Optimal Synthesis Conditions Research Articles

Recent advances in machine learning and deep learning-enabled studies on transition metal dichalcogenides

Abstract The machine learning and deep learning (ML/DL) techniques have significantly advanced the understanding and utilization of TMDs by enabling efficient analysis, prediction, and optimization of their properties. ML/DL methods permit rapid screening, optimization and analysis of two-dimensional (2D) material candidates, potentially accelerating the discovery and development of TMDs with desired electronic, optoelectronic, and energy storage properties. This review provides a comprehensive review of machine learning and deep learning (ML/DL) methods to enhance 2D materials research via the optimization of synthesis conditions, interpretation of complex data sets, and the use of generative adversarial networks and variational autoencoders for innovative material design and image processing tasks. Furthermore, it highlights the potential of ML/DL techniques in predicting and tailoring the electronic, optical, and mechanical properties of 2D materials to meet specific application requirements.

Preparation of Expandable Polymer Plugging Agent and Its Application in Water‐Based Drilling Fluid

ABSTRACTIn order to reduce the economic loss caused by well leakage and the lag of drilling progress, it is very important to use plugging materials reasonably and effectively. Expandable polymer materials can better fill cracks and holes of different sizes by absorbing water expansion and deforming. In this article, an expandable polymer plugging agent (PSMAN) was prepared by soap‐free emulsion polymerization using methyl methacrylate (MMA), styrene (St), 2‐acrylamide‐2‐methylpropanesulfonic acid (AMPS) as reaction monomers, N‐hydroxymethyl acrylamide (NMA) as a cross‐linking agent, and ammonium persulfate (APS) as initiator. The optimal synthesis conditions were determined by designing the orthogonal experiments, and the various properties of the materials were tested and evaluated. The experimental results show that PSMAN has good high temperature resistance, spherical structure, and median particle size of 15.099 μm, and the water absorption rate of room temperature at 24 h reaches 37.8 g/g, and pressure bearing capacity can reach 5 MPa. The addition of polymer to water‐based drilling fluid can increase the viscosity of drilling fluid and improve the rheological properties of drilling fluid by a small amount. Under normal temperature and medium pressure, the polymer can form a dense film on the surface of the mud cake, thereby reducing the filtration of drilling fluid and effectively improving the stability of the wellbore.

Efficient removal of 4-chlorophenol by activation of peroxymonosulfate with synthesized high-performance MnOx/CBC catalysts

Effective activation of peroxymonosulfate (PMS) is critical to remove chlorophenols (CPs) in the well-used sulfate radical advanced oxidation processes (SR-AOPs). Though manganese oxides (MnOx) have shown remarkable performance in activating PMS in SR-AOPs, the ease of agglomeration and relatively low crystallinity of MnOx can seriously decreases their activation efficiency. In this study, Camellia oleifera shell-based biochar (CBC) was employed as the support to load MnOx to prevent agglomeration, using the so-called co-precipitation approach. At the same time, low-temperature carbothermal reduction was utilized to increase crystallinity of MnOx while still maintaining promising surface structure of CBC. Using 4-chlorophenol (4-CP) as a representative for CPs, the synthesized MnOx/CBC showed high performance in activating PMS for degradation of 4-CP, with removal percentage up to 84.28%. Furthermore, the effects of roasting time, mass ratio between biochar and Mn, and roasting temperature on synthesis of MnOx/CBC were systematically investigated through the response surface methodology, and the obtained quadratic multinomial regression model can well predict the optimal synthesis condition. Finally, the underlined PMS activation mechanism by MnOx/CBC was explored, where main reactive oxygen species involved in degradation were found to be SO4•−, •OH, 1O2 and O2•−, and a possible routine was proposed. Overall, this work demonstrates the great potential of MnOx/CBC for activation of PMS for removing CPs.

