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Polyaniline (PANI) is a promising conductive polymer for use in energy storage applications. Here, a one-step hydrothermal method of PANI polymerization on carbon felt electrode was synthesized using an azo dye, a bisulfonated dichloro anionic dye molecule to enhance an efficient textile-based flexible supercapacitor electrode material for energy storage applications. The electrode material synthesized at concentration of 2 mM AY17 exhibits 814.1 F g-1 at the scan rate of 5 mV s-1 with multiwall carbon nanotubes (MWCNTs). Due to electrostatic interaction with the polymer, the presence of high electronegativity Cl atoms in the dye molecule significantly improves the PANI structure's electron donor/acceptor properties. A symmetric supercapacitor exhibits an energy density of 11.7 W h kg−1 at a power density of 300 W kg−1, and it is 4.5 W h kg−1 at 1800 W kg−1 in 3.0 M KCl aqueous electrolyte. The capacitance retention performance value of the symmetric supercapacitor exhibited 81.76% after 2500 cycles.

Phenylketonuria (PKU) is a critical disease in the disorder of amino acid metabolism, which mostly emerges in children. The most common method used in PKU treatment is the detection of L-phenylalanine (PHEA) as the biomarker of PKU. In the present work, a new molecularly imprinted electrochemical electrode based on WS2 nanoflowers (NFs) on N,B-doped graphene (WS2 NFs/N,B-GR) is presented for PHEA assay in milk samples. First of all, WS2 NFs/N,B-GR was synthesized via a high-efficiency hydrothermal synthesis. Cyclic voltammetry was applied to the electrochemical cell, including PHEA as a template molecule and pyrrole as a monomer, to form PHEA-imprinted electrochemical electrodes. Then, the structural and morphological features of WS2 NFs and WS2 NFs/N,B-GR were investigated in detail by various analytical methods. The limit of quantification and limit of detection values were obtained as 1.0 × 10-11 and 3.0 × 10-12 M, respectively, by a PHEA-imprinted electrochemical electrode. Finally, a PHEA-imprinted electrochemical sensor having a high degree of selectivity, stability, and reusability is presented in the literature for early diagnosis of PKU. © 2022 American Chemical Society. All rights reserved.

In the present study, a Bi$_2$WO$_6$/ZnWO$_4$ photocatalyst was successfully constructed by a modified hydrothermal synthesis method with different molar concentrations of Bi$_2$WO$_6$ with respect to ZnWO$_4$. The variation in molar concentrations of Bi$_2$WO$_6$ changed the photocatalytic properties of the Bi$_2$WO$_6$/ZnWO$_4$ catalyst. The synthesized Bi$_2$WO$_6$/ZnWO$_4$ photocatalyst was characterized by various techniques to decipher its structural and spectral properties. The interaction of Bi$^{2+}$ ionic charge carriers and many-body effects cause the band gap to narrow in Bi$_2$WO$_6$/ZnWO$_4$, as shown by PL analysis. The decrease in band gap energies (E$_g$) from 4.7 eV (ZnWO$_4$) to 3.5 eV (30% Bi$_2$WO$_6$/ZnWO$_4$) is beneficial because less energy is required to excite the valence electrons. The maximum degradation of Plasmocorinth B dye was found with 30% Bi$_2$WO$_6$/ZnWO$_4$ under UV irradiation. This increased activity of 30% Bi$_2$WO$_6$/ZnWO$_4$ can be attributed to the (i) synergistic effect in the bicrystalline framework of Bi$_2$WO$_6$ and ZnWO$_4$, (ii) the high close contact between Bi$_2$WO$_6$ and ZnWO$_4$, and (iii) the small crystallite size. The photocatalytic activity of synthesized Bi$_2$WO$_6$/ZnWO$_4$ photocatalyst shows its significant potential in water/ wastewater treatment application.

Glycerol steam reforming (GSR) is one of the promising technologies that can realize renewable hydrogen production and efficient utilization of crude glycerol. To illuminate the functions of Ca content (3%, 6%, 9%, and 12 %, by mass) and preparation method for Ni/ATP catalyst structure and its catalytic behaviors, the Ni-xCa/ATP (x=3%, 6%, 9%, and 12%, by mass) catalysts are prepared by co-impregnation (ci) and hydrothermal synthesis (hs) method and then tested in GSR. Characterization results of XRD, N2 adsorption-desorption, H2-TPR, HRTEM, XPS, and NH3/CO2-TPD demonstrate that the combined effect between appropriate Ca additive (6%, by mass) and hs enhance catalyst reducibility, uniform distribution of Ca additive and nickel species over ATP, and adsorption for CO2. This attributes to hs method protects the ATP framework through suppressing the interaction of Ca with ATP and promotes the formation of Ni-CaOx interface sites. Therefore, Ni-6Ca/ATP-hs exhibits the highest conversion (86.77%) of glycerol to gas product and H2 yield (76.17%) and selectivity (58.56%) during GSR. Furthermore, XRD, HRTEM, TG-DTG and Raman analyses confirm that Ni-6Ca/ATP-hs also reveals outstanding anti-sintering and coke resistance. In addition, the structural evolution process of Ni/ATP catalyst with Ca introduction and hs method is presented. Considering the high performance, simple preparation process and low cost, the as-prepared catalyst providing new opportunities for utilization of glycerol derived from biodiesel industry.

