Synthesis Conditions Research Articles

Amine-modified SiO2 aerogel for efficient adsorption of low-pressure CO2: Response surface methodology optimization and adsorption mechanism

Amine-modified SiO2 aerogel (AMSA) has shown tremendous potential in CO2 capture due to its unique three-dimensional network structure and excellent stability. However, it still faces many challenges in the preparation optimization, adsorption enhancement at low CO2 partial pressure, and mechanism elucidation. Hence, in this paper, the response surface methodology is employed for the first time and the optimal preparation conditions for AMSA are determined. A regression model is successfully established to accurately predict the CO2 adsorption capacity of AMSA under different synthesis conditions (with a relative error of only 0.98 %). Additionally, the AMSA prepared at optimal conditions exhibits high CO2 adsorption capacity of 2.11 mmol/g and excellent stability (only decreased by 1.44 % after 8 cycles) at 10 % CO2 partial pressure, indicating enormous application potential. Notably, the CO2 adsorption mechanism by AMSA at different temperatures and partial pressures are revealed in detail through fitting with the Freundlich isotherm and the double-exponential model, as well as thermodynamic parameter calculations. Firstly, the CO2 adsorption behavior belongs to the multi-layer adsorption behavior with uneven energy of active sites. Secondly, the CO2 adsorption capacity and rate are jointly controlled by molecular motion and chemical reaction equilibrium, diffusion and chemical reaction steps, respectively. Finally, the adsorption process is exothermic and spontaneous, and the level of disorder decreases at the gas-solid interface. This study not only achieves efficient adsorption of low-pressure CO2, but also deepens the understanding of gas-solid interface adsorption mechanisms, providing scientific basis and technological support for the development of novel efficient AMSA adsorbent materials.

Optimization of synthesis conditions of hydrochar and pyrohydrochar from fish bones for their use in the adsorption of fluoride from water

In this study, the optimization of the synthesis variables of hydrochar (HC) and pyrohydrochar (PHC) obtained from pleco fish spines that would generate the highest fluoride adsorption capacity and synthesis yield was carried out. For this purpose, a D-Optimal experimental composite central design was established using response surface methodology (RSM) considering three levels for temperature and synthesis time. Hydrochar was produced by hydrothermal carbonization at temperatures of 180–240 °C for 4–8 h in the presence of water under autogenous pressure. On the other hand, pyrohydrochar was obtained by pyrolysis of hydrochar in the absence of water at temperatures of 350–650 °C for 1–2 h at autogenous pressures (2–20 MPa). The results of the D-Optimal design indicated that the materials synthesized at lower temperatures and times, particularly at 180 °C - 4 h (HC1) and 350 °C - 1.5 h (PHC5), achieved the highest adsorption yield and capacity, with values of 87.9 % and 5.27 mg g−1; and 94.8 % and 5.73 mg g−1 for HC1 and PHC5, respectively. Analysis of variance (ANOVA) on the synthesis model revealed that temperature and carbonization time are significant factors, both factors have an influence on HC and PHC fluoride adsorption capacity and HC yield and only temperature affects PHC yield. The optimum synthesis conditions to obtain the highest yields were 180 °C for 4 h and 350 °C for 1 h for HC and PHC, respectively, with 88.4 % and 96.2 % values. As for the maximum adsorption capacity, the optimum temperature and time values were 185 °C for 4 h and 378 °C for 1 h for HC and PHC, respectively, reaching adsorption capacities of 5.27 mg g−1 and 5.64 mg g−1. In addition, HC1 and PHC5 materials were characterized by N2 physisorption, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), CHNS elemental analysis and scanning electron microscopy (SEM). These materials showed differences among themselves, where the higher specific area of PCH5 with 137 m2 g−1, with respect to HC1 with 119 m2 g−1, stands out, as well as a higher concentration of basic sites, being 1.65 and 1.40 meq g−1 for HC1 and PHC5, respectively, on the other hand, the FTIR showed the same functional groups present on the surface, although in the SEM it was observed that the surface of HC1 presented small fractures, which disappeared when subjected to the pyrolysis process, in addition, the TGA showed a greater amount of organic matter in HC1 that could affect the adsorption of fluorides. The effect of pH on the adsorption capacity of HC1 and PHC5 fluorides was also investigated, revealing an increase of this capacity with decreasing solution pH due to electrostatic forces.