Optimization of Nano-Hydroxyapatite Production from Limestone with Effect of Gelatin Concentration and pH in Sol-Gel Synthesis

Nano hydroxyapatite is one of the biomaterials that has proven to be a very potential material due to its ability to bind directly with bone tissue. Limestone with a calcium carbonate content of 99.87% was used as a calcium source for the economical and sustainable synthesis of hydroxyapatite. The sol-gel method was chosen for the in situ gelatin synthesis process due to its ability to produce nanoparticles with high homogeneity. The particle size of nanohydroxyapatite can increase the surface area to volume ratio thus affecting the interaction with surrounding cells and tissues. Gelatin was added in various concentrations of 10%, 20%, and 30% as an innovative cell growth support modifier. The synthesis was also carried out at pH 9, 10, and 11 to evaluate its effect on hydroxyapatite formation. Optimal synthesis conditions were obtained at 30% gelatin concentration and pH 10, which resulted in the highest yield of 93.95%. Product characterization included Fourier Transform Infra-Red analysis, which showed the presence of typical hydroxyapatite functional groups (PO₄³-, OH-) and carbonate groups (CO₃²-). Scanning Electron Microscopy characterization showed nano-sized particles in the range of 443-578 nm with a granular structure. Porosity was found to be 72.52% making it ideal for cancellous bone tissue engineering applications.

A two-step hydrothermal synthesis of fly-ash-based ZSM-5 zeolite and its catalytic properties in NO removal

The pursuit of carbon peaking and carbon neutrality goals necessitates flexible operation and deep peaking of coal-fired units, thus placing heightened demands on nitrogen oxide (NOX) emission control. Fly ash, a solid waste rich in silicon (Si) and aluminum (Al), should be fully leveraged, and the high-value synthesis of zeolite represents a viable utilization method. In this context, fly ash-based zeolite was prepared as a catalyst to facilitate the generation of active oxides from H2O2, combined with alkali solution absorption, to achieve efficient denitrification. This approach effectively transforms ‘waste to pollution’ mitigation. The optimal synthesis conditions for FA-ZSM-5 zeolite were established using the alkali fusion hydrothermal synthesis method, with fly ash as the raw material. The specified conditions were NaOH/FA = 1.2, SiO2/Al2O3 = 40, H2O/Al2O3 = 1325, TPAOH/Al2O3 = 10, ZSM-5-seed addition of 5 %, and a hydrothermal temperature and time of 140 °C for 24 h. Experimental parameters were meticulously investigated to ascertain their impact on nitric oxide (NO) removal efficiency. The highest removal efficiency was achieved under specific conditions: a reaction temperature of 140 °C, an H2O2 concentration of 6 %, a catalyst dose of 0.3 g, an NO concentration of 600 mg/m3, and an SO2 concentration of 1000 mg/m3. Finally, analysis of the catalytic oxidation mechanism revealed that H2O2, when catalyzed by FA-ZSM-5 zeolite, generates ·OH radicals with strong oxidizing properties, thereby facilitating the oxidative removal of NO.

Dynamic simulation-driven analysis of cadmium, nickel, cobalt, and iron adsorption mechanisms in zeolite LTA synthesized from Bentonite

A practical and cost-effective method was successfully developed for synthesizing high-performance zeolite LTA from bentonite clay by fine-tuning activation steps and crystallization parameters. The optimal synthesis conditions and crystallization mechanism were investigated. The synthesized zeolites were characterized using XRD, FTIR, and SEM-EDS techniques. The results highlight the significant influence of factors such as crystallization temperature, duration, and the effect of sodium hydroxide concentration on the formation of zeolites. Optimal conditions set at a crystallization temperature of 97°C, duration of 24 hours, and NaOH concentration of 4M yielded pure zeolite LTA, boasting high crystallinity levels. Achieving a peak crystallinity of 82%. The obtained zeolite LTA showed an exceptional Cd (II) ion exchange capacity. A mechanism involving adsorption of Cd2⁺, Ni2⁺, Co2⁺, and Fe2⁺ ions in zeolite LTA at the α and β-cages has been proposed using dynamic simulation. This mechanism supports all experimental results, in particular for LTA- Cd2⁺, Cd2⁺ ions are predominantly distributed in both α and β-cages, with a denser distribution in the α-cages, indicating a strong preference for these sites due to their geometric and electronic environment. The resulted zeolite LTA demonstrated ability for successful Cd (II) removal, affirming its utility as an efficient material in environmental remediation industries.