The utilization of coal fly ash derived from circulating fluidized bed combustion (CFBFA) still faces great challenges because of its unique characteristics. In this study, a zeolitic material with Na-P1 zeolite as the main phase was successfully synthesized via a hydrothermal method by using CFBFA as the raw material. The effects of hydrothermal temperature, time, and added CTAB amount on the characterizations of synthesized materials were investigated by XRD, SEM, and XPS. The properties of the optimal zeolitic material and its adsorption performance for Pb2+ in aqueous solution were evaluated. The influences of pH, initial concentration, dosage, and temperature on Pb2+ adsorption were also examined. Results revealed the following optimal parameters for the synthesis of zeolitic material: NaOH concentration of 2 mol·L-1, solid-to-liquid ratio of 1:10 g·ml-1, hydrothermal temperature of 110 °C, hydrothermal time of 9 h, and CTAB amount of 1 g (per 100 ml solution). The adsorption capacities of the zeolitic material reached 329.67, 424.69, and 542.22 mg·g-1 when the pH values of aqueous solution were 5, 6, and 7, respectively. The Pb2+removal efficiency can reach more than 99% in aqueous solution with the initial concentrations of 100–300 mg·L-1 under pH 6 and suitable adsorbent dosage. The adsorption and kinetics of Pb2+ on the zeolitic material can be described by Langmuir isotherm and pseudo-second-order kinetic models, respectively. The ion exchange between Pb2+ and Na+ and chemisorption are the main adsorption mechanism. All these findings imply that the synthesis of low-cost adsorbent for Pb2+ removal from weak acid and neutral aqueous solution provides a highly effective method to utilize CFBFA.

A microstructured cover flow mixer equipped with two cyclone structures was used for stable continuous hydrothermal synthesis of ZnO nanoparticles from Zn(NO$_3$)$_2$ and NaOH aqueous solutions in supercritical water. The effects of the NaOH/Zn(NO$_3$)$_2$ ratio, Zn(NO$_3$)$_2$ molality, and flow rate on Zn conversion, crystal structure, particle size, particle morphology, and mixer clogging were examined. The advantages of this mixer were identified by comparing with the results obtained using the same chemical conditions with tee-type, cross-type, and central collision-type mixers.

Crystallization of DNL-6, a silicoaluminophosphate (SAPO) based molecular sieve with the RHO topology, was investigated under both the hydrothermal synthesis (HTS) and dry-gel conversion (DGC) conditions. Crystallization of DNL-6 under the HTS conditions is rather fast. But a combination of crystallization under the DGC conditions and reducing reaction temperature slow down the reactions, allowing for intermediates to be captured. Under the DGC conditions, DNL-6 crystallizes through a semi-crystalline layered phase. The nature of this intermediate is aluminophosphate (AlPO) rather than SAPO with most P atoms having a local environment of P(–O–Al)3(OH). The surfactant (cetyltrimethylammonium chloride) used for synthesis appears to be part of the layered intermediate. Si is directly incorporated in the DNL-6 framework via SM II mechanism when the semi-crystalline AlPO phase is transforming to DNL-6 with the assistance of a very small amount of water. Both the structure directing agent and the surfactant play a role in the formation of DNL-6, as they were found within the final synthesized products. SEM data show that hydrothermal synthesis produces a much more crystalline product. The facts that the semi-crystalline layered phase was also observed in the powder X-ray diffraction patterns of the solid samples obtained under the HTS conditions and that the evolution of the local structure around P and Al in the intermediate phases are similar imply that under the reaction conditions employed in the present study, the formation pathways of DNL-6 under the HTS and DGC conditions appear to have some similarities.

A large surface area with high active site exposure is desired for the nano-scaled electrocatalysts fabrication. Herein, taking NiMoO4 nanorods for example, we demonstrated the advantages of the microwave-assisted hydrothermal synthesis method compared to the traditional hydrothermal approaches. Both monoclinic structured NiMoO4 in the nanorods morphology are found for these samples but it is more time-saving and efficient in the Ni-Mo synergism for the catalyst obtained by microwave-assisted hydrothermal syntheses method. When evaluated for urea oxidation, the current density can reach 130.79 mA/cm2 at 1.54 V, about 2.4 times higher than that of the counterpart catalyst (54.08 mA/cm2). Moreover, largely improved catalytic stability, catalytic kinetics and rapid charge transfer ability are found on the catalyst obtained by the microwave-assisted approach. The high catalytic performance can be attributed to the high surface area and active site exposure of NiMoO4 nanorods formed by microwave irradiation. Considering the less time, facile synthesis condition and efficient components synergism, the microwave-assisted hydrothermal synthesis method might work better for the nanostructure electrocatalysts fabrication.

Die kontinuierliche hydrothermale Synthese (CHTS) stellt ein vielversprechendes Verfahren zur Herstellung metalloxidischer Nanopartikel dar. Das Prinzip beruht auf der Vermischung einer kalten wässrigen Metallsalzlösung mit einem nahe-/überkritischen Wasserstrom. Durch die außergewöhnlichen Eigenschaften des überkritischen Wassers kommt es zur Partikelbildung. Neben der Studie des Einflusses der Prozessparameter auf die resultierende Partikelgröße und -verteilung ist die Restkonzentration an gelöstem Metallsalz von Interesse. Diese kann mittels der Impedanzspektroskopie analysiert werden. Dazu werden an einer modifizierten CHTS-Anlage Vorversuche durchgeführt, um zukünftig die Restkonzentration direkt bestimmen zu können.

