Molar Solution Research Articles

Correlation between the structural, morphological, optical, nanomechanical, and tribological properties of ZnO films by USPT with their photocatalytic activities

The present work focused on studying the nanomechanical properties of ZnO thin films deposited on glass substrates using the ultrasonic spray pyrolysis technique. Structural and morphological properties are related to processing conditions, which affect mechanical, optical, and photocatalytic properties. To produce the ZnO films, three different molarities of spraying solution have been used which are 0.05 M; 0.075; and 0.10. The increase in the concentration of the spray solution led to an improvement in the crystal structure with the average crystallite size increasing from 28 nm to 35 nm. Morphological investigations revealed that the spherical nanoparticles with various size distributions. The rough surface topology emerged as a result of increasing solution molarity. Optical band gap values of the films decreased from 3.29 to 3.27 eV. Photocatalytic efficiency reached 93 % for ZnO film produced at higher solution molarity. Improved hardness values were determined for all films. Scratch tests showed better adhesion behavior for ZnO film at low solution molarity. Results indicate that solution molarity is an important parameter of the physical and photocatalytic properties of ZnO films as well as mechanical behaviors.

Facile synthesis of CuCo2O4@CdS nanoheterostructure for asymmetric supercapacitor

The abundant active sites, high theoretical capacitance, and cost-effective synthesis of transition metal oxides@sulfides (TMOs@TMSs) have made them a highly desirable choice as active electrode materials for supercapacitors. This study demonstrated the successful fabrication of a CuCo2O4@CdS nanoheterostructure electrode using a simple and economical co-precipitation method The morphology, physicochemical properties, and electrochemical behavior of this electrode were subsequently studied. The synthesized CuCo2O4@CdS nanoheterostructure was characterized using Infrared Fourier-transform spectroscopy, X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, High-resolution transmission electron microscopy, N2 adsorption/desorption isotherms and atomic force microscopy. The electrochemical performance was studied using cyclic voltammetry, impedance spectroscopy, and galvanostatic charge-discharge (GCD) measurements with a 6 Molar KOH aqueous electrolytic solution. Results from powder X-ray diffraction pattern and energy dispersive X-ray revealed the formation of CuCo2O4@CdS nanoheterostructure. Furthermore, SEM images showed the formation of more spherical structures in nanoheterostructure. The results of optical measurements of thin films were analyzed, which showed an increase in the energy gap (Eg) of CuCo2O4 nanoparticles when combined with cadmium sulfide (CdS). Additionally, the intensity of photoluminescence of the CuCo2O4@CdS nanoheterostructure was lower compared to the pure nanoparticles. Moreover, the newly synthesized CuCo2O4@CdS nanoheterostructure showed a specific capacitance of 257.5 F g−1 at a current density of 0.5 A g−1 via a three-electrode galvanostatic charge-discharge system, respectively. In the asymmetric device, the supercapacitor yielded an optimum energy density and power density of 19.6 Wh kg−1 and 700 W kg−1 at 1 A g−1 current density, respectively. Although the capacitance retention was maintained at nearly 85.2 % after 4000 cycles at a current density of 3 A g−1.

Eco-friendly impact of a novel green Melilotus officinalis extract as a sustainable inhibitor to reduce acid corrosion of copper.

In this study, we deployed green Melilotus officinalis extract (MOE) as a corrosion inhibitor for copper. The anticorrosion properties of MOE for Cu in 1 M HNO3 were investigated by various experimental and numerical techniques, including potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and a weight loss (WL) method at different temperatures. Additionally, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis (EDX) and atomic force microscopy (AFM) were utilized to examine the surface morphology of Cu with and without the extract. By contrasting the inhibition effectiveness with and without the extract, the inhibition efficiency (% IE) was observed. The WL method revealed that 300 ppm of the extract had an IE of 93.8% for Cu immersed in one molar HNO3 solution. The MOE was classified as a mixed type according to the PDP study since it delayed both cathodic and anodic processes, with a cathodic predominance. At 25-45 °C, MOE's free adsorption energies were 23.1-21.5 kJ mol-1, showing that mixed-type adsorption occurred on the Cu surface. Additionally, the Langmuir adsorption isotherm and the adsorption data from the WL tests of MOE showed a good match. The extract could adsorb spontaneously onto the metal surface, according to the thermodynamic conditions. Analysis of the corrosion product using different techniques revealed that a protective layer had formed on the metal's surface. Hence, MOE had a good corrosive inhibitive effect on Cu in HNO3 solution. It turned out that all the methods used gave consistent results.