Synthesis of MFI zeolites with hierarchical porosity by dry‐gel conversion

AbstractDry‐gel conversion (DGC), which directly converts zeolite gel into crystals by vapor, is considered a promising method for reducing amounts of zeolite precursors and easily controlling crystallization. Synthesis of MFI zeolites employing the DGC method with different amounts of tetrapropylammonium bromide (TPABr) and sodium hydroxide (NaOH) was studied to investigate the effect of TPABr and NaOH on the crystallization of MFI zeolite, with the optimal condition for synthesis found to be 0.05625 for both NaOH/SiO2 and TPABr/SiO2. Additionally, carbon black (CB) was added onto the MFI zeolite precursor gel as a hard template to generate mesopores into zeolite frameworks. The resultant MFI zeolite with CB synthesized by the DGC method showed mesoporosity, with pore size distribution similar to the particle size of CB. However, the conventional hydrothermal method could not generate mesopores in MFI zeolite due to the separation of zeolite crystals from CB templates during crystallization.

Enhanced Electrochemical Performance of NiCo‐Layered Double Hydroxides: Optimal Synthesis Conditions and Supercapacitor Applications

AbstractIn the quest for high‐performance supercapacitor electrode materials, layered double hydroxides (LDHs) containing transition metals, particularly nickel–cobalt layered double hydroxides (NiCo‐LDH), have garnered significant attention due to their distinctive structural and electrochemical properties. In this study, five different temperatures, five distinct reaction times, and four varied Ni:Co ratios to determine the optimal reaction conditions are established. Utilizing these parameters, NiCo‐LDH via a one‐step hydrothermal method is synthesized. Under optimal conditions the specific capacitance reaches 400.2 C g−1 at a current density of 1 A g−1. The assembled supercapacitor has a high energy density of 51.59 µWh cm−2 at a power density of 1.125 mW cm−2. After 10 000 cycles, the capacity retention is 70%, indicating good cycling stability and demonstrating potential for application in supercapacitors. These tests provide theoretical and data‐based support for subsequent experiments and present new opportunities for advancing energy storage and conversion technologies.

Finding environmental-friendly chemical synthesis with AI and high-throughput robotics

Recent environmental challenges have resulted in tremendous interest in Green Chemistry, which includes designing chemical products and processes that reduce the use of environmentally harmful substances. Until now, finding new environmental chemical synthesis has mainly been a trial-and-error process, requiring trained expertise and a lot of work. Here, we report a high-throughput process, combining AI techniques and robotic synthesis, allowing us to find a more environmentally friendly way to synthesize an existing material. The model materials in this study are to replace nitrate salts (NO3−), which might be responsible for algae bloom if leaked into open water, with a chloride salt (Cl−), a naturally abundant ion, in the synthesis of a metal-organic framework (MOF), Zn-HKUST-1. Our high-throughput process starts with using large language models (LLM)-based literature summary to create a database on the synthesis of Zn-HKUST-1 with NO3−, so that optimized concentrations of Cl− can be suggested. Subsequently, these suggestions are tested with automatic robotic processes, increasing the speed and precision of the experiments, and finding the optimal synthesis condition. Then, by using human verification as a foundation, we developed an AI-based automated classification algorithm to automatically sort the acquired images into crystals and non-crystals, focusing on low-resource settings. We successfully obtained MOF crystals from ZnCl2 precursors with this process, which proves that our process holds the promise to accelerate the discovery of new Green Chemistry processes.

