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Nanomaterials are emerging as important contributors in various applications and can be used especially in environmental catalysis. Herein, a brief summary on the basic knowledge of supercritical hydrothermal synthesis (SCWHS) is presented, including the synthesized functional nanomaterials, the effects of different experimental conditions on the properties of nanoparticles, and examples of their applications in environmental catalysis, highlighting the environmental and economic advantages of SCWHS. This review focuses on supercritical water as an environmentally friendly particle engineering tool for the production of high-quality, high-yield nanoparticles and the possibility of achieving their continuous production in industry. Nanoparticles are nucleated within a short time and their particle size can be controlled by SCWHS. Therefore, attention is given to the relationship between the formation and experimental conditions, as well as the properties of the obtained material in terms of particle size, surface area, crystallinity, morphology and surface properties. In addition, SCWHS can combine organic wastewater treatment, waste resource utilization and nanoparticle synthesis, and the in situ-generated nanoparticles can promote the oxidation of organic wastewater and the resourceful conversion of solid wastes as well as have production value as a by-product. The work may provide guidance for the further development of SCWHS, preparation of functional nanomaterials, and exploration of multiple 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]

Abiotic synthesis of CH 4 in seafloor hydrothermal fluids is generally assumed to occur via heterogeneous reactions on mineral surfaces. Stepwise homogeneous reduction of CO 2 has, however, been suggested as an alternative (but sluggish) abiotic pathway to CH 4 , potentially via metastable species of intermediate oxidation states. In this study, we examine the effect of two temperature-dependent methylated species − methanol (CH 3 OH) and methanethiol (CH 3 SH), on homogeneous CH 4 formation rates under long-term simulated hydrothermal conditions. Aqueous solutions containing formic acid (H13COOH, generating 13CO 2 and H 2) were heated with and without H 2 S at 300–325 °C (35 MPa) in a flexible Au reaction cell over several years without added minerals. Substantial 13C-labeled CH 4 and CH 3 OH production from 13CO 2 was observed over 4.3 yr, with aqueous CH 4 formation varying with CH 3 OH abundance – a strong function of dissolved H 2 abundance and, inversely, temperature. CH 4 production was slower at 325 °C with lower CH 3 OH concentrations (in equilibrium with CO 2 and H 2), and faster at 300 °C, accompanying an equilibrium-controlled increase in CH 3 OH. Fastest CH 4 production occurred at 300 °C following injection of H 2 S and H13COOH, which led to rapid formation (<4 days) of 13C-labeled CH 3 SH that subsequently decomposed over a further 0.8 yr, partly to 13CH 4. Heating aqueous 13CH 4 to 345–387 °C (33–35 MPa) in the presence of an oxidizing hematite-magnetite-pyrite assemblage, however, yielded no detectable CH 3 SH after 112 days indicating the reverse reaction is inhibited under favorable thermodynamics. Neither direct reduction of CO 2 to CH 3 SH nor CO 2 -CH 3 SH equilibrium were evident at 300 °C, implying CH 3 SH and CH 3 OH play disparate roles in homogeneous carbon reduction to CH 4. Longer chain hydrocarbons (C 2+ alkanes) remained low throughout the experiments. CH 3 SH abundances previously reported in vent fluids at the Von Damm hydrothermal field correlate strongly with demonstrably abiotic HCOOH there, suggesting the reduction of HCOOH to CH 3 SH observed in this study may also occur in vent fluids. A comparison of mineral-free 13CH 4 production rates reported here with 13CO 2 reduction experiments involving minerals indicates that homogeneous reduction proceeds at similar rates to purported transition metal-catalyzed 13CH 4 production, and is generally faster than experiments with either added olivine or ultramafic rock. Previous claims of substantial mineral-catalyzed abiogenic CH 4 production are therefore not supported by our study. Homogeneous CO 2 reduction may be a significant source of methylated compounds and CH 4 in hydrothermal fluids characterized by decadal (or longer) residence times, such as those found in mineral-hosted inclusions or occluded fractures in igneous basement, requiring only moderate temperatures and abundant H 2 to proceed. [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]

The development of advanced efficient and durable non-precious metal-based anode catalysts for photo-assisted direct methanol fuel cells remains a significant challenge. In this study, Ce-doped Co3O4 (Ce–Co3O4) was prepared by a three-step process involving hydrothermal synthesis, cation exchange and calcination. The introduction of Ce can not only induce more Co3+ with oxidation properties, but also expand the light absorption range and improve the separation efficiency of photogenerated electron–hole pairs. In an alkaline solution and under visible light irradiation, Ce–Co3O4 showed high current density (31.4 A g−1), high photo-response current (3.52 A g−1) and good long-term stability (the current density retention was 82% after 13 h under visible light irradiation). The reaction mechanism for the photo-assisted methanol oxidation was investigated by a series of optical characterization studies (UV-vis diffuse reflectance spectroscopy, Mott–Schottky, photoluminescence spectroscopy, and electron paramagnetic resonance). The results indicated that the strong oxidative photogenerated hole (h+), ˙OH, and ˙O2− were beneficial for the oxidation of methanol and COads. This study provides a good idea for the design of efficient non-precious metal based anode catalysts for photo-assisted direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

