Hydrothermal Synthesis Research Papers - Academia.edu (original) (raw)

2025, Geochimica et Cosmochimica Acta

The aim of the present work was to study the thermodynamic equilibria between water and a homo-ionic montmorillonite SWy-1 saturated by different cations. The choice of this smectite is justified by the large set of experimental data available from the literature for eight different interlayer cations: Na + , K + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ . In particular, studies by and are providing heat of adsorption data, pairs of desorption-adsorption isotherms, and information about the partition of adsorption-desorption water molecules between external surfaces and internal spaces. By calculating the effective amount of hydration water as the difference between the so-called gravimetric water and the surface covering water, a thermodynamic model was then developed, based on the concept of considering an asymmetric subregular binary solid solution between a fully hydrated and a anhydrous smectite. A set of six thermodynamic parameters (DH hyd ; S hyd and four Margules parameters) was extracted by a least square method from measurements of enthalpies of adsorption and paired adsorption-desorption isotherms for each interlayer cation. These six initial parameters were then used to determine a complete set of standard thermodynamic hydration parameters (DH hyd ; DG hyd ; DS hyd , heat capacity, molar volume, and number of interlayer H 2 O) and quantify, for each cation, the number of moles of hydration water molecules as a function of relative humidity and temperature. The validation of the standard state thermodynamic properties of hydration for each end member was carried out using three approaches: (1) a comparison with experimental isotherms obtained on hetero-ionic and homo-ionic SWy-1 smectite at different temperatures; (2) a comparison with the experimental integral enthalpy and entropy of hydration of the SWy-1 smectite; and (3) a comparison with experimental isotherms acquired on various smectites (Upton, MX80, Arizona) with different layer charges. Eventually, the present work demonstrates that, from a limited number of measurements, it is possible to provide the hydration thermodynamic parameters for hydrated smectites with different compositions and under different conditions of temperature and relative humidity, using the newly developed predictive model.

2025, Inorganic Chemistry

Microcrystalline zirconium phosphate (ZrP) has been synthesized by precipitating a Zr(IV) salt (i.e., zirconium propionate, chloride, or oxide chloride) with H 3 PO 4 from aqueous solutions of oxalic acid (H 2 C 2 O 4 ) at 80 °C. Independent of the Zr(IV) salt, crystalline materials have been obtained with reaction yields >90% and reaction time of one day for the following molar ratios: H 3 PO 4 /Zr = 6 and H 2 C 2 O 4 /Zr = 10. The material prepared from Zr propionate (ZrP prop ) has been further investigated by scanning electron microscopy, thermogravimetry, and ion exchange titrations. Structural characterization has been performed by X-ray powder diffraction and solid state 1 H-31 P 2D correlation NMR experiments. Structural parameters obtained by Rietveld analysis of powder diffraction data agree with those reported in the literature for single crystal determinations. Moreover, NMR data show that the closest proton environment of the phosphorus atom in ZrP prop is the same as in ZrP samples of similar crystallinity prepared according to literature methods.

2025, Nanoscale advances

Correction for 'Influence of the surrounding medium on the luminescence-based thermometric properties of single Yb 3+ /Er 3+ codoped yttria nanocrystals' by Jefferson Augusto Oliveira Galindo et al., Nanoscale

2025, Zeitschrift für anorganische und allgemeine Chemie

2025, Dalton Transactions

2025, Jurnal Pengolahan Hasil Perikanan Indonesia

The increasing production of cuttlefish has been associated with the increasing of by-product waste particularly cuttlebone. Cuttlebone is known to contain an inorganic element in form of calcium carbonate(CaCO3) which can be utilized as a source of calcium oxide (CaO) for hydroxyapatite synthesis. This study was aimed to determine the physicochemical characteristics of the cuttlebone and the optimum calcination temperature for CaO extraction and hydroxyapatite synthesis. This study was divided into three steps. Firstly, analysis of the cuttlebone physicochemical properties; secondly, extraction and characterization of the CaO with different calcination temperature (500°C, 600°C, 700°C for 6 hours); and thirdly, hydroxyapatite synthesis using a combination of hydrothermal method at 200°C 6 hours and different calcination treatments (800°C, 900°C, 1,000°C for 1 hour). The results showed that the cuttlebone contained moisture 3.54±0.11%,lipid 0.32±0.19%, protein 4.78±0.23%, carbohydra...

2025, Synthetic Metals

Here, we report a binder-free synthesis of microrods-like manganese phosphate thin film over stainless steel substrate by a facile, single-pot hydrothermal method. The XRD analysis reveals that, the formation of manganese phosphate [Mn 3 (PO 4 ) 2 ] material of a monoclinic crystal structure. From SEM images observed microrods like morphology of manganese phosphate with an average width of ∼25 μm. The manganese phosphate electrode shows a better electrochemical performance with a specific capacitance of 145 F g -1 at 0.2 mA cm -2 current density in 1.0 M Na 2 SO 4 electrolyte. Moreover, the flexible solid-state symmetric electrochemical energy storage device was assembled with PVA-Na 2 SO 4 solid gel-electrolyte consists of manganese phosphate as anode and cathode electrode. The corresponding symmetric supercapacitor achieves a high energy density of 11.7 Wh kg -1 at a high power density of 1.41 kW kg -1 with an excellent specific capacitance of 37 F g -1 at 0.1 mA cm -2 current density. Manganese phosphate shows long-term electrochemical cyclic stability at a current density of 0.8 mA cm -2 for 9000 galvanostatic charge-discharge cycles with excellent capacitance retention (99 %). This excellent capacitive performance confirms that the manganese phosphate is promising material and fabricated flexible solid-state symmetric supercapacitor has high potential in the field of portable and bendable energy storage devices.

