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Trace-level detection of isopropanol is important for human health monitoring and air quality surveillance. In this work, we report synthesis of high surface area two-dimensional (2D) nanoflakes of CuAl 2 O 4 using surfactant-assisted hydrothermal process and its application in ppb level detection of isopropanol. X-ray diffraction revealed the polycrystalline nature of the spinel and a nano crystallite size of 42 nm. The 2D morphology of CuAl 2 O 4 was confirmed using field emission scanning electron microscope whereas BET revealed the mesoporous nature and a high surface area of 41.8 m2g-1. The surface oxidation states of the material were found through X-ray photoelectron spectroscopy. The 2D CuAl 2 O 4 demonstrated excellent sensing towards isopropanol with its response varying from 11.8 to 84.5 % (500 ppb–10 ppm) at 300 °C. The limit of detection of the spinel was found to be 56 ppb at its optimum operating temperature of 300 °C. In addition, the sensing layer was found to have response times in range 1101 s for 500 ppb to 168 s for 10 ppm and recovery times in the range 300 s for 500 ppb to 570 s for 10 ppm. [ABSTRACT FROM AUTHOR]

The woven carbon fibers (WCF) fabrics were functionalized by growing copper-oxide (CuO) nanostructures using Seed-assisted hydrothermal technique. The effective growth of CuO on surface hydrolyzed WCF samples were achieved by seeding followed by growth treatment in the prepared precursor solution. The impact of hydrothermal process parameters such as number of seeding cycles, duration of growth treatment and molar concentration of growth solution were studied by performing 96 set of experiments with three repetitions. In this work detailed analysis of structural, morphological, and elemental attributes of the CuO-coated WCF fabrics samples have been done. The WCF fabrics were uniformly coated with monoclinic CuO nanostructures having nanopellets, nanoflakes, nanowires, and nanoflowers morphologies. Different characterization techniques such as field emission scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, FT-IR spectroscopy and thermo-gravimetric analyzer were used to study different attributes of CuO-modified WCF samples. The number of seeding treatments and the length of growth treatment had a significant impact on growth of CuO nanostructures on WCF. The detailed analysis exhibits that the developed CuO-modified WCF samples may enhance interfacial surface area, bonding capacity and reduce void content by allowing nanostructures to cross-link together and with polymer matrix while fabricating composite materials. [ABSTRACT FROM AUTHOR]

N-butanol, a volatile organic compound prevalent in numerous industrial processes, poses significant risks to human health and the environment if not properly monitored. Consequently, the development of high-sensitivity n-butanol sensors is imperative. For this reason, NdFeO 3 nanoparticles were successfully synthesized by hydrothermal method and used for the detection of n-butanol. They were fully analyzed using characterization techniques such as XRD, BET, EDX, SEM, TEM and XPS. The test results revealed that the prepared samples exhibited a granular structure with an average diameter of approximately 65 nm. The specific surface area measured 15.415 m2/g, and the pore size was determined to be 16.638 nm. The NdFeO 3 sensor responds up to 441 for 100 ppm n-butanol at 260 °C, response and recovery times were 33 s and 7 s respectively. The response value of the NdFeO 3 sensor is still 4.3 for 1 ppm n-butanol with a minimum detection limit of 0.024 ppm. Simultaneously, the NdFeO 3 sensor has excellent selectivity, stability and moisture resistance. These good sensing properties indicate that this work provides a possible strategy for developing an economical and repeatable high performance gas sensor for the detection of n-butanol. [ABSTRACT FROM AUTHOR]

ZnO is a promising thermoelectric ceramic material, but the low electrical conductivity and high thermal conductivity restrict its satisfactory thermoelectric performance. Chemical doping is an effective way to improve the thermoelectric properties of ZnO. Due to the valence states and similar ionic radii of Fe3+ and Zn2+, Fe was selected as the effective dopant for ZnO. In this work, Fe-doped ZnO samples were prepared using hydrothermal synthesis and microwave sintering technology under oxygen-depleted conditions. The electrical conductivity of sintered Fe-doped ZnO was greatly improved owing to the energy band adjustment. The maximum power factor of 3108 μW/mK2 at 800 K was obtained from Zn 0.997 Fe 0.003 O, which is about 4.4 times greater than that of pure ZnO. Meanwhile, the small grain size (300–500 nm) and residual pores resulted from microwave rapid sintering in an oxygen-depleted environment, as well as the point defects caused by Fe3+ substituting for Zn2+, significantly reduced the thermal conductivity. Finally, the highest ZT value of 0.91 has been achieved in Zn 0.997 Fe 0.003 O at 800 K. [ABSTRACT FROM AUTHOR]

[Display omitted] Designing and developing suitable oxygen evolution reaction (OER) catalysts with high activity and stability remain challenging in electrolytic water splitting. Hence, NiFe@NC@MoS 2 core-bishell composites wrapped by molybdenum disulphide (MoS 2) and nitrogen-doped graphene (NC) were prepared using hydrothermal synthesis in this research. NiFe@NC@MoS 2 composite exhibits excellent performance with an overpotential of 288 mV and a Tafel slope of 53.2 mV·dec−1 at a current density of 10 mA·cm−2 in 1 M KOH solution, which is superior to commercial RuO 2. NC and MoS 2 bishells create profuse edge active sites that enhance the adsorption ability of OOH* while lowering the overall overpotential of the product and improving its oxygen precipitation performance. The density function theory(DFT) analysis confirms that the layered MoS 2 in NiFe@NC@MoS 2 provides additional edge active sites and enhances electron transfer, thus increasing the intrinsic catalytic activity. This research paves a novel way for developing OER electrocatalysts with excellent catalytic performance. [ABSTRACT FROM AUTHOR]

Employment of yeasts as bio-templates to obtain hollow structured microspheres is recognized as a promising strategy in the view of resource utilization and sustainable development. In this study, carbon modified Bi 2 MoO 6 /Bi 2 S 3 hollow microspheres with rich oxygen vacancies were successfully prepared via in situ hydrothermal synthesis instead of removing yeast templates by calcination. As-obtained samples were characterized using SEM, EDS, TEM, XRD, XPS, EPR and UV–vis DRS analysis. It was shown that carbon modified Bi 2 MoO 6 /Bi 2 S 3 hollow microspheres, with a diameter of 2.2 μm, inherited the ellipsoidal shape from primitive yeast templates. In situ hydrothermal synthesis not only resulted in the integration of yeast-derived carbon into the Bi 2 MoO 6 structure through Bi–O–C and Mo–O–C bonds, but also produced oxygen vacancy defects in the sample. Under visible light irradiation, the carbon modified Bi 2 MoO 6 /Bi 2 S 3 photocatalyst exhibited an excellent degradation efficiency, achieving 87.0 % removal of methylene blue (MB) within 100 min. With photoelectric tests and active species trapping experiments, the potential mechanism for the remarkable photocatalytic performance of carbon modified Bi 2 MoO 6 /Bi 2 S 3 was discussed preliminarily. This work explored an economical, simple and feasible approach for the multi-strategy modification of photocatalysts, and provided a new cognition on the versatile application of biological templates in material design and fabrication. [ABSTRACT FROM AUTHOR]

The study proposes the utilization of microwave-assisted methods for converting neutralization slag (NS) into hydroxyapatite (HAP), offering an alternative to the conventional hydrothermal method. The microwave-assisted approach addresses the challenges encountered in hydrothermal reactions, such as particle agglomeration, reduced specific surface area, prolonged reaction time, high temperature requirements, and inadequate saturation adsorption capacity. By employing the response surface methodology with a Box-Behnken design, the study found that the microwave-assisted method significantly reduced the synthesis time from 90 to 25 min and the temperature from 120 °C to 56 °C. Furthermore, the microwave method consumed only 1/43 of the energy utilized in hydrothermal synthesis. To assess the performance of the synthesized HAP, various detection methods were utilized, including XRD, SEM-EDS, FTIR, Zeta potential, and ICP, which analyzed the crystal structure, crystallinity, morphology, chemical composition, and surface charge of HAP. The BET method was used to measure the specific surface area, further confirming the successful synthesis of HAP. The HAP synthesized through this microwave-assisted method exhibited a saturation adsorption capacity of up to 98.4 mg/g of fluoride ions from vanadium industrial raffinate. This study demonstrates that the microwave-assisted method provides a viable solution for reducing energy consumption and enhancing HAP synthesis efficiency for wastewater treatment in the vanadium industry. [Display omitted] [ABSTRACT FROM AUTHOR]