The induced formation and regulation of closed-pore structure for biomass hard carbon as anode in sodium-ion batteries

Biomass hard carbon is regarded as an advanced anode materials for sodium ion batteries (SIBs) since it possesses balanced performance including satisfactory specific capacity, suitable operating voltage window and low cost. Although numerous instances of utilizing biomass-derived hard carbon in SIBs have been observed, the unregulated pore structure of these hard carbon materials significantly constrains the electrochemical performance of SIBs, leading to diminished initial Columbic efficiency (ICE) and plateau capacity. Herein, taking a biomass hard carbon derived from waste camellia seed shells (CSSHCs) as a template, we display a correlation between synthesis conditions and pore structure of CSSHCs. CSSHCs are synthesized via a facile route including pre‑carbonization, purifying, mechanical ball-milling and high-temperature carbonization, and it is found that adjusting the secondary calcination temperature can induce the formation of closed pore structure, which is of great benefit to increase the ICE and the plateau-capacity. Besides, it is also proved that the obtained CSSHCs anodes obey a sodium storage mechanism that can be classified as “adsorption-intercalation-pore filling”, which endows SIBs with a competitive electrochemical performance. Specifically, the obtained biomass hard carbons at 1300 °C exhibits the best electrochemical performance among these anodes with the reversible capacity of as high as 270.0 mAh g−1 and a high ICE of 80.1 %, together with an excellent cycle stability (91.0 % capacity retention after 200 cycles at 0.1C, 1C = 300 mA g−1). Therefore, this study provides a significant exploration and raw material support for the further utilization of the waste biomass and sustainable development of the anode materials for the large-scale application of SIBs.

Comprehensive Evaluation of Process Parameters in the Green Synthesis of Iron Oxide Nanoparticles Using Moringa olifera extract.

This study investigates the green synthesis of iron oxide nanoparticles using Moringa olifera ethanolic extract and evaluates the impact of various process parameters on their physicochemical characteristics. The parameters examined include synthesis time, temperature, pH, stirring speed (RPM), and the ratio of extract to iron precursors. The findings reveal that a lower proportion of the extract increases the entrapment efficiency of the nanoparticles. Specifically, batch ME3 (3:1 ratio) produced the smallest nanoparticles at 117.8 nm, with a drug release of 75.54% and the highest entrapment efficiency at 60.28%. Extending the synthesis time to three hours in batch TM3 resulted in a drug release of 74.23% and a particle size of 116.3 nm. Batch TEM1, synthesized at 70°C, showed the highest entrapment efficiency and a favorable drug release profile of 71.09%, with the smallest particle size of 105.24 nm, suggesting that higher synthesis temperatures favor smaller particle sizes. Adjusting the pH to 10 in batch PM3 achieved a drug release efficiency of 76.02%. Batch RM5, synthesized with a stirring speed of 750 RPM, demonstrated a particle size of 95.7 nm and a drug release of 78.26%, indicating that higher stirring rates produce smaller nanoparticles and enhance drug release. These results highlight the significance of optimizing synthesis conditions to produce nanoparticles with desired properties. The use of M. olifera extract as a sustainable reducing and stabilizing agent presents an environmentally friendly approach to nanotechnology. This method has potential applications in drug delivery systems and various other industries, emphasizing the importance of green synthesis in creating sustainable and efficient nanomaterials.