Enhancing corrosion resistance of mild steel in acid pickling bath: An investigation of new quinazoline derivatives by synthesis, electrochemical analysis EFM, surface analysis, AFM, DFT and molecular dynamics simulation

The current study examines the ability of two novel heterocyclic Quinazoline derivatives, 2-(4-bromophenyl)-3-phenyl-2,3-dihydroquinazolin-4(1H)-one (DHQ-4-Br) and 2-(4-hydroxy-3-methoxyphenyl)-3-phenyl-2,3-dihydroquinazolin-4(1H)-one (DHQ-3-OMe-4-OH) to adsorb and protect mild steel against corrosion in a molar solution of hydrochloric acid (HCL). The two materials were identified using nuclear magnetic resonance (NMR) spectroscopy and the experimental investigation employed potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM), and impedance spectroscopy (EIS). The findings demonstrated that DHQ-4-Br and DHQ-3-OMe-4-OH exhibit increasing inhibitory effectiveness as the concentration of the inhibitors increases. Polarization test results suggest that the two inhibitors exhibited mixed-type behavior. The inhibitory efficiency of DHQ-4-Br and DHQ-3-OMe-4-OH was 94.65 % and 83.94 % respectively. In addition, the Langmuir adsorption model was employed better to understand the adsorption process of the two compounds. The existence of a barrier layer surrounding the SM was demonstrated using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), and atomic force microscopy (AFM). The results of the density functional theory (DFT) show that the inhibitors that can take electrons have the strongest interactions with the iron surface.

Cold Consolidation of Pharmaceutical Waste Glass Powders Through Alkali Activation and Binder Jet 3D Printing.

The recent COVID-19 emergency has led to an impressive increase in the production of pharmaceutical vials. This has led to a parallel increase in the amounts of waste glass; manufacturers typically recover material from faulty containers by crushing, giving origin to an unrecyclable fraction. Coarse fragments are effectively reused as feedstock for glass melting; on the contrary, fine powders (<100 microns), contaminated by metal and ceramic particles due to the same crushing operations, are landfilled. Landfilling is also suggested for pharmaceutical containers after medical use. This study aims at proposing new opportunities for the recycling of fine glass particles, according to recent findings concerning alkali activation of pharmaceutical glass, combined with novel processing, i.e., binder jetting printing. It has already been shown that pharmaceutical glass, immersed in low-molarity alkaline solution (not exceeding 2.5 M NaOH), undergoes surface dissolution and hydration; cold consolidation is later achieved, upon drying at 40-60 °C, by a condensation reaction occurring at hydrated layers of adjacent particles. Binder jetting printing does not realize a full liquid immersion of the glass powders, as the attacking solution is selectively sprayed on a powder bed. Here, we discuss the tuning of key parameters, such as the molarity of the attacking solution (from 2.5 to 10 M) and the granulometry of the waste glass, to obtain stable printed blocks. In particular, the stability depends on the formation of bridges between adjacent particles consisting of strong T-O bonds (Si-O-Si, Al-O-Si, B-O-Si), while degradation products (concentrating Na ions) remain as a secondary phase, solubilized by immersion in boiling water. Such stability is achieved by operating at 5 M NaOH.