The preparation of synthetic (Zr,U)SiO4 solid solution is challenging, as the conventional high-temperature solid-state method limits the solubility of uranium (4 ± 1 mol%) in the orthosilicate phase due to its thermodynamic instability. However, these compounds are of great interest as a result of (Zr,U)SiO4 solid solutions, with uranium contents exceeding this concentration, being observed as corium phases formed during nuclear accidents. It has been identified that hydrothermal synthesis pathways can be used for the formation of the metastable phase, such as USiO4. The investigation carried out in this study has indeed led to the confirmation of metastable (Zr,U)SiO4 compounds with high uranium contents being formed. It was found that (Zr,U)SiO4 forms a close-to-ideal solid solution with uranium loading of up to 60 mol% by means of hydrothermal treatment for 7 days at 250 °C, at pH = 3 and starting from an equimolar reactant concentration equal to 0.2 mol L−1. A purification procedure was developed to obtain pure silicate compounds. After purification, these compounds were found to be stable up to 1000 °C under an inert atmosphere (argon). The characterisation methods used to explore the synthesis and thermal stability included powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and Raman spectroscopies, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). [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]

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]

Herein, an aromatic ring aldehyde (salicylaldehyde, SL) was grafted onto the biopolymer matrix of the magnetic chitosan (CS/Fe3O4) to yield a recoverable promising adsorbent for the removal of acid red 88 (AR88 dye) from aqueous media. Various characterization methods such as VSM, pHpzc, CHNS, XRD, SEM–EDX, FTIR, and BET were used to determine the physicochemical properties of CS-SL/Fe3O4. A Box-Behnken design (BBD) was adopted to optimize the experimental parameters of A: CS-SL/Fe3O4 dose (0.02–0.1 g), B: [AR88] concentration (10–50 mg/L), C: pH (4–10), and D: contact time (10–90 min) on the adsorption performance of CS-SL/Fe3O4 with the AR88 dye. The Freundlich isotherm and pseudo-second-order kinetic models were applicable to describe the dye adsorption rate of AR888. The maximum dye adsorption capacity (qmax) of the hydrothermally grafted CS-SL/Fe3O4 with AR88 was 137.3 mg/g at a fixed adsorbent dosage (0.09 g) and pH (4.16). Various intermolecular interactions such as electrostatic, π-π stacking, n-π interactions, and H-bonding contribute to AR88 adsorption by CS-SL/Fe3O4. This study introduces a recoverable and a promising magnetic grafted chitosan adsorbent for the removal of an anionic dye from aqueous media. Moreover, this adsorbent can be further applied to the removal of other types of water contaminants in aquatic environmental media. [ABSTRACT FROM AUTHOR]

Indonesia is an archipelagic country with two continents and an ocean, where it produces abundant marine products and the second largest marine source in the world, such as cuttlefish. Besides, it was for food, cuttlefish also produced shells as waste. Actually, this waste has been used for animal feed but in small scale. Others are still waste and cause pollution if not handled properly. Cuttlefish shell waste (CSW) is the basic ingredient for making hydroxyapatite (HA), while it was the main bone compound. Meanwhile, HA demand in the market is very high due to bone defects. The novelty of the research was to fulfil the increasing need for HA at low price and prevent air, water, and soil pollution by using circular economic principles (reused), and it has economic value. Synthesis HA was used microwave hydrothermal method. The CSW and coral were obtained from the pet market in Yogyakarta. They were crushed and calcined to the temperature of 900°C to obtain calcium oxide (CaO). Then, CaO was synthesized by microwave hydrothermal to obtain HA powder. Synthetic HA was characterized by the Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and thermogravimetric analysis (TGA). The Ca/P ratio of HA CSW and coral are 1.7 and 1.87, respectively. Moreover, coral HA has higher crystallinity than CSW (48%). The TGA shows that the highest weight loss occurred in HA CSW (16.57%). The conclusion is that both CSW and coral are raw materials used to produce HA. [ABSTRACT FROM AUTHOR]

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WO3 is a promising candidate material for gas sensors due to its simple preparation, convenient operation, diverse structure and high electron mobility. However, WO3 gas sensors often have problems such as high operating temperature, high-energy consumption and sensitive characteristics easily affected by environmental humidity. In this paper, an effective method to improve the gas sensitivity of WO3 gas sensor by using composite carbon nanomaterials is explored. The results show that the composite of WS2/WO3 and carbon spheres, C@WS2/WO3 composite gas-sensitive material shows good sensing performance for triethylamine (TEA) at low temperatures. In addition, excellent TEA selectivity, good stability, and good response recovery characteristics are also achieved. Compared with pure WS2/WO3 material, the sensor response of C@WS2/WO3 composite is as high as 24.6 at the optimal operating temperature of 240∘C, compared with 21.81 of pure WS2/WO3 material. [ABSTRACT FROM AUTHOR]

