Search

In this study, we used a 6-methyl-2,3-pyridine dicarboxylate ligand to develop the frameworks. Two novel compounds, [Zn2(L)2(H2O)4] (1) and [Cd(L)(H2O)] (2) (where L = 6-methyl-pyridine-2,3-dicarboxylate) were produced. The compounds were characterized by elemental analysis, powder X-ray diffraction, Fourier-transform infrared spectroscopy and single crystal X-ray crystallography. We successfully tuned the framework dimensionality by varying the size of the metal ions from small Zn to large Cd ions. Single crystal X-ray investigations of compound 1 show a good dimeric motif, while compound 2 shows a 2D network. In compound 1, the dimeric units are further bonded by strong hydrogen bonds and create a 3D network whereas compound 2 produces a 2D layer that in turn connects via short contacts to form a 3D network in the crystallographic space.

Multidrug-resistant strains (MDRs) are becoming a major concern in a variety of settings, including water treatment and the medical industry. Well-dispersed catalysts such as BiPO4, ZnO nanoparticles (NPs), and different ratios of BiPO4/ZnO nanocomposites (NCs) were synthesized through hydrothermal treatments. The morphological behavior of the prepared catalysts was characterized using XRD, Raman spectra, PL, UV–Vis diffuse reflectance spectroscopy (UV-DRS), SEM, EDX, and Fe-SEM. MDRs were isolated and identified by the 16s rDNA technique as belonging to B. flexus, B. filamentosus, P. stutzeri, and A. baumannii. The antibacterial activity against MDRs and the photocatalytic methylene blue (MB) dye degradation activity of the synthesized NPs and NCs were studied. The results demonstrate that the prepared BiPO4/ZnO-NCs (B1Z4-75:300; NCs-4) caused a maximum growth inhibition of 20 mm against A. baumannii and a minimum growth inhibition of 12 mm against B. filamentosus at 80 μg mL−1 concentrations of the NPs and NCs. Thus, NCs-4 might be a suitable alternative to further explore and develop as an antibacterial agent. The obtained results statistically justified the data (p ≤ 0.05) via one-way analysis of variance (ANOVA). According to the results of the antibacterial and photocatalytic study, we selected the best bimetallic NCs-4 for the photoexcited antibacterial effect of MDRs, including Gram ve+ and Gram ve− strains, via UV light irradiation. The flower-like NCs-4 composites showed more effectiveness than those of BiPO4, ZnO, and other ratios of NCs. The results encourage the development of flower-like NCs-4 to enhance the photocatalytic antibacterial technique for water purification.

Rare-earth-doped GdPO4 nanoparticles have recently attracted much scientific interest due to the simultaneous optical and magnetic properties of these materials and their possible application in bio-imaging. Herein, we report the hydrothermal synthesis of GdPO4:Eu3+ nanoparticles by varying different synthesis parameters: pH, : molar ratio, and Eu3+ concentration. It turned out that the Eu3+ content in the synthesized nanoparticles had little effect on particle shape and morphology. The synthesis media pH, however, has showed a pronounced impact on particle size and distribution, i.e., the nanoparticle length can be adjusted from hundreds to tens of nanometers by changing the pH from 2 to 11, respectively. Increasing the : molar ratio resulted in a decrease in nanoparticle length and an increase in its width. The temperature-dependent measurements in the 77–500 K range revealed that the GdPO4:50%Eu3+ sample maintains half of its emission intensity, even at room temperature (TQ1/2 = 291 ± 19 K).