Effect of sodium gluconate addition on setting, hardening, and microstructure behaviour of hybrid alkaline mortar

In this investigation, the influence of adding 2 %, 4 %, 7 %, and 10 % sodium gluconate (SG) on the setting time of hybrid alkaline paste, and hardened and microstructure properties of hybrid alkaline mortar mixes were examined, and the results were compared with a control mix that made without addition of sodium gluconate. The hybrid alkaline paste and mortar mixes were prepared using a fixed proportion of OPC/fly ash (25 %/75 %), NaOH solution molarity of 9 M, and sodium silicate to hydroxide ratio of 1.5. The results of this investigation found that the quick setting and abrupt loss of flowability of the control mix were improved by adding sodium gluconate, however, more promising results were observed at 7 % and 10 % sodium gluconate. The delay in polymerization due to lower availability of calcium ions, and adsorption of carboxyl and hydroxyl groups associated with sodium gluconate on the unreacted particles of binding materials and earlier formed products assisted in prolonging the time required for hardening. Further, the compressive strength declined at a higher dosage of sodium gluconate, however, the mortar mixes made with 2 % and 4 % sodium gluconate exhibited higher compressive strength than the control mix. The peak intensity of albite, nepheline, and C–S–H gel decreased at higher dosages of sodium gluconate, which was supported by a weaker microstructure characterized by more pores, micro-cracks, and partially reacted fly ash particles. Furthermore, the lower bridging oxygen content and greater Si–O–Na/ Si–O–T ratio at higher dosage of sodium gluconate confirms the delayed polymerization process.

HTS library plate rejuvenation using a DMSO-rich atmosphere

Dry DMSO can rapidly pull water vapor out of the air due to its hygroscopic nature. This is a well-documented problem within drug discovery, particularly within high-throughput screening (HTS). This hydration is caused by atmospheric moisture being absorbed each time a compound library is used. This effect becomes increasingly pronounced when a compound library is used routinely. The result of this hydration is a change to both the total volume of solution and the concentration of sample still in solution. This can result in a large amount of variability in the measured biological activity of a sample depending on the library usage. In this paper, we show the detrimental effects the hydration of sample libraries has on the reproducibility of biological data and present a novel way to remove it from HTS library plates. Our approach involves creating a DMSO-rich environment, created by placing anhydrous DMSO in compound storage pods purged with nitrogen, and incubating library plates in this environment for up to 3 days. Quantification via evaporative light scattering detection (ELSD) showed that removing water greatly increased the molarity of solutions, with a greater effect being seen for compounds with poor solubility. We also demonstrated how this approach can restore the inhibitory activity of stock solutions of compounds (pIC50) of samples containing ∼30 % water from >30 µM to sub-micromolar after moisture removal. This method improves the reliability of tested compounds in HTS by potentially saving pharmaceutical companies hundreds of thousands of dollars in screening campaigns and increasing the quality of data.

Correlation between Electrolyte Concentration and Lithium Morphology during Lithium Bis(fluorosulfonyl)amide–Tetraglyme Electrolyte Deposition–Dissolution Reactions

Electrodeposition and chemical dissolution reactions of Li are strongly affected by the electrolyte concentration at the electrode surface. In this study, we investigated the processes involved in the formation of Li deposits at various electrolyte concentrations and different numbers of deposition–dissolution cycles. Growth of the deposits during the cycles was assessed using a digital microscope. The thickness of the fibrous layer was strongly dependent on the electrolyte solute–solvent molar ratio. The thickness of the fibrous layer increased as the number of cycles increased when the electrolyte solute–solvent molar ratio was low but decreased when the molar ratio was high. Temporal changes in the electrolyte concentration and in the diffusion layers near the electrode were identified using a laser interference microscope. The results led us to conclude that there are three fibrous Li deposit growth models that occur at different solvent–solute molar ratios.

Self-powered high performance UV photodetectors based on spin coated n-ZnO/p-Si heterostructure

Self-powered photodetectors with high responsivity and external quantum efficiency (EQE) are in great demand for various practical applications. This paper reports the fabrication and evaluation of self-powered, high-performing ultraviolet photodetectors with fast switching action. A p-n junction was formed by spin coating n-type ZnO on p-silicon substrates. The photodetector showed a responsivity of 0.15 A/W and an EQE of 52 %. The switching speed of devices was as low as 250 ms, even under zero bias. XRD analysis revealed the hexagonal wurtzite structure and AFM images confirmed the good quality of the films with roughness values as low as 2 nm. Defect analysis was done by photoluminescence studies. The molarity of the precursor solution and the annealing temperature were varied to optimize the performance. Sample with molarity 0.5 M annealed at 500 °C showed the best results.