Effect of Synthesis Conditions on the Composition, Local Structure and Electrochemical Behavior of (Cr,Fe,Mn,Co,Ni)3O4 Anode Material

AbstractDisordered high entropy spinels (HES) (Cr,Fe,Mn,Co,Ni)3O4 were obtained by solid‐state synthesis and co‐precipitation using various powder precursors. They were characterized by a complex of physico‐chemical methods and investigated as anode materials for lithium‐ion batteries (LIBs). According to XRD and TEM data, the materials are single‐phase. The structural characterization of the samples obtained at 773, 973, and 1273 K was determined using Raman and Mössbauer spectroscopy, and magnetic measurements. The degree of spinel inversion and lattice distortion (microstrains) decrease with increasing synthesis temperature, while the crystallite size increases. The insufficient nickel content in the samples ensures a more uniform distribution of iron cations in both sublattices, which leads to an increase in the lattice parameters and has a positive effect on the de‐/lithiation. Repeated ball‐milling of HES material, prepared by co‐precipitation, increases its specific capacity from 284 mAh g−1 to 492 mAh g−1 at a current density of 100 mA g−1 after 25 cycles. Besides, the smaller crystallite size reduces the volume changes in the materials during de‐/lithiation.

Investigation of Olive Leaf Polyphenol Extract Loaded Silver Nanoparticle Optimization by Box-Behnken Design.

Silver nanoparticles (AgNPs) are synthesized and optimized by reducing and stabilizing them with olive leaf extract. The successful synthesis of AgNPs was verified by UV-vis spectroscopy, SEM imaging, and DLS measurements, demonstrating characteristic features such as a surface plasmon resonance peak, spherical morphology, crystalline structure, and narrow size distribution with good stability. Utilizing Box-Behnken Design (BBD), the optimal synthesis conditions were determined, with a silver nitrate concentration of 1 mM, olive leaf extract volume of 10 mL, and reaction time of 60 minutes, yielding AgNPs with desirable properties. Statistical analysis revealed the significant influence of individual variables and their interactions on AgNP characteristics. Lower concentrations of silver nitrate and olive leaf extract led to smaller particle sizes and higher zeta potentials, while longer reaction times resulted in larger particles and lower zeta potentials. Among the experimental runs, Run 11 exhibited the most favorable properties, with 54 nm particle size, -36 mV zeta potential, and an encapsulation efficiency of 92.28%. ANOVA analysis further elucidated the significant effects of synthesis parameters on zeta potential, particle size, and encapsulation efficiency. In conclusion, the optimized formulation obtained through BBD offers a tailored approach for the synthesis of AgNPs with desired properties, suitable for various applications such as biomedical, catalytic, and sensing applications. The comprehensive understanding of synthesis parameters and their effects provided by this study facilitates the rational design of AgNPs for specific applications, enhancing their potential in diverse fields.

Impact of Mn/Ni and Li/(Mn+Ni) ratios on phase equilibrium and electrochemical performance of the high voltage spinel LiNi0.5Mn1.5O4

LiNi0.5Mn1.5O4 (LNMO) emerges as a promising spinel-type positive electrode material for lithium-ion batteries (LIBs) due to its low cost and high operating voltage (4.8 V vs. Li+/Li), attributed to the Ni4+/Ni3+/Ni2+ redox couples, which contribute to high energy density, a crucial requirement for next-generation LIBs. In this study, we investigate the influence of Mn/Ni and Li/(Mn + Ni) ratios on the phase equilibrium and electrochemical performance of LNMO positive electrode materials. A series of 18 samples were synthesized using a two-stage solid-state method with varying Mn/Ni and Li/(Mn + Ni) ratios and annealing under different atmospheres. These synthesis conditions have major impact on the composition and level of purity of LNMO phases, as well as on the nature of the impurities themselves. Mn excess significantly enhances the electrochemical performance, with superior discharge capacity, coulombic efficiency, and capacity retention for the Mn-rich sample with Li/(Mn + Ni) = 0.50. A comprehensive structural analysis combining synchrotron X-ray and neutron powder diffraction gives an in-depth characterization of these samples with a clear differentiation between the global Mn content within samples and that within the LNMO phase.

