Herein, we have synthesized different BWO samples at different temperatures and evaluated their electrochemical oxidation of Rhodamine B dye in an aqueous medium. The prepared samples were ...characterized using X-ray diffraction combined with Rietveld refinements, scanning electron microscope coupled with energy dispersive elemental mapping, and thermogravimetric and differential thermal analyses. All the samples crystallize in the orthorhombic Pca21 structure. The crystallite size increased with temperature. The calculated surface areas from the XRD data ranged from 38 to 7 m2 g−1 for BWO-600 to BWO-900, respectively. The optimal BWO loadings on the GCE electrode were 5 × 10−8 mol cm−2 recording the best electrocatalytic efficiency for RhB electrodegradation in 15 min (100%) in 0.1 M of NaCl. The BWO-600 recorded the best activity compared to other BWO samples. The electrocatalytic activity was explained by the high surface area and small crystallite size compared to the other samples. The BWO-600 showed extended electrode reutilization for up to four cycles of reuse under the reported conditions.
Electrochemical CO2 reduction reaction (CO2RR) is one of the most challenging targets of current energy research. Multi-electron reduction with proton-coupled reactions is more thermodynamically ...favorable, leading to diverse product distribution. This requires the design of stable electroactive materials having selective product generation and low overpotentials. In this review, we have explored different CO2RR electrocatalysts in the gas phase and H-cell configurations. Five groups of electrocatalysts ranging from metals and metal oxide, single atom, carbon-based, porphyrins, covalent, metal–organic frameworks, and phthalocyanines-based electrocatalysts have been reviewed. Finally, conclusions and prospects have been elaborated.
Substantial improvement is needed in efficient and affordable decolorization and disinfection methods to solve the issues caused by dyes and harmful bacteria in water and wastewater. This work ...involves the photocatalytic degradation of methylene blue (MB) as well as gram-negative and gram-positive bacteria by cobalt-doped tin oxide (Co-SnO2) nanoparticles (NPs) and Co-SnO2/SGCN (sulfur-doped graphitic carbon nitride) nanocomposites (NCs) under sunlight. The coprecipitation approach was used to synthesize the photocatalysts. Maximum methylene blue (MB) photocatalytic degradation was seen with the 7% Co-SnO2 NPs compared to other (1, 3, 5, and 9 wt.%) Co-SnO2 NPs. The 7% Co-SnO2 NPs were then homogenized with different amounts (10, 30, 50, and 70 weight %) of sulfur-doped graphitic carbon nitride (SGCN) to develop Co-SnO2/SGCN heterostructures with the most significant degree of MB degradation. The synthesized samples were identified by modern characterization methods such as FT-IR, SEM, EDX, UV-visible, and XRD spectroscopies. The Co-SnO2/50% SGCN composites showed a significant increase in MB degradation and degraded 96% of MB after 150 min of sunlight irradiation. Both gram-negative (E. coli) and gram-positive (B. subtiles) bacterial strains were subjected to antibacterial activity. All samples were shown to have vigorous antibacterial activity against gram-positive and gram-negative bacteria, but the Co-SnO2/50% SGCN composites exhibited the maximum bactericidal action. Thus, the proposed NC is an efficient organic/inorganic photocatalyst that is recyclable and stable without lowering efficiency. Hence, Co-SnO2/50% SGCNNC has the potential to be employed in water treatment as a dual-functional material that simultaneously removes organic pollutants and eradicates bacteria.