Supercapacitor with high specific capacity is desirable for various energy storage and high powerdensity applications. Though Graphene has been the preferred material for high current density, nanocomposites have been attempted to increase the specific capacitance. Hydrothermal synthesis of cadmium sulfide/graphene (CdS/G) nanocomposite with CdS nanoparticles anchored/decorated over the graphene sheets is reported. The structural studies reveal the hexagonal phase of the prepared materials. The specific surface area (BET) and porosity is found to increase upon nanocomposite formation. The electrochemical characteristics such as cyclic voltammetry (CV), GCD and EIS of the CdS/G nanocomposite have been investigated. The capacitance of CdS/G nanocomposite almost doubled to 248 Fg−1 indicating the enhanced performance of the nanocomposite system and in addition it also showed excellent cycling stability of 74.8 percent after 1000 cycles. The supercapacitor investigated retained the initial energy density after charge-discharge, at 0.5 A/g for 1000 cycles. The graphene nanosheets increased the specific surface area and interfacial electron transfer of the composite material. It enhances the specific capacitance and cyclic stability of the supercapacitor device.

The synthesis of magnetic iron–carbon composites (Fe/C) from waste avocado seeds via hydrothermal carbonization (HTC) has been demonstrated for the first time. These materials are shown to be effective in adsorption and catalytic applications, with performances comparable to or higher than materials produced through conventional processing routes. Avocado seeds have been processed in high-temperature water (230 °C) at elevated pressure (30 bar at room temperature) in the presence of iron nitrate and iron sulfate, in a process mimicking natural coalification. Characterization of the synthesized material has been carried out by X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectrometry (ICP-OES), Fourier-transform infrared spectroscopy (FT-IR), magnetometry, and through surface area measurements. The supported iron particles are observed to be predominately magnetite, with an oxidized hematite surface region. The presence of iron catalyzes the formation of an extended, ordered polymeric structure in the avocado seed-derived carbon. The magnetic Fe/C has been demonstrated as an adsorbent for environmental wastewater treatment using methylene blue and indigo carmine. Kinetic analysis suggests that the adsorbates are chemisorbed, with the positive surface charge of Fe/C being preferential for indigo carmine adsorption (49 mg g–1). Additionally, Fe/C has been evaluated as a heterogeneous catalyst for the hydroalkoxylation of phenylacetylene with ethylene glycol to 2-benzyl-1,3-dioxolane. Product yields of 45% are obtained, with 100% regioselectivity to the formed isomer. The solid catalyst has the advantages of being prepared from a waste material and of easy removal after reaction via magnetic separation. These developments provide opportunities to produce carbon-based materials for a variety of high-value applications, potentially also including energy storage and biopharmaceuticals, from a wide range of lignocellulosic biomass feedstocks.

Deep-ultraviolet (deep-UV) nonlinear optical (NLO) crystals are key materials in creating tunable deep-UV lasers for frequency conversion technology. However, practical application of the sole usable crystal, KBe2 BO3 F2 , has been hindered by the high toxicity of beryllium and its layering tendency in crystal growth. Herein, we report a beryllium-free deep-UV NLO material NaSr3 (OH)(B9 O16 )[B(OH)4 ] (NSBOH), synthesized by a covalent bond modification strategy under hydrothermal conditions. Moisture-stable NSBOH exhibits strong second-harmonic generation (SHG) at 1064 nm (3.3 × KH2 PO4 ) and 532 nm (0.55 × β-BaB2 O4 ), both amongst the largest powder SHG responses for a deep-UV borate, with good phase-matchability and a short wavelength cutoff edge (below 190 nm). NSBOH possesses a 3D covalent anionic [B9 O19 ]∞ honeycomb-like framework with no layering. The Sr2+ and Na+ ions, residing in the cavities of the anionic framework, act as templates for the assembly and favorable alignment of NLO-active groups, resulting in an optimal balance between strong SHG activities and wide UV transparency. These merits indicate NSBOH is a very attractive candidate for deep-UV NLO applications.

The WO3 is a promising photoanode material for photoelectrochemical (PEC) water oxidation. Loading co-catalysts is an effective strategy for favoring the charge transfer and light harvesting of WO3, which can in turn improve its PEC performance. Herein, the ferrihydrite (Fh), a kind of poorly crystalline iron oxide material, was loaded on the WO3 photoanode through a two-step hydrothermal synthesis. The obtained Fh/WO3 photoanode exhibited a remarkable photocurrent density of 0.6 mA/cm2 at 1.23 V (vs. RHE), which was 1.79 times higher than the bare WO3. For the Fh/WO3 photoanode, the bulk charge separation efficiency is 45.6% and the photoconversion efficiency is 0.066%, which are both higher than the bare WO3. The decorated Fh can form an additional interface between the WO3 and the electrolyte, which decreases the impedance and favors the charge transfer. Moreover, the Fh can function as a hole storage layer, which can temporarily store the photogenerated holes and induce the longer lifetime of charge carriers, thus improving the charge separation and water oxidation reaction kinetics.

During the synthesis of CdTe quantum dots (QDs) by the hydrothermal method, a CdS shell layer is naturally formed by the thermal decomposition of thiol ligands, and CdTe/CdS core/shell QDs are produced. Herein, we investigate the selective synthesis of CdTe and CdTe/CdS QDs to control the thermal decomposition of thiol ligands by changing the Te/Cd molar ratio of the precursor solutions. ...