2025, Critical Reviews in Solid State and Materials Sciences

Zinc Oxide is an important and multi-purpose material in various industries due to its particular chemical and physical properties. Discovering a cheap, fast, clean, safe, and easy to use method, to synthesize this oxide nanoparticle has attracted a lot of attention in recent applications. The unique properties of the microwave and its special heating capabilities have yielded desirable outcomes by combining different synthesis methods. In the recent years, the vast majority of studies focus on the microwave-assisted synthesis of zinc oxide nanoparticles. This review article attempts to go over the recent advancements on the synthesis of zinc oxide nanoparticles with the aid of microwave, different morphologies and applications obtained by this method. Various microwave-assisted synthesis methods are classified, including the solution-based methods such as hydrothermal, solgel, and combustion methods. Morphology of the nanoparticles can affect the properties, and subsequently, applications of these nanoparticles. On the other hand, there is great diversity of morphological and synthesis conditions of zinc oxide nanoparticles. Thus, categorizing the synthesis techniques and providing features of them, facilitates the selection of appropriate method for designing new hierarchical structures with potential properties for future applications. Also it is endeavored to focus on the formation mechanisms of these methods. Finally, the various morphologies obtained under microwave radiation and their formation mechanisms are discussed and the effective factors in the synthesis are analyzed and presented. The potential and suitable fields of development and progress in the future studies are also proposed.

2025, Adsorption Science & Technology

Ordered mesoporous materials of MCM-41 and SBA-15 type were synthesized under non-hydrothermal conditions using different molar ratios of surfactant/silica, ranging from 0.07 to 0.27 for MCM-41 and from 0.009 to 0.021 for SBA-15. Nitrogen adsorption/desorption isotherms at 77 K were used to evaluate the specific surface areas, with values up to 1450 m 2 /g and 1100 m 2 /g being obtained for MCM-41 and SBA-15, respectively. Scanning electron microscopy was carried out to study the morphology of the materials. The sizes of the primary mesopores and the pore thicknesses were assessed by a geometrical method using X-ray diffraction and nitrogen adsorption data. The results for the pore sizes were compared with those obtained by a recently reported method (VBS-method) and the Non-Local Density Functional Theory (NLDFT) model, both proposed to evaluate the pore-size distribution of these materials. It was found that, under the synthesis conditions, the surfactant/silica molar ratio had an important effect on the final characteristics of these materials.

2025, Industrial & Engineering Chemistry Research

This paper describes the development of membranes based on perfluoro polymers for the separation of aqueous ethanol mixtures in pervaporation or vapor permeation mode. Hydrophobic perfluoro polymers were selected because their chemical and thermal stability allows them to be used at temperatures up to 130 °C in hot ethanol/water vapors. The permeance and selectivity of membranes made from these polymers are quite different from the properties of the cross-linked hydrophilic membranes that are commonly used to separate water/ ethanol mixtures. Perfluoro polymers absorb less than 1% liquid in mixtures ranging from pure water to pure ethanol. As a result, the water permeance and water/ethanol selectivity of the membranes are essentially independent of feed water/ethanol composition. However, the water permeances of perfluoro membranes are low for commercial applications. Multilayer composite membranes, consisting of a perfluoro protective layer and a selective hydrophilic polymer underlayer, have the stability of hydrophobic perfluoro membranes combined with the high permeances and good selectivities of hydrophilic membranes.

2025, Angewandte Chemie International Edition

Angabe der unten stehenden Digitalobjekt-Identifizierungsnummer (DOI) zitiert werden. Die deutsche Übersetzung wird gemeinsam mit der endgültigen englischen Fassung erscheinen. Die endgültige englische Fassung (Version of Record) wird ehestmöglich nach dem Redigieren und einem Korrekturgang als Early-View-Beitrag erscheinen und kann sich naturgemäß von der AA-Fassung unterscheiden. Leser sollten daher die endgültige Fassung, sobald sie veröffentlicht ist, verwenden. Für die AA-Fassung trägt der Autor die alleinige Verantwortung.

2025, Proceedings of the National Academy of Sciences of the United States of America

The hydrothermal synthesis of zeolites carried out in batch reactors takes a time so long (typically, on the order of days) that the crystallization of zeolites has long been believed to be very slow in nature. We herein present a synthetic process for ZSM-5, an industrially important zeolite, on the order of seconds in a continuous flow reactor using pressurized hot water as a heating medium. Direct mixing of a well-tuned precursor (90 °C) with the pressurized water preheated to extremely high temperature (370 °C) in the millimeter-sized continuous flow reactor resulted in immediate heating to high temperatures (240-300 °C); consequently, the crystallization of ZSM-5 in a seed-free system proceeded to completion within tens of or even several seconds. These results indicate that the crystallization of zeolites can complete in a period on the order of seconds. The subtle design combining a continuous flow reactor with pressurized hot water can greatly facilitate the mass production ...