The development and study of Na ion batteries are expanding. This study employs the hydrothermal technique to produce single-phase, well-crystallized, fluorine-added O3-type NaFe1-xMgxO2. Using XRD, ...FESEM, and HRTEM, the sample’s phase structure and morphological information were characterized. Initially, without adding fluorine the electrode suffers from poor stability at high voltage ranges and also during long-term cycling. So, fluorine was added to the structure and the electrochemical performance of the material was greatly increased. The electrochemical performance of O3-type positive electrode materials for rechargeable Na ion batteries is evaluated. The capacity of fluorine-added O3-type NaFe1-xMgxO2 is approximately 163 mAh g−1 (50 mA g−1). Adding fluorine to the host structure increases the stability of the electrode, leading to improved electrochemical performance during long-term cycling. The electrochemical results indicate that fluorine-added O3-type NaFe1-xMgxO2 cathode material for cost-effective and environmentally friendly sodium-ion batteries is promising. Fluorine-based electrodes will be a future for Na ion energy storage devices
Magnesium and its alloys have tremendous potential as biodegradable implant materials but finding the right compromise between corrosion resistance and mechanical properties is an ongoing ...investigation. This study utilized equal channel angular pressing (ECAP) to fabricate Magnesium-ZX 30 alloy with a refined uniform microstructure. ECAP processing via routes Bc and A for up to four passes resulted in the evolution of dynamically recrystallized textured α-Mg ultrafine grains with a high fraction of low-angle boundaries. 4Bc and 4A processing via ECAP yielded significant grain refinements of 91.6% and 86.5%, respectively compared to the as-annealed condition. X-ray diffraction verified that the α-Mg phase dominated the microstructure as a result of ECAP processing promoting the dissolution of second phases due to the high density of dislocations and vacancies it generated. Electrochemical analysis revealed that ECAP reduced galvanic corrosion and pitting corrosion. Compared to the as-annealed sample, all ECAP-processed conditions displayed a significant decrease in corrosion rates, most notably among them is the 4A condition (97%). Moreover, the surge in grain boundary density and in grain boundary misorientations accelerated the formation of the passivation film, which enhanced the corrosion resistance compared to the as-annealed conditions by 254%, 418% for the 4Bc and 4A processed conditions, respectively. This was corroborated by an immersion test conducted in ringer lactate solution for 360 h. This current work signifies that ECAP processing is capable of producing ZX30 alloy medical implants with high mechanical properties and excellent corrosion resistance that make it suitable for future in-vitro research.
Graphical Abstract
An ultrasound-assisted probe sonication route effectively prepared pure CuO and two-dimensional CuO-ZnO nanocomposites (NCs) for different ratios of CuO and ZnO, and the experimental and theoretical ...methods investigated the structural, photocatalytic, and electrochemical properties. The XRD (X-ray diffraction) patterns revealed a crystallite size (D) range of 25 to 31 nm for pure CuO and CuO-ZnO NCs. According to calculations, the sample’s optical energy bandgap value (Eg) for the NCs is between 1.72 and 2.15 eV. Under UV light irradiation, the photocatalytic discoloration of pure CuO and CuO-ZnO NCs on fast blue (FB) dye was assessed. Under the influence of UV light, the CuO with 10% ZnO composite degrades 83.4% of the dye, which is greater than pure CuO and other NCs. The electrochemical properties of the prepared NCs materials have been studied using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The specific capacitance values were found to be 248 Fg−1, 301 Fg−1, 352 Fg−1, and 277 Fg−1 for CuO, CuO + 5% ZnO, CuO + 10% ZnO, and CuO + 15% ZnO, respectively, at 1 A/g current density. Galvanostatic charge–discharge tests for these designed NCs show excellent capacitance performance in supercapacitors applications. These innovative results could be considered for expanding novel resources to scale for dual applications in photocatalysis and supercapacitors.
Copper and its related alloys are frequently adopted in contemporary industry due to their outstanding properties, which include mechanical, electrical, and electronic applications. Equal channel ...angular pressing (ECAP) is a novel method for producing ultrafine-grained or nanomaterials. Modeling material design processes provides exceptionally efficient techniques for minimizing the efforts and time spent on experimental work to manufacture Cu or its associated alloys through the ECAP process. Although there have been various physical-based models, they are frequently coupled with several restrictions and still require significant time and effort to calibrate and enhance their accuracies. Machine learning (ML) techniques that rely primarily on data-driven models are a viable alternative modeling approach that has recently achieved breakthrough achievements. Several ML algorithms were used in the modeling training and testing phases of this work to imitate the influence of ECAP processing parameters on the mechanical and electrical characteristics of pure Cu, including the number of passes (N), ECAP die angle (φ), processing temperature, and route type. Several experiments were conducted on pure commercial Cu while altering the ECAP processing parameters settings. Linear regression, regression trees, ensembles of regression trees, the Gaussian process, support vector regression, and artificial neural networks are the ML algorithms used in this study. Model predictive performance was assessed using metrics such as root-mean-squared errors and R
scores. The methodologies presented here demonstrated that they could be effectively used to reduce experimental effort and time by reducing the number of experiments runs required to optimize the material attributes aimed at modeling the ECAP conditions for the following performance characteristics: impact toughness (I
), electrical conductivity (E
), hardness, and tensile characteristics of yield strength (σ
), ultimate tensile strength (σ
), and ductility (D
).