Latent fingerprint detection and identification using yellow-emitting YOF:Pr3+ nanophosphor

In this study, YOF:Pr3+ nanophosphors were synthesized using the microwave-assisted hydrothermal route. The structural and morphological properties of the nanophosphors calcined at different temperatures were studied in detail to optimize the synthesis conditions. The visible region and near-infrared (NIR) photoluminescence (PL) properties of the nanophosphors were obtained. Intense emission bands were observed in the blue and red regions under 250 nm excitation. The CIE chromaticity diagram showed that the color coordinates of the nanophosphors were located in the yellow region. The optimum Pr3+-concentration was found to be 0.002 mol fraction. The application of YOF: 0.002 Pr3+ nanophosphor for latent fingerprint detection was examined and evaluated on different types of surfaces. The nanophosphor demonstrated excellent adherence to the ridge patterns and sufficient sensitivity required for distinguishing between the ridges and the furrows. Different levels of detail were also observed that provided necessary information for the individualization of the fingerprints. The results suggest that the prepared YOF:Pr3+ nanophosphor can be a potential candidate for the rapid visualization and detection of latent fingerprints.

Facile synthesis of zeolitic‐imidazole framework‐67 (ZIF‐67) for the adsorption of indigo carmine dye

AbstractThis study aims to synthesize ZIF‐67 for the adsorption of indigo carmine (I.C.) dye. ZIF‐67 materials were synthesized under different conditions and the synthesis condition of ZIF‐67 giving the best adsorption efficiency was obtained. In batch adsorption studies, pH, adsorbent amount, contact time, initial dye concentration, and temperature effects were investigated. Adsorption data were applied to Langmuir, Freundlich, and Temkin isotherm models. The best correlation value was obtained in Langmuir isotherm (R2 = 0.999). The adsorption of I.C. dye with ZIF‐67 occurred in a monolayer with a homogeneous surface according to Langmuir isotherm. The highest adsorption capacity value of ZIF‐67 metal–organic framework for I.C. dye was found as 370 mg/g. Kinetic model studies were also performed and pseudo first‐order, pseudo second‐order, and intraparticle diffusion models were used. Pseudo second‐order was the best fitting kinetic model to the data (R2 = 0.997). Adsorption mechanisms of ZIF‐67 for I.C. dye include electrostatic interaction, π–π interaction, and hydrogen bonding. Thermodynamic studies showed that I.C. removal by ZIF‐67 is an exothermic and spontaneous process. ZIF‐67 was characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), field emission scanning electron microscope (FE‐SEM), and N2 adsorption–desorption. The surface area of synthesized ZIF‐67 was found 1493 m2 g−1. The salt concentration effect on I.C. adsorption by ZIF‐67 was also investigated, showing an increase in adsorption capacities with increasing salt concentration. The regeneration study was carried out and after 5 cycles, the reduction in efficiency was 21%.

Синтез 5-амино-3-арил-1H-пиразол-4-карбонитрилов на основе гидразинов или бензгидразидов в условиях ультразвуковой активации

Pyrazoles containing amino and carbonitrile groups have a wide range of biological activities, including antimicrobial, antiinflammatory, antitumor, antioxidant, and are used to create pesticides and dyes. Also, these compounds are synthons for the preparation of various polyheterocyclic compounds. New potentially biologically active 5-amino-3-aryl-1H-pyrazole-4-carbonitriles containing pharmacophoric substituents have been obtained via three-component condensation reactions of malonic dinitrile with substituted aromatic aldehydes and benzhydrazides or hydrazines. This work considers the limits of applicability of hydrazines and hydrazides as weak nucleophiles in similar processes. The described target compounds have been synthesized using the «green chemistry» approach under ultrasonic activation in water or a mixture of water and isopropyl alcohol in the presence of triethylamine as base catalyst. The applicability of this environmentally friendly, economical and efficient approach for the synthesis of nitrogen-unsubstituted (7, 8) and N-aryl- (4, 6) or N-aroyl-substituted (1–3) pyrazole-4-carbonitriles has been demonstrated. The target pyrazole-4-carbonitrile (2) is formed and Schiff base (2’) is released as a by-product in the reaction of the weak binucleophile 3-nitrobenzhydrazide with 4-benzyloxy-3-methoxybenzaldehyde and malonic dinitrile. Step-by-step syntheses have shown that the initial reaction of a three-component interaction can be either croton condensation or the formation of a Schiff base. In any case, during subsequent heterocyclization, unstable substituted pyrazolines are formed, which aromatize to the target pyrazoles in the presence of atmospheric oxygen under synthesis conditions. The composition and structure of the products have been confirmed by elemental analysis, NMR 1H, 13C spectroscopy, HSQC, and HMBC heteronuclear correlations.