White metatitanic acid H2TiO3 (HTO)/TiO2 composites with co‐exposed [111]‐, {010} and {101} facets were successfully synthesized by employing the white suspension of [TMA+]2[TiO3]2− as the precursor via a hydrothermal soft chemical synthesis method in the presence or absence of 1‐ethyl‐3‐methylimidazolium bromide ([Emim]Br), 4‐bromine imidazole (Bmim) and 1‐methyl‐3‐propylimidazole tetrafluoroborate ([Pmim]BF4) ionic liquids. The structure, morphology, specific surface areas, microstructure, surface properties, and charge migration behaviors of HTO/TiO2 composites vary depending on the selected ionic liquid. The apparent rate constant of the Bmim‐HTO/TiO2 composite was the highest, at 0.0353 min−1, which was approximately 1.35, 1.38, 1.44, 2.67, and 88.25 times higher than that of [Pmim]BF4‐HTO/TiO2 (0.0262 min−1), [Emim]Br‐HTO/TiO2 (0.0256 min−1), No IL‐HTO/TiO2 (0.0245 min−1), CM‐TiO2 (0.0132 min−1) and Blank samples (0.0004 min−1), respectively. Compared with CM‐TiO2 and other HTO/TiO2 samples, the Bmim‐HTO/TiO2 composite featuring cuboid anatase TiO2 nanocrystals with co‐exposed [111]‐facets and {101} facets, exhibited superior photocatalytic activity in degrading methylene blue (MB) under ultraviolet light irradiation. This exceptional performance can be attributed to its cooperative effects, including a larger specific surface area, the co‐exposure of [111]‐ and {101} facets, a suitable heterojunction structure, and the most efficient charge carrier separation. This work introduces a hydrothermal soft chemical process for preparing HTO/TiO2 composite with controllable morphology and co‐exposed reactive facets, which holds promise for practical applications in removing organic pollutants from printing and dyeing wastewater. [ABSTRACT FROM AUTHOR]

Curcumin, known for its proapoptotic, chemo‐preventive, chemo‐therapeutic, antioxidant, anti‐inflammatory, anticancer, and antimicrobial properties, suffers from poor bioavailability, limiting its applications. This study aims to enhance curcumin's bioavailability using carbon dots (CDs) synthesized from fruit peels as a novel nano formulation. CDs were synthesized via hydrothermal synthesis using banana and orange peels as carbon sources, and functionalized with curcumin to improve its solubility and cellular uptake. The synthesis and functionalization of CDs were confirmed using Fluorescence spectrophotometer, FT‐IR, and HR‐TEM. The curcumin‐loaded CDs exhibited superior antimicrobial activity, with minimum inhibitory concentrations of 22 μg/mL for Staphylococcus aureus (S. aureus), 11 μg/mL for Bacillus subtilis (B. subtilis), and 22 μg/mL for Bacillus cereus (B. cereus). Additionally, the developed CDs demonstrated enhanced antioxidant activity compared to curcumin in DMSO. The findings indicate that curcumin‐loaded CDs significantly increase the biological activity of curcumin, offering a promising approach for its incorporation into functional foods, beverages, and pharmaceutical products. This study highlights the novel use of CDs to overcome the bioavailability issues of water‐insoluble bioactive compounds like curcumin, presenting a significant advancement in nano‐formulation technology. [ABSTRACT FROM AUTHOR]

Microporous aluminosilicate zeolites are useful industrial catalysts. However, their hydrothermal synthesis is a multistep process with complicated and unclear reactions, limiting their rational functional design. Herein, we compare the formation pathway and the structural and catalytic properties of several CHA zeolites to obtain fundamental knowledge for intentionally controlling the catalytic function of zeolites. Three CHA zeolites were synthesized using different starting silica/alumina sources in the presence of tetraethylammonium hydroxide as an inexpensive organic structure‐directing agent. FAU zeolite and an amorphous synthesis gel prepared using two different methods were used as starting materials. The obtained CHA zeolites were applied for exhaust gas purification (selective catalytic reduction of NOx with ammonia, NH3‐SCR), and their structural characteristics and formation pathways were investigated using a combination of analytical methods. Stepwise gel preparation (SGP), which divides the compositional control of the amorphous synthesis gel, promotes the decomposition of the initial additive (zeolite seed), resulting in the formation of CHA zeolites with abundant micropores and paired Al sites. This structural feature obtained using the SGP method improves the catalytic durability of the NH3‐SCR reaction. The present relationship, including different crystallization phenomena, structures, and catalytic abilities, provides useful insights into rational zeolite synthesis and its application. [ABSTRACT FROM AUTHOR]

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]

Transition metal oxide nanocomposites with heterostructures have gained a lot of attention for use in supercapacitors owing to their low cost, high surface area, fast transport of ions and electrons and high specific capacitance due to efficacious interplay between the electrode and the electrolytes. In this study, we fabricated tri-metallic Cu, Mn, Ni(CMNO), bi-metallic Mn, Ni(MNO) and mono-metallic Ni(NO) oxides through a facile hydrothermal route. All the fabricated materials were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDX), and their electrochemical properties were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge (GCD). The CMNO material showed remarkable electrochemical performance with a specific capacitance of 790.63 F g−1 at a current density of 1 A g−1, surpassing the performance of MNO (438.4 F g−1) and NO (290.82 F g−1). Furthermore, CMNO showed high cycling stability with a retention of 96.7% specific capacitance after 8000 cycles. Based on remarkable and unique properties, the CMNO material is regarded as a promising material for new-generation pseudo-capacitor applications. [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]

The hydrothermal carbonization (HTC) technique and subsequent pyrolysis were applied. Herein, two different types of biobased feedstocks, sucrose (Suc) and Miscanthus (Mis), were chosen. Urea served as N precursor for the in situ doping. HTC of Suc and Mis with urea leads to N‐doped hydrochars (N‐HCs). Suc and Mis decompose in different, complex degradation pathways, which leads to the emergence of N‐HCs consisting of distinct ratios of N‐containing primary chars (N‐PCs) and secondary chars (N‐SCs). After pyrolysis, maximum N contents of 5.6 wt % and 4.8 wt % of the N‐doped pyrolyzed hydrochar (N‐PHC) electrodes from Suc and Mis, respectively were reached. The role of PC and SC formation on the impact of N‐doping in the context of physicochemical properties of the N‐PHCs was compared with each other. In this study, they were tested with respect to the influence of N‐PCs and N‐SCs on their electrochemical performance in energy storage application. It turned out that the electrical conductivity (EC) and specific capacitances increased. Highest EC value of 129.1 S ⋅ cm−1 was obtained with N‐PHC based on Suc. Simultaneously, enhanced average specific capacitances of 47.0 F ⋅ g−1 at 5 mV ⋅ s−1 and 3.5 F ⋅ g−1 at 100 mV ⋅ s−1 are ascertained with N‐PHCs from Suc and Mis, respectively. [ABSTRACT FROM AUTHOR]