Adsorption of hexavalent chromium from wastewater using magnetic biochar derived from peanut hulls

In this study, the utilization of peanut hulls as a precursor for the preparation of magnetic biochar through pyrolysis was investigated. To enhance the magnetic and adsorption properties of the biochar, the peanut hulls biomass was modified using ferric chloride hexahydrate and magnesium chloride hexahydrate. Response surface methodology was employed to evaluate the influence of biomass metal concentration, pyrolysis temperature, pyrolysis period and flow of nitrogen on the yield and Cr (VI) adsorption efficiency of the synthesized biochar. A 17-run experimental matrix was generated using Optimal Design to investigate the interactions among four input parameters. The results led to the development of a quadratic model, which demonstrated a high degree of predictability in accordance with the experimental data. Analysis of variance (ANOVA) confirmed that the models for yield and Cr (VI) adsorption efficiency were highly significant (p < 0.05), with coefficients of determination (R2) values of 0.891 and 0.988, respectively. The optimal synthesis conditions for producing biochar with superior physicochemical properties were identified as a pyrolysis temperature of 300 °C, a pyrolysis duration of 2 h, a metal-to-biomass ratio of 0.5, and a constant flow of nitrogen. A desirability of 85% was achieved through numerical optimization, corresponding to a yield of 63% and complete Cr (VI) removal. Further optimization of Cr (VI) adsorption efficiency, considering the effects of pH (3–12), adsorbent loading (1–15 g/L), and initial Cr (VI) concentration (5–20 mg/L), was performed using a 19-run experimental matrix. ANOVA for Cr (VI) adsorption efficiency model revealed high significance (p < 0.05) with an R2 value of 0.916.The magnetic biochar demonstrated a remarkable adsorption efficiency of 98% under the experimental conditions of solution pH 3, adsorbent dosage of 5 g/L, and an initial Cr (VI) concentration of 20 mg/L. The desirability of 100% was obtained by a numerical optimization method representing Cr (VI) removal of 98%. The adsorption behaviour was adequately described by the Freundlich isotherm model, suggesting multilayer adsorption, with a maximum adsorption capacity of 12 mg/g. Biochar also proved to have strong magnetic properties which enhanced solid-liquid separation post adsorption experiments.

Facile synthesis of Cu2O nano-microspheres anode for lithium-ion batteries

Transition metal oxide anode materials exhibit high theoretical specific capacities and can meet the energy density requirements through reasonable design. In this work, a facile wet-chemical method to fabricate Cu2O nano-microspheres anode for lithium-ion batteries with controllable size varied from 0.4 ∼ 1.2 μm is introduced, which basically using copper acetate as copper precursor and ascorbic acid as reducing agent. The solvent composition (DI water only or DI water:Ethanol = 1:1), solution alkalinity (amount of NaOH input), and synthesis temperature are investigated as factors affecting the size and morphology of Cu2O nano-microspheres. The samples are characterized by X-ray diffraction, transmission electron microscope and scanning electron microscope. Nanoparticle cluster structure is observed in the reaction product with the bi-solvent system. With the optimized synthesis condition, the prepared Cu2O anode (size of ∼ 455 ± 41 nm) delivers an initial discharge capacity of 539 mAh/g at a current density of 0.5C, 100 cycles of cyclic discharge at 0.5C with a capacity retention rate of 84.73 %. At the current density of 2C, the specific capacity is 347 mAh/g. Even at a large current density of 5C, the specific capacity is still as high as 219 mAh/g, indicating good rate capability.

Silver Nanoparticles Formed Directly on a Screen-Printed Electrode/Graphene Oxide: A One-Step Electrochemical Synthesis and an Effective 2,4,6-Trichlorophenol Electrochemical Sensor

Abstract A graphene oxide/silver nanoparticles (GO/AgNPs) nanocomposite was synthesized directly onto a screen-printed electrode (SPE) using a one-step electrochemical synthesis process. The obtained result is that the SPE electrode was modified by AgNPs with an average diameter of 11.5 nm which distributed evenly on GO sheets. A 0.01 M AgNO3 solution dropped onto the SPE/GO electrode and a chronoamperometry (CA) method with a potential of −1.2 V and a time period of 10 seconds were the optimal synthesis conditions. Then, the SPE/GO/AgNPs electrode was applied in developing an electrochemical sensor to detect 2,4,6-trichlorophenol (2,4,6-TCP) using a square wave voltammetry method. A reasonable cost, a wide linear range (0.05–1.0 mM), a low detection limit (0.85 μM), a high repeatability, a good selectivity, a high durability, and especially, a rapid detection time (&lt; 1 minute) thanks to the ability to directly detect 2,4,6-TCP were the outstanding advantages of the fabricated electrochemical sensor. Moreover, the electrochemical sensor based on the SPE/GO/AgNPs electrode was also applied to detect 2,4,6-TCP in a tap water sample using a standard addition method.