Optimizing the synthesis conditions of CaAl‐layered double hydroxide and poly (3‐hydroxybutyrate)/CaAl‐LDH nanocomposite for potential use in antibacterial drug delivery

AbstractCalcium aluminum layered double hydroxide (CaAl‐LDH) has gained significance for drug delivery applications due to its multiple advantages, including high drug‐loading capacity, pH sensitivity, biocompatibility, high acceptable intake values of metal ions, and its ability to provide sustained release of the intercalated drug. In this study, pristine CaAl‐LDH was synthesized by co‐precipitation method at different pH values (9 and 10) and aging times (16 and 24 h) to obtain LDH with higher d‐spacing, which is beneficial for achieving a high drug loading efficiency. Ofloxacin (OFX), an antibiotic drug, was loaded into CaAl‐LDH via regeneration (CaAl‐LDH‐OFX(RG)) and co‐precipitation (CaAl‐LDH‐OFX(CPT)) methods, and achieved drug loading of 28.3% and 36.5%, respectively. The release behavior of OFX from CaAl‐LDH‐OFX(RG) and CaAl‐LDH‐OFX(CPT) formulations was examined in simulated conditions representing the gastrointestinal tract. CaAl‐LDH‐OFX(RG) showed less initial burst release of OFX compared to CaAl‐LDH‐OFX(CPT) in acidic as well as neutral pH conditions. In order to overcome the degradation of the drug before reaching the target site, CaAl‐LDH‐OFX(RG) was reinforced at 1, 3, and 5 wt% in poly (3‐hydroxybutyrate) (PHB) matrix by sonication‐assisted solution casting method. The PHB‐based nanocomposites were characterized by XRD, FESEM, TGA, and FTIR analyses. FESEM characterization of PHB‐based films loaded with 3 wt% of CaAl‐LDH‐OFX(RG) revealed compact morphology without any aggregate formation. Moreover, PHB/3CaAl‐LDH‐OFX(RG) films demonstrated sustained release of OFX at pH 1.2 (95.60% in 96 h), pH 6.8 (78% in 113 h), and pH 7.4 (40.90% in 107 h). The promising potential of PHB‐based formulations for antibacterial drug delivery systems was confirmed by their significant antibacterial activity against Escherichia coli and Staphylococcus aureus.Highlights pH and aging time influence the structural characteristics of pristine CaAl‐LDH. Ofloxacin loaded CaAl‐LDH prepared by co‐precipitation and regeneration methods. Sustained release of ofloxacin from poly (3‐hydroxybutyrate)‐based formulation. Poly (3‐hydroxybutyrate)‐based formulations exhibit excellent antibacterial activity.