2025, Electrochimica Acta

Novel three-dimensional hierarchical heterostructures composed of two-dimensional SnS 2 nanoflakes and zero-dimensional SnO 2 nanoparticles were fabricated via a one-step hydrothermal method. Size of the heterostructures was ca. 2 µm in diameter, and individual SnS 2 nanoflakes with thickness of ca. 150 nm were connected to central core of the heterostructures. The SnO 2 nanoparticles in a diameter of ca. 5 nm uniformly covered entire surface of the SnS 2 nanoflakes. Moreover, both of these structures were highly crystalline. Meanwhile, amorphous carbon was formed within the heterostructures. The SnS 2 /SnO 2 /C hierarchical heterostructures had a high initial specific reversible capacity of 1065.7 mAh g -1 , stable cycling stability of 638 mAh g -1 after 30 cycles, and superior rate capability of 550.8 mAh g -1 at 1C rate. These SnS 2 /SnO 2 /C hierarchical heterostructures showed better performance than individual SnS 2 and SnO 2 nanomaterials, and the performance was even higher than the graphene-SnS 2 and graphene-SnO 2 nanohybrid materials. This is attributed to a synergistic effect of high surface area, which is provided by the unique SnS 2 internal nanoflake layered structures decorated with ultra-fine SnO 2 nanoparticles, and an effective beneficial buffer matrix to accommodate the large volume change upon cycling, which is caused by the side-products such as Li 2 S or Li 2 O. The SnS 2 nanoflake was deduced to play a similar role as graphene material, since both possess 2D conducting layer structures. The uniform carbon dispersion within the structures also stabilizes the structures and improves electrical conductivity of the hierarchical heterostructures.

2025, Iranian Journal of Chemistry & Chemical Engineering-international English Edition

This paper presents a novel microwave-assisted hydrothermal technique for synthesizing tin(II) oxide nanoparticles. This technique can be used for producing large quantities of homogeneous nanoparticles in a short time. The effect of the solution molarity, final pH, hydrothermal processing time and microwave power were studied. The tin(II) oxide structure verified from XRD and the mean crystallite size was evaluated to be about 5 nm using the Debye-Scherrer formula on the most intense peak. The particle size was measured from STM pictures in the range between 4-5 nm. For different samples, UV-Vis spectroscopy showed the absorption peak due to tin(II) oxide at about 240 nm and an exitonian peak at about 280 nm that shifted with respect to solution molarity, final pH, hydrothermal processing time and microwave power. The photoluminescence spectroscopy (PL) results showed the emission peaks in the visible spectrum range. The results showed that synthesized SnO nanoparticles have a dire...

2025, Materials Letters

Evaporation-induced self-assembly has been applied in the synthesis of crack-free mesoporous carbon monolith with good mechanical stability using a waste plant material as carbon precursor and triblock copolymer F127 as template. The carbon monolith was characterized using transmission electron microscopy, scanning electron microscopy, nitrogen adsorption-desorption measurement, X-ray diffraction and Fourier transform infrared spectroscopy. The results showed that the carbon monolith is mesoporous, has a surface area of 219 /g, and a narrow pore size distribution of 6.5 nm.

2025, Materials Letters

A new microwave-assisted hydrothermal synthesis of carbon monolith is reported in this work. The process uses microwave heating at 100 °C under acidic condition by employing a triblock copolymer F127 as the template, and resorcinol–formaldehyde as the carbon precursor. Scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen sorption measurements, transmission electron microscopy, X-ray studies and thermogravimetic analysis were used to characterize the synthesized material. The carbon monolith is crack-free, mesoporous and has a high surface area of 697 m2/g. The results demonstrate that the microwave-assisted hydrothermal synthesis is a fast and simple approach to obtain carbon monoliths, as it reduces effectively the synthesis time from hours to a few minutes which could be an advantage in the large scale production of the material.

2025, Applied Surface Science

Gross, The role of the synthetic pathways on properties of Ag 2 S nanoparticles for photothermal applications,

2025, Asian Journal of Chemistry

The primary motivation for the study to develop simple eco-friendly green synthesis of silver nanoparticles using leaf extract of Eucalyptus citriodora as reducing and capping agent. The green synthesis process was quite fast and silver nanoparticles were formed within 0.5 h. The synthesis of the particles was observed by UV-visible spectroscopy by noting increase in absorbance. Characterization of the particles was carried out by X-ray diffraction, FTIR and electron microscopy. The developed nanoparticles demonstrated that E. citriodora is good source of reducing agents. UV-visible absorption spectra of the reaction medium containing silver nanoparticles showed maximum absorbance at 460 nm. FTIR analysis confirmed reduction of Ag + to Ag 0 atom in silver nanoparticles. The XRD pattern revealed the crystalline structure of silver nanoparticles. The SEM analysis showed the size and shape of the nanoparticles. The method being green, fast, easy and cost effective can be recommended for large scale production of AgNPs for their use in food, medicine and materials.

2025, Nanomaterials

In this article, a short-time hydrothermal method is developed to prepare CuBi2O4 nanocolumn arrays. By using Bi(NO3)3·5H2O in acetic acid and Cu(NO3)2·3H2O in ethanol as precursor solutions, tetragonal CuBi2O4 with good visible light absorption can be fabricated within 0.5 h at 120 °C. Tetragonal structured CuBi2O4 can be formed after 15 min hydrothermal treatment, however it possesses poor visible light absorption and low photocatalytic activity. Extending the hydrothermal treatment duration to 0.5 h results in a significant improvement invisible light absorption of the tetragonal CuBi2O4. The CuBi2O4 obtained through 0.5 h hydrothermal synthesis shows a band gap of 1.75 eV and exhibits the highest photocatalytic performance among the CuBi2O4 prepared with various hydrothermal time. The removal rate of methylene blue by the 0.5 h CuBi2O4 reaches 91% under visible light irradiation for 0.5 h. This study proposes a novel strategy to prepare photoactive CuBi2O4 nanocolumn arrays with...