Hydrothermal synthesis is a technique which enables preparing many perovskites with specific crystal structures, chemical compositions, and morphologies. Thus, a bibliometric analysis of 1087 articles from the Scopus database (1975–2023) related to the keywords "perovskites" and "hydrothermal synthesis" was conducted using the VOSviewer software program. The results of the bibliometric analysis showed that the 1087 articles have 23,286 citations. Materials Letters has the highest number of publications (2.85%) regarding the journals in which these articles are published. China has the highest number of publications (34.50%) and citations (33.56%) related to these articles. Regarding the institutions affiliated with these articles, Jilin University in China concentrates 5.34% of the publications and 6.08% of the citations. In terms of authors, Han, G. has the highest number of publications (2.02%). Finally, the top three keywords with the highest number of occurrences were "perovskite", "hydrothermal synthesis" and "scanning electron microscopy". Based on bibliometric analysis, LaNiO 3 perovskites were chosen to evaluate the influence of hydrothermal synthesis parameters on their morphologies and, consequently, how these morphologies affect their applications. Thus, the temperature and time ranges used for the synthesis parameters were 160–230 °C and 6–48 h, respectively. Furthermore, the pH range used was 7.6–13, and the mineralizers used to adjust the pH were ammonia, potassium hydroxide, and sodium hydroxide. The temperature and time ranges used for the calcination parameters were 550–800 °C and 2–6 h, respectively. Additionally, LaNiO 3 perovskites obtained sphere, cube, rod, disc, and hollow morphologies. The soft templates used to obtain these morphologies were glycine, glycerin, isopropanol, polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), citric acid, and urea. The specific surface areas of the perovskites varied between 5.2 and 35.8 m2 g−1. Finally, the most common application for LaNiO 3 perovskites was the methane reforming for hydrogen production. [Display omitted] • Sphere-like morphology was the most designed for LaNiO 3 perovskites. • Reforming methane for hydrogen production was the most widely used application. • The catalytic properties of LaNiO 3 perovskites depend on their morphology. • Rod-LaNiO 3 showed the best catalytic performance in DRM, without carbon deposition. [ABSTRACT FROM AUTHOR]

Hydrogen is widely recognized as a renewable and clean energy source that has the potential to reduce dependence on fossil fuels. However, it is crucial to develop efficient, affordable, and sustainable electrocatalysts for hydrogen production through water splitting. To tackle this challenge, a bilayer Ni–Fe–Co-based sulfide was hydrothermally grown on Ni foam to boost the hydrogen evolution reaction (HER). SEM images revealed the micro-sized NiFe sheets decorated with NiCo nanosheets on the surface. The (NiFe/NiCo)S@NF electrocatalyst demonstrated outstanding performance towards HER in a 1 M KOH solution, where only a low overpotential of 185 mV vs. RHE was required at −10 mA/cm2, being considerably lower than those for NiFeS@NF (230 mV), NiCoS@NF (229 mV), NiFe@NF (237 mV) and NiCo@NF (256 mV) electrodes. This improvement could be attributed to the synergistic effect between constituents, the presence of Ni 3 S 2 and NiCo 2 S 4 phases, and the higher exposed area provided by the 3D nano/micro structure of the (NiFe/NiCo)S@NF electrocatalyst. Furthermore, this electrocatalyst exhibited the lowest Tafel slope of 76 mV/dec compared to NiFeS@NF (92 mV/dec), NiCoS@NF (87 mV/dec), NiFe@NF (89 mV/dec), and NiCo@NF (102 mV/dec), indicating its faster HER kinetics. Finally, in a two-electrode system of (NiFe/NiCo)S@NF||(NiFe/NiCo)S@NF, a low voltage of 1.58 V was required to obtain a current density of 10 mA/cm2 and the synthesized electrocatalyst had excellent stability over 12 h electrolysis. The achieved results proved that the (NiFe/NiCo)S electrocatalyst has great potential as a highly efficient electrode material for alkaline HER. [Display omitted] • Trimetallic sulfide electrocatalyst of (NiFe/NiCo)S@NF was synthesized using hydrothermal. • The composition of this electrocatalyst had a synergistic impact towards HER. • The hierarchical nano/micro structure contributed to the outstanding activity for HER. • This electrocatalyst exhibited stability during 12 h of electrolysis. [ABSTRACT FROM AUTHOR]