Quartz glass powder is a type of silicon-rich industrial waste. Accumulation of this waste has led to resource wastage and environmental pollution. In this paper, quartz glass powder is used as raw material for preparing xonotlite through hydrothermal synthesis. The effects of Ca/Si (C/S) molar ratio, liquid/solid ratio, reaction temperature, and reaction time on the conversion of quartz are studied. The phase and structural changes of glass powder are analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Based on this, the conversion mechanism of quartz in glass powder is explained. The dissolution rate of quartz in an alkaline solution is a critical factor that restricts hydrothermal reactions. The conversion rate of quartz can be effectively increased by raising reaction temperature and extending reaction time. When the reaction temperature is 240 °C and the reaction time reaches 14 h, the conversion of quartz can reach 94.5 wt%. This study reveals the conversion mechanism of quartz in hydrothermal reactions and provides a theoretical basis for the efficient utilization of glass powder. [ABSTRACT FROM AUTHOR]

This study introduces a novel approach to addressing environmental issues by developing fish-scale carbon nanoparticles (FSCNPs) with a wide range of colors from discarded fish scales. The process involves hydrothermally synthesizing raw tamban (Sardinella) fish scales sourced from Universal Canning, Inc. in Zamboanga City, Philippines. The optimization of the synthesis was achieved using the response surface methodology with a Box–Behnken design. The resulting FSCNPs exhibited unique structural and chemical properties akin to carbonized polymer dots, enhancing their versatility. The solid-state fluorescence of these nanoparticles can be modulated by varying their concentration in a polyvinylpyrrolidone matrix, yielding colors such as blue, green, yellow, and red-orange with Commission Internationale de l'Eclairage coordinates of (0.23, 0.38), (0.32, 0.43), (0.37, 0.43), and (0.46, 0.48), respectively. An analysis of the luminescence mechanism highlights cross-linking emissions, aggregation-induced emissions, and non-covalent interactions, which contribute to concentration-dependent fluorescence and tunable emission colors. These optical characteristics suggest that FSCNPs have significant potential for diverse applications, particularly in opto-electronic devices. [ABSTRACT FROM AUTHOR]

Organic pollutants entering water bodies lead to severe water pollution, posing a threat to human health. The activation of persulfate advanced oxidation processes using carbon materials derived from MOFs as substrates can efficiently treat wastewater contaminated with organic pollutants. This research uses NH2-MIL-101(Fe) as a substrate, doped with Fe2+ and Co2+, to prepare Fe/Co-CNs through a one-step carbonization method. The surface morphology, pore structure, and chemical composition of Fe/Co-CNs were investigated using characterization techniques such as XRD, SEM, TEM, XPS, FT-IR, BET, and Raman. A comparative study was conducted on the performance of catalysts with different Fe/Co ratios in activating PMS for the degradation of organic pollutants, as well as the effects of various influencing factors (the dosage of Fe/Co-CNs, the amount of peroxymonosulfate (PMS), the initial pH of the solution, the TC concentration, and inorganic anions) on the catalyst's activation of persulfate for TC degradation. Through radical quenching experiments and post-degradation XPS analysis, the active radicals in the FeCo-CNs/PMS system were investigated to explain the possible mechanism of TC degradation in the Fe/Co-CNs/PMS system. The results indicate that Fe/Co-CNs-2 (with a Co2+ doping amount of 20%) achieves a degradation rate of 93.34% for TC (tetracycline hydrochloride) within 30 min when activating PMS, outperforming other Co2+ doping amounts. In addition, singlet oxygen (1O2) is the main reactive species in the reaction system. [ABSTRACT FROM AUTHOR]

In this work, we reported the synthesis of honey bee (Apis mellifera) venom-derived nanoparticles via a hydrothermal method. This method not only ensures the preservation of the bee venom's bioactive components but also enhances their potential stability, thus broadening the scope for their applications in the biomedicinal field. The synthesis method started with the homogenization suspension of bee venom, followed by its hydrothermal process to synthesize bee venom nanoparticles (BVNPs). The successful synthesis of BVNPs was characterized using various characteristic techniques such as Ultraviolet–visible (UV–Vis) spectroscopy, Fourier Transforms Infrared (FTIR) Spectroscopy, Zeta Potential (ZP), Liquid Chromatography-Mass Spectrometry (LCMS), and Transmission Electron Microscopy (TEM). The synthesis of BVNPs through biosynthesis is shown by the visible violet-brown color development at 347 nm by UV–Vis spectroscopy. FTIR analysis revealed the presence of several functional groups in the BVNPs, including alcohols (–OH), phenols (C6H5–), carboxylic acids (–COOH), amines (–NH2, –NH–), aldehydes (–CHO), ketones (–CO–), nitriles (–CN), amides (–CO–N–), imines (–CNH–), esters (–COO–), and polysaccharides. These functional groups, as confirmed by their specific stretching and bending vibrational modes, contribute to the diverse biological activities of BVNPs, including cytotoxicity against MCF-7 breast cancer cells. The ZP of the BVNPs indicated good colloidal stability at − 45 mV. LCMS analysis confirmed the presence of major bioactive molecules, including melittin & apamin and TEM analysis shows the BVNPs exhibited a quasi-spherical shape with good dispersion, the average size was approximately 25 nm, with some being smaller (quantum dots) and interplanar spacing of 0.236 nm indicated a highly ordered crystalline structure. Moreover, the anticancer efficacy of the BVNPs was ascertained through in vitro assays against MCF-7 breast cancer cells, showing a dose-dependent cytotoxic effect. The findings of this study underscore the viability of hydrothermal synthesis in producing biologically active and structurally stable BVNPs, with a significant potential for anticancer activities. [ABSTRACT FROM AUTHOR]

The current trends in research and development of FCC catalyst is focused on the formulation of active matrices that serve as pre-crackers, with the objective of reducing the diffusional resistance of the longer chain hydrocarbon molecule in the feed. In this study, an aluminosilicate active matrix was synthesised from metakaolin using hydrothermal method. The experimental variables that were varied were hydrothermal temperature, in the range of 80 to 110 ℃, and hydrothermal time, in the range of 12 to 72 hours, to investigate the best conditions for synthesising the active matrix. Subsequently, the active matrix was subjected to a series of analyses, including X-ray fluorescence, X-ray diffraction, N2 physisorption, NH3-temperature programmed desorption, Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetry, with the objective of determining its composition, crystal characteristics, surface characteristics, acidity, functional groups, material structure, and thermal characteristics. Additionally, the active matrix was tested for its intrinsic cracking activity using the micro activity test (MAT). The results indicate that the best temperature for hydrothermal synthesis of the active matrix is 80 °C. The active matrix synthesised with a heating time of 24 hours demonstrated the highest light cycle oil yield, reaching 38.9 wt%. Meanwhile, the active matrix synthesised at 48 hours exhibited the most favourable characteristics, with a specific surface area of 144.23 m²/g and a pore volume of 0.9933 cm³/g, as well as the highest cracking conversion of 70.0 wt%. [ABSTRACT FROM AUTHOR]

In this study, undoped and Ni-doped ZnS nanoparticles were fabricated using a hydrothermal method to explore their structural, optical, and surface properties. X-ray diffraction (XRD) analysis confirmed the cubic crystal structure of ZnS, with the successful incorporation of Ni ions at various doping levels (2%, 4%, 6%, and 8%) without disrupting the overall lattice configuration. The average particle size for undoped ZnS was found to be 5.27 nm, while the Ni-doped samples exhibited sizes ranging from 5.45 nm to 5.83 nm, with the largest size observed at 6% Ni doping before a reduction at higher concentrations. Fourier-transform infrared (FTIR) spectroscopy identified characteristic Zn–S vibrational bands, with shifts indicating successful Ni incorporation into the ZnS lattice. UV–visible spectroscopy revealed a decrease in the optical band gap from 3.72 eV for undoped ZnS to 3.54 eV for 6% Ni-doped ZnS, demonstrating tunable optical properties due to Ni doping, which could enhance photocatalytic performance under visible light. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed the uniform distribution of Ni within the ZnS matrix, while X-ray photoelectron spectroscopy (XPS) provided further confirmation of the chemical states of the elements. Ni doping of ZnS nanoparticles alters the surface area and pore structure, optimizing the material's textural properties for enhanced performance. These findings suggest that Ni-doped ZnS nanoparticles offer promising potential for applications in photocatalysis, optoelectronics, and other fields requiring specific band gap tuning and particle size control. [ABSTRACT FROM AUTHOR]