Using sustainable photocatalysts, photocatalytic degradation has emerged as one of the viable strategies to combat water pollution through eco-friendly and cost-effective means. Visible-light-active ...Ag3PO4/Mn-ZnO nanocomposite photocatalysts were produced in this study using a simple hydrothermal method and varied concentrations of Ag3PO4 to Mn-ZnO ranging from 0 to 5 wt percent. X-ray diffraction, scanning electron microcopy, energy-dispersive X-ray, transmission electron microscopy, UV–visible spectroscopy, Fourier transform infra-red spectrophotometer, and photoluminescence spectroscopy were used to examine the structural, morphological, and optical properties of synthesized materials. Visible light was used to test the photocatalytic activity of produced Ag3PO4/Mn-ZnO photocatalysts for the breakdown of tetracycline (TC) hydrochloride. In comparison to the other samples, the 3% Ag3PO4/Mn-ZnO nanocomposite exhibited superior activity as a result of improved visible light absorption and suppressed charge carrier recombination. In addition, this sample demonstrated good stability of TC in an aqueous environment after five consecutive cycles. This research will enhance the scope of photocatalysis for environmental applications.
Several physics-based models have been utilized in material design for the simulation and prediction of material properties. In this study, several machine-learning (ML) approaches were used to ...construct a prediction model to analyze the influence of equal-channel angular pressing (ECAP) parameters on the microstructural, corrosion and mechanical behavior of the biodegradable magnesium alloy ZK30. The ML approaches employed were linear regression, the Gaussian process, and support vector regression. For the optimization of the alloy’s performance, experiments were conducted on ZK30 billets using different ECAP routes, channel angles, and number of passes. The adopted ML model is an adequate predictive model which agreed with the experimental results. ECAP die angles had an insignificant effect on grain refinement, compared to the route type. ECAP via four passes of route Bc (rotating the sample 90° on its longitudinal axis after each pass in the same direction) was the most effective condition producing homogenous ultrafine grain distribution of 1.92 µm. Processing via 4-Bc and 90° die angle produced the highest hardness (97-HV) coupled with the highest tensile strength (344 MPa). The optimum corrosion rate of 0.140 mils penetration per year (mpy) and the optimum corrosion resistance of 1101 Ω·cm2 resulted from processing through 1-pass using the 120°-die. Grain refinement resulted in reducing the corrosion rates and increased corrosion resistance, which agreed with the ML findings.
The hexagonal close-packed (HCP) crystal structure of Mg alloys lead to poor formability as well as other undesirable mechanical behaviors in an otherwise highly sought-after alloy for commercial ...use. This study investigates the evolution of microstructure, texture, corrosion and mechanical behaviors in Mg–Zn–Mn (ZM31) alloy after processing using Equal Channel Angular Pressing (ECAP). Dynamic recrystallization was evident in the ECAP-processed samples, correlated with a substantial fiber structure, and resulted in the attainment of notable grain refinement and high lattice strain. Average grain sizes of 2.2 and 2 μm were achieved via 2 and 4-Pass Bc processing, respectively. This significant refinement yielded lower corrosion rates through enhancement of the thickness, coherency, and stability of formed protective oxide layers. The corrosion rate in the NaCl medium was substantially enhanced by 99.5% after four passes via route Bc. The recrystallized fine structure was found to have contributed to yield strength, ultimate strength, and microhardness improvements. Deformation enhanced yield and ultimate strengths by 132% and 64%, respectively. The distinctive grain refinement mechanism exhibited through the current ECAP procedure has potential to pave the way for novel and impactful utilizations of ZM31 in industries that demand exceptional mechanical and corrosion performance.