Enhancing Recycled Concrete Performance by Using Chemical Activators

The need for sustainable and eco-friendly construction materials and processes is rising significantly. In these circumstances, recycling of concrete can be a lifesaver. Although, various recycling techniques have already been introduced. But none of them can fulfill the term recycle refers to. They mostly focus on merely reusing coarse aggregates (CA) or fine aggregates (FA). To come out of this, this paper is focused not only on the reuse of both coarse and fine materials (RCA, RFA) but also on introducing a new process in which those materials can be used in their old form, as recycling refers to. In this experiment, we use all kinds of materials recollected from recycled concrete (fine, coarse, recycled cement particles). Those materials are vetted into two parts. One is for recycling coarse aggregates and one is for rebuilding concrete using recovered fine, coarse, and cement particles. First, we discuss the collection and treatment system procedure of recycled demolished concrete. The second part will consist of various standardized tests for reuse and evaluation. The third part will describe the treatment needed for the materials for chemical (Using Na2SiO3, NaOH, and Na2CO3) reactivation. Finally, we will test the recycled material’s performance as concrete and establish an authentic process of recycling and reusing concrete materials. With that, we obtain the most optimum usage of recycled concrete aggregate mixing ratio Cement: CA (coarse aggregate): RCA (recycled coarse aggregate): FA (fine aggregate): RFA (recycled fine aggregate) is 1: 2: 2: 0.8: 1.2: 0.8 (With molar solution of Na2SiO3 and NaOH + KOH) and other ration of mixing with their respected properties (Compressive Strength).

Solvation free energy in governing equations for DNA hybridization, protein-ligand binding, and protein folding.

This work examines the thermodynamics of model biomolecular interactions using a governing equation that accounts for the participation of bulk water in the equilibria. In the first example, the binding affinities of two DNA duplexes, one of nine and one of 10 base pairs in length, are measured and characterized by isothermal titration calorimetry (ITC) as a function of concentration. The results indicate that the change in solvation free energy that accompanies duplex formation (ΔGS) is large and unfavorable. The duplex with the larger number of G:C pairings yields the largest change in solvation free energy, ΔGS = +460 kcal·mol-1per base pair at 25 °C. A van't Hoff analysis of the data is complicated by the varying degree of intramolecular base stacking within each DNA strand as a function of temperature. A modeling study reveals how the solvation free energy alters the output of a typical ITC experiment and leads to a good, though misleading, fit to the classical equilibrium equation. The same thermodynamic framework is applied to a model protein-ligand interaction, the binding of ribonuclease A with the nucleotide inhibitor 3'-UMP, and to a conformational equilibrium, the change in tertiary structure of α-lactalbumin in molar guanidinium chloride solutions. The ribonuclease study yields a value of ΔGS = +160 kcal·mol-1, whereas the folding equilibrium yields ΔGS ≈ 0, an apparent characteristic of hydrophobic interactions. These examples provide insight on the role of solvation energy in binding equilibria and suggest a pivot in the fundamental application of thermodynamics to solution chemistry.

Low and High Gas Tungsten Arc Welding Heat Inputs Influence on Corrosion of Stainless Steel Weldments

In this study, influence of low and high heat inputs on corrosion susceptibility of 304L austenitic stainless steel (ASS) in simulated 0.5 molar solution of NaCl was investigated. Gas tungsten arc welding (GTAW) was used to generate low and high levels welding heat input. Microstructures of the weldments were examined, using metallurgical optical microscope (OMM) (Olympus GX51), while the corrosion behaviours were evaluated by potentiodynamic polarization tests, and corrosion data were recorded, using a computer-based data logging system – Autolab PGSTAT 204N. From the results, the evolving microstructures of the weldments before corrosion were characteristically heterogeneous; austenite (γ) was the leading phase, while ferrite (α) grains were dispersed within the γ matrix. Fusion zone (FZ) and heat affected zone (HAZ) microstructures after corrosion were characterised by pits of varying sizes with different alignments. And at GTAW speed, current and voltage of 7.2 mm/s, 200A and 40V, corresponding to low heat inputs, there were few number and size of pits relative to 1.7 mm/s, 200A and 40V, corresponding to high heat input. Shift in corrosion potentials (Ecorr) toward less negative direction, that is more nobility was observed at the low heat inputs induced GTAW parameters as compared to the corresponding high heat inputs induced GTAW parameters. In general, corrosion susceptibility of 304L ASS in the simulated 0.5 molar solution of NaCl was heightened at high heat inputs induced GTAW parameters as compared to the corresponding low heat inputs parameters.