The effect of heating rate on microstructure and electrochemical performance of nickel-rich layered oxides cathode materials

Nickel-rich layered oxides have attracted significant attention as promising cathode materials for lithium-ion batteries due to their high specific capacity, rate capability, and relatively low cost. However, the material still faces challenges such as harsh synthesis conditions, easy cation mixing and large residual alkali on the surface, severely limiting its practical applications. To overcome these drawbacks, this study successfully synthesized a series of LiNi0.8Co0.1Mn0.1O2 (NCM) cathode materials with different heating rates. The results indicate that appropriately reducing the heating rate can improve the cycling performance of the material and reduce cation mixing and surface residual alkalinity. Specifically, among the four samples, the LiNi0.8Co0.1Mn0.1O2 sample (NCM-2 °C min-1) exhibites a lower Li⁺/Ni²⁺ mixed arrangement and fewer surface residual alkalis, demonstrating good cycling performance and rate capability. The NCM-2 °C min-1 sample provides an excellent initial discharge capacity of 210.4 mAh g⁻¹ under 0.1 C conditions, and it achieves the highest capacity retention rate (85.9%) after 100 cycles at 1 C, while the capacity retention rates for NCM-1 °C min-1, NCM-3 °C min-1, and NCM-4 °C min-1 are 75.4%, 75.2%, and 71.2%, respectively. NCM-2 °C min-1 sample also showed excellent rate performance, especially at high rates. The discharge capacity remains at 151.6 mAh g-1 at 10 C, which is much higher than that of other samples (149.3 mAh g-1 for NCM-1 °C min-1, 123.5 mAh g-1 for NCM-3 °C min-1, and 120.6 mAh g-1 for NCM-4 °C min-1). The research of synthesis technology has important guiding significance for the synthesis of high-stability high-nickel layered oxide materials.

Biogenic Synthesis of Silver Nanoparticles Mediated by Aronia melanocarpa and Their Biological Evaluation.

In the present study, two A. melanocarpa berry extracts were used for the synthesis of silver nanoparticles (AgNPs). After the optimization of synthesis, the AgNPs were characterized using UV-Vis, FTIR, EDX, DLS, and STEM analyses. The stability in different media, phytotoxicity, as well as antimicrobial and antioxidant activities were also evaluated. The ideal synthesis conditions were represented by a 3 mM AgNO3 concentration, 1:9 extract:AgNO3 volume ratio, alkaline medium, and stirring at 40 °C for 120 min. The synthesis was confirmed by the surface plasmon resonance (SPR) peak at 403 nm, and the strong signal at 3 keV from the EDX spectra. FTIR analysis indicated that polyphenols, polysaccharides, and amino acids could be the compounds responsible for synthesis. Stability tests and the negative zeta potential values showed that phytocompounds also play a role in the stabilization and capping of AgNPs. The preliminary phytotoxicity studies on T. aestivum showed that both the extracts and their corresponding AgNPs had an impact on the growth of roots and shoots as well as on the microscopic structure of leaves. The synthesized AgNPs presented antimicrobial activity against S. aureus, E. coli, and C. albicans. Moreover, considering the results obtained in the lipoxygenase inhibition, the DPPH and hydroxyl scavenging activities, and the ferrous ion chelating assay, AgNPs exhibit promising antioxidant activity.

Biotreatment of Industrial Pollutant (Carbon Dioxide) and its Role in Bioplastics Production

Polyhydroxyalkanoates (PHAs) are a class of biopolymers with characteristics resembling those of petrochemical-based plastics that have gained recent attention and a growing amount of research effort due to their environmental friendliness. Numerous bacteria, including Alcaligenes spp., Pseudomonas spp., Staphylococcus spp., and algae create (PHAs) in the presence of carbon and limiting nutrients like nitrogen, and these biopolymers can successfully replace industrial plastics. Therefore, the goal of this study is to employ carbon dioxide, an industrial pollutant emitted into the environment, as a cheap carbon source to lower production costs and remove pollution at the same time. Only three of the nine bacterial isolates utilized were able to synthesize the polymer in the presence of CO2, and the best isolate was belonging to the genus Alcaligenes after 48 hours of incubation at 30°C and pH 7, which are the optimal conditions for polymer synthesis. Bacterial growth resulted in the production of 5.2gm/l of PHA and 6.2gm/l of biomass under these conditions.