2025, Journal of Materials Science

ZnO single crystals with thickness up to 12 mm, 2 inches in ''diameter'' and weight of about 150 g have been grown from KOH, NaOH, and K 2 CO 3 based hydrothermal solutions on the seeds of (0001) orientation. The addition of LiOH up to 3.0-4.5 mol/L allowed to decrease the growth rate of ZnO crystals along the h0001i crystallographic direction. For positive and negative monohedra, it was achieved 0.12 and 0.01 mm/day, respectively, at temperature 340 °C and DN = 10 °C. The best ZnO etching agent was found to be the solutions 25 mol% HCl + 3 mol% NH 4 F at room temperature, and etching time 5 min. The dislocation density of ZnO crystals varied from 240 cm À2 to 3,200 cm À2 in the case of growth rates 0.04 mm/day to 0.11 mm/day, respectively. It was also found that ZnO crystals grown are stable in air, oxygen, nitrogen, and argon atmosphere as well as in vacuum at the temperatures up to 1,000 °C under thermal treatment during 4 h.

2025, Applied Surface Science

The influence of temperature on water incorporation into barium titanate films grown hydrothermally was investigated. The films were prepared using titanium foils that were immersed in 0.5 M barium hydroxide aqueous solutions for 4 h. Working temperatures were 100, 150 and 2158C. The samples were characterized by X-ray diffraction, Auger electron spectroscopy, forward recoil spectrometry and thermal desorption spectrometry. The latter showed that water was incorporated mainly in the molecular form and that this was favored at lower temperatures, leading to a slightly larger unit cell as has been observed in hydrothermal powders. Films grown at lower temperatures exhibited stronger XRD reflections.

2025, Materials

A traditional semiconductor (WO3) was synthesized from different precursors via hydrothermal crystallization targeting the achievement of three different crystal shapes (nanoplates, nanorods and nanostars). The obtained WO3 microcrystals were analyzed by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectroscopy (DRS). These methods contributed to the detailed analysis of the crystal morphology and structural features. The synthesized bare WO3 photocatalysts were totally inactive, while the P25/WO3 composites were efficient under UV light radiation. Furthermore, the maximum achieved activity was even higher than the bare P25’s photocatalytic performance. A correlation was established between the shape of the WO3 crystallites and the observed photocatalytic activity registered during the degradation of different substrates by using P25/WO3 composites.

2025

Today, the goal of refineries is not just to maximize the conversion of crude oil but to fabricate cleaner products. There are many individual processes for the obtaining of desired products such as catalytic reforming, fluid catalytic cracking, hydrocracking, thermal cracking and hydrotreating. Hydrotreating processes are reductive hydrogen treatments of the organic molecules contained in crude oil, to remove heteroatoms like nitrogen, oxygen or sulfur. Hydrotreating processes are also used to upgrade and process crude oil into high-value products. The motivation to remove sulfur and nitrogen from fuels is due to the fact that the burning of S and N containing fuels presents a severe danger to the environment through the formation of acid rain from SO 2 or NO x emissions. The hydrotreating process needs a large amount of hydrogen to treat crude oils. Pressure varies from 10-20 atm for naphtha to 25-40 atm for gas oil. Temperature conditions are

2025, Journal of Materials Science

Nanostructured SnSe was fabricated using hydrothermal methods followed by sintering in an evacuated-and-encapsulated ampoule. The effects of reaction temperature (150-170 °C), duration (6-12 h) and sintering temperature (450-580 °C) on the electronic transport are investigated. It is found that both the electrical conductivity and thermopower of hydrothermally synthesized and nanostructured SnSe increase with temperature and follow the variable range hopping process. As a result, disorder-induced improvement of electronic transport combined with low thermal conductivity on the pressed sample face perpendicular to the pressed direction leads to zT = 0.54 at 550 K for the sample sintered at 500 °C, demonstrating a significant improvement of zT value in the intermediate temperature range for the SnSe system.

2025, Materials Science and Engineering: C

Nanostructured materials are made by highly disordered powders with large distribution of particle size, morphologies and structures. They are classically nanoparticles of oxides, metals or supported metals. Microporous and mesoporous materials offer new trends in that it is possible to confine particles of oxides or metals into their channel or cavities and control, in this way, their size. In this contribution, we present an overview on different types of materials able to host metals or oxides and in particular, we focus on crystalline Ž . metal-aluminophosphates MeAPOs . These materials have, beside active centres for selective catalytic reactions, peculiar properties that depend both on the incorporated metal ions and on the structure of the aluminophosphate.

2025, Microporous and Mesoporous Materials

VAlPO-5 and VAlPO-11 catalysts were synthesized and their structural features characterized by a range of spectroscopic techniques (UV-Vis, Raman and IR spectroscopies) revealing valuable information on the nature of the incorporated vanadium species. A preliminary investigation into the catalytic potential of these catalysts was carried out by studying the epoxidation of cyclopentene to its corresponding epoxide using a solid source of ''active" oxygen, acetylperoxyborate (APB) as the oxidant. UV-Vis spectra showed strong bands in the 40,000-35,000 cm À1 range, that can be assigned to isolated Td-like oxovanadium(V) (V 5+ = O vanadyls), along with a component around 35,000 cm À1 due to a small fraction of Td V 5+ = O in di-or oligomeric V x O y clusters. The V 5+ = O ions were reversibly transformed to V 4+ = O species by reduction, and could also change their coordination (to octahedral geometry) in the presence of water molecules. The presence of isolated V 5+ = O was confirmed by resonant Raman studies. IR spectroscopy of adsorbed probes (CO and NO) revealed the presence of two families of framework V 4+ = O ions with different Lewis acidity V 4þ A and V 4þ B forming monocarbonyls (bands at 2192 cm À1 and 2184 cm À1 ) and dinitrosyls (bands at 1905-1755 cm À1 and 1835-1680 cm À1 ). Small differences in the local environment of the vanadyl ions (symmetry, defects), that can have an influence over their Lewis acidity, did not play a major role in influencing the overall product selectivity, whilst the differences in rate and turnover frequency could be explained on the basis of the differing pore diameters of the two catalysts.