Two‐dimensional non‐layered tellurene (Te) can serve as a promising candidate in transistor applications because of its high carrier mobility and air stability. However, it is still quite challenging in aspect of ultra‐thin channel and gate‐control ability in conventional metal‐oxide‐semiconductor field‐effect transistor architecture. This work proposes a facile thinning strategy for solution‐proceed Te flakes and fabricates a junction field‐effect transistor (JFET) architecture, that has well addressed the above‐mentioned two issues. Through a mild oxidative thinning process, the post‐growth Te flakes are thinned from bulk to few‐layer, guaranteeing the highly efficient electrostatic doping as a transistor channel. Then, a four‐terminal JFET‐based on p‐Te and n‐ReS2 is designed, achieving a multifunctional integration of rectification diode, p‐ and n‐channel transistor in one single device. By accessing different contact scheme, the ReS2/Te p‐n diode is explored with a rectification ratio of 103, the p‐channel JFET exhibits a high hole mobility of 317.6 cm2V−1s−1, ideal low subthreshold swing of 84 mV dec−1. While the n‐channel JFET is obtained with electron mobility of 67.6 cm2 V−1s−1 and SS of 229 mV dec−1. Both p‐ and n‐channel devices showcase clear saturation characteristic with ultra‐small pinch‐off voltage (≈0.4 V), which is crucial for low‐power logical and integrated circuit applications. [ABSTRACT FROM AUTHOR]

ABSTRACT We present a groundbreaking technique for controllably synthesizing nanosized semiconductive two‐dimensional (2D) (Cu–S)n metal–organic framework (MOF)/graphene nanocomposites for electrochemical sensing of neurotransmitter 2‐phenethylamine (PEA). The (Cu–S)n MOF size is controlled by graphene oxide proportions, enhancing electrocatalytic activity. The modified electrode exhibits a surface area increase from 0.0639 to 0.1906 cm2 and impressive limit of detection (0.0156 and 0.004 μM) within linear ranges of 15–200 μM and 1–10 μM, offering exceptional selectivity, reproducibility, and repeatability for biosensing. [ABSTRACT FROM AUTHOR]

Asphodelus-based CQDs were successfully synthesized in a single step by the hydrothermal synthesis method for detection of β-carotene. TEM, XRD, FTIR, XPS, Zeta potential, UV–Vis absorption and fluorescence measurements were taken to structurally and optically characterize the newly synthesized CQDs. It was determined that the characterized CQDs show high selectivity and sensitivity only to β-carotene among 11 different biomolecules. The detection limit of CQDs for β-carotene was calculated as 8.28 µM. It was determined that the new CQDs respond very quickly and stably without interfering with any other biomolecules. The studies in different pH environments exhibited that CQDs can detect β-carotene at all pH studied. Real sample experiments show that β-carotene can be determined accurately and reliably in practical applications with the novel CQDs. It was thought that the results obtained from this study will make significant contributions to the studies on β-carotene detection, which are limited in the literature. [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 work, we explored the hydrothermal synthesize and crystallization process of SAPO‐34 zeolites from two‐dimensional layered silicate magadiite by using tetraethylammonium hydroxide (TEAOH) as a templating agent. Comprehensive characterization was conducted by XRD, SEM, FTIR, Raman, and BET. Time‐resolved PXRD analysis revealed that SAPO‐34 zeolite exhibited a steep growth curve when the crystallization time was 30 h, and the crystallinity reached 98.65 % at 48 h. Specifically, the disruption of the magadiite layer exposed charged silanol groups on the surface, fostering an affinity for AlO4 and PO4 species, thereby initiating the nucleation process. Under the guidance of TEAOH, these nucleation sites transformed into SAPO‐34 nuclei, gradually advancing towards crystallization. FTIR and Raman analyses affirmed the presence of 6Rs, followed by D6R and 4Rs SBUs, along with the characteristic CHA structure. Combined with 29Si NMR established that disaggregated silicate minerals served as zeolite synthesis "seeds", enhancing nucleation sites and overall crystallization efficiency. [ABSTRACT FROM AUTHOR]

Cerium oxide, CeO2 nanoparticles (NPs) have been synthesized through various methods to achieve the desired physicochemical properties. However, high temperatures, pressure and long reaction time were involved. In this study, ultra-small CeO2 NPs were successfully synthesized using the hydrothermal method but under a favourably low temperature (70 ℃) for 4 hours using cerium nitrate hexahydrate, Ce(NO3)3 • 6 H2O and sodium hydroxide, NaOH as the precursors while deionized water was used as the solvent. The synthesized ultra-small CeO2 NPs were characterized using field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX), ultraviolet visible (UV-Vis) spectrometer, Fourier transform infrared (FTIR) spectroscopy, X-Ray Diffraction (XRD) and Brunauer-Emmett-Teller (BET) method. The synthesized ultra-small CeO2 NPs were determined to have an average particle size of 3.54 nm, crystallite size of 3.05 nm and a high specific surface area of 185 m2 g-1. UV-Vis spectrum also showed absorption peak at 310 nm and FTIR spectrum intense peak at 447.20 cm-1 indicating the presence of CeO2 NPs. FTIR, EDX and XRD diffraction pattern have proved that the synthesized CeO2 NPs is of high purity. This study has successfully synthesized ultra-small CeO2 NPs with optimal conditions of hydrothermal treatment at 70℃ for 4 hours and a percent yield of ~99%. [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]

A hydrothermal method which can convert free cesium ions into stable pollucite at low temperatures was established in this work, avoiding any evaporation pollution during the disposal of cesium containing waste. Meanwhile, rapid synthesis under hydrothermal conditions was achieved using seed guidance, which shorten the growth time of pollucite crystals to 8 h, and making the treatment and disposal of cesium containing wastewater faster. Standard leaching test results show that the leaching rate of Cs was very low (< 3.5 × 10−7 g·m2·d), it still has good thermal stability at a temperature of 1300 °C, when the cesium content in pollucite reaches 20%. [ABSTRACT FROM AUTHOR]

