Advanced Journal of Chemistry, Section A
Volume:7 Issue: 2, Spring 2024

In this study, a hydrothermal approach has been employed for the synthesis of copper antimony oxide films. Cu2Sb2O exhibits an amorphous phase prior to annealing and a polycrystalline phase (monoclinic structure) after annealing at temperatures ranging from 200 to 400oC, as showed by the XRD. The angles of 26.934o, 34.228o, and 38.362o correspond to the diffraction peaks (111), (211), and (311). High annealing temperature caused the film's lattice to reform and crystalize, which could cause cell ignition. The diffraction angles of the peaks moved higher because it was assumed that the annealing process affected the material. The unannealed Cu2Sb2O material displays small nanoparticles and a noteworthy nanoflake structure. Under different annealing temperatures, the nanoparticle's size increases when the film surface is ignited at higher pressure. When nanoparticle clusters were present during annealing, the material's surface energy increased. The absorption spectra displayed a consistent high rate of absorption between 200 to 600 nm, but showed a considerable decline beyond this range, with the minimum point noted between 700 to 850 nm. Yet it increased again between 980 and 1100 nm wavelength range. Light absorption is high in Cu2Sb2O, specifically in ultraviolet and blue regions. The film's absorbance increased from 0.145 to 0.185 a.u. when Cu2Sb2O was annealed at 200 °C. An increase in temperature from 200 to 400 °C caused an improvement in Cu2Sb2O's absorbance because of its susceptibility to temperature. The low reflectance of the films in both areas makes them ideal for both solar and photovoltaic cells. As the annealing temperature increased from 200 to 400 °C, the synthesized Cu2Sb2O film's bandgap energy decreased from 1.78 eV to a range of 1.66–1.21 eV.

Carbon nanotubes (CNTs) have gained massive attention given their special and unique features including high surface area, suitable chemical and electrochemical stability, unique mechanical and electronic features, as well as unidimensional structure. Two groups of CNT-based hybrids that have received much attention include nanotube/metal nanoparticles and nanotube/oxide nanoparticles hybrids. There are two major methods for preparing such hybrids: (I) in situ formation of nanoparticles in the presence of nanotubes, (II) use of prefabricated nanoparticles and binding them to the nanotube surface. In the CNTs decoration, the aim is to deposit nanoparticles with adhesivity on the nanotubes surface and a suitable bonding should be established between these two materials. Meanwhile, to achieve a hybrid with improved properties, the initial nanotube features should be kept as much as possible. Three principal methods have been evaluated for CNTs decoration: (I) electrochemical deposition and electroless, (II) chemical deposition, and (III) physical deposition. In this study, the aim is to examine different methods of CNTs decoration and to present the mechanism of methods. For this purpose, different examples related to each method and the effective parameters have been evaluated and discussed. Likewise, recent advances in CNTs decoration with metal and metal oxide nanoparticles have been explored in different applications.

The biological activity and properties of fourteen cyclic peptides were investigated using in silico approach. The predicted features for the studied compounds using 6-31G* via Spartan 14 software were lipophilicity, the highest occupied molecular orbital energy, the lowest occupied molecular orbital energy, HOMO/LUMO energy gap, dipole moment, molecular weight, and polar surface area. The descriptors obtained perfectly described the activities of the studied ligands. Likewise, the studied ligands were docked against sedoheptulose-7-phosphate isomerase [PDB id: 2x3y] and it was observed that all the ligands examined in this work have higher binding affinity than the ceftazidime (referenced drug) except compound 9 and 12. The predicted compounds proved to have higher binding affinities than the referenced compound and these were further confirmed using molecular dynamic simulation as well as pharmacokinetics studies.

The development of novel techniques for the efficient construction of heterocyclic compounds is an major issue in the preparation of organic compounds. The piperidine building block acts as a substantial task in the inhibitory activity of compounds and thus is very important in influencing biological properties such as antioxidant, anti-Alzheimer and free radical scavenging activities. Highly substituted piperidine analogs play a remarkable role in the synthesis of pharmaceutical compounds as important structural components in active and natural biological compounds. This review summarized advances in the synthesis of highly substituted piperidine analogs and their antioxidant and anti-Alzheimer properties. Antioxidant activities are inversely proportional to IC50 value. In addition, new green methods for the preparation of piperidine building blocks, such as: non-toxic catalysis, water-initiated processes, solvent-free reactions, etc., are also presented. This review study is designed to assist scientists looking for suitable substrates for the construction of biologically active piperidine analogs.

