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In this study, we report elaboration of a thin film of CoOx on a low carbon unalloyed steel substrate by electrochemical route and the study of its electrocatalytic performances with respect to the evolution reaction of oxygen (OER) in NaOH medium. The elaborated deposits were well-characterized using X-ray diffraction. Kinetic and thermodynamic parameters such as exchange current density, Tafel slope, reaction order with respect to OH– ions and apparent activation energy were studied. The CoOx displays satisfactory OER performance in an alkaline medium, with a low overvoltage of 362 mV at 10 mA/cm2 and a Tafel slope of 81 mV/dec at 293 K. The apparent kinetic activation energy (= 29.79 kJ/mol) was similar to those obtained for the reported catalytic electrode materials. The O2 gas obtained on the cobalt oxide electrode was 2.865 mmol/s.cm2, which is 28 times higher than that obtained for the platinum electrode (0.102 mmol/s.cm2). Chronoamperometry demonstrates a better electrochemical stability under a polarization potential of 2 V in 1 M NaOH for nearly 25 h. The low cost, the high OER performance, as well as the good stability of the CoOx electrode make it a promising candidate for the industrial-scale water electrolysis. [ABSTRACT FROM AUTHOR]

The purpose of this research is to evaluate the adsorption kinetics, isotherms and thermodynamic parameters correlating the removal of 60Co2+ radioactive ions from waste water of the primary cooling circuit of the Nuclear Uranium Reactor (Nur / Draria-Algeirs) on Fe(III)-modified Algerian bentonite. Characterization was done using X-ray diffraction, SEM analysis, X-ray Photoelectron Spectroscopy and BET method. The pseudo-second-order kinetic model provided the best fit to experimental data. The two-parameter adsorption model of Langmuir and both of the three-parameter models Langmuir–Freundlich and Toth are the most appropriate for fitting experimental results. The adsorption process was found to be endothermic in nature. [ABSTRACT FROM AUTHOR]

AbstractOur research described in this article examined the physical aging of natural rubber (NR) and nitrile rubber (NBR) compounds reinforced with nano-silica (n-SiO2) particles. The impact of NR and nano-silica content on the mechanical, spectral, and thermal properties of the composites was assessed using Shore hardness, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results showed that after 8 days of aging in toluene or xylene at room temperature, high NR content caused significant swelling in the non-polar solvents, unlike NBR, which prevented rubber chain stretching and reduced the free volume. The transport mechanism of the toluene and xylene was pseudo-Fickian and slightly dependent on the nano-silica content. The hardness of the vulcanized blends increased with NBR and silica incorporation due to better dispersion of the particules and rubber-filler interaction, leading to high cross-linking density. XRD patterns confirmed the filler intercalation within the polymer matrix, causing a diffraction shift to a lower 2θ value of the various reflectures. Differential thermogravimetric analysis (DTGA) revealed that the n-SiO2 nanoparticles enhanced the thermal stability due to strong polymer chain interactions. These findings suggest that nano-silica-filled NR/NBR blends have significantly improved physical, mechanical, and thermal properties, supporting their potential for advanced elastomer-based materials in industrial applications. [ABSTRACT FROM AUTHOR]

Abstract: The novel semi conducting configuration n-Bi2S3/Y-zeolite is elaborated by exchange reaction between H/Y-zeolite and Bi3+. The precipitation of Bi2S3 is achieved with thiourea, and activated by ultra sound probe at a frequency of 20 kHz for 60 min. X-ray diffraction and Raman spectroscopy confirm the formation of Bi2S3 which crystallizes in an orthorhombic symmetry. The scanning electron microscopy (SEM) shows uniform and rough surface with fine Bi2S3 crystallites. The specific surface area (S BET = 87.82 m2 g−1) is ∼seven times greater than that of Bi2S3 (9.57 m2 g−1) prepared under the same conditions. The Mott–Schottky characteristic gives a flat band potential of 0.465 V NHE. The electrical conductivity of Bi2S3 is correlated to the optical gap (E g = 1.40 eV) and photo-electrochemical characterization to establish the energetic diagram of the hetero-system Bi2S3/Y-zeolite/KOH solution. The latter predicts a spontaneous hydrogen evolution upon visible light. An enhancement of twice with respect to Bi2S3 is obtained in presence of as holes scavenger. The best performance (292 μmol H2 (g catalyst)−1 h−1) occurs at pH ∼13.1 with a light-to-chemical energy yield of 0.12%. [Copyright &y& Elsevier]

In this work, TiO2 layers are synthetized on Ti6Al4V alloy substrate by electrochemical anodizing process in fluoride‐containing alkaline electrolytes and under different applied voltages (10, 20, and 30 V). The scanning electron microscopy (SEM) reveals a nearly regular and vertical alignment of TiO2 nanotubes (≈80–100 nm) for specimen treated at 20 V and an agglomerate of particles with no particular orientations for those specimens treated at 10 and 30 V. The X‐ray diffraction (XRD) indicates the formation of mixed phases of anatase and rutile. Wettability measurements exhibit hydrophilic and superhydrophilic surfaces, according to the anodization parameters. The electrochemical impedance spectroscopy (EIS), performed in a simulated body fluid (Hank's solution), reveals an increase in corrosion resistance for a bias potential of 20 V (262 kΩ) owing to the evolution in TiO2‐layer thickness, and then decreases for higher anodizing potential values due to the chemical dissolution of the obtained layer. TiO2 nanostructured layers for biomedical application are synthesized on Ti6Al4V substrate by electrochemical anodizing process in fluoride‐containing alkaline electrolyte under different applied voltages. The effects of anodizing parameters on the morphology, crystal phases, and the surface wettability are investigated. The electrochemical test in a simulated body fluid (Hank's solution) indicates the best corrosion resistance for specimen anodized at 20 V. [ABSTRACT FROM AUTHOR]