In this study, cobalt phosphate (Co3[PO4]2) nanosheets were synthesized through a microwave‐assisted hydrothermal method with enhanced electrochemical properties. The synthesis was carried out at different microwave heating times (3, 5, 10, and 15 min) at a fixed temperature of 200°C. The structural properties of the synthesized Co3(PO4)2 nanosheets were investigated via XRD, FESEM‐EDS and TEM studies, while the electrochemical parameters were evaluated through CV, GCD, and EIS in a standard 3‐electrode cell with 1 M KOH as an electrolyte at a room temperature. The results reveal that Co3(PO4)2 nanosheets synthesized at 5 min microwave heating time exhibited maximum electrochemical performance owing to its excellent structural and morphological properties and thus reported a specific capacity of 130.98 and 164.52 C/g at a scan rate of 10 mV/s and a current density of 1 A/g, respectively. Furthermore, a stability test of the synthesized electrode material reported excellent cyclic stability of the electrode with 101% retention of the initial value of its specific capacity after 1000 cycles. [ABSTRACT FROM AUTHOR]

It is prominent and imperative to synthesize gas-sensitive materials using energy-efficient and environmentally friendly methods to enhance their properties. The current paper employs hydrothermal method porous reduced graphene oxide (P-rGO) and zinc oxide (ZnO) with flower-like structure complexes (PGZ) to detect the acetone gas. The gas sensitivity of the PGZ sensor demonstrate a response of 30.38 for 50 ppm acetone, accompanied by a rapid response recovery time of 5 s/7 s at operating temperature of 240 °C. Moreover, the remarkable long-term stability (<15 % fluctuation over 9 cyclic response cycles and 7 weeks of intermittent testing) of the PGZ gas sensor ensures its suitability for practical applications. The P-rGO enlarges the specific surface area of the material, which is conducive to accelerating the electron transfer in the reaction as well as the adsorption and desorption of the target gas, resulting in a rapid response recovery time. The porous structure can also effectively inhibit the agglomeration and growth of ZnO nanoparticles, thus improving long-term stability. Consequently, our study provides a new strategy for the application of 2D materials in gas sensing. [ABSTRACT FROM AUTHOR]

The efficacy of oxalate–phosphate–amine metal–organic frameworks (OPA-MOFs) as highly efficient slow-release fertilizers in acidic soils is well established. However, a research gap exists concerning the impact of OPA-MOFs on soils with high levels of calcium carbonate. Thus, two distinct types of OPA-MOFs with enhanced specific surface areas were synthesized and utilized in field experiments. A randomized complete block design was employed to evaluate the effect of five different fertilizers on nitrogen (N) and phosphorus (P) contents in wheat at various growth stages cultivated in calcareous soil. The treatments comprised OPA-MOF1, OPA-MOF2, IF1 (urea and triple superphosphate fertilizer), IF2 (ammonium nitrate and triple superphosphate fertilizer), and a control, each with three replications. N and P contents of the wheat plants were assessed at Zadoks growth stages 13 and 40, as well as in the wheat grains. The findings indicated that the highest grain yield was obtained with IF1 (1439.86 kg ha−1), followed by IF2 (1146.83 kg ha−1). In contrast, the OPA-MOF treatments yielded lower grain yields (OPA-MOF1: 1020.64 kg ha−1, OPA-MOF2: 845.06 kg ha−1). Moreover, OPA-MOF1 exhibited a more pronounced effect on the slow release of N and P elements due to its more regular structure, resulting in higher N content during the middle growth stage and a greater grain yield compared to OPA-MOF2.Highlights: The N and P contents were measured at Zadoks growth stages 13, 40, and at the maturity of wheat grains. OPA-MOFs effectively increased nitrogen content in the shoot and grain of wheat. Application of OPA-MOFs can improve yield, biomass, and 1000-seed weight in wheat. OPA-MOF1 showed better performance than OPA-MOF2 in increasing grain P content. OPA-MOFs showed a slower trend in biomass production compared to IF1 and IF2. [ABSTRACT FROM AUTHOR]

Transition metal disulfides (MS2; M = Mo and W) nanostructures were successfully synthesized by a hydrothermal methodology based on the reaction between transition metal (Mo/W) and S sources at 240 °C for 24 hours. Detailed structural, morphological and optical analyses were performed using XRD, TGA/DSC, FESEM/EDX, HRTEM and UV-Vis spectroscopy. Gross structural investigations reveal that the crystalline nature of MS2 materials with flake-like and rod-like morphologies. MoS2 in 2D flake-like morphology with thickness of about 15 nm (± 2nm) and WS2 in 1D rod-like morphology with width between 7-9nm (±0.5nm) were achieved. The UV-Vis spectroscopy data elucidate two different optical band gaps 1.88 eV and 2.29 eV were achieved for MoS2 nanoflakes, and for WS2 nanorods it was 1.84 eV. The simple and cost-effective synthesis approach with detailed microstructure analyses and optical properties indicate a great potential of nanostructured MoS2 and WS2 as a vital component in new-generation semiconductor and optoelectronics devices. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (AZIBs) and supercapacitors (SCs) have wide application prospects in the field of energy storage device due to high-safety, low cost, and environmental friendliness. However, their large-scale application is hampered by the lack of suitable electrode materials. In this work, the smooth CuBi2O4 nanosheets with thickness of about 4–5.5 nm have been prepared by a simple one-step hydrothermal method, and are reported as electrode materials of these two types of devices. Encouragingly, the as-prepared CuBi2O4 nanosheets exhibit fast electronic/ion diffusion, good reversibility and high pseudo-capacitance for AZIBs and SCs. For the AZIBs, CuBi2O4 nanosheets endows high capacity of 186 mAh g−1 after a long-term stability of 800 cycles, Zn storage mechanism is also discussed. For the SCs, it delivers 666.7 F g−1 at 10 A g−1, with 95.8 pct capacitance retention after 7000 cycles. The result suggests a prospect use as electrode material for advanced AZIBs and SCs. [ABSTRACT FROM AUTHOR]