Ion Correlations Decrease Particle Aggregation Rate by Increasing Hydration Forces at Interfaces.

The connection between solution structure, particle forces, and emergent phenomena at solid-liquid interfaces remains ambiguous. In this case study on boehmite aggregation, we established a connection between interfacial solution structure, emerging hydration forces between two approaching particles, and the resulting structure and kinetics of particle aggregation. In contrast to expectations from continuum-based theories, we observed a nonmonotonic dependence of the aggregation rate on the concentration of sodium chloride, nitrate, or nitrite, decreasing by 15-fold in 4 molal compared to 1 molal solutions. These results are accompanied by an increase in repulsive hydration forces and interfacial oscillatory features from 0.27-0.31 nm in 0.01 molal to 0.38-0.52 nm in 2 molal. Moreover, molecular dynamics (MD) simulations indicated that these changes correspond to enhanced ion correlations near the interface and produced loosely bound aggregates that retain electrolyte between the particles. We anticipate that these results will enable the prediction of particle aggregation, attachment, and assembly, with broad relevance to interfacial phenomena.

Spectrophotometric determination for green hydrophobic deep eutectic solvent-based microextraction of Brilliant Blue FCF (E133) from beverages

In this study, a simple, sensitive, and rapid method called green hydrophobic deep eutectic solvent-based liquid-liquid microextraction was developed to extract Brilliant Blue FCF dye from beverages. This method utilizes hydrophobic DES obtained by forming tetrabutylammonium bromide and 1-octanol in a 1:5 ratio as green extraction solvent. The transition of Brilliant Blue FCF to the DES phase occurred on its own, without the need for any reagents such as added salt or tetrahydrofuran. Several crucial factors were tried to get the best extraction efficiency, including species, DES volume and molar ratio, solution pH, ultrasonication, and centrifugation time. Under optimum conditions, extraction recoveries were achieved in the range of 95.1–101.3 % with the method developed for Brilliant Blue FCF. The detection and determination limits were observed to be 4.1 μg l-1 and 12.1 μg l-1, respectively. In addition, the relative standard deviation values for the method's accuracy were found to be 2.23 % and 3.48 % within and between days, respectively. It has been established that the developed method is highly environmentally friendly thanks to the application of the Analytical GREENness (AGREE) and Green Analytical Procedure Index (GAPI) tools. This study shows that DES applications can be carried out without the use of emulsifiers and dispersants by prioritizing the use of hydrophobic DES compounds as environmentally friendly and green extraction solvents in food samples.

Assessment of Warionia saharea Essential Oil as a Green Corrosion Inhibitor for Mild Steel in HCl: Experimental and Computational Studies

The objective of this research work is the study of the inhibitory effect of Warionia saharea essential oil (WSEO) on the corrosion of mild steel (MS) in molar HCl solution, employing both experimental and theoretical methods. This inhibitory effect (IE) has been evaluated by using a combination of weight loss measurements (LW) and various electrochemical methods, such as open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) experiments. The LW results indicated that IE increased with inhibitor concentration, reaching 83.34% at 3.00 g/L. The PDP analysis suggested that WSEO functions as a mixed inhibitor, while in the EIS results the Rct values increased with inhibitor concentration to reach 165.8 Ω cm2 at 2.00 g/L, suggesting a defensive film formation by WSEO molecules over the metallic surface. The thermodynamic study demonstrated that the WSEO molecules adsorption on the MS surface followed a Langmuir isotherm, involving mixed physical and chemical (physicochemical) adsorption on the MS surface. Theoretical methods, including density functional theory (DFT) and molecular dynamics (MD) simulations, were employed to elucidate the inhibition mechanisms of the three main components of WSEO. The quantum chemical analysis, using density functional theory (DFT) and molecular dynamics (MD) simulations, showed a low ΔEgap value of 6.30 eV and a low adsorption energy (Eads) value on an Fe (110) substrate of −258 Kcal/mol for (E)-Nerolidol, indicating the significant contribution of this molecule to the overall corrosion inhibition effect of WSEO. The scanning electron microscope (SEM) analysis verified the presence of a protective film formed by the inhibitor on the MS surface. This study highlights the potential of WSEO as a sustainable and green corrosion inhibitor in acidic environments.