2025, Journal of Advanced Ceramics

Co 2+ doped TiO 2 nanocrystals were synthetized by a hydrothermal treatment procedure applied to precursor dispersion of titania nanotubes and Co 2+ ions. Mixture of polygonal and prolate spheroid-like nanocrystals was obtained. The results of X-ray diffraction (XRD) analysis showed that resulted nanocrystals retain anatase crystal phase for both dopant concentrations (1.69 and 2.5 at%), but the crystal lattice parameters were affected. Reflection spectra revealed altered optical properties compared to bare TiO 2 . Room temperature ferromagnetic ordering with saturation magnetic moment in the range of 0.001-0.002 B /Co  was observed for both measured films made of Co 2+ doped TiO 2 nanocrystals.

2025

Two tests were conducted to establish parameters for the use of a zeolite, namely clinoptilolite, as swine feed additive in improving digestion and thus reducing manure mineral content. The first test was conducted in the laboratory to establish the ammonium binding potential of the experimental zeolite and the second test consisted in feeding one of 8 rations to 24 hogs. The experimental zeolite (90%+ clinoptilolite) was subjected to laboratory simulated digestive tract conditions which demonstrated that clinoptilolite is stable even at a pH of 1.5 and that it releases less than 10% of its already low heavy metal content. Furthermore, clinoptilolite lost only 15% of its ammonium adsorption capacity at a pH of 1.5 (120 cmol (+) /kg), compared to a pH of 7.0 (140 cmol (+) /kg). The second test used a combination of four (4) clinoptilolite levels (0, 2, 4 and 6%), 2 feed qualities (standard energy and protein versus 90% standard energy and protein). The trial used 192 hogs split into ...

2025, RASAYAN Journal of Chemistry

Bovine bone is a natural resource having valuable calcium phosphate compounds as a potential bioceramics powder feedstock. This study manipulated the calcium phosphates via hydrothermal processes after calcium phosphatecontaining bone was calcined and extracted. Here the resulting powder precursors obtained after calcining at 900 °C for 5 hours were hydrothermally processed for varying times at 110°C (1–5 h), yielding mainly biphasic calcium phosphates (-tricalcium phosphate and hydroxyapatite) formation with a minute lime according to XRD analysis. Calcination and hydrothermal processing can effectively produce a high amount of hydroxyapatite proportion (> 99 wt.%) with nano crystallite sizes (30-50 nm). After 5-hour calcination, the SEM images revealed the powder product with size uniformity (1 µm) and plate-like morphology. The powdered bovine bone was then subjected to DTA, DTG, and TG analyses to determine its thermal behavior. Calcination temperatures from 300 to 600 OC re...

2025, CrystEngComm

Development of polymeric materials from agroecological significance. Cashew Nut Shell Liquid (CNSL) is an industrial byproduct obtained from the cashew plant Anacardium occidentale L. CNSL consists of a mixture of natural phenols with a side chain of fifteen carbon atoms which contain one, two and three unsaturated bonds and as a major component around 90 % anacardic acid (AA) and 10 % AA cardanol, cardol and 2-methyl cardol. CNSL is regarded as a versatile and valuable raw material for wide applications such as additives for lubricants, diesel engine fuels, antioxidants, stabilizers, flame retardants, resins, inks, hydro intermediates as well as biomedical applications. In the present work we have taken an attempt to synthesize co cheaply available CNSL natural source to evaluate their biological activity by various antimicrobial strains. The synthesis has been carried out by "solid NMR and 13C-NMR spectral techniques have been complexes/polymers. TGA and DSC techniques have been used to evaluate their thermal properties. Antimicrobial activity of the co-ordination complexes/polymers has been tested by agar diffusion method against different pathogenic microbial strains to evaluate their potential biomedical applications. The synthesized complexes show higher lipophilicity and chemical stability, along with higher thermal stability and antimicrobial activities in comparison to virgin ligand. solve the problems of high solvent consumption and long reaction for preparing the metal complexes.

2025, ChemInform

Photocatalyst and Its Multiple Applications. -The title photocatalyst is hydrothermally synthesized from an aqueous suspension containing Zn(NO 3)2, Pr6O11, and oxalic acid (autoclave, 120 C, 48 h) followed by calcination at 450 C for 4 h. Pr6O11-ZnO shows photocatalytic activity toward degradation of Acid Violet 7 under natural sunlight. It exhibits good direct current and photoconductivity, which make the catalyst useful for soliton wave communication and solar cell applications. Pr 6O11 -ZnO modified Si(OEt)4 coated substrates show significant hydrophobic properties and can be used as self-cleaning material for industrial applications. -(BALACHANDRAN, S.;

2025, Chemistry: A European Journal

2025, Materials Letters

A novel, by-product assisted phase selective synthesis of InOOH was reported. The InOOH was synthesized using indium nitrate with oxalic acid in a hydrothermal process at 225 1C for 10 h without using any other templates. The nitric acid formed as a by-product played an important role in the formation of InOOH. Controlled experiments showed that in the absence of by-product no InOOH was formed. The influence of various hydrothermal experimental parameters on the formation of InOOH was also investigated in this study. The XRD pattern indicated the formation of well crystallized orthorhombic InOOH and the FE-SEM results confirmed the formation of flower-like morphological InOOH. The synthesized InOOH has indicated excellent photocatalytic activity on the degradation of Methyl Orange (MO) dye under UV light irradiation. A plausible mechanism of InOOH formation has also been proposed based on the experimental observation.