Austenitic stainless steel 316's role in industrial applications has spurred extensive but fragmented studies, presenting challenges in synthesizing its diverse properties. This study comprehensively investigates its fracture properties, analyzing the interplay of mechanical traits, microstructural nuances, strain rates, operational temperatures, hydrogen and helium impacts, heat treatment effects, and fracture behaviors across varying operational parameters. Analysis reveals a robust correlation between microstructure and mechanical characteristics, specially yield stress and fracture topography. Predictive models like Hall-Petch equation and Gibson-Ashby micromechanical model adeptly project these mechanical attributes. Deformation strain-rate surpasses relative porosity density in impact. Higher relative density prompts increased slip bands and grain deformation at constant strain rates, indicating local shear as the primary fracture mode, evident from observed shear bands. Hydrogen's influence, though delayed, assumes a secondary dominant deformation mechanism. While low strain rates do not alter failure modes due to hydrogen damage, its primary impact lies in reducing stress required for dislocation displacement and crack propagation, thereby diminishing tensile strength. External hydrogen exhibits a pronounced effect in some instances. Heat treatment significantly modifies the ferrite-cementite phase interface, impacting fracture morphology, notably at higher temperatures. Controlled annealing enhances fracture resistance at the expense of potential strength reduction, necessitating cautious execution due to heightened hydrogen embrittlement risk from reduced grain boundary chromium. This study seeks to consolidate insights into 316 SS fracture behavior, offering future research directions and practical implications for optimizing its performance in varied industrial settings.

Zn based composite coatings reinforced with TiO2 nanoparticles were fabricated via electrodeposition with 5, 10, and 15 g/L TiO2 concentration under variant current densities of 0.08, 0.1 and 0.12 A/cm2. Field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), x-ray diffraction analysis (XRD), weight loss measurements, salt spray technique, anodic polarization, and eventually potentiodynamic polarization tests were conducted and the corresponding findings were discussed. Rising the electrodeposition current density from 0.08 to 0.12 A/cm2 for both pure Zn and Zn-TiO2 coatings led to deposit more and smaller crystals and with incorporation of TiO2 nanoparticles, the morphology changed from hexagonal crystals to flake type grains. Increasing the TiO2 concentration from 5 to 15 g/L, steadily lowered the TiO2 incorporate rate (vol.%). Accordingly, the same smoothness and even more uniformity with smaller crystallites was observed at 15 g/L compared to that of 5 g/L. Weight loss measurements, salt spray tests and anodic polarization test showed remarkable superior corrosion resistance of Zn-TiO2 (5 g/L) than that of pure Zn coating. An increas in icorr (µA/cm2) from 0.08 to 0.1 A/cm2 occurred, followed by a decrease from 0.1 to 0.12 A/cm2 for pure zinc coating. By increasing the current density from 0.08 to 0.12 A/cm2 for Zn-TiO2 coating, a steadily decrease of icorr was observed. Furthermore, by rise of TiO2 (%C) from 5 to 15 g/L, icorr experienced a significance increase that could be ascribed to the remarkable reduction in TiO2 vol.%. Ultimately, the optimum corrosion resistance belonged to the electrodeposited Zn-TiO2 (5 g/L) coating deposited 0.12 A/cm2 exhibiting the lowest amount of icorr of 2.7 µA/cm2 equal to 1.6 mpy.

Todays, activated carbon derived from biomass sources has wide applications. In this study, activated carbon of tea waste has been considered for adsorption of phenylephrine hydrochloride drug from aqueous solution via batch adsorption process. The adsorption tests were carried out under several conditions such as equilibrium time, pH, adsorbent dose, and temperature. FESEM, TEM, and EDX techniques applied for characterization of activated carbon of tea waste before and after adsorption. The equilibrium results fitted to Langmuir and Freundlich isotherm models and it has been described as well via Freundlich model with best multilayer adsorption efficiency. According to analyses and experimental data, activated carbon of tea waste as a low cost, economically feasible and abundantly available adsorbent has great potential to high removal efficiency for phenylephrine hydrochloride drug.