Niobium-based oxides can be used in several applications due to a diverse set of properties. In this work, Na2Nb2O6.H2O sodium niobate nanowires were obtained by hydrothermal synthesis at low temperature. Dehydrated sodium niobate (Na2Nb2O6) and sodium niobate with perovskite structure (NaNbO3) were obtained by submitting Na2Nb2O6.H2O to heat treatment (350 °C and 500 °C, respectively). To obtain protonic niobates, sodium niobates were immersed in nitric acid in order to promote ion exchange reactions. From this procedure, protonic niobates (H3O)2Nb2O6.H2O and (H3O)2Nb2O6 were obtained. The sample NaNbO3 did not undergo any transformation. Cyclic voltammetry tests carried out in a neutral aqueous solution 1 M Na2SO4 showed a wide potential window for both niobates (sodium and protonic). However, the protonic niobate samples (H3O)2Nb2O6.H2O and (H3O)2Nb2O6 presented much higher current density values than the sodium niobates. This result can be related to a structural rearrangement that allowed a significant increase in the intercalation of sodium Na + ions from the electrolyte into the structure of these protonic niobates, when polarized. Therefore, in this work, it was demonstrated that it is possible to obtain protonic niobates from sodium niobates, as well as, it was verified the distinct electrochemical behavior between these materials.

Manganese dioxide compounds are widely used in electrochemical applications e.g. as electrode materials or photocatalysts. One of the most used polymorphs is gamma-MnO2 which is a disordered intergrowth of pyrolusite beta-MnO2 and ramsdellite R-MnO2. The presence of intergrowth defects alters the material properties, however, they are difficult to characterise using standard X-ray diffraction due to anisotropic broadening of Bragg reflections. We here propose a characterisation method for intergrown structures by modelling of X-ray diffraction patterns and pair distribution functions (PDF) using gamma-MnO2 as an example. Firstly, we present a fast peak-fitting analysis approach, where features in experimental diffraction patterns and PDFs are matched to simulated patterns from intergrowth structures, allowing quick characterisation of defect densities. Secondly, we present a structure-mining-based analysis using simulated gamma-MnO2 superstructures which are compared to our experimental data to extract trends on defect densities with synthesis conditions. We applied the methodology to a series of gamma-MnO2 samples synthesised by a hydrothermal route. Our results show that with synthesis time, the intergrowth structure reorders from a R-like to a beta-like structure, with the beta-MnO2 fraction ranging from ca. 27 to 82% in the samples investigated here. Further analysis of the structure-mining results using machine learning can enable extraction of more nanostructural information such as the distribution and size of intergrown domains in the structure. Using this analysis, we observe segregation of R- and beta-MnO2 domains in the manganese oxide nanoparticles. While R-MnO2 domains keep a constant size of ca. 1-2 nm, the beta-MnO2 domains grow with synthesis time.

A series of Mo-containing MFI zeolites with different Mo loadings (Mo-MFI-n, n represent the initial Si/Mo molar ratio) was hydrothermally synthesized by using tetrapropylammonium hydroxide as the template and Mo-EDTA complex as the Mo source. Various characterization results demonstrated that the use of the Mo-EDTA complex is beneficial for the incorporation of more Mo species into the MFI-type zeolites. The special complexing capability of EDTA2– plays a critical role in adjusting the release rate of the Mo species to combine with the Si tetrahedron species during the zeolite growth process, thus leading to a uniform distribution of Mo in the MFI framework. In addition, a small portion of extra-framework Mo clusters may be distributed inside the channels or near the pore window of the zeolites. The catalytic properties of these Mo-containing MFI zeolites were evaluated for the epoxidation of cyclohexene with H2O2 as the oxidant. The composition-optimized catalyst, Mo-MFI-50, efficiently converted cyclohexene to the corresponding epoxide with a relatively high conversion (93%) and epoxide selectivity (82%) at 75 °C after 9 h of reaction. Moreover, the resultant Mo-containing MFI catalyst exhibited excellent structural stability and recoverability and was easily recycled by simple filtration without the need for calcination treatment.