This study delves into the effects of carbonation curing and autoclave–carbonation curing on the properties of calcium oxide–belite–calcium sulfoaluminate (CBSAC) cementitious material aerated concrete. The objective is to produce aerated concrete that adheres to the strength index in the Chinese standard GB/T 11968 while simultaneously mitigating CO2 emissions from cement factories. Results show that the compressive strength of CBSAC aerated concrete with different curing regimes (autoclave curing, carbonation curing, and autoclave–carbonation curing) can reach 4.3, 0.8, and 4.1 MPa, respectively. In autoclave–carbonation curing, delaying CO2 injection allows for better CO2 diffusion and reaction within the pores, increases the carbonation degree from 19.1% to 55.1%, and the bulk density from 603.7 kg/m3 to 640.2 kg/m3. Additionally, microstructural analysis reveals that delaying the injection of CO2 minimally disrupts internal hydrothermal synthesis, along with the formation of calcium carbonate clusters and needle-like silica gels, leading to a higher pore wall density. The industrial implementation of autoclavecarbonation curing results in CBSAC aerated concrete with a CO2 sequestration capacity ranging from 40 to 60 kg/m3 and a compressive strength spanning from 3.6 to 4.2 MPa. This innovative approach effectively mitigates the carbon emission pressures faced by CBSAC manufacturers. [ABSTRACT FROM AUTHOR]

Infections originating from pathogenic microorganisms can significantly impede the natural wound-healing process. To address this obstacle, innovative bio-active nanomaterials have been developed to enhance antibacterial capabilities. This study focuses on the preparation of nanocomposites from thermally reduced graphene oxide and zinc oxide (TRGO/ZnO). The hydrothermal method was employed to synthesize these nanocomposites, and their physicochemical properties were comprehensively characterized using X-ray diffraction analysis (XRD), High-resolution transmission electron microscopy (HR-TEM), Fourier-transform infrared (FT-IR), Raman spectroscopy, UV-vis, and field-emission scanning electron microscopy (FE-SEM) techniques. Subsequently, the potential of TRGO/ZnO nanocomposites as bio-active materials against wound infection-causing bacteria, including Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, was evaluated. Furthermore, the investigated samples show disrupted bacterial biofilm formation. A reactive oxygen species (ROS) assay was conducted to investigate the mechanism of nanocomposite inhibition against bacteria and for further in-vivo determination of antimicrobial activity. The MTT assay was performed to ensure the safety and biocompatibility of nanocomposite. The results suggest that TRGO/ZnO nanocomposites have the potential to serve as effective bio-active nanomaterials for combating pathogenic microorganisms present in wounds. [ABSTRACT FROM AUTHOR]

This research focused on the synthesis of biphasic titania nanowires from commercially available anatase titania via hydrothermal method to improve its antimicrobial activity. The electron microscope scanning (SEM) showed that the titania nanowires structures were successfully synthesized with width varying from 17 to 96 nm and length from 0.7 to 8 μm. The titania nanowires have biphasic structure of brookite and anatase, as observed from the X-ray diffraction pattern. The band gap was calculated from the ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS) spectra at 3.3eV, which is between the range of pure anatase and pure brookite band gap. The crystallite size of the titania nanowires was calculated using the Scherer equation and showed a much smaller crystallite size compared to commercial titania. The antimicrobial activity of the titania nanowires was then investigated against gram-negative and gram-positive bacteria. They exhibited improved antimicrobial activity against the Gram-negative Pseudomonas aeruginosa and Escherichia coli along with Gram-positive Bacillus subtilis. Interestingly, their inhibition zone was comparable to the antibiotic tetracycline. Meanwhile, the commercial titania did not show any antimicrobial activity on any tested bacterial strains. The improved antimicrobial activity of the titania nanowires was attributed to its biphasic phase, small particle size, and its one-dimensional morphology. [ABSTRACT FROM AUTHOR]

This study aims to enhance electrochemical energy storage in supercapacitors by optimizing the synthesis temperature of MoO 3 nanostructures using a hydrothermal technique. MoO 3 nanostructures were synthesized using a hydrothermal technique, with reaction temperatures ranging from 140 to 230 °C for 24 h. The materials were analyzed using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–Vis) spectroscopy. The findings indicate that at 200 °C, a pure hexagonal phase of MoO 3 was obtained, while different temperatures resulted in a combination of orthorhombic and hexagonal phases. The SEM analysis demonstrated that the morphology of the MoO 3 nanostructures varied depending on the synthesis temperature. These variations encompass the particles, spherical planar structures, and nanorods. The prepared samples were subjected to electrochemical analysis to explore their electrochemical properties, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD). The electrochemical performances of the prepared samples varied depending on the temperature at which the MoO 3 samples were prepared, resulting in different morphologies. The sample prepared at 220 °C exhibited the highest specific capacitance (C S) of 330 F/g, a minimal charge-transfer resistance (R CT) of 1800 Ω, an energy density of 16.50 Wh/kg, and a power density of 150 W/kg with symmetric and asymmetric device C S values of 125 and 115 F/g, respectively, compared to the other prepared samples. The observed outcomes can be attributed to the diverse morphology of MoO 3 nanostructures and the high electrochemical active surface area (ECSA) of 7.43 × 10−5 F/cm2 that were synthesized at different hydrothermal temperatures. This diversity in morphology and ECSA leads to the presence of active surface area sites, thereby enhancing electrochemical activity. These findings highlight the effect of synthesis temperature on the morphology, crystal structure, and electrochemical performance of MoO 3 nanostructures for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs), as porous materials, have great potential for exploring high-performance electrochemiluminescence (ECL) probes. However, the constrained applicability of MOFs in the realm of ECL biosensing is primarily attributed to their inadequate water stability, which consequently impairs the overall ECL efficiency. Herein, we developed a competitive ECL biosensor based on a novel tightest structural ruthenium-based organic framework emitter combining the proximity hybridization-induced catalytic hairpin assembly (CHA) strategy and the quenching effect between the Ru-MOF and ferrocene for detecting paraquat (PQ). Through a simple hydrothermal synthesis strategy, ruthenium and 2,2ʹ-bipyrimidine (bpm) are head-to-head self-assembled to obtain a novel tightest structural Ru-MOF. Due to the metal–ligand charge-transfer (MLCT) effect between ruthenium and the bpm ligand and the connectivity between the internal chromophore units, the Ru-MOF exhibits strong ECL emissions. Meanwhile, the coordination-driven Ru-MOF utilizes strong metal–organic coordination bonds as building blocks, which effectively solves the problem of serious leakage of chromophores caused by water solubility. The sensitive analysis of PQ is realized in the range of 1 pg/mL to 1 ng/mL with a detection limit of 0.352 pg/mL. The tightest structural Ru-MOF driven by the coordination of ruthenium and bridging ligands (2,2ʹ-bipyrimidine, bpm) provides new horizons for exploring high-performance MOF-based ECL probes for quantitative analysis of biomarkers. [ABSTRACT FROM AUTHOR]

Strategies to make more efficient use of sunlight have been developed. Different synthesis parameters have been studied for the production of multiphase photocatalysts. In this work, for the first time, the performance of a one-step nitrogen-assisted hydrothermal synthesis of TiO 2 using TiO 2 –P25 as a Ti precursor was investigated for the degradation of methylene blue under visible light irradiation. Urea and ethylenediamine (EDA) were evaluated as nitrogen sources. The produced photocatalysts had a rod-like nanostructure with the formation of mesopores. The resulting phase was a heterojunction of anatase, TiO 2 (B), and rutile, which enhanced charge separation. The presence of nitrogen during the hydrothermal reaction altered the morphology of TiO 2 , impacting the crystallite size. The U photocatalyst (urea source) achieved the best result for visible light with prior adsorption, degrading around 11 % of methylene blue in 5 h. This shows that it is possible to obtain a photocatalyst with superior performance to TiO 2 –P25 under both ultraviolet and visible light. This study presents an efficient strategy for improving the optical response of TiO 2 by using nitrogen during a hydrothermal reaction, which has potential for industrial applications. • TiO 2 was synthesized by a one-step hydrothermal reaction with nitrogen. • Urea and ethylenediamine were used as nitrogen sources. • The nitrogen sources altered the morphology of the TiO 2. • Adsorption affected the photocatalytic activity and kinetic constants. • The best photocatalytic performance was for the urea-assisted reaction. [ABSTRACT FROM AUTHOR]