Cork activated carbon as a new sustainable electrode for electrochemical desalination: Customized surface chemistry for improved performance

Capacitive deionization (CDI) desalination has proven to be a promising solution to combat water scarcity, standing out for its efficiency and low energy consumption. In this study we investigated the feasibility and sustainability of using recycled cork stoppers as carbon electrodes for CDI. The cork stoppers underwent carbonization at three different temperatures (500, 700 °C, and 900 °C) and then activation with Potassium hydroxide (KOH) at 850 °C. The as-obtained electrodes (ECAC) demonstrated salt adsorption capacities (SAC) comparable to other biowaste carbon electrodes. The potential of zero charge (EPZC) values of the electrodes reflected the influence of synthesis conditions on their surface properties. Considering the EPZC, symmetric configuration, in which both electrodes (cathode (-) || (+) anode) were made of the same material (ECAC(-)||(+)ECAC), and asymmetric electrodes, using different materials (ECAC(-)||(+)YP80-F) were investigated. The use of asymmetric electrodes proved to be mandatory to obtain high charging efficiency and desalination capacity. It was found that the EPZC determines the correct electrode configuration to prevent the deleterious effect of co-ions repulsion. Herein, we used the carbonization temperature as a new strategy to tune the EPZC in order to obtain electrodes with the desired surface properties for application in CDI, thus avoiding the usual laborious and costly chemical-based approaches. Regarding the desalination performance, asymmetry combined with the appropriate cell potential was optimized to obtain charging efficiencies close to 100 % and maximum SAC, thus resulting in minimized specific energy consumption. This study not only confirms the efficacy of cork stoppers as electrodes for CDI but also promotes the use of recycled materials, contributing to a circular economy and environmental impact mitigation.

Predictive Controller for Large-Scale Fuzzy Polynomial Systems

This paper presents an innovative method to tackle the predictive-control challenges associated with large-scale fuzzy polynomial systems comprising interconnected polynomial fuzzy systems. This study models large-scale nonlinear fuzzy systems in a polynomial framework, which can reduce the number of fuzzy rules. We derive the conditions for controller synthesis in the main theorem using the Lyapunov theory and sum-of-squares technique. Simulation results confirm the validity and efficiency of this approach.

Enhancing the Acidity Window of Zeolites by Low-Temperature Template Oxidation with Ozone.

Revisiting the impact of the first and often deemed trivial postsynthetic step, i.e., a high-temperature oxidative calcination to remove organic templates, increases our understanding of thermal acid site evolution and Al distributions. An unprecedented degree of control over the acidity of high-silica zeolites (SSZ-13) was achieved by using a low-temperature ozonation approach. Fourier transform infrared spectroscopy of adsorbed probe molecules and solid-state NMR spectroscopy reveal the complexity of the thermal evolution of acid sites. Low-temperature activated (ozonated) zeolites maintain the original Brønsted acidity content and high defect content and have virtually no Lewis acidity. They also preserve the "as-made" Al distribution after crystallization and show a clear link between synthesis conditions and divalent cation capacity, as measured with aqueous cobalt ion uptake. The synthesis protocol is found to be the main contributor to Al proximity, yielding record high exchange capacity when ozonated. After conventional calcination at 500-600 °C, however, the presence of water leads to the gradual depletion of Brønsted acid sites, in particular, in small crystals. This work indicates that low-temperature ozonation followed by thermal activation at different temperatures can be used as a novel tool for tuning the amount and nature of acid sites, providing insights into the activity of zeolites in acid-catalyzed reactions, such as CO2 hydrogenation to dimethyl ether, and thereby expanding the possibilities of rational acidity tuning.

"Straw in the Clay Soil" Strategy: Anticarbon Corrosive Fluorine-Decorated Graphene Nanoribbons@CNT Composite for Long-Term PEMFC.