Zinc sulfide nanospheres (ZnS NSs) were prepared by hydrothermal synthesis and graphene oxide (GO) was prepared by the Hummer’s method. ZnS NSs-rGO/ITO electrode was synthesized by heat treatment at a certain temperature, which was used for the detailed electrochemical determination of levodopa (LD). Finally, they were annealed to form the ZnS NSs-rGO/ITO electrode for detecting levodopa (LD). The results reveal that the ZnS NSs with the diameter of ~1 μm are covered by rGO. The ZnS NSs-rGO/ITO electrode has a good sensitivity of 1.43 μA μM −1 for the determination of LD in the concentration range of 1–40 μM. Moreover, it also shows a good selectivity, reproducibility and stability. In order to verify the practicability, we also use the electrode to detect LD in human serum. The detection results also prove that the electrode can be used in real life.

Oxide-based afterglow materials were usually produced through high-temperature treatment (> 1000 °C), which brought both considerable energy consumption and safety risk to manufacturer. Here, we report the growth of a halide-based double perovskite, Cs 2 Na x Ag 1-x InCl 6 :y%Mn, via a facile hydrothermal reaction at 180 °C. Through a co-doping strategy of both Na + and Mn 2+ , the as-prepared crystals exhibited a red afterglow featuring a high color purity (~ 100%) and a long duration time (> 5400 s), three orders of magnitude longer than those solution-processed organic afterglow crystals. The energy transfer (ET) process between self-trapped excitons (STE) and activators was investigated through time-resolved spectroscopy, which suggested an ET efficiency up to 41%. Importantly, the nominal concentration of dopants, especially in the case of Na + , was found a useful tool to control both energy level and number distribution of traps. Cryogenic afterglow measurements suggested that the afterglow phenomenon was likely governed by thermal-activated exciton diffusion and electron tunneling process. Our work provided a convenient access to a new class of afterglow materials with low lattice energy, representing a paradigm for low-temperature synthesis of afterglow crystals.

Pure CeVO4 and Dy-doped CeVO4 nanorods containing different weight contents of Dy dopant were synthesized by hydrothermal method. Effect of Dy dopant on photodegradation of methylene blue (MB) and rhodamine B (RhB) was evaluated under UV light irradiation within 80 min. Pure CeVO4 and Dy-doped CeVO4 nanorods were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM) and UV–visible spectroscopy. In this research, CeVO4 nanorods are tetragonal phase with the detection of main peak shift after being doped with Dy. The length of nanorods is deceased from 50 to 200 nm for pure CeVO4 to 50–100 nm for 3% Dy-doped CeVO4. Photodegradation of MB and RhB by CeVO4 nanorods under UV light irradiation is improved by Dy-dopant that plays the role in accepting electrons and reducing electron–hole recombination. MB and RhB solutions degraded by 3% Dy-doped CeVO4 nanorods was 94% and 93% within 80 min, respectively.

MnO2 nanorods are prepared using a hydrothermal method, and used as precursors for the synthesis of LiMn2O4 nanorod-based active material for the cathode of lithium-ion batteries. The effects of additives, pressure, reactant concentration in the solution, and reaction time during the hydrothermal synthesis on the morphology of MnO2 are examined. For the synthesis of the LiMn2O4 nanorods, two synthetic methods, hydrothermal processing of the MnO2 precursor in a Li-containing solution, and the solid-state reaction of the precursor with LiOH·H2O powder are tested. The morphological and electrochemical properties of the resulting materials are then analyzed. The rate and cycle performances of the LiMn2O4 nanorods are considerably improved by a composite coating of Li-ion-conductive Li2O–2B2O3 and electrically conductive carbon. Because the conductive properties of these coating materials can be obtained with low crystallinity of them, superior coating performance is attainable with relatively low-temperature of after heating, which is advantageous in preserving the morphology of LiMn2O4 nanorods.

Photocatalysts have been extensively used for hydrogen evolution or organic degradation. In this work, two different heterojunction types of composite photocatalysts, 1T-MoS2@TiO2 with Schottky heterojunction and 2H-MoS2@TiO2 with type-II heterojunction, are synthesized via hydrothermal synthesis. These two composite materials exhibit excellent photocatalytic activity toward the degradation of tannic acid, which is a typical organic in nuclear wastewater. At an optimal loading of 16% 1T-MoS2, the 1T-MoS2@TiO2 shows the highest degradation capacity of 98%, which is 3.2 times higher than that of pure TiO2. The degradation rate of 16% 1T-MoS2@TiO2 is much higher than that of 13% 2H-MoS2@TiO2. The enhanced photocatalytic activity might be attributed to the improved charge transfer according to the mechanism investigation, supported by the X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) analyses. This work provides new opportunities for constructing highly efficient catalysts for nuclear waste disposal.

Herein, we report a facile hydrothermal synthesis of MnO2 nanoparticles anchored multi walled carbon nanotubes (MnO2@MWCNTs) as potential anode materials for lithium-ion (Li-ion) batteries. The prepared MnO2@MWCNTs were characterized by several techniques which confirmed the formation of MnO2 nanoparticles anchored MWCNTs. The X-ray diffraction and Raman-scattering analyses of the prepared material further revealed the effective synthesis of MnO2@MWCNTs. The fabricated Li-ion battery based on MnO2@MWCNTs exhibited a reversible capacity of ~823 mAhg−1 at a current density of 100 mAg−1 for the first cycle, and delivered a capacity of ~421 mAhg−1 for the 60 cycles. The coulombic efficiency was found to be ~100% which showed excellent reversible charge–discharge behavior. The outstanding performance of the MnO2@MWCNTs anode for the Li-ion battery can be attributed to the distinctive morphology of the MnO2 nanoparticles anchored MWCNTs that facilitated the fast transport of lithium ions and electrons and accommodated a broad volume change during the cycles of charge/discharge.