Concerning environmental issues, including global warming and the reduction of hydrocarbon assets, the utilization of environmentally sustainable energy production is imperative nowadays. In this regard, water electrolysis is considered the most prominent and ecologically sustainable technique for the production of hydrogen. However, owing to its sluggish OER, designing electrode materials with remarkable efficiency becomes crucial for boosting the functioning of water electrolysis. In the present investigation, we successfully developed the SnSe catalyst incorporated into graphitic carbon nitride (g-CN) via a simple hydrothermal approach. The various approaches were used to characterize g-CN/SnSe nanocomposite. Meanwhile, g-CN/SnSe nanocomposite demonstrated exceptional catalytic properties for OER under 1.0 M alkaline electrolyte (KOH), which exhibited low overpotential (241 mV) to obtain ideal j (10 mA cm−2) and an exceptional stability (20 h). It also demonstrated a low onset potential (1.27 V), a significant electrochemical active surface area (ECSA) of 592.5 cm2 and an impressive Tafel value (38 mV dec−1), significantly superior to the pure SnSe nanomaterial. The observed improved performance can be attributed to enhanced morphological properties and significant surface area. The above-reported nanocomposite (g-CN/SnSe) shows great potential for OER and other electrochemical systems because of its numerous active sites, faster electron transfer process, exceptional durability and good electrical conductivity. [ABSTRACT FROM AUTHOR]

The present work deals with the hydrothermal synthesis of a Na-A (LTA) zeolite using rice husk as a starting material. The focus was on defining the most favorable conditions for the synthesis of zeolite Na-A from rice husk in order to economize on both energy (i.e., synthesis temperatures) and reaction time and to enlarge the field of the pure and isolated synthesized phase. Four sets of experiments were carried out at environmental pressure temperatures varying from 40 °C to 85 °C with a SiO2/Al2O3 ratio from 1.75 to 3.5. Optimal conditions for crystallization of the Na-A zeolite from rice husk were reached at 60 °C with a SiO2/Al2O3 ratio of 1.75. Sixty degrees Celsius represents the minimum known temperature used for the synthesis of NaA zeolite from rice husk. The products of synthesis were characterized by X-ray diffraction, scanning electron microscopy, infrared and Raman spectroscopy. The purity of the synthesized zeolite is verified here for the first time through quantitative phase analysis using the combined Rietveld and reference intensity ratio methods. [ABSTRACT FROM AUTHOR]

Introduction of mesopore system into zeolite crystals is always deemed to be an effective strategy to improve diffusion and acidic accessibility. In this work, a hierarchically structured ZSM-5 with an ultra-small intracrystalline mesopore structure was prepared by using lysine as a pore-forming agent via a hydrothermal crystallization procedure. The structured and textured properties of the as-synthesized samples were characterized by XRD, SEM, EDS, TEM, NH3-TPD, FT-IR and N2 adsorption–desorption isothermals. The results showed that a purely-phased hierarchical ZSM-5 zeolite with a size of 2–6 nm mesopore can be obtained under the condition of lysine/Al2O3 = 2–8. The addition of lysine in the precursor not only generated an ultra-small mesopore system, but also had a significant effect on the acidity of the synthesized sample: With the increased amount of added lysine, the acid density and acid strength of the as-prepared zeolite catalyst were gradually weakened. The effects of the introduced hierarchical pore structure and the tailored acid sites on the catalytic performance of the catalysts were investigated during methanol dehydration to hydrocarbons reaction. The introduced hierarchical pores and the weakened strong acids significantly improved the stability of the catalyst. Meanwhile, the reduced acid density strongly inhibited hydrogen transfer of light olefins intermediate and then increased the selectivity toward light olefins on the hierarchical zeolite catalysts. [ABSTRACT FROM AUTHOR]

Owing to their flexibility and high thermal resistance, para-aramid based Kevlar™ fabric substrates are an ideal candidate for obtaining flexible gas sensors for new-generation wearable technologies. The morphology of the surface of the substrate where the target gas comes into contact directly affects the important features of the sensor such as detection limit, selectivity, and response. In this context, a feasible technique is introduced to enhance the efficiency of flexible gas sensors utilizing ZnO/Kevlar™, entailing the modification of ZnO morphology. ZnO based gas sensing layers were deposited on Kevlar™ fabric substrates by a two-stage method. Initially, seed layer was produced on Kevlar™ fabric using the ultrasonic bath method, with five different seed layer processing times ranging from 1 min to 20 min. In the nucleation, all nanostructured layers were deposited by hydrothermal method with constant parameters and under the same conditions. As the seeding time was increased, nanorods (1D) formed on the surface became flakes (2D), leading to considerable improvement in NH3 gas sensing properties. The sensor with a 5-min seeding time showed a sensitivity of 49 % at an optimal operating temperature of 190 °C, while the sensor produced in 20 min showed the best response performance with 169 % at 130 °C for 50 ppm NH3 gas. The increase in seeding time not only reduced the operating temperature of the gas sensor through the conversion from 1D nanostructure to 2D, but also significantly increased the sensor response. Under constant hydrothermal conditions and solution concentration, the density per unit area increases. However, after 10 min of seeding, the length of nanorods shortens and turn into a rod-flake hybrid morphology. A superior sensor performance was demonstrated for the samples examined. The obtained results also showed that flexible Kevlar™ fabric could be a feasible and interesting substrate for nanostructured ZnO-based NH3 gas sensors. [Display omitted] [ABSTRACT FROM AUTHOR]

Bimetallic nickel‐iron based oxides are regarded as one of the most promising catalysts for the oxygen evolution reaction (OER). In this study, we show that the precursor metal salts can affect the OER activity of the resulting Ni/Fe oxide under the same hydrothermal synthesis conditions. Pure sulfate, pure nitrate and mixed sulfate/nitrate metal salts were used to fabricate NiFe based oxide materials and to study the importance of the precursor choice for the OER. The results show that the nature of the precursor used in the synthesis of the bimetallic nickel‐iron materials can influence different multi‐phase catalysts to form which effects the OER. [ABSTRACT FROM AUTHOR]

The hydrothermal synthesis of Ba1−xCoxTiO3 (BCT) ceramic nanocrystals across varied substitution fractions (x = 0, ..., 1) is the subject of this study. Hydrothermal synthesis is well known for producing high-purity and well-crystallized nanocrystals. A thorough examination is conducted to examine the effects on the structural and electrical properties of the resultant BCT nanocrystals by altering the cobalt substitution fraction. X-ray diffraction (XRD) is used to analyze the structure, while complex impedance spectroscopy (CIS) is used to analyze the electrical properties. As the cobalt content rises, XRD examination reveals a smooth transition from the ferroelectric BaTiO3 phase to the ferromagnetic CoTiO3 phase, offering extensive insights into the phase composition and crystallographic alterations. This phase shift is important because it creates new opportunities to adjust the properties of the material for particular uses. The electrical activity of BCT nanocrystals is clarified further by CIS measurements. A distribution of relaxation times, frequently linked to complex microstructures or heterogeneous materials, is suggested by the detected non-Debye relaxation. A thermally activated conduction process, in which higher temperatures promote the passage of charge carriers, is suggested by the temperature-dependent increase in conductivity. This behavior is strongly dependent on the cobalt content, suggesting that cobalt enhances electrical conductivity and crystallinity through a catalytic effect. A frequency-dependent dielectric constant that rises with temperature and cobalt content is shown by investigating the dielectric characteristics of BCT nanocrystals. Improved polarization mechanisms inside the material are suggested by this increase in dielectric constant, which may be the result of cobalt ion presence. With a thorough grasp of the dielectric behavior, the examination of the loss angle further validates the non-Debye relaxation process. [ABSTRACT FROM AUTHOR]

Utilizing the full potential of reproducible biomass resources is crucial for the sustainable development of humanity. In this study, biochar (MPC) was prepared through the microwave-assisted pyrolysis of sugarcane bagasse. Subsequently, Co nanoparticles were introduced by microwave-assisted hydrothermal treatment to form a highly dispersive Co/MPC material. Characterization results indicated that Co nanoparticles were wrapped by thin carbon layers and uniformly dispersed on a carbon-based skeleton via a microwave-assisted hydrothermal synthesis approach, providing high-activity space. Thus, the prepared material was limited to glassy carbon; on the electrode surface, a cobalt-based sensing platform (Co/MPC/GCE) was built. On the basis of this constructed sensing platform, a linear equation was fitted by the concentration change of current signal I and H2O2. The linear range was 0.55–100.05 mM; the detection limit was 1.38 μM (S/N = 3); and the sensitivity was 103.45 μA cm−2 mM−1. In addition, the effect this sensor had on H2O2 detection of actual water samples was conducted by using a standard addition recovery method; results disclosed that the recovery rate and RSD of H2O2 in tap water samples were 94.0–97.6% and 4.1–6.5%, respectively. [ABSTRACT FROM AUTHOR]