Spin coating deposition of tin oxide thin films: Influence of solution concentration

Tin oxide (SnO2) thin films were deposited on glass substrates using a cost-effective spin coating method. The effect of solution molarity on their microstructural, optical, and electrical properties was investigated. For this purpose, solutions of tin chloride salt were prepared with various molarity in the range of 0.1M to 0.25M. The synthesized films structure and morphology were characterized by different techniques such as X-ray diffraction and scanning electron microscopy. The optical and electrical properties were studied by mean of UV-Vis spectroscopy and four probes conductivity measurement. The X-ray diffraction patterns of all samples revealed well-crystallized and pure SnO2 films with tetragonal rutile structure. The scanning electron microscopy images reveal a smooth and dense film pinholes free. The optical analyses show that the films exhibit an optical transparency that reaches up to 98% in the visible range and that the optical band gap decreases from 3.97 to 3.82 eV when the concentration increases from 0.1M to 0.25M. The films’ electrical conductivity varies in the range from 76 to 100 (Ω cm)–1. The largest figure of merit of 9.8 × 10–3 was measured in the films prepared at low solution concentration.

Viable Approach of Tuning Oxide Semiconductor Thin Films in Solution‐Processed Heterojunction Thin Films Transistors for Both Higher Performances and Stability

AbstractMetal‐oxide thin‐film transistors (TFTs) have garnered much attention because of their advantages such as high transparency, low leakage current, and low processing temperature. However, there is a need to continuously improve their mobility and bias stability for application to next‐generation advanced electronics. In this study, the thickness of bilayer semiconductors is finely controlled to enhance the charge transport characteristics and bias stability in solution‐processed heterojunction oxide TFTs. The thicknesses of the top and bottom layers in the bilayer are individually adjusted by controlling solution molarity. The introduction of a bilayer channel improved the electrical performance of oxide TFTs via effective charge transport. However, trap‐limited conduction becomes dominant in the bilayer with an excessively thick top layer, thereby leading to a significant reduction in mobility and positive bias stability. Meanwhile, although increasing the bottom layer thickness contributes to improved mobility and reliability, it causes a serious negative shift in threshold voltage (VTH). TFTs with an optimized bilayer structure show high mobility at a VTH close to 0 V and have particularly excellent positive bias stress stability. This study on bilayer channel thickness will be beneficial for developing advanced transistors with optimized bilayer or multilayer channels.

Spinel nickel ferrite (NiFe2O4) materials synthesized via spray-pyrolysis for electrochemical supercapacitor application

To explore potential applications of NiFe2O4-based supercapacitors in various energy storage systems, including portable electronic devices, electric vehicles, and grid energy storage, highlighting the advantages and challenges of using NiFe2O4 in these applications. To identify and propose future research directions for further improving the performance of NiFe2O4 supercapacitors. In the study focuses on optimizing concentration of synthesis to achieve desirable structural and electrochemical properties, characterizing the synthesized materials, and assessing their specific capacitance, energy density, power density, cycle stability, and rate capability. The different molar precursor solutions were utilized for the formation of NiFe2O4 thin films by using the cost-effective spray pyrolysis technique. The impact of different molarities on the structural, morphological, elemental, optical, and charge storage performance of NiFe2O4 thin films has been studied. In the XRD studies identified the cubic crystalline structure with Fd-3 m space group symmetry of NiFe2O4. The FE-SEM shows the grain-like surface morphology of NiFe2O4 thin films. The EDAX study reveals that NiFe2O4 thin films were stoichiometric. Bandgap energy values of the thin films were observed in the range of 1.97 to 2.2 eV with allowed direct band gap transitions. The maximum specific capacitance for NiFe2O4 thin film was found to be 707 Fg−1 at 2 mVs−1 with the wider potential window of − 0.8 to + 1 .6 V in 1 M KOH aqueous electrolyte. GCD study confirms the pseudocapacitive behavior of NiFe2O4 thin films. The maximum specific energy and specific power were found to be 83.88 WhKg−1 and 5.294 KWkg−1 at a current density of 0.002 Ag−1. Such as spinel ferrite NiFe2O4 thin film electrodes as an excellent candidate material for electrochemical supercapacitor applications.