Optimization of the physiochemical synthesis parameters of the Se/CMC nanocomposite: Antibacterial, antioxidant, and anticancer activity.

Selenium nanoparticles (Se NPs) have gained growing significance due to their remarkable therapeutic qualities, decreased toxicity, enhanced bioavailability, and biocompatibility compared to other selenium compounds. Se NPs were synthesized using ascorbic acid (AA) and carboxymethyl cellulose (CMC) as reducing and capping agents, respectively. This was carried out by optimizing the physiochemical preparation parameters (e.g., precursor salt concentration, AA concentration, temperature, and pH). Characterization of the optimized Se/CMC nanocomposite sample was conducted using several techniques including UV-Vis spectroscopy, FT-IR, X-ray XRD, TEM, SEM, EDX, DLS, and Zeta potential. The UV-Vis spectra results indicate that the synthesized Se/CMC nanocomposite exhibits a most prominent surface plasmon resonance (SPR) peak at λmax = 270 nm. The diameter of the synthesized Se/CMC nanocomposite varied between 100 and 500 nm as observed in TEM images, and as verified by the DLS technique. Moreover, the Z-potential evaluated for the Se/CMC nanocomposite using the most optimal synthesis conditions was -21.8 ± 4.48 mV. The results obtained showed that Se/CMC nanocomposite had a more significant impact on Gram-negative clinical bacterial isolates (23 ± 0.97 mm) than Gram-positive (22 ± 0.95 mm). Additionally, the synthesized nanocomposite showed a highly antioxidant activity (83 %) of inhibition DPPH free radicals results using DPPH assay. Also, the fabricated Se/CMC nanocomposite has good anticancer activity (168 μg/mL) against the liver HepG2 cell line using MTT assay. Hence, the Se/CMC nanocomposite that was prepared has promising prospects in the field of healthcare owing to its enhanced capacity as an antioxidant, anticancer, and antibacterial agent.

Radiation driven synthesis of MnSe nanoparticles with dual luminescence and magnetic characteristics and its role in photocatalytic reactions

Many biomedical applications can greatly benefit from the combination of photoluminescence and magnetic properties of non-toxic manganese-based nanomaterials and thus, it demands for synthesizing such materials in an aqueous environment. The present work reports aqueous synthesis of starch-capped manganese selenide (MnSe) nanoparticles (NPs) through a steady-state gamma irradiation route under ambient pressure and room temperature. As radiolysis is considered as the cleanest method among available chemical approaches, we preferred to employ this technique and endeavored to establish optimal conditions of such synthesis. The as-produced MnSe nanocrystals demonstrated strong photoluminescence with a quantum yield of ca. 32% and co-existence of paramagnetic with antiferromagnetic behavior. To look into possible light-induced reactions with aromatic molecules, the effectiveness of synthesized particles on photo-induced degradation of dyes of similar structure was investigated. The proposed strategy may pave the way for synthesizing magneto-fluorescent nanoparticles in aqueous medium, which may find immense scope in nano-photonics and nano-biotechnology including biological assays, labelling and imaging.