Efficient removal of radioactive cesium from complex wastewater is a challenge. Unlike traditional precipitation and hydrothermal synthesis, a novel vast specific surface area adsorbent of copper hexacyanoferrates named EA-CuHCF was synthesized using a one-pot solvothermal method under the moderate ethanol media characterized by XRD, SEM, EDS, BET, and FTIR. It was found that the maximum adsorption capacity towards Cs+ was 452.5 mg/g, which is far higher than most of the reported Prussian blue analogues so far. Moreover, EA-CuHCF could effectively adsorb Cs+ at a wide pH range and low concentration of Cs+ in geothermal water within 30 minutes, and the removal rate of Cs+ was 92.1%. Finally, the separation factors between Cs+ and other competitive ions were higher than 553, and the distribution coefficient of Cs+ reached up to 2.343 × 104 mL/g. These properties suggest that EA-CuHCF synthesized by the solvothermal method has high capacity and selectivity and can be used as a candidate for Cs+ removal from wastewater.

The present work focuses on the hydrothermal synthesis and properties of porous coordination polymers of metal-porphyrin framework (MPF) type, namely, {[Pr-4 (H2TPPS)(3)]center dot 11H(2)O}(n) (UPJS-10), {[Eu/Sm(H2TPPS)]center dot H3O+center dot 16H(2)O}(n) (UPJS-11), and {[Ce-4(H2TPPS)(3)]center dot 11H(2)O}(n) (UPJS-12) (H2TPPS = 4,4',4 '',4'''-(porphyrin-5,10,15,20-tetrayptetrakisbenzenesulfonate(4)). The compounds were characterized using several analytical techniques: infrared spectroscopy, thermogravimetric measurements, elemental analysis, gas adsorption measurements, and single-crystal structure analysis (SXRD). The results of SXRD revealed a three-dimensional open porous framework containing crossing cavities propagating along all crystallographic axes. Coordination of H2TPPS4- ligands with Ln(III) ions leads to the formation of 1D polymeric chains propagating along the c crystallographic axis. Argon sorption measurements at -186 degrees C show that the activated MPFs have apparent BET surface areas of 260 m(2)g(-1) (UPJS-10) and 230 m(2) g(-1) (UPJS-12). Carbon dioxide adsorption isotherms at 0 degrees C show adsorption capacities up to 1 bar of 9.8 wt % for UPJS-10 and 8.6 wt % for UPJS-12. At a temperature of 20 degrees C, the respective CO2 adsorption capacities decreased to 6.95 and 5.99 wt %, respectively. The magnetic properties of UPJS-10 are characterized by the presence of a close-lying nonmagnetic ground singlet and excited doublet states in the electronic spectrum of Pr(III) ions. A much larger energy difference was suggested between the two lowest Kramers doublets of Ce(III) ions in UPJS - 12. Finally, the analysis of X-band EPR spectra revealed the presence of radical spins, which were tentatively assigned to be originating from the porphyrin ligands.

In situ MAS NMR studies on the monitoring of hydrothermal synthesis of zeolites are reviewed. The first part of the review contains information on the experimental techniques used for the in situ NMR studies in static and MAS conditions. In the second part, the main capabilities of the in situ 1 H, 11 B, 13 C, 14 N, 19 F, 23 Na, 27 Al, 29 Si and 31 P MAS NMR for the elucidation of the mechanism of hydrothermal synthesis of zeolites are examined and the data on NMR lines identification are summarized. In the last part the main application areas of the techniques are considered and illustrated with examples taken from the mechanistic studies of zeolites A, X, MFI and BEA synthesis. A cross-reference index between the materials studied, the experimental approaches used, the mechanistic information obtained, and the corresponding literature sources is established.

Core-shell structured hierarchical SSZ-13 microspheres with mesopore and zeolitic micropore were obtained via combining zeolite crystallization and post-synthesis fluoride etching. Secondary pores ...

Selective photocatalysis is a very promising direction to improve the activities of photocatalysts. Combining the technique of molecular imprinting (MIP) with heterogeneous photocatalysis can be an appealing approach to achieve our aim. Herein, using the MIP technique, the monoclinic MIP-BiVO4 was successfully synthesized by the presence of rhodamine B (RhB) during the hydrothermal synthesis. The synthesized MIP-BiVO4 possessed better adsorptive and photocatalytic activities than pristine BiVO4. RhB added in the synthesis process worked as a template and served a crucial role in the formation of the MIP-BiVO4 morphology. The photoelectrochemical analysis verified the superiority of MIP-BiVO4 sample in the transfer and separation of the electron–hole pairs. Holes played the most crucial role in the degradation of the pollutants. The effective approach combining MIP technique in the synthesis of photocatalysts would provide some guidance to selective photocatalysis field for designing and synthesizing highly efficient photocatalysts.

Solar photocatalytic degradation of dye using zinc oxide (ZnO) is a sustainable and efficient wastewater treatment method which could mineralize the dye to carbon dioxide and water without creating secondary waste or sludge. Sunlight is a natural source of light that extends over both ultraviolet and visible range which could irradiate ZnO to initiate the photocatalytic reaction for degradation of dye. The dried Luffa cylindrica (LC), the sponge gourd is suitable to be applied as a biotemplate in synthesis as it is fibrous and porous that will lead to high surface area of the synthesized material. In this study, a biomimetic zinc oxide was synthesized by using LC as biotemplate via simple hydrothermal synthesis method. Both synthesized ZnO samples were characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM) to confirm their crystalline phase and morphology, respectively. Compared with the non-templated ZnO, the biotemplated ZnO possessed relatively high crystallinity with higher diffraction peaks that assigned to the hexagonal wurtzite structure. Significant difference could be observed between the morphology of the ZnO synthesized without biotemplate and the ZnO synthesized with LC. It was found that the Luffa-templated ZnO inherited the structure of LC which the spherical nanoparticles connected continuously to each other in a dendritic-like morphology, while relatively large micron-sized particles were obtained in the ZnO synthesized without biotemplate. Photocatalytic activity of the synthesized ZnO was evaluated by degradation of Reactive Green 19 (RG19) under natural solar light irradiation. Results showed that enhanced photocatalytic degradation of RG19 at 65.8% was achieved in Luffa-templated ZnO compared with that of the non-templated ZnO which was only 40.8%. This indicated that the Luffa-templated ZnO possessed improved physical properties which could enhance its photocatalytic activity.