Alkaloid extract of seed Citrullus colocynthis as novel green inhibitor for mild steel corrosion in one molar HCl acid solution: DFT and MC/MD approaches

The study was designed to explore the corrosion prevention capabilities of Citrullus colocynthis seeds alkaloid-rich extract (CSEA) on MS in a 1 M HCl environment by use of electrochemical and theoretical methods. Notably, Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization were used to probe the impact of immersion time and temperature. Energy-dispersive X-ray spectroscopy (EDX) and spanning electron microscopy (SEM) were used to confirm the presence of a protective layer on the substrate surface. Density functional theory (DFT) method was used to optimize the investigated species by use of B3LYP/6–31 + G(d, p) level of theory. The global and local quantum chemical reactivity descriptors were calculated to explore the inhibition corrosion efficiency and to identify the most favorable sites for electrophilic and nucleophilic attacks. Monte Carlo (MC) and molecular dynamics simulation (MDS) methods were used to study the interactions between corrosion inhibitor and metal surface. Noteworthy, results showed that CSEA exhibited an impressive inhibition efficiency, which reached 94.3% with a concentration of 2 g/L at 298 K. Potentiodynamic polarization revealed that the extract acted as a mixed-type inhibitor. Nyquist graphs showed that charge-transfer resistance and dæouble-layer capacitance both rised with increasing CSEA concentration, suggesting better inhibition efficiency. Notably, the Langmuir adsorption isotherm is well-aligned with the adsorption of inhibitor compounds. Importantly, all aforementioned theoretical methods were in agreement with the experimental findings. The outcome of the present work supported using Citrullus colocynthis seeds alkaloid-rich extract as ecofriendly agents to prevent corrosion.

انماء تراكيب نانوية من أكسيد الزنك بطريقة التحلل المائي الحراري لقيم مختلفة من درجة الحامضية

تم تحضير تراكيب نانوية (زهرية وعصي) الشكل من اكسيد الزنك بالطريقة الحرارية المائية عند 90 درجة مئوية لمدة ثلاث ساعات. تم تحضير ثلاثة محاليل بقيم درجة الحامضية 9 و10 و11 وبمولارية 0.028 مولاري، على قواعد زجاجية / بذور ZnO. كان لجميع العينات المحضرة نمط حيود متعدد التبلور مع حيود سائد من المستوى (002). مع زيادة درجة الحامضية، زاد حجم البلوري إلى حد أقصى قدره 37.6 نانومتر. أظهرت صور الانبعاث الحقلي لمجهر الماسح الإلكتروني تكمن اهمية البحث في انماء تراكيب مختلفة من اكسيد الزنك من خلال التحكم بدرجة الحامضية حيث أظهرت النتائج ظهور تراكيب زهرية عند الحامضية 11 وبحجم جسيمي 100-800 نانومتر، وانماء تراكيب نانوية بشكل حزمة من العصي عند الحامضية 10 وبحجم جسيمي 500-800 نانومتر وانماء اكسيد الزنك بشكل عصي منفردة عمودية على السطح عند الدرجة الحامضية 9 وبحجم حبيبي 70-80 نانومتر. أظهرت الخصائص البصرية انخفاضًا في النفاذية من 78.75 الى 79.32 وزيادة في قيم فجوة الطاقة من 3.18 الكترون فولط الى 3.31 الكترون فولط مع زيادة درجة الحامضية.