Carbon corrosion poses a significant challenge in polymer exchange membrane fuel cells (PEMFCs), leading to reduced cell performance due to catalyst layer degradation and catalyst detachment from electrodes. A promising approach to address this issue involves incorporating an anticorrosive carbon material into the oxygen reduction reaction (ORR)electrode, even in small quantities (≈3wt% in electrode). Herein, the successful synthesis of fluorine-doped graphene nanoribbons (F-GNR) incorporated with graphitic carbon nanotubes (F-GNR@CNT), demonstrating robust resistance to carbon corrosion is reported. By controlling the synthesis conditions using an exfoliation method, the properties of the composite are tailored. Electronic structural studies, employing density functional theory (DFT) calculations, to elucidate the roles of fluorine dopants and graphitic carbon nanotubes (CNTs)in mitigating carbon corrosion are conducted. Physicochemical and electrochemical characterization of F-GNR@CNT reveal its effectiveness as a cathode additive at the single-cell scale. The addition of F-GNR@CNT to the Pt/C cathode improves durability by enhancing carbon corrosion resistance and water management, thus mitigating the flooding effect through tailored surface properties. Furthermore, advanced impedance analysis using a transmission line model is performed to gain insights into the internal resistance and capacitive properties of electrode structure.

Enhanced electrolytic production of hypochlorous acid using phosphorus-modified carbon felt electrodes: A study in disinfectant synthesis

In this study, we fabricated phosphorus-modified carbon felt electrode anodes for chloride oxidation in saline solutions to produce HClO via electrocatalysis, forming a compound fungicide saline applicable for debridement and disinfection. A low-cost phosphorus-modified carbon felt electrode (P@CF) with high chlorine evolution reaction activity was synthesized to address the reduced efficiency of CER and the solution's pH increase. Heteroatoms P and O were introduced into the carbon felt by phosphoric acid activation followed by heat treatment. The maximum active chlorine concentration on the P@CF electrode could reach 616.8 mg/L in 60 min under the optimal synthesis conditions of a phosphoric acid mass fraction of 30%, a phosphoric acid impregnation time of 3 h, and a heat treatment temperature of 300 °C. The active chlorine concentration was 1.8 times higher on the P@CF electrode compared to the original carbon felt electrode. The optimal reaction conditions for the generation of active chlorine were as follows: salt concentration of 9 g/L, voltage of 7 V, and electrode spacing of 2 cm as verified by response surfaces. This electrolysis reaction follows one-stage reaction kinetics. Subsequently, the disinfection efficacy of the produced disinfectants was examined. The prepared disinfectant was also compared to a commercially available hypochlorite disinfectant, showing similar disinfection effects on E. coli for both.

Hydrophobic iron oxide nanoparticles: Controlled synthesis and phase transfer via flash nanoprecipitation

Iron oxide nanoparticles (IONPs) synthesized via thermal decomposition find diverse applications in biomedicine owing to precise control of their physico-chemical properties. However, use in such applications requires phase transfer from organic solvent to water, which remains a bottleneck.Through the thermal decomposition of iron oleate (FeOl), we systematically investigate the impact of synthesis conditions such as oleic acid (OA) amount, temperature increase rate, dwell time, and solvent on the size, magnetic saturation, and crystallinity of IONPs. Solvent choice significantly influences these properties, manipulating which, synthesis of monodisperse IONPs within a tunable size range (10-30 nm) and magnetic properties (75 to 42 Am2Kg-1) is obtained.To enable phase transfer of IONPs, we employ flash nanoprecipitation (FNP) for the first time as a method for scalable and precise size control, demonstrating its potential over conventional methods. Poly(lactic-co-glycolic acid) (PLGA)-coated IONPs with hydrodynamic diameter (Hd) in the range of 250 nm, high colloidal stability and high IONPs loadings up to 43% were obtained, such physicochemical properties being tuned exclusively by the size and hydrophobicity of starting IONPs. They showed no discernible cytotoxicity in human dermal fibroblasts, highlighting the applicability of FNP as a novel method for the functionalization of hydrophobic IONPs for biomedicine.