The effect of the catalyst preparation method on the catalytic activity of Fe-ZSM-5 for the partial oxidation of methane with H2O2 in an aqueous phase was examined. UV–vis spectroscopy and FT-IR spectroscopy after NO adsorption were used to characterize the prepared catalysts. Various preparation methods, including wet impregnation, solid-state ion-exchange, chemical vapor impregnation, hydrothermal synthesis, and aqueous phase ion-exchange were compared. Among them, the aqueous phase ion-exchange method demonstrated the best results in producing isolated or oligonuclear extra-framework Fe species, which showed the highest catalytic activity. On the other hand, bulk iron oxides did not decompose H2O2 nor did they activate methane. The total product yield and the amount of H2O2 consumed increased with increasing Fe content in the case of the Fe-ZSM-5 catalyst prepared using an ion-exchange method. However, the fraction of less active Fe species, such as iron oxide clusters and larger iron oxide aggregates on the external crystal surface, increased with the Fe content, resulting in a decrease in the total product yield per Fe content and the amount of H2O2 consumed per Fe content.

To simplify the complicated synthetic techniques so that getting CuII-SSZ-13 zeolites with ideal structures and CuII cations distribution, and to interrogate CuII cations dynamics dependent NH3 mediated performance of selective catalytic reduction (NH3-SCR) of NO and hydrothermal stability, a microwave-assisted hydrothermal synthesis route was performed to prepare CuII exchanged SSZ-13 zeolite catalysts. The effects of synthetic temperature and time on the structure of SSZ-13 zeolite and NH3-SCR performance are clarified. The types and numbers of CuII species of fresh and hydrothermal aged samples were precisely explored. The NH3-SCR activity, N2 selectivity of fresh and aged CuII-SSZ-13 zeolites synthesized by different conditions are evaluated, respectively. Experimental characterizations demonstrate that the CuII-SSZ-13 zeolites can be synthesized with short crystallization time assisted with microwave treatment. The microwave synthesis temperature and time can affect the nucleation and growth process of SSZ-13 and thus resulting in SSZ-13 with different framework structures and various affinity to CuII ions. When the temperature and time are 175 °C and 9 h, the as-synthesized CuII-SSZ-13 sample shows a stable framework structure, large specific surface area, and more [Z2CuII] speciation. This sample also shows excellent catalytic activity and hydrothermal stability. Characterization results also show that the microwave treatment can strengthen the Al-O-Si bonds in the zeolite framework. Our work provides a facile strategy to synthesize CuII-SSZ-13 zeolite and atomic-level understanding of catalytic property and hydrothermal stability.

Herein we report the hydrothermal synthesis, characterization and biological applications of h-MoO3 and silver doped MoO3 nanoparticles (NPs). The phase formations of the synthesized NPs were identified using X-Ray diffraction studies and vibrational spectral studies. The average crystallite size of the NPs tends to decrease with increase in doping concentration. The surface morphology and the elemental composition of the nanoparticles were observed from SEM and EDAX analysis. The crystallite nature was obtained from HRTEM images. The band gap energies obtained from UV-DRS spectra for h-MoO3 (3.26 eV) were found to decrease as the concentration of the dopant (Ag) increases (3.22–2.76 eV). The antibacterial activity of the prepared nanoparticles was tested against some gram positive and gram negative bacterial strains viz., Staphylococcus aureus and Bacillus cereus, Citrobacter koseri and Pseudomonas aeruginosa respectively. Also their seed germination properties were studied on foxtail and finger millet seeds for a period of seven days.

The wound environment is a breeding ground for pathogens, and traditional wound dressing materials lack antibacterial properties. In this work, we aimed to develop PVA/chitosan (P/C)-based wound dressing scaffolds with anti-infective properties using Cu2ZnSnS4 quantum dots (CZTS QDs) to prevent infections in the wound. CZTS quantum dots were prepared by a simple hydrothermal process and characterized using appropriate techniques such as TEM, XRD, FTIR spectrum, and UV-Vis absorption spectroscopy. CZTS QDs were subsequently loaded at different concentrations onto PVA/chitosan membranes (0, 1.6, 2.5 and 3.3% w/w, based on the total polymer quantity). The chemical structure, contact angle and mechanical properties of the membranes were analyzed, and their antimicrobial activities and cell viability were also investigated. The cytocompatibility of the membranes and cell morphology was investigated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and SEM. Based on studies on the interactions between membranes and cells, it was determined that incorporation of CZTS QDs into the membrane did not cause toxicity. To the best of our knowledge, this is the first report on loading CZTS QDs into membranes for tissue engineering applications, and the overall findings suggest that CZTS QDs-integrated membranes might have potentially appealing uses as antimicrobial films for wound healing., Tarsus University Scientific Research Projects Coordination Department; [MF.22.003], AcknowledgementsThe authors thank the Tarsus University Scientific Research Projects Coordination Department (Project no: MF.22.003) for the supports.