2025, Journal of The Electrochemical Society

Indium oxide (In 2 O 3 ) doped zinc oxide (ZnO) nanocomposites were successfully synthesized through a facile microwave hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N 2 adsorption-desorption isotherms (BET) and UV-Vis diffuse reflectance spectroscopy. The morphology of In 2 O 3 -ZnO composites was observed to be like flowers, and the diameter of particles constituting the porous petal was about 30 nm. The photoelectrocatalytic test results showed that the photoelectrocatalytic methylene blue (MB) degradation efficiency using In 2 O 3 -ZnO nanocomposites as photocatalysts under visible light irradiation and a certain voltage could reached above 95.3% after 60 min, much higher than that of In 2 O 3 particles and ZnO particles. The enhanced photoelectrocatalytic activity was attributed to the doping of In 2 O 3 and applied voltage, which beneficially reduced the recombination of electrons and holes in the photoelectrocatalytic process, therefore, it promoted the production of active species (•OH and •O - 2 ).

2025, INTERNATIONAL JOURNAL OF RESEARCH IN SCIENCE AND TECHNOLOGY

The Nanocrystalline tungsten oxide(WO3) is synthesized on fluorine-doped tin oxide (FTO) glass substrates employing hydrothermal technique. The structure, phase and morphology of these WO3 thin films were characterized using X-ray diffraction (XRD), UV-Vis Transmittance, scanning electron microscopy(SEM), Energy dispersive spectra (EDX). The Hydrothermal deposition technique can be potentially used to obtain uniform nanocrystalline WO3 films on a considerably larger area..The synthesized WO3 nanocrystalline is excellent substitute for various application and these films are equally comparable to the ones obtained by other sophisticated methods such as, vacuum or plasma deposition techniques.

2025, Materiali in Tehnologije

Nanocrystalline rutile TiO2 doped with various amounts of manganese (Mn) atoms was prepared using a hydrothermal synthesis route and a polycrystalline TiO2 precursor. The diffuse reflectance spectra of the highly doped rutile nanocrystallites display a notable red shift in the band-gap transition. The absorbing band edge moved to the visible range when the Mn content in the rutile nanocrystallite exceeded 0.4 %. The doped rutile nanocrystallites were analysed using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV-Vis spectroscopy. The Kubelka-Munk band-gap approximation was used to examine the narrowing of the band gap in comparison with the pure rutile TiO2 nanocrystallites. The doped rutile nanocrystallites displayed a remarkable decrease in the photocatalytic activity due to the formation of recombination sites induced by Mn ions incorporated into the crystal structure of the TiO2. Keywords: suspension, TiO2, rutile, doped with inorganic metal elements, UV absorber Z uporabo hidrotermalne sinteze in polikristalinini~ne rutilne oblike nanodelcev TiO2, smo pripravili nanokristalini~ne rutilne delce, dopirane z Mn. S pomo~jo UV-VIS difuzivno refleksijske spektroskopije smo zaznali izrazit premik absorpcijskega roba k valovnim dol`inam vidne svetlobe. Energijska vrzel z Mn dopiranega TiO2 se je z nara{~anjem koncentracije dopanta o`ala. Za analizo dopiranih rutilnih TiO2 nanodelcev smo uporabili rentgensko pra{kovno difrakcijo (XRD), elektronsko mikroskopijo (TEM, HRTEM), UV-Vis spektroskopijo, kalkulacijo energijskih vrzeli s Kubelka Munk pribli`kom. Pri merjenju fotokatalitske aktivnosti, z metodo degradacije izopropanola v alkohol, smo ugotovili, da dopiranje rutilne oblike TiO2 z Mn povzro~i inhibicijo fotokatalitske aktivnosti, kar smo pripisali tvorbi rekombinacijskih centrov, ki nastanejo pri dopiranju z Mn ioni v kristalno re{etko TiO2.

2025, Journal of Alloys and Compounds

We have synthesized strontium hexaferrite particles in an alkaline medium using a hydrothermal process at 180 • C. Our results show that to obtain a quasi-single SrFe 12 O 19 phase, the Fe/Sr ratio in the initial solution must be equal to 8. However, the powders obtained contain traces of ␣-Fe 2 O 3 and SrCO 3 . The SrFe 12 O 19 hexaferrite particles are hexagonal-shaped platelets about 2 m wide and 40 nm thick. When heated to 1000 • C, SrCO 3 reacts with SrFe 12 O 19 to give Sr 4 Fe 6 O 13 . According to XRD analysis, Mössbauer spectrometry and magnetic measurements, the magnetization axis of the single-phase SrFe 12 O 19 particle is perpendicular to the platelets. For an Fe/Sr ratio higher than 8, the ␣-Fe 2 O 3 phase becomes the major phase and for a ratio lower than 8, the amount of SrCO 3 increases. For an Fe/Sr ratio equal to 5, the formation of the Sr 3 Fe 2 (OH) 12 phase is also observed.

2025, physica status solidi (a)

In this work, Eu 3þ and Tb 3þ doped GdPO 4 nanocrystals, with different shapes were successfully synthetized by an original hydrothermal method. The particles morphology was modified changing the pH value and using glycerol as co-solvent in the synthesis. Depending on the synthesis conditions, TEM analyses have revealed the achievements of nanowires and nanoparticles with narrow size distributions. Their structural, morphological, and photoluminescent properties were investigated and compared. Luminescent composite films based on silicone polymer were prepared using GdPO 4 :Eu 3þ and GdPO 4 :Tb 3þ with different morphology as filler.