A vanadium ion valence state constant high-entropy perovskite system was synthesized using the hydrothermal method with a trivalent vanadium ion as the vanadium source. The B-site of the perovskite crystal lattice was loaded with five atoms in equal proportions. We tried to synthesize the Sr(TiZrHfVNb)O3 high-entropy system using different methods. However, the valence state of the vanadium ion could only be kept constant using the hydrothermal process in the valence balanced high-entropy composition system. There was significant vanadium element segregation and second phase in the Sr(TiZrHfVNb)O3 system prepared using the solid-state reaction process. Also, obvious vanadium ion valence state ascending from V3+ to V5+ appeared in this high-entropy system with an increase in calcination temperature. Inconspicuous vanadium element segregation appeared at 900 °C, the significant segregation phenomenon and second phase appeared at 1200 °C, and the particle size increased with the temperature. This meant that the high-entropy value could not only stabilize the crystal phase, but also stabilize the ionic valence state. Moreover, the constant trivalent vanadium ion valence state could provide coordinated performance with a wide optical response range and a low band gap for the high-entropy system. This suggests that the system might grow a potential ceramic material for optical applications. [ABSTRACT FROM AUTHOR]

This study reports the synthesis of InVO4/α-Fe2O3 heterojunction photocatalysts with different stoichiometric ratios via a two-step hydrothermal synthesis reaction. The prepared photocatalysts were characterized by XRD, SEM, TEM, XPS, and other methods. The prepared composites exhibited good photocatalysis of tetracycline hydrochloride. Among the InVO4/α-Fe2O3 heterojunction photocatalysts with different ratios, the InVO4/0.25α-Fe2O3 photocatalyst showed the highest degradation rate for 20 mg L−1 tetracycline hydrochloride. After three photocatalytic runs, it still exhibited excellent stability and reusability. Meanwhile, this study also found that superoxide radical anion (-O2−), electron (e−), hydroxyl radical (·OH), and photogenerated hole (h+) are the basic active substances in the photocatalytic process. [ABSTRACT FROM AUTHOR]

VO 2 @C core–shell structure is designed and prepared to boost the NH 4 + storage of VO 2. VO 2 @C core–shell composite delivers a specific capacity of ∼300 mAh/g at 0.1 A/g, superior to the values of VO 2 (∼238 mAh/g). [Display omitted] Aqueous nonmetallic ion batteries have garnered significant interest due to their cost-effectiveness, environmental sustainability, and inherent safety features. Specifically, ammonium ion (NH 4 +) as a charge carrier has garnered more and more attention recently. However, one of the persistent challenges is enhancing the electrochemical properties of vanadium dioxide (VO 2) with a tunnel structure, which serves as a highly efficient NH 4 + (de)intercalation host material. Herein, a novel architecture, wherein carbon-coated VO 2 nanobelts (VO 2 @C) with a core–shell structure are engineered to augment NH 4 + storage capabilities of VO 2. In detail, VO 2 @C is synthesized via the glucose reduction of vanadium pentoxide under hydrothermal conditions. Experimental results manifest that the introduction of the carbon layer on VO 2 nanobelts can enhance mass transfer, ion transport and electrochemical kinetics, thereby culminating in the improved NH 4 + storage efficiency. VO 2 @C core–shell composite exhibits a remarkable specific capacity of ∼300 mAh/g at 0.1 A/g, which is superior to that of VO 2 (∼238 mAh/g) and various other electrode materials used for NH 4 + storage. The NH 4 + storage mechanism can be elucidated by the reversible NH 4 + (de)intercalation within the tunnel of VO 2 , facilitated by the dynamic formation and dissociation of hydrogen bonds. Furthermore, when integrated into a full battery with polyaniline (PANI) cathode, the VO 2 @C//PANI full battery demonstrates robust electrochemical performances, including a specific capacity of ∼185 mAh·g−1 at 0.2 A·g−1, remarkable durability of 93 % retention after 1500 cycles, as well as high energy density of 58 Wh·kg−1 at 5354 W·kg−1. This work provides a pioneering approach to design and explore composite materials for efficient NH 4 + storage, offering significant implications for future battery technology enhancements. [ABSTRACT FROM AUTHOR]

A hydrothermal method was employed to synthesize the precursor of nano-zirconium carbide, which was subsequently heat treated at high temperatures under vacuum to obtain finely dispersed nanometer-sized zirconium carbide powder through a carbothermic reduction reaction. Scanning Electron Microscopy (SEM) was utilized to examine the microstructure of the precursors obtained under different hydrothermal conditions and carbon contents. The effects of different heat treatment temperatures on the microstructure of the products were analyzed. Transmission Electron Microscopy (TEM) confirmed the boundary coating structure of the hydrothermal precursor and provided insights into the phase structure of the nanometer-sized zirconium carbide. The reaction mechanism and temperature involved in the carbothermic reaction process were determined through calculations. Furthermore, the energy, phase and microstructure of the reaction were investigated using Thermogravimetric Analysis (TG-DSC) and X-ray Diffraction (XRD) at different temperatures. The obtained results revealed that the zirconium carbide precursor was synthesized via the hydrothermal method exhibited a core-shell structure with a boundary coating, which not only ensured uniform contact between C and ZrO 2 particles but also facilitated the formation of zirconium carbide. The results show that the most suitable process parameters are Zr/C 1: 7, 240 °C and 24 h. The thermodynamic calculation results show that ZrO 2 combines with carbon to form CO and ZrC when the temperature reaches 1656.56 °C. As the temperature rises, CO reacts with ZrO 2 to form ZrC and CO 2. TG-DSC shows that the carbothermal reduction reaction starts at 1100 °C and reaches its peak at 1418 °C. XRD analysis confirms that when the temperature reached 1450 °C ZrC appeared. At 1600 °C, the phase transition of ZrC is basically completed. TEM images showed that the synthesized zirconium carbide particles were about 30 nm. [ABSTRACT FROM AUTHOR]

Hydrogen zirconium phosphate (HZP) is a ceramic material with the formula HZr 2 (PO 4) 3 that can potentially offer anhydrous protonic conductivity, with thermostability for the intrinsic protons up to 650 °C, and good chemical stability in aqueous environments or acid gases. Despite the attraction of these features for electrolyte applications, such as gas separation, fuel cells or electrolysers, work on this material remains in its infancy. A possible reason for this lack of attention may be related to the complexity to obtain the HZP material as a pure phase. For this reason, the current article examines a new hydrothermal synthesis method to produce the ammonium precursor, NH 4 Zr 2 (PO 4) 3 , in its phase pure form, and consequently a refined overall route to produce the desired HZP target material. In the synthesis of the ammonium precursor, we underscore the precise control of reaction conditions that are necessary to obtain the pure NH 4 Zr 2 (PO 4) 3 material, both in its cubic and hexagonal structural polymorphs. For reaction times of 10 h, the cubic phase is obtained by employing a hydrothermal temperature of 150 °C and an aqueous ammonia volume of 2.1 mL, while the hexagonal phase is obtained for a hydrothermal temperature of 200 °C and an aqueous ammonia volume between 2.3 and 2.4 mL. Subsequently, we investigate the required conditions to convert hexagonal NH 4 Zr 2 (PO 4) 3 fully to hexagonal HZr 2 (PO 4) 3 via thermal treatment at 600 °C for 5 h, assessed by a combination of X-ray diffraction and infrared spectroscopy. In this way this article aims to open up further research on this interesting HZP material by documenting a robust route for its preparation. [ABSTRACT FROM AUTHOR]

Hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs) are crucial for renewable energy production. Developing stable, cost-effective, and highly catalytic HER and OER electrocatalysts is paramount. In this study, a combination of hydrothermal synthesis and annealing was used to fabricate nickel sulfide (Ni3S2) particle–embedded nanotubes supported on nickel (Ni) foam (Ni3S2 PN/NF). The Ni3S2 PN/NF structures featured a highly branched morphology with a large specific surface area, surpassing that of conventional Ni metal nanotubes. This design increased the number of reactive sites and enhanced the charge-transfer process. The Ni foam substrate expanded the contact area of Ni3S2, thereby improving conductivity and facilitating the adsorption/desorption of intermediates on the Ni3S2 surface. Density functional theory calculations showed that the electronic structure of Ni3S2 provides excellent conductivity. Moreover, the multi-branched structure and inherent conductivity of the NiS nanomaterials enhanced the Ni3S2 PN/NF performance in 1M KOH, with overpotentials of 87 and 210 mV with iR compensation at 10 mA cm−2 for the HER and OER, respectively. The synthesized Ni3S2 PN/NF also exhibited robust durability for 20 h. These results demonstrate that Ni3S2 PN/NF is an excellent catalyst for both HER and OER. [ABSTRACT FROM AUTHOR]

Background: Alveolar bone augmentation is a complex process influenced by a multitude of factors. The materials applied in augmentation procedures must be confirmed as non-toxic, and their physicochemical properties should allow proper bone reconstruction. The specifics of oral surgical procedures require the use of regenerative biomaterials with antimicrobial properties. This study focuses on the physicochemical characteristics of chosen nanosized biomaterials, as well as their cytotoxicity and antimicrobial properties. Methods: nanosized hydroxyapatite and fluorapatite (abbreviated as nHAp and nFAp) pellets were manufactured using a microwave hydrothermal synthesis method. The impact on Candida albicans, Streptococcus mutans, and Lactobacillus rhamnosus strains activity and adherence to apatites was tested. Cytotoxic evaluation was performed based on the differentiation process of MC3T3 cells. The effectiveness of MC3T3 differentiation was confirmed by Alizarin Red staining. Results: Contact with both biomaterials caused a reduction in the mean microbial count of S. mutans and C. albicans strains, as observed. Studied biomaterials demonstrated enhanced proliferation of MC3T3 cells, with the exception of the 1:1 nFAp concentration. Conclusions: Both biomaterials enhance the proliferation of fibroblasts and limit the activity of specific oral pathogens in vitro. The research clearly demonstrates the advantage of nFAp over nHAp, with a notable reduction in microbial count of Candida albicans and Streptococcus mutans over time. The lowest microbial count reduction was observed in the case of L. rhamnosus. Further research is required in order to fully understand the specifics of nHAp and nFAp antimicrobial action. However, the results were found to be more favourable for nFAp biomaterial. [ABSTRACT FROM AUTHOR]

Abstract In this work, we reported the synthesis of honey bee (Apis mellifera) venom-derived nanoparticles via a hydrothermal method. This method not only ensures the preservation of the bee venom’s bioactive components but also enhances their potential stability, thus broadening the scope for their applications in the biomedicinal field. The synthesis method started with the homogenization suspension of bee venom, followed by its hydrothermal process to synthesize bee venom nanoparticles (BVNPs). The successful synthesis of BVNPs was characterized using various characteristic techniques such as Ultraviolet–visible (UV–Vis) spectroscopy, Fourier Transforms Infrared (FTIR) Spectroscopy, Zeta Potential (ZP), Liquid Chromatography-Mass Spectrometry (LCMS), and Transmission Electron Microscopy (TEM). The synthesis of BVNPs through biosynthesis is shown by the visible violet-brown color development at 347 nm by UV–Vis spectroscopy. FTIR analysis revealed the presence of several functional groups in the BVNPs, including alcohols (–OH), phenols (C6H5–), carboxylic acids (–COOH), amines (–NH2, –NH–), aldehydes (–CHO), ketones (–CO–), nitriles (–CN), amides (–CO–N–), imines (–CNH–), esters (–COO–), and polysaccharides. These functional groups, as confirmed by their specific stretching and bending vibrational modes, contribute to the diverse biological activities of BVNPs, including cytotoxicity against MCF-7 breast cancer cells. The ZP of the BVNPs indicated good colloidal stability at − 45 mV. LCMS analysis confirmed the presence of major bioactive molecules, including melittin & apamin and TEM analysis shows the BVNPs exhibited a quasi-spherical shape with good dispersion, the average size was approximately 25 nm, with some being smaller (quantum dots) and interplanar spacing of 0.236 nm indicated a highly ordered crystalline structure. Moreover, the anticancer efficacy of the BVNPs was ascertained through in vitro assays against MCF-7 breast cancer cells, showing a dose-dependent cytotoxic effect. The findings of this study underscore the viability of hydrothermal synthesis in producing biologically active and structurally stable BVNPs, with a significant potential for anticancer activities. Graphical Abstract

Abstract Infections originating from pathogenic microorganisms can significantly impede the natural wound-healing process. To address this obstacle, innovative bio-active nanomaterials have been developed to enhance antibacterial capabilities. This study focuses on the preparation of nanocomposites from thermally reduced graphene oxide and zinc oxide (TRGO/ZnO). The hydrothermal method was employed to synthesize these nanocomposites, and their physicochemical properties were comprehensively characterized using X-ray diffraction analysis (XRD), High-resolution transmission electron microscopy (HR-TEM), Fourier-transform infrared (FT-IR), Raman spectroscopy, UV-vis, and field-emission scanning electron microscopy (FE-SEM) techniques. Subsequently, the potential of TRGO/ZnO nanocomposites as bio-active materials against wound infection-causing bacteria, including Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, was evaluated. Furthermore, the investigated samples show disrupted bacterial biofilm formation. A reactive oxygen species (ROS) assay was conducted to investigate the mechanism of nanocomposite inhibition against bacteria and for further in-vivo determination of antimicrobial activity. The MTT assay was performed to ensure the safety and biocompatibility of nanocomposite. The results suggest that TRGO/ZnO nanocomposites have the potential to serve as effective bio-active nanomaterials for combating pathogenic microorganisms present in wounds.

This study explores the influence of hydrothermal temperatures on the synthesis of ZnO-Bentonite composites and their efficiency in the adsorption and photodegradation of Methylene Blue dye. ZnO nanoparticles were integrated into Na-Bentonite, with composites synthesized at hydrothermal temperatures of 100°C and 200°C. Various characterization techniques such as XRD, FTIR, UV-Vis DRS, TG-DTA and BET were utilized to analyze the structural and thermal properties. The results show that the composite synthesized at 200°C exhibits superior performance, with a maximum adsorption capacity of 120.48 mg/g at 50°C, significantly higher than the 49.26 mg/g achieved by the composite synthesized at 100°C. Moreover, the enhanced crystallinity and increased surface area, as evidenced by a 16 nm crystallite size at 100°C and 22 nm at 200°C, led to improved photocatalytic activity. The research concludes that higher hydrothermal temperatures improve both adsorption and photodegradation efficiency, making the composite synthesized at 200°C more effective for environmental applications.

The hydrothermal synthesis of Ba1−xCoxTiO3 (BCT) ceramic nanocrystals across varied substitution fractions (x = 0, …, 1) is the subject of this study. Hydrothermal synthesis is well known for producing high-purity and well-crystallized nanocrystals. A thorough examination is conducted to examine the effects on the structural and electrical properties of the resultant BCT nanocrystals by altering the cobalt substitution fraction. X-ray diffraction (XRD) is used to analyze the structure, while complex impedance spectroscopy (CIS) is used to analyze the electrical properties. As the cobalt content rises, XRD examination reveals a smooth transition from the ferroelectric BaTiO3 phase to the ferromagnetic CoTiO3 phase, offering extensive insights into the phase composition and crystallographic alterations. This phase shift is important because it creates new opportunities to adjust the properties of the material for particular uses. The electrical activity of BCT nanocrystals is clarified further by CIS measurements. A distribution of relaxation times, frequently linked to complex microstructures or heterogeneous materials, is suggested by the detected non-Debye relaxation. A thermally activated conduction process, in which higher temperatures promote the passage of charge carriers, is suggested by the temperature-dependent increase in conductivity. This behavior is strongly dependent on the cobalt content, suggesting that cobalt enhances electrical conductivity and crystallinity through a catalytic effect. A frequency-dependent dielectric constant that rises with temperature and cobalt content is shown by investigating the dielectric characteristics of BCT nanocrystals. Improved polarization mechanisms inside the material are suggested by this increase in dielectric constant, which may be the result of cobalt ion presence. With a thorough grasp of the dielectric behavior, the examination of the loss angle further validates the non-Debye relaxation process.