Received: 10.10.22. Revised: 04.11.22. Accepted: 05.11.22. Available online: 10.11.22. The authors acknowledge G.N. Bondarenko and L.A. Solovyov for performing the PXRD, S.N. Vereshchagin for the STA, E.V. Mazurova for the SEM-EDS, O.A. Levitskaya and V.R. Kuzik for the AAS analysis. The paper is concerned with (i) the hydrothermal synthesis of hydrous zirconium dioxide (HZD) bearing analcime (HZD–ANA, zirconia-analcime) and (ii) its sorption properties with respect to Cs+ and Sr2+. The HZD–ANA particles were synthesized from coal fly ash cenospheres composed of aluminosilicate glass with (SiO2/Al2O3)wt.=3.1 and characterized by PXRD, SEM-EDS, STA, and low-temperature N2 adsorption. The non-radioactive simulant solutions of different acidity (pH = 2–10) and Cs+/Sr2+ content (0.5–50.0 mg/L) were used in the work. The effect of synthesis conditions on the HZD–ANA particle size, zirconia content and localization as well as the sorption behavior with respect to Cs+ and Sr2+ (capacity, KD) were clarified. It was found that the small-sized HZD–ANA composites surpasses the Zr-free analcime and large-sized HZD–ANA material in the Cs+ and Sr2+ sorption parameters (KD ~ 104–106 mL/g). The conditions to synthesize the zirconiaanalcime composite of the highly enhanced sorption ability with respect to Sr2+ (KD ~ 106 mL/g) were determined. The high-temperature solid-phase re-crystallization of Cs+/Sr2+-exchanged HZD–ANA composites was shown to occur at 1000 °C, resulting in a polyphase system based on nepheline, tetragonal ZrO2, and glass phase. This research was funded by Ministry of Science and Higher Education of the Russian Federation (Budget Project No. 0287-2021-0013 for the Institute of Chemistry and Chemical Technology SB RAS). The reported study was conducted by using the equipment of Krasnoyarsk Regional Research Equipment Centre of SB RAS for SEM-EDS, PXRD and AAS analyses and Siberian Federal University for STA, PXRD and ICP-MS analyses.

Though well-recognized, the molecular-level understanding of the multifunctional roles of amines in the condensation of polysilicic acids, which is one of the key processes in hydrothermal synthesis of zeolites, is still limited. Taking ethylamine as a prototype, we investigated the mechanism of polysilicic acid condensation in the existence of organic amines in aqueous solution with extensive first-principles-based calculations. Because of the high proton affinity, ethylamine exists as amine silicates and alters the subsequent condensation mechanisms from a 1-step lateral attack mechanism accompanied with simultaneous intermolecular proton transfer in neutral aqueous solution to a 2-step SN2-like mechanism. Specifically, the 5-coordinated Si species that were not observed on pathways of condensation in neutral solution are effectively stabilized by the ethylamine cations as intermediates, and the barriers for condensation of ortho-silicic acid are significantly reduced from 133 kJ/mol in neutral solution to 58 and 63 kJ/mol for formation of the 5-coordinated Si intermediate and proton transfer for water release, respectively. Similar variations of mechanisms and barriers for condensation were also observed in the formation of cyclic trimers as well as linear and cyclic tetramers of ortho-silicic acids. Based on these, it was proposed that apart from acting as structure-directing agents, pore fillers, and pH adjusters, organic amines can also function as promoters in the condensation of polysilicic acids.

In this study, well-separated Fe-doped ZnAl2O4 nanosheets were synthesized by a co-precipitation assisted hydrothermal method (220 °C). The as-synthesized nanosheets were characterized by X-ray diffraction, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV- diffuse reflectance spectroscopy and vibrating sample magnetometer studies. The diffraction patterns reveal that there is no noticeable effect of doped Fe ions on the crystal structure of ZnAl2O4. This also confirms the crystallinity and pure spinel structure formation. In addition, no characteristic diffraction peaks related to any impurity, cluster formation, or secondary phase of Fe were detected. The XPS spectra of Fe-doped ZnAl2O4 confirms the presence target elements such as Zn, Al, O, and Fe. It is also confirmed the existence of mixed oxidation states, i.e., Fe2+ and Fe3+, in the optimized sample ZAO-Fe-3 (i.e., 3% of Fe ions doped ZnAl2O4). TEM images of pure ZnAl2O4 show a micro-hexagonal structure, whereas the Fe-doped ZnAl2O4 exhibits nanosheet-like structure. DRS analysis confirms that Fe doping modifies the bandgap energy of ZnAl2O4 with increasing Fe content. The M–H hysteresis curves of Fe-doped ZnAl2O4 exhibited clear room temperature ferromagnetism.

The syntheses and crystal structures of two bimetallic molecular compounds, namely, bis[bis(6,6′-dimethyl-2,2′-bipyridine)copper(I)] hexafluoridozirconate(IV) 1.134-hydrate, [Cu(dmbpy)2]2[ZrF6]·1.134H2O (dmbpy = 6,6′-dimethyl-2,2′-bipyridyl, C12H12N2), (I), and bis[bis(6,6′-dimethyl-2,2′-bipyridine)copper(I)] hexafluoridohafnate(IV) 0.671-hydrate, [Cu(dmbpy)2]2[HfF6]·0.671H2O, (II), are reported. Apart from a slight site occupany difference for the water molecule of crystallization, compounds (I) and (II) are isostructural, featuring isolated tetrahedral cations of copper(I) ions coordinated by two dmbpy ligands and centrosymmetric, octahedral anions of fluorinated early transition metals. The tetrahedral environments of the copper complexes are distorted owing to the steric effects of the dmbpy ligands. The extended structures are built up through Coulombic interactions between cations and anions and π–π stacking interactions between heterochiral Δ- and Λ-[Cu(dmbpy)2]+ complexes. A comparison between the title compounds and other [Cu(dmbpy)2]+ compounds with monovalent and bivalent anions reveals a significant influence of the cation-to-anion ratio on the resulting crystal packing architectures, providing insights for future crystal design of distorted tetrahedral copper compounds.