2025, Mehran University Research Journal of Engineering and Technology

Titanium dioxide (TiO2) has been utilized for photovoltaic devices mostly as electron selective ply. Most of the transition metal complexes like TiO2 possess wider band gap to predominant relying on morphology of nano-particles. Most of the metal oxides possess excellent ability of harvesting extensive part of sunlight. This study reports, synthesis of TiO2 by using two different techniques i.e., sol-gel and hydrothermal. Later nano films was applied on fluorine doped tin oxide glass through spin coating at ambient temperature. Particles of TiO2 were synthesized at different temperatures however rest of the variable like solvent, concentration and amount of precursor were static. Nanoparticles of anatase titania synthesized through sol-gel had higher crystallinity. Particle size of synthesized particles was 12.2 nm at 25 o C. Subsequently particles produced through hydrothermal procedure were large with an average particle size of 16 nm at 100 o C. FTIR further confirmed the synthesis of anatase titania at 400-800 cm -1 . X-ray diffraction technique also confirmed the synthesis of titania at 25.3 o , 38.0 o , 47 o , 54.5 o , 62.7 o and 78 o . UV-visible spectroscopy was performed to analyze optical properties exhibiting peak absorbance at 424 nm. This synthesized TiO2 anatase is extensively used for photovoltaic application.

2025, Mehran University Research Journal of Engineering and Technology

Titanium dioxide (TiO2) has been utilized for photovoltaic devices mostly as electron selective ply. Most of the transition metal complexes like TiO2 possess wider band gap to predominant relying on morphology of nano-particles. Most of the metal oxides possess excellent ability of harvesting extensive part of sunlight. This study reports, synthesis of TiO2 by using two different techniques i.e., sol-gel and hydrothermal. Later nano films was applied on fluorine doped tin oxide glass through spin coating at ambient temperature. Particles of TiO2 were synthesized at different temperatures however rest of the variable like solvent, concentration and amount of precursor were static. Nanoparticles of anatase titania synthesized through sol-gel had higher crystallinity. Particle size of synthesized particles was 12.2 nm at 25o C. Subsequently particles produced through hydrothermal procedure were large with an average particle size of 16 nm at 100o C. FTIR further confirmed the synthesis...

2025, Inorganica Chimica Acta

), have been obtained by hydrothermal synthesis and structurally characterized by single crystal diffraction. Their electrochemical properties were evaluated by solution-state differential pulse voltammetry. The voltammograms of all four compounds show two peaks which are separated by large potential values indicating a strong interaction between two ferrocene moieties in each structure.

2025, Rev. Soc. Quím. …

Se prepararon sólidos micro/mesoporosos del tipo MOR/MCM-41, con diferentes relaciones Si/Al. Para esto se colocó 3,15g de zeolita en solución de NaOH 3M y se agitó la suspensión por 30 min. Luego se agregaron 40 g de una solución de bromuro de hexadeciltrimetil-amonio (CTAB al 16% p/p) y se agitó por 30 minutos nuevamente. La mezcla fue depositada en un reactor de acero revestido de teflón y tratada hidrotérmicamente a 373 K por 24 h. Después de esto, el pH fue ajustado a 8,5. La mezcla fue depositada nuevamente en el reactor por 24 h más a 373 K. El producto sólido fue recuperado por filtración y se lavó con etanol y agua desionizada, para posteriormente secarlo en aire a 353 K y luego calcinarlo 6 h a 823 K. La forma ácida de estos sólidos fue obtenida mediante intercambio iónico en solución de NH NO 1 M a 343 K. Esos compuestos fueron caracterizados por MEB, EDX, DRX, TGA 4 3 y adsorción de N . Los sólidos obtenidos presentan áreas superficiales y volúmenes de poro

2025, Journal of Crystal Growth

Cadmium sulfide (CdS) one dimensional (1D) nanocrystals were prepared using a polyethylene glycol (PEG) assisted hydrothermal synthesis. X-ray diffraction result confirms that the nanorods are of hexagonal structure and the selected area electron diffraction (SAED) identifies the single crystalline nature of the sample. The sample was systematically characterized by UV-vis absorption, photoluminescence (PL) spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal analysis. The UV-vis absorption spectrum indicates the narrow size distribution of the CdS nanorods. The absorption band edge is seen shifted to 505 nm than the bulk material and the corresponding band gap is found to be 2.45 eV. The PL emission peak is detected around 550 nm. From SEM and EDX analysis, the morphology of the aggregates and the composition of the obtained product are identified. The TEM micrographs indicate that the CdS nanorods exhibit well defined morphology and high crystalline quality with narrow size distribution of lengths and widths. The TG/DTA traces of the nanopowder show four major stages of weight loss.

2025

Tin oxide (SnO2), a versatile metal oxide due to its wide range of applications and its nature as an amphoteric oxide, has attracted researchers globally for many decades. Hydrothermal synthesis of wide band gap oxides with controllable nano shape and size is of primary attraction leading to myriad areas of applications such as electrodes in Lithium-ion batteries, gas sensing, photo-catalyst etc. to name a few. In this work, we have synthesized different types of nanostructures of Tin oxide through low temperature(180oC) Hydrothermal process by varying the concentration of its precursor solution (SnCl4.5H2O) from 0.0625M to 0.25M. The characterization of as -Synthesized SnO2 done using UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X ray (EDX) and X-Ray Diffraction (XRD) confirm synthesis of tin oxide and formation of various nanostructures as a function of concentration of the precursor solution. The evolution of various shapes of nanostructures has been...