In this paper, nitrogen‐doped carbon quantum dots (N‐CQDs) are synthesized by the hydrothermal method. N‐CQDs exhibit strong fluorescence, and N‐CQDs are well dispersed in water as well as in various organic solvents. N‐CQDs emit multi‐color fluorescence from blue to red, with wavelengths in the range of 450–650 nm without the need for purification. Furthermore, the fluorescence emission of N‐CQDs was selectively quenched after adding Fe3+ ions. N‐CQDs were used as a nanoprobe for the detection of Fe3+ ions, showing a good linear correlation between the fluorescence emission and the concentration of Fe3+ in the Fe3+ concentration range from 0 to 100 μM. The limit of detection (LOD) was 55.7 μM for Fe3+ in water and 40.2 μM in fetal bovine serum (FBS) samples. The study shows that the synthesized N‐CQDs have low cost and great potential for application in biological analysis. [ABSTRACT FROM AUTHOR]

Hollow mesoporous hydroxyapatite (HM-HAP) composites coated with titania are prepared to increase the stability and catalytic performance of titania for azo dyes present in the wastewater system. In this work, HM-HAP particles were first synthesized by a hydrothermal method utilizing the CaCO3 core as a template and then coated with titania to form TiO2/HM-HAP composites. Utilizing SEM, XRD, XPS, BET, FTIR, EDS, UV–vis DRS spectroscopy, and point of zero charge (PZC) analysis, the coating morphological and physicochemical parameters of the produced samples were analyzed. The photocatalytic efficiency of the synthesized coated composites was assessed by the degradation of methyl red (MR) dye in water. The results indicated that TiO2/HM-HAP particles could efficiently photodegrade MR dye in water under UV irradiation. The 20% TiO2/HM-HAP coating exhibited high catalytic performance, and the degradation process was followed by the pseudo-first-order (PFO) kinetic model with a rate constant of 0.033. The effect of pH on the degradation process was also evaluated, and the maximum degradation was observed at pH 6. The analysis of degraded MR dye products was investigated using LC-MS and FTIR analysis. Finally, a good support material, HM-HAP for TiO2 coatings, which provides a large number of active adsorption sites and has catalytic degradation performance for MR dye, was revealed. [ABSTRACT FROM AUTHOR]

Oxalic acid (OA) is a predominant constituent in kidney stones, contributing to 70–80% of all cases. Rapid detection of OA is vital for the early diagnosis and treatment of kidney stone conditions. This work introduces a novel electrochemical sensing approach for OA, leveraging vanadium disulfide (VS2) nanoflowers synthesized via hydrothermal synthesis. These VS2 nanoflowers, known for their excellent electrocatalytic properties and large surface area, are used to modify glassy carbon electrodes for enhanced OA sensing. The proposed OA sensor exhibits high sensitivity and selectivity across a wide linear detection range of 0.2–20 μM, with an impressively low detection limit of 0.188 μM. The practicality of this sensor was validated through interference studies, offering a promising tool for the early diagnosis and monitoring of kidney stone diseases. [ABSTRACT FROM AUTHOR]

A sample of a catalytic system based on nickel and a carbon-containing material, microcellulose, was obtained using a hydrothermal synthesis method. A catalytic study of the synthesized system in the process of selective hydrogenation of carbon monoxide and carbon dioxide was carried out with calculation of the apparent activation energy. The sample was demonstrated to be highly active in the selective hydrogenation reactions of carbon oxides. A 100% conversion of carbon monoxide and carbon dioxide and selectivity for methane of 90 and 80%, respectively, were obtained. [ABSTRACT FROM AUTHOR]

In recent years, cerium dioxide (CeO2) has attracted considerable attention owing to its remarkable performance in various applications, including photocatalysis, fuel cells, and catalysis. This study explores the effect of nickel (Ni) doping on the structural, thermal, and chemical properties of CeO2 nanorods, particularly focusing on oxygen vacancy-related phenomena. Utilizing X-ray powder diffraction (XRD), alterations in crystal structure and peak shifts were observed, indicating successful Ni doping and the formation of Ni2O3 at higher doping levels, likely due to non-equilibrium reactions. Thermal gravimetric analysis (TGA) revealed changes in oxygen release mechanisms, with increasing Ni doping resulting in the release of lattice oxygen at lower temperatures. Raman spectroscopy corroborated these findings by identifying characteristic peaks associated with oxygen vacancies, facilitating the assessment of Ni doping levels. Ni-doped CeO2 can catalyze the ultrasonic degradation of methylene blue, which has good application prospects for catalytic ultrasonic degradation of organic pollutants. Overall, this study underscores the substantial impact of Ni doping on CeO2 nanorods, shedding light on tailored catalytic applications through the modulation of oxygen vacancies while preserving the nanorod morphology. [ABSTRACT FROM AUTHOR]