Intrinsic physical property and unique nanostructures of microwave absorbing materials play an important role in their electromagnetic energy conversion. One-dimensional microstructure has been considered as an idea structure for microwave absorbers. Herein, heterogeneous rod-like Ni@Carbon (Ni@C) composites were synthesized by a handy hydrothermal reaction and a subsequent calcination treatment. Morphology analysis indicated that the resultant nanorods are composed by carbon and uniformly dispersed Ni nanoparticles (NPs). The rod-like carbon-magnetic structure could be adequately regulated via hydrothermal synthesis, resulting in tunable nano-micro structure and electromagnetic parameters. Benefiting from the magnetic–dielectric synergetic effect, the appropriate calcination temperature could improve the electromagnetic energy loss. In addition, the polarizing effect between nickel and carbon is demonstrated by density functional theory calculation. Therefore, this rod-like Ni@C composite reveals a favorable microwave absorption. The Ni@C nanorods (NC-3) possess a minimum reflection loss (RLmin) of −58.7 dB with a thickness of 1.66 mm at 13.9 GHz and achieved an effective absorption bandwidth (EAB) of 4.4 GHz. Furthermore, the carbon matrix of Ni@C acts as protective layer for Ni NPs, which could provide stable microwave absorbing performance even after one year measurement. This work introduces a facile and versatile strategy to design rod-like carbon structure as high-efficiency and stable microwave absorbers.

Searching for novel anode materials to address the issues of poor cycle stability in the aqueous lithium-ion battery system is highly desirable. In this work, ammonium vanadium bronze (NH4 )2 V7 O16 with brick-like morphology has been investigated as an anode material for aqueous lithium-ion batteries and Li+ /Na+ hybrid ion batteries. The two novel full cell systems (NH4 )2 V7 O16 ||Li2 SO4 ||LiMn2 O4 and (NH4 )2 V7 O16 ||Na2 SO4 ||LiMn2 O4 both demonstrate good rate capability and excellent cycling performance. A capacity retention of 78.61 % after 500 cycles at 300 mA g-1 was demonstrated in the (NH4 )2 V7 O16 ||Li2 SO4 ||LiMn2 O4 system, whereas no capacity attenuation is observed in the (NH4 )2 V7 O16 ||Na2 SO4 ||LiMn2 O4 system. The reaction mechanisms of the (NH4 )2 V7 O16 electrode and impedance variation of the two full cells were also researched. The excellent cycling stability suggests that layered (NH4 )2 V7 O16 can be a promising anode material for aqueous rechargeable lithium-ion batteries.

Geometrically frustrated systems play an important role in studying new physical phenomena and unconventional thermodynamics. Charge ordered defect pyrochlores AM2+M3+F6 offer a convenient platform for probing the interplay between electron distribution over M2+ and M3+ sites and structural distortions; however, they are limited to compounds with M2+/3+ = V, Fe, Ni, and Cu due to difficulties in the simultaneous stabilization of other 3d elements in the +2 and +3 oxidation states. Herein, we employ Cl- anions under hydrothermal conditions for the mild reduction of Mn2O3 in concentrated HF to obtain the CsMn2+Mn3+F6 composition as a phase pure sample and study its properties. The magnetism of CsMn2F6 was characterized by measuring the magnetic susceptibility and isothermal magnetization data, and a magnetic transition to a canted antiferromagnet state was found at 24.1 K. We determined the magnetic structure of CsMn2F6 using powder neutron diffraction, which revealed successive long-range ordering of the Mn2+ and Mn3+ sites that is accompanied by a second transition. The role and strength of magnetic exchange interactions were characterized using DFT calculations.

Considering the full utilization of energy and pursuing thin-film capacitors with high energy-storage density, the grain size engineering is used to adjust domain size, in order to enhance the energy-storage efficiency and energy-storage density of thin-film capacitors. Therefore, in this work, lead-free Bi0.5Na0.5TiO3 (BNT) films with designed grain size were grown on Nb-doped SrTiO3 (Nb:STO) (001) single-crystalline substrates by modulating the mineralizer concentrations via hydrothermal synthesis. The nature of epitaxial growth near the single-crystalline substrates was proved by transmission electron microscopy (TEM). In addition, the phenomenon of the decrease of grain size and the increase of [100] in-plane orientation with the decline of mineralizer concentrations were clarified by grazing-angle incidence X-ray diffraction (GIXRD) and field emission scanning electron microscope (FESEM). By reducing the grain size, an ultrahigh energy-storage efficiency (η) of 75.56% and superior the recoverable energy-storage density (Wrec) of 16.47 J/cm3 were acquired in pure Bi0.5Na0.5TiO3 films. Furthermore, the fine-grained film exhibits weak dependence on the frequency and has excellent anti-fatigue property. Therefore, hydrothermal synthesis is an efficient, inexpensive, and easy method, which is the most promising way to adjust grain size and energy storage of the film capacitor.