Optimizing Synthesis of Anionic Surfactant‐Modified Carbon Black for Enhanced Ammonium Adsorption

The increasing levels of ammonium in wastewater pose serious environmental issues, highlighting the urgent need for effective adsorbents to facilitate its removal. Although conventional biological treatment methods have certain drawbacks, adsorption using carbonaceous materials, such as carbon black produced from waste tires, presents a promising alternative for ammonium removal. However, the use of these materials has not been thoroughly investigated. This study focuses on optimizing the synthesis of carbon black modified with anionic surfactants to improve its capacity for ammonium adsorption. Utilizing Response Surface Methodology (RSM) and a Box‐Behnken design, the optimization process examined key variables, including reaction time, surfactant concentration, carbon black dosage, and surfactant type. Comprehensive characterization of the adsorbent was conducted to analyze its surface properties, functional groups, morphology, and elemental composition. The regression models produced highly accurate results with an R2 value of 0.9437. The optimal synthesis conditions were identified as a 12.30‐hour reaction time, a surfactant concentration of 8 mmol/L of sodium dodecylbenzene sulfonate, and a carbon black dosage of 30 g, achieving an ammonium removal efficiency of 84.80%. This study offers a scalable solution for ammonium removal in wastewater, promising practical applications and future sustainable waste management research.

Optimization of AgNPs production from Fusarium oxysporum H39 and its effectiveness as nanopesticides facing Pectobacterium carotovorum

In response to the increasing shortage of agrochemicals in developing countries, which directly impacts farmers' livelihoods, this study investigates the synthesis of silver nanoparticles (AgNPs) employ the enzymatic extract from a native strain of Fusarium oxysporum H39. These nanoparticles were assessed for their antibacterial efficacy facing potato tuber soft rot caused by Pectobacterium carotovorum. The optimal conditions for AgNP synthesis were determined to be a concentration of 3 mM, a pH of 10, and a temperature of 27°C over a 24-hour period. Under these conditions, spherical nanoparticles with an average size of 12.3 ± 4.3 nm were produced. FTIR analysis indicated the presence of organic compounds on the surface of the AgNPs, as evidenced by bands corresponding to C-O, C-N, and C-C bonds. The nanoparticles demonstrated significant nanopesticide activity facing the phytopathogenic bacterium P. carotovorum, with minimum inhibitory concentrations (MICs) of 25 ppm and 50 ppm identified through microdilution and macrodilution assays, respectively. Additionally, in controlled substrate tests, preventive treatment of tubers with a 100 ppm dose of AgNPs significantly reduced the weight of macerated tissue, the primary symptom of the disease.

Construction of Mesoporous Aluminosilicate Thin Films on ITO Electrodes for Immobilizing a Cationic Ru(II) Water Oxidation Catalyst

AbstractAluminosilicate (Al‐SiO2) thin films with vertically aligned mesochannels were successfully synthesized on Indium Tin Oxide (ITO) electrodes and employed for the immobilization of a cationic Ru(II) water oxidation catalyst without requiring linker groups. Optimal synthesis conditions yielded uniform mesoporous Al‐SiO2 films with tunable Al content, high surface area (568 m2/g), 3.94 nm pore size, and 155 nm thickness. Electrochemical studies confirmed the presence of the immobilized Ru complex undergoing diffusion‐controlled Ru(III/II) and Ru(IV/III) electron transfer. The Ru loading reached 4.71 nmol/cm2 at Si/Al=9.6, with higher Al content enhancing loading amounts via cation exchange. The Ru‐modified electrode exhibited high electrocatalytic water oxidation activity, achieving 75.3 % Faradaic efficiency and a turnover number of 298.6 for O2 evolution for 1 hour. This work provides a new approach to construct porous environments on an electrode surface to immobilize positively charged transition‐metal complexes as catalysts, offering potential applications in the development of electrocatalytic systems for energy conversion.

Synthesis and Evaluation of High-Temperature Resistant Polymer Plugging Agent for Water-Based Drilling Fluids.