[Display omitted] • The S=O bond formed via hydrothermal method tightly binds oxygen-rich vacancy WO 3 with N -doped Zn 0.6 Cd 0.4 S. • Oxygen vacancies introduced into WO 3 serve as bridging sites, facilitating a closer interaction with N -doped Zn 0.6 Cd 0.4 S. • An efficient Z-scheme charge transfer mechanism was formed in the composites. • An excellent hydrogen evolution activity of 21.98 mmol·g−1 was obtained under visible light irradiation. Photocatalytic water splitting technology for H 2 production represents a promising and sustainable approach to clean energy generation. In this study, a high concentration of oxygen vacancies was introduced into tungsten trioxide (WO 3) to create a vacancy-rich layer. This modified WO 3 (WO 3-x) was then combined with N -doped Zn 0.6 Cd 0.4 S through a hydrothermal synthesis, resulting in the formation of a Z-scheme heterojunction composite aimed at enhancing photocatalytic performance. Under visible light, the H 2 production activity of the composite reached an impressive 8.52 mmol·g−1 without adding co-catalyst Pt. This corresponds to enhancements of 7.82 and 4.39 times the production yield of pure ZCS and ZCSN, respectively. However, the hydrogen production increased to 21.98 mmol·g−1 when Pt was added as a co-catalyst. Furthermore, an array of characterizations were employed to elucidate the presence of oxygen vacancies and the establishment of the Z-scheme heterojunction. This structural enhancement significantly facilitates the utilization of photo-generated electrons while effectively preventing photo-corrosion of ZCSN, thus improving material stability. Our study provides a new scheme for the incorporation of oxygen-rich vacancy and the construction of Z-scheme heterojunction, demonstrating a synergistic effect that greatly advances photocatalytic performance. [ABSTRACT FROM AUTHOR]

An intricately designed one-pot hydrothermal approach was utilized to synthesize yolk-shelled Co 3 Fe 1 glycerate, demonstrating its role as a highly efficient electrocatalyst for the oxygen evolution reaction. [Display omitted] • A convenient method to synthesize a range of CoFe gly with controllable surface morphologies. • The yolk-shell structure of Co 3 Fe 1 gly ensures uniformly distributed active sites, promoting efficient mass transfer. • Co 3 Fe 1 gly shows great potential for advancing electrode material development. CoFe-based catalysts are efficient electrocatalysts for the oxygen evolution reaction (OER) in alkaline media. Here, we present a simple one-pot hydrothermal method for synthesizing a series of CoFe glycerates with controllable surface morphologies and investigate their potential as highly efficient catalysts for the OER in alkaline media. These CoFe glycerates exhibit a unique yolk-shell microsphere structure assembled from ultrathin nanosheets. The adjustment of the surface nanosheet size is achieved by varying the CoFe ratio, ensuring a more efficient electrocatalytic system for the OER process. Due to the abundant active sites provided by the yolk-shell structure and interleaved ultrathin nanosheets, Co 3 Fe 1 glycerate (Co 3 Fe 1 gly) demonstrates a low overpotential (283 mV) and a small Tafel slope (44.61 mV dec−1) at 10 mA cm−2. Additionally, Co 3 Fe 1 gly exhibits excellent durability in alkaline electrolytes. Moreover, a series of characterizations demonstrate that the active sites of Co 3 Fe 1 gly are the high-valence Co species generated during the OER process. This study opens a promising avenue for utilizing efficient and low-cost electrocatalysts to enhance OER performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A unique carbon coating Ge nanospheres with a cubic hollow structure (Ge@C) is controllably designed and synthesized by using low-cost GeO 2 as precursor. • The hollow Ge@C nanostructure not only provides abundant internal space to alleviate volumetric expansion of Ge, but also facilitates the transmission of Li+ and electrons. • The hollow Ge@C shows very superior lithium storage performance with enhanced Li+ adsorption ability and low Li+ diffusion energy barrier. • This work is a very important breakthrough for the development of high-performance Ge based anode for lithium ion batteries. Germanium based nanomaterials are very promising as the anodes for the lithium ion batteries since their large specific capacity, excellent lithium diffusivity and high conductivity. However, their controllable preparation is still very difficult to achieve. Herein, we facilely prepare a unique carbon coating Ge nanospheres with a cubic hollow structure (Ge@C) via a hydrothermal synthesis and subsequent pyrolysis using low-cost GeO 2 as precursors. The hollow Ge@C nanostructure not only provides abundant interior space to alleviate the huge volumetric expansion of Ge upon lithiation, but also facilitates the transmission of lithium ions and electrons. Moreover, experiment analyses and density functional theory (DFT) calculations unveil the excellent lithium adsorption ability, high exchange current density, low activation energy for lithium diffusion of the hollow Ge@C electrode, thus exhibiting significant lithium storage advantages with a large charge capacity (1483 mAh/g under 200 mA g−1), distinguished rate ability (710 mAh/g under 8000 mA g−1) as well as long-term cycling stability (1130 mAh/g after 900 cycles under 1000 mA g−1). Therefore, this work offers new paths for controllable synthesis and fabrication of high-performance Ge based lithium storage nanomaterials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical core-shelled CoMo-LDH@CuCo 2 S 4 NWAs/NF is prepared by hydrothermal synthesis and electrodeposition. • The electrode exhibits a high specific capacity of 1265.9 C g−1 at 1 A g−1. • The electrode shows a 92.2% capacity retention ratio at 10 A g−1 after 10, 000 cycles. • The energy density of the assembled HSC device is 52.2 Wh kg−1 at the power density of 983.9 W kg−1. The development of core-shelled heterostructures with the unique morphology can improve the electrochemical properties of hybrid supercapacitors (HSC). Here, CuCo 2 S 4 nanowire arrays (NWAs) are vertically grown on nickel foam (NF) utilizing hydrothermal synthesis. Then, CoMo-LDH nanosheets are uniformly deposited on the CuCo 2 S 4 NWAs by electrodeposition to obtain the CoMo-LDH@CuCo 2 S 4 NWAs/NF electrode. Due to the superior conductivity of CuCo 2 S 4 (core) and good redox activity of CoMo-LDH (shell), the electrode shows excellent electrochemical properties. The electrode's specific capacity is 1271.4 C g−1 at 1 A g−1, and after 10, 000 cycles, its capacity retention ratio is 92.2 % at 10 A g−1. At a power density of 983.9 W kg−1, the CoMo-LDH@CuCo 2 S 4 NWAs/NF//AC/NF device has an energy density of 52.2 Wh kg−1. This indicates that CoMo-LDH@CuCo 2 S 4 /NF has a great potential for supercapacitors. [ABSTRACT FROM AUTHOR]

In the present study, we have developed molybdenum diselenide (MoSe2) nanosheets via an effective hydrothermal process by varying synthesis temperatures in a high-yield production. XRD results illustrate that all the products indexed to a hexagonal crystal phase of MoSe2 (2H-MoSe2) with crystallite sizes around 7 nm. TEM and HRTEM images confirmed a high-quality crystalline feature of MoSe2 nanosheets. Interestingly, the identified interplanar spacing of 0.61 nm corresponds to a well-organized atomic-scale arrangement with (hkil: 0002) plane of 2H-MoSe2 crystal. Additionally, Moiré fringes of different periodicities are clearly visible in some crystalline regions suggesting that MoSe2 nanosheets are well crystallized. The selected area electron diffraction patterns elucidate ring-like diffraction patterns indicating the polycrystalline nature of all the prepared MoSe2 nanosheets. UV–Vis absorption spectra scrutinize the mechanism for photo-response phenomenon and the observed excitonic peaks evidently demonstrate that the synthesized MoSe2 is in a semiconducting 2H phase with an optical bandgap ranging from 1.78 to 1.93 eV. Moreover, MoSe2 nanosheets possess a prominent methylene blue (MB) dye adsorption capacity of 50–70% and 54–83% in lower and higher adsorption times, respectively. In a nutshell, this study reveals the potential environmental application in the adsorption of organic dye MB in wastewater of hydrothermally produced MoSe2 nanosheets with structural and optical properties. [ABSTRACT FROM AUTHOR]

Like-caviar molybdenum ferrite nanoparticles (MoFe2O4 NPs) have been successfully synthesized via a hydrothermal route in the presence of the negative surfactant (sodium dodecyl sulfate (SDS)). SDS acts as a template, stabilizer, and stops the aggregating process through storage. The mean crystal size of MoFe2O4 NPs rises with decorating it with Al2O3. Based on SEM analysis, the shapes of MoFe2O4, Al2O3, and their composite demonstrated like-caviar, like-brain cells, and like-grains, respectively. Al2O3 has been chosen to incorporate with spinel MoFe2O4 to make it color more light, this crucial step is necessary to enhance their optical characteristics. FTIR spectra observed the MoFe2O4 NPs are inverse spinel. The photo-decolorization test employs indigo carmine (IC) as a model pollutant. The quantum yields (Φ) of IC dye decolorization with studied photocatalysts are low, which may be created by quencher materials, dimerization of dye molecules, and photophysical deactivation processes (ISC process). Moreover, the photocatalytic activity of using MoFe2O4 raised after being decorated with alumina, which revealed an increase in the surface acidity, hydroxyl group adsorption, size, band gap, pHpzc of MoFe2O4 from 2.9–3.6 to 4.2–5.9 after decorated alumina. This pH is suitable for decolorizing IC dye, which has a pH of solution equal to 5.3.