2025

Los contaminantes emergentes se encuentran frecuentemente en los efluentes acuosos deindustrias químicas, farmacéuticas y petroquímicas, siendo los procesos de oxidación avanzada(POA), tales como oxidación catalítica húmeda con H 2 O 2 (CWPO) una buena opción paraeliminarlos. En este trabajo se plantea el uso de catalizadores preparados a partir de celulosaestructurada en esferas como soporte de nanopartículas de cobre. Un método ecológico se empleapara sintetizar in situ el cobre en presencia de ácido ascórbico como agente reductor del precursorde cobre. La forma esférica permite su fácil recuperación, además de tratarse de una matrizorgánica, económica, renovable y biodegradable, para eliminar fenol, el cual se emplea típicamentecomo molécula sonda de contaminantes emergentes. Los resultados mostraron que la actividad delos catalizadores no está directamente vinculada con la concentración de cobre depositado en lasesferas. Si bien deberá mejorarse la eficiencia de los catalizadore...

2025, DOAJ (DOAJ: Directory of Open Access Journals)

2025, International Journal of Environmental Analytical Chemistry

In this study, niobium (Nb) and silver (Ag) codoped TiO 2 (TNA) mesoporous nanoparticles were synthesised by sol-gel (TNA-SG) and hydrothermal (TNA-H) methods. The synthesized samples were calcined under an air atmosphere for 1 hour at 550°C. The prepared samples were characterised by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), N2 adsorptiondesorption isotherms (BET-BJH), UV-Vis spectrophotometry, field emission scanning electron microscopy (FESEM) and highresolution transmission electron microscopy (HR-TEM). The results of X-ray analysis, the presence of anatase phases in the sol-gel method and the combination of anatase and rutile in the hydrothermal method was confirmed. The effect of synthesis method on the crystalline structure, specific surface area, pore size distribution, and photocatalytic activity of the synthesised samples was studied. The photocatalytic activity of the nanoparticles for the degradation of the methylene blue dye solution for the hydrothermal nanoparticles was better than the sol-gel method. The photocatalytic degradation efficiency of hydrothermal and sol-gel method was about 92.06% and 95.6%, respectively.

2025, Journal of Alloys and Compounds

SrFe 12 O 19 /CoFe 2 O 4 composite nanoparticles were successfully synthesized by a one-pot hydrothermal route and the structural and morphological properties were studied in details. The XRD pattern results confirmed SrFe 12 O 19 /CoFe 2 O 4 composite formation at Co/Sr ratio of 0.5 with some residual second phases of SrCO 3 and Fe 2 O 3 . FTIR spectra showed the strong absorption bands in the range of 440e650 cm À1 , which are related to FeeO bonds. FESEM images illustrated that the Co-ferrite nanoparticles would nucleate on the surface of plate-liked Sr-ferrite particles by increasing of Co/Sr ratio. At the ratio of 0.5, whole surface of Sr-ferrite particles was covered by Co-ferrite nanoparticles. HRTEM images confirmed the SrFe 12 O 19 /CoFe 2 O 4 nanocomposite formation with the average particle size of 8 nm at the Co/Sr ratio of 0.5. Cyclic voltammetry suggesting the pseudocapacitance behavior of the samples where the specific capacitance in the potential window of À1.4 -0 V and scan rate of 50 mV s À1 increased from 133 F g À1 in pure Sr-ferrite to 634 F g À1 at the Co/Sr ¼ 0.5. Subsequently, specific capacitance decreased to 275 F g À1 at Co/Sr ¼ 1. These results were also confirmed by galvanostatic charge-discharge (GCD) curves and the effect of variation of the scan rates were evaluated. 79% of the initial capacitance maintains for the sample with Co/Sr ratio of 0.5 after 5000 continuous cyclic voltammetry at the scan rate of 50 mV s À1 which confirms the superior performance of the prepared electrode as a supercapacitor material.

2025, Asian Journal of Chemistry

2025

There are many people who have contributed in part to the success of the work. Firstly, thanks must go to Basil Chassoulos, who has helped to fix and maintain the laboratory equipment. Secondly to Professor Eric Van Steen, who helped me through many a hard time, when I did not see the light at the end of the tunnel. Also to Dr Ashley Robins, who gave me moral support and more. I would also like to thank the Technikon Witwatersrand and the NRF, as well as Prattley Engineering for financial support and supplying the natural zeolite. Wits University catalysis group and School of Chemistry helped to supply me with chemicals and equipment. Thank you to Mahlanu Nayo, Mtwakazi Ncetezo, and Stembile Goba who were students that assisted me in several of the experiments. To my supervisor Dr A.F.Mulaba-Bafubiandi, thank you for your continual encouragement, friendship and direction, especially towards the end, and to Professor Neil Coville for your expert advice, and assistance. Thanks to Technikon Witwatersrand for reducing my lecturing load. Thanks to African Amines for supplying me with methylamines for calibrations. Thanks to Professor Craig Williams from the UK for supplying me with synthetic clinoptilolite. Thank you all. iii Abbreviations BET-Brunauer, Emmett, and Teller C/N-Carbon to Nitrogen ratio Clino-Clinoptilolite Clinocat 2-Modification of clinoptilolite using acid and base treatment CSTR -Continuous stirred tank reactor DMA-Dimethylamine DME-Dimethyl ether KOH-Potassium hydroxide Lab-Laboratory Me0H-Methanol MMA-Monomethylamine MTG-Methanol to gasoline process MTO-Methanol to Olefin process NH3-Ammonia Re-Reynolds number TCD-Thermal Conductivity Detector TEPA-Triethylpolyacetate TMA-Trimethylamine TPD-Temperature programmed desorption XRD-X-ray diffraction ZSM-5-Catalyst used in the MTG process