As the exploration and development of deep wells have emerged as a key option to extract more oil and gas resources trapped underneath, high-temperature formations impose stringent requirements on the thermal stability of plugging agents used in water-based drilling fluids. In this work, β-cyclodextrin, with its unique conical toroidal rigid stable structure and internal hydrophobic and external hydrophilic special adsorption capacity, was first grafted with maleic anhydride to prepare a silicone polymer and then copolymerized with dimethyldiallylammonium chloride (DMDAAC) in the presence of coupling agent vinyltriethoxysilane (A151) and cross-linking divinylbenzene (DVD) to finally obtain a high-temperature resistant plugging agent (AMMD). Subsequently, the molecular structure was evidenced and the performance of AMMD was examined in the polysulfonate-base fluid via a series of tests including high-temperature high-pressure filtration loss, sand tray plugging, and drilling fluid displacement, and the results were compared with the counterpart Soltex under the same conditions. The optimal synthesis conditions for the plugging agent were found as total monomer concentration of 25%, initiator mass fraction of 1% (based on the mass of monomers), monomer feed ratio of m (DVD):m(A151):m(DMDAAC):m(MD) of 15:3:2:15, pH value of 10, reaction temperature of 75 °C, and reaction time of 4 h. FT-IR spectra indicated that the monomers used to prepare AMMD were successfully involved in the reaction for the design of the plugging agent structure. TGA showed that AMMD has a total weight loss of about 35.98% in the range of 284 to 453 °C. Moreover, the addition of 3%AMMD into the base fluid produced a 4.38-fold and 3.8-fold filtration loss control over 60 min at 200 °C using 400 and 800 mD sand trays, respectively, which were comparatively higher than the commercially available Soltex (ca. 3.72-fold and 3.14-fold, respectively, using 400 and 800 mD). This then contributed to AMMD's superior plugging performance in drilling fluid based on the drilling fluid displacement experiment, implying that AMMD could find potential use as a plugging agent in polysulfonate drilling fluid under severe geothermal conditions.

Comparative Analysis of Anodized TiO2 Nanotubes and Hydrothermally Synthesized TiO2 Nanotubes: Morphological, Structural, and Photoelectrochemical Properties.

This study presents a comparative analysis of anodization and hydrothermal techniques for synthesizing TiO2 nanotubes directly on titanium foil. It emphasizes its advantages as a substrate due to its superior conductivity and efficient charge transfer. Optimized synthesis conditions enable a thorough evaluation of the resulting nanotubes' morphology, structure, and optical properties, ultimately assessing their photoelectrochemical and photocatalytic performances. Scanning electron microscopy (SEM) reveals differences in tube diameter and organization. An X-ray diffraction (XRD) analysis shows a dominant anatase (101) crystal phase in both methods, with the hydrothermally synthesized nanotubes exhibiting a biphase structure after annealing at 500 °C. UV-Vis and photoluminescence analyses indicate slight variations in band gaps (around 0.02 eV) and recombination rates. The anodized TiO2 nanotubes, exhibiting superior hydrophilicity and order, demonstrate significantly enhanced photocatalytic degradation of a model pollutant, amido black (80 vs. 78%), and achieve a 0.1% higher photoconversion efficiency compared to the hydrothermally synthesized tubes. This study underscores the potential advantages of the anodization method for photocatalytic applications, particularly by demonstrating the efficacy of direct TiO2 nanotube growth on titanium foil for efficient photocatalysis.

Ferrates (VI) ; Alternative products in water treatment : their electrochemical synthesis

This study focuses on determining the optimum conditions for the electrochemical generation of ferrates in concentrated NaOH solution. Various operating parameters, including electrolyte concentration, current density, temperature, electrolysis duration, and the composition and form of the anode, were investigated to enhance the yield of electrochemical ferrate (VI) ion production. The synthesized ferrates were characterized using UV-visible and FTIR spectroscopic techniques. Experimental results confirmed the formation of ferrate ions, with optimal synthesis conditions identified as follows: a current density of 11.96 mA/cm², NaOH concentration of 16 M, electrolysis time of 1 hour, temperature of 25°C, and the use of white cast iron as the anode material. These conditions were found to yield the highest efficiency for sodium ferrate production. The spectroscopic analysis effectively verified the presence of ferrate (VI) ions, providing valuable insights into the electrochemical synthesis process. This study contributes to the advancement of ferrate synthesis techniques, potentially offering an efficient route for large-scale production.