In this work, La-doped In2O3 microflowers were successfully prepared by a one-step hydrothermal method. Doping La into the In2O3 lattice causes lattice distortion of In2O3, leading to the change of morphology from cubic to nanosheets. The gas sensing tests show that La doping significantly improves the sensing performance to n-butanol compared to the pristine In2O3. 5% La-In2O3 exhibits the highest sensing response (~ 61.34 to 100 ppm n-butanol) among the various doping amounts of La, which is six times higher than that of the pristine In2O3 (~ 10.12) at the optimal operating temperature of 320 °C. This sample also show short response and recovery times, high selectivity and long-term stability. The enhanced sensing performance is mainly attributed to (1) the tunned bandgap by doping La, which effectively improves the electron transfer ability and produces a thicker electron depletion layer, and (2) the unique morphology and abundant lattice defects of the La-In2O3 samples, providing increased adsorption and reactive sites. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) stands out as an eco-friendly, cost-effective method for generating renewable carbon-based materials from biomass. The HTC process yields products such as hydrochars and carbon dots (CDs), possessed of notable photocatalytic capabilities due to their unique physicochemical features. Additionally, pairing traditional photocatalysts with hydrochar derivatives elevates their performance, rendering them more effective. Recent times have witnessed a surge in interest in these hydrochar based photocatalysts (HC-photocatalysts). Their appeal stems from multiple attributes: impeccable performance, adaptability to visible light, and adjustable physicochemical properties. This review delves deep into the evolving landscape of these HC-photocatalysts, segmenting them into three distinct categories: hydrochars, hydrochar-based CDs (HC-CDs), and hydrochar-based composites (HC-composites). For each category, we dissect their synthesis routes, unravel the photocatalytic mechanisms, and explore various enhancement strategies. We further traverse their versatile applications, spanning environmental treatment, disinfection, energy conversion, and organic synthesis. In the end, we spotlight the prevailing challenges and uncharted territories in the domain of HC-photocatalysts. In essence, this review serves as a guide, furnishing a theoretical foundation and steering directions for future explorations and tangible implementations of HC-photocatalysts. Highlights: Biomass can be converted into highly efficient photocatalysts by HTC. Photocatalytic mechanisms and modifications of hydrochars and HC-CDs are discussed. The roles of carbons in HC-composite photocatalysts are reviewed. HC-photocatalysts have shown various environmental, energy and other applications. Prospects and guidelines for theoretical and application research are listed. [ABSTRACT FROM AUTHOR]

The present study investigates the photocatalytic properties of hydrothermally synthesized TiO2 nanowires (NWs) for CO2 reduction in H2O vapor. It has been demonstrated that TiO2 NWs, thermally treated at 500–700 °C, demonstrate an almost tenfold higher yield of products compared to the known commercial powder TiO2 P25. It has been found that the best material is a combination of anatase, TiO2-B and rutile. The product yield increases with increasing heat treatment temperature of TiO2 NWs. This is associated with an increase in the degree of crystallinity of the material. It is shown that the best product yield of the CO2 reduction in H2O vapor is achieved when the TiO2 NW photocatalyst is heated to 100 °C. [ABSTRACT FROM AUTHOR]

In recent years, algae have emerged as a promising feedstock for biofuel production, due to their eco-friendly, sustainable, and renewable nature. Various methods, including chemical, biochemical, and thermochemical processes, are used to convert algal biomass into biofuels. Pyrolysis, a widely recognized thermochemical technique, involves high temperature and pressure to generate biochar and bio-oil from diverse algal sources. Various pyrolytic processes transform algal biomass into biochar and bio-oil, including low pyrolysis, fast pyrolysis, catalytic pyrolysis, microwave-assisted pyrolysis, and hydropyrolysis. These methods are utilized to convert a range of microalgae and cyanobacteria into biochar and bio-oil. In this publication, we will discuss catalytic pyrolysis using mesoporous materials, such as SBA-15. Mesoporous catalysts have earned significant attention for catalytic reactions, due to their high surface area, facilitating the better distribution of impregnated metal. Pyrolysis conducted in the presence of a mesoporous catalyst is viewed more as efficient, compared to reactions occurring within the smaller microporous cavities of traditional zeolites. SBA-15 supports with incorporated Zr and/or Ce were synthesized using the direct hydrothermal synthesis method. The catalyst was characterized using structural and morphological technical analysis and utilized for the pyrolysis reaction of the algal biomass. [ABSTRACT FROM AUTHOR]

This investigation explores the potential of enhancing aqueous zinc-ion batteries (AZIBs) through the introduction of a novel cathode material, NH4V4O10 (NVO), combined with reduced graphene oxide (rGO). Utilizing Density Functional Theory (DFT), it was hypothesized that the incorporation of rGO would increase the interlayer spacing of NVO and diminish the charge transfer interactions, thus promoting enhanced diffusion of Zn2+ ions. These theoretical predictions were substantiated by experimental data acquired from hydrothermal synthesis, which indicated a marked increase in interlayer spacing. Significantly, the NVO–rGO composite exhibits remarkable cyclic durability, maintaining 95% of its initial specific capacity of 507 mAh g−1 after 600 cycles at a current density of 5 A g−1. The electrochemical performance of NVO–rGO not only surpasses that of pristine NVO but also outperforms the majority of existing vanadium oxide cathode materials reported in the literature. This study underscores the effective integration of theoretical insights and experimental validation, contributing to the advancement of high-performance energy storage technologies. [ABSTRACT FROM AUTHOR]

In this study, a trisodium citrate (TSC)-assisted hydrothermal method is utilized to prepare three-dimensional hydroxyapatite (3D HA). Understanding the role of TSC in the preparation of 3D HA crystals may provide valuable methods to design advanced biomaterials. As one of the indexes of solution supersaturation, the initial pH (ipH) value can not only directly affect the nucleation rate, but also affect the growth of HA crystals. In this work, the effect of the ipH on the microstructure, particle size distribution, and specific surface area of the 3D HA is explored. Results showed that the morphology of 3D HA transformed from a bundle to a dumbbell ball and then a dumbbell with an increase in the ipH. A corresponding mechanism of such a structural evolution was proposed, providing inspiration for the fabrication of innovative 3D HA structures with enhanced biological functionality and performance. [ABSTRACT FROM AUTHOR]

In this work, β-NiS nanoparticles (NPs) were efficiently prepared by a straightforward hydrothermal process. The difference in morphology between these NiS NPs was produced by adding different amounts of thiourea, and the corresponding products were denoted as NiS-15 and NiS-5. Through electrochemical tests, the specific capacity (Cs) of NiS-15 was determined to be 638.34 C g−1 at 1 A g−1, compared to 558.17 C g−1 for NiS-5. To explore the practical application potential of such β-NiS NPs in supercapacitors, a hybrid supercapacitor (HSC) device was assembled with activated carbon (AC) as an anode. Benefitting from the high capacity of the NiS cathode and the large voltage window of the device, the NiS-15//AC HSC showed a high energy density (Ed) of 43.57 W h kg−1 at 936.92 W kg−1, and the NiS-5//AC HSC provided an inferior Ed of 37.89 W h kg−1 at 954.79 W kg−1. Both HSCs showed excellent cycling performance over 6000 cycles at 10 A g−1. The experimental findings suggest that both NiS-15 and NiS-5 in this study can serve as potential cathodes for high-performance supercapacitors. This current synthesis method is simple and can be extended to the preparation of other transition metal sulfide (TMS)-based electrode materials with exceptional electrochemical properties. [ABSTRACT FROM AUTHOR]