In this study, we fabricated an efficient and low-cost carbon-doped titania (C–TiO2) counter electrode (CE) as a substitute for platinum (Pt) in dye-sensitized solar cells (DSSCs). By varying different weight ratios, C–TiO2 samples were synthesized through the hydrothermal synthesis method followed by calcination in a tube furnace. The doctor blade coating method was used to deposit thin films of the synthesized samples onto the fluorine-doped tin oxide (FTO) substrates. Structural and morphological properties were studied by using various analytical techniques. Moreover, the electrochemical and photo-conversion characteristics of the fabricated CEs were investigated. Cyclic voltammetry (CV) results of the fabricated CEs showed electrocatalytic activity comparable to the Pt in the DSSCs. Meanwhile, photovoltaic measurement results showed the best-performing 15% C–TiO2 CE having 1.56% power conversion efficiency (PCE) as compared to Pt, which is 2.12%. This study proposed a simple method to fabricate a low-cost and efficient C–TiO2 CE for DSSCs. [ABSTRACT FROM AUTHOR]

Herein, a method for synthesizing highly porous single phase of α‐Ni(OH)2 via hydrothermal route is presented. Nitrogen‐ and phosphorous‐functionalized carbon dots (N,P‐CDGMP) are first synthesized by thermal refluxing of 1,5′‐guanosine monophosphate (GMP) in ethylene glycol. Then Ni(OH)2 is synthesized in the presence of N,P‐CDGMP by hydrothermal method. Microflower‐like morphology of porous nanocomposite of Ni(OH)2‐[N,P‐CDGMP] with significantly enhanced Brunauer–Emmett–Teller surface area (454 m2 g−1) is formed, which is 32 times higher than that of the pristine Ni(OH)2. The cyclic voltammetry plot suggests battery‐type supercapacitor with a specific capacity of 632 C g−1, which is 6 times higher than the pristine Ni(OH)2 (107 C g−1). The enhanced specific capacity of Ni(OH)2‐[N,P‐CDGMP] is attributable to better intercalation–deintercalation of electrolyte ions in the suitable pore volumes. Electrode kinetic studies measured at a scan rate of 0.005 V s−1 suggest that about 86% of charge is stored via diffusion‐controlled process and the charge storage by surface‐controlled capacitive process is higher at higher scan rate (e.g., at 0.1 V s−1). The application of Ni(OH)2‐[N,P‐CDGMP] is demonstrated by fabricating a hybrid supercapacitor device Ni(OH)2‐[N,P‐CDGMP]//porous activated carbon from eucalyptus wood. The retention of specific capacitance of the device is 75% after 3000 cycles with maximum energy density of 31 Wh kg−1 and power density of 0.76 kW kg−1. [ABSTRACT FROM AUTHOR]

Herein, we report a new type of non-enzymatic nanostructured biosensor designed for the concurrent determination of dopamine, cholesterol, and glucose in human blood samples. The prepared biosensor using low-temperature one-pot hydrothermal processing is a Zn-doped SnO2-dispersed nitrogen-doped reduced graphene oxide (N-rGO)/Zn-SnO2 nanocomposite. This modified electrode allows direct electron transfer and thus offers electrochemical techniques to detect target molecules in analytes without the use of enzymes. The biosensor displayed good voltammetric responses within the human reference range: 20–70 nM for dopamine, 1–8 mM for cholesterol, and 1–10 mM for glucose. It also showed excellent reusability and can be restored by washing with ethanol. Due to the use of Zn-doped SnO2 nanoparticles for enhanced catalytic activity and N-rGO for high conductivity and active sites, sensitive and selective detection can be achieved. This hybrid composite demonstrates excellent catalytic activity, repeatability, stability, and clinical comparability for real-time measurement of dopamine, cholesterol, and glucose simultaneously. [ABSTRACT FROM AUTHOR]

Heteroatom (such as Ti, Sn, Zr, and Hf) zeolites that contain Lewis acid site (LAS) centers with tetrahedral coordination confined in micropores with various topologies are able to catalyze reactions distinct from those catalyzed by Brønsted acid sites (BASs). In particular, these LAS centers are able to coordinate with two oxygen atoms of one or two oxygenated molecules on a single LAS simultaneously, which are suitable for the conversion of biomass-derived oxygenates via unique reaction pathways, and have been widely explored in the conversion of biomass-derived oxygenates to value-added products. In this review, methods of conventional hydrothermal synthesis, improved direct synthesis (such as interzeolite transformation and dry gel conversion) and post-synthesis (such as solid-state ion change, structural reconstruction and grafting) are compared. Next, approaches for the qualification and quantification of the location (framework or extra-framework), fine structure (closed or open), and acidity of heteroatom centers are summarized. Thereafter, we present the applications of Lewis acid zeolites in the conversion of platform oxygenates of hexoses, furan derivatives and acid derivatives via reactions of isomerization, Meerwein–Ponndorf–Verley reduction, oxidation, and ketonization. Notably, the integration of multiple steps into a one-pot cascade reaction for the conversion of oxygenates (for example, glucose to 5-hydroxymethylfurfural and furfural to γ-valerolactone) mediated by the synergy of LASs and BASs or metal sites is also discussed. Finally, the opportunities and challenges in the low-cost synthesis and large-scale application of Lewis acid zeolites for the green and sustainable synthesis of chemicals are proposed. [ABSTRACT FROM AUTHOR]