.
Industrial electrochemistry, Physical and theoretical chemistry
Li0.84Ni0.08MnPO4/C composite cathode materials for lithium ion battery are synthesized by sol-gel method followed by heat treatment in the air. Field-emission scanning electron microscopy (FE-SEM) measurements show that firing temperature affects the morphology of the end products. X-ray powder diffraction (XRD) analysis indicates that the samples are olivine-structured. The galvanostatic charge-discharge results show that the optimal firing temperature registers 400°C, and that sample Ni008-20%-400 possessed the best properties with its initial discharge capacity of 145.3 mAhg-1 at 0.02C rate and good capacity retention at a high C-rate.
Industrial electrochemistry, Physical and theoretical chemistry