Propane dehydrogenation (PDH), employing Pt- or Cr-based catalysts, represents an emerging industrial route for propylene production. Due to the scarcity of platinum and the toxicity of chromium, alternative PDH catalysts are being pursued. Herein, we report the construction of Zn-containing zeolite catalysts, namely Zn@S-1, for PDH reaction. Well-isolated zinc cations are successfully trapped and stabilized by the Si-OH groups in S-1 zeolites via in-situ hydrothermal synthesis. The as-prepared Zn@S-1 catalysts exhibit good dehydrogenation activity, high propylene selectivity, and regeneration capability in PDH reaction under employed conditions. The in-situ partial reduction of zinc species is observed and the partially reduced zinc cations are definitely identified as the active sites for PDH reaction.

NiMoS2 is a promising material for various functional applications and highly compatible with GO to make hybrid nanocomposites with excellent characteristics for supercapacitor electrode material. Deposition of NiMoS2 was achieved on the rGO(reduced Graphene Oxide) surface to form a NiMoS2−rGO nanocomposite by the method of the facile hydrothermal synthesis process. XRD pattern shows the crystalline nature of composites. Raman and EPMA result interpreting the composites formation and elements compositions, respectively. The sheet-like morphology of rGO was found in the composites by FESEM images. Particles distribution was confirmed by HR-TEM. The electrochemical properties of the pure NiMoS2 and NiMoS2–rGO composites have been studied by cyclic voltammetry analysis. The results revealed that the NiMoS2/5% rGO nanocomposites exhibit high specific capacitance compared to pure NiMoS2 due to the synergistic effects of NiMoS2 and rGO in the composite material. The photocatalytic behavior of the prepared nanocomposites for dye degradation was tested. The quantity of rGO has significantly improved the photocatalytic behavior of NiMoS2/rGO composites. The studies on degradation mechanism, the N2 adsorption/desorption isotherms, pore size distribution behavior and % of removal of MB reveal the enhanced photocatalytic performance of sysnthesised composites.

Herein, we report the single-step synthesis of ZnO nanostructures by a simple urea hydrolysis method. Pure phase ZnO and hydrozincite (Zn5(CO3)2 (OH)6) nanostructures are easily obtained separately at the optimized hydrothermal conditions, which involve controlling the urea concentration and reaction parameters such as temperature and time. Outside of these conditions, hydrozincite (Zn5(CO3)2 (OH)6) with a small admixture of basic zinc carbonate Zn4CO3 (OH)6⋅H2O are obtained as by products. X-ray diffraction and electron microscopy reveal that the obtained ZnO sample is comprised of spherical nanoparticles and have a hexagonal wurtzite crystalline structure. Further, a single-step synthesis approach was developed that produces micron sized rod-shaped ZnO structures.

Outstanding ferroelectric and piezoelectric properties of PbZrxTi1-xO3 (PZT) make nano and sub-micrometer particles of this material interesting for future nanotechnological applications as well as for fundamental studies of ferroelectricity at the nanoscale. In the present work, the prospects of a new hydrothermal approach were explored to control the particle size, aggregation stage, and composition of the PZT with the target composition of Zr/Ti = 60/40 (x = 0.6). Starting with water-soluble Zr-, Ti-, and Pb-precursors, the PZT formation was examined in the broad base (KOH) concentration range. The PZT particle size and composition were governed by the ratio of KOH with respect to Pb and not by the absolute KOH concentration (cKOH). The incorporation of Zr into the PZT perovskite phase began to decline at KOH:Pb ≤ 1.7 and at KOH:Pb > 20. In the concentration range of 20 ≥ KOH:Pb > 1.5, the PZT particles adopted a cube-like shape, the size of which decreased with a decrease in the KOH:Pb ratio. The smallest (

We provide the material synthesis method, crystal structure information, and characterization of a novel mixed-valent metal oxide KIn0.33IIITe0.67VITe2IVO7, closely related to zirconolite (CaZrTi2O7), a radioactive waste immobilized material, having a 3D framework. The reported metal oxide containing an alkali-metal cation (K+), main-group cation (In3+), tellurate, and tellurite has been synthesized as both single crystals and a pure polycrystalline phase through a hydrothermal synthesis method. Single-crystal X-ray diffraction indicates that KIn0.33Te2.67O7 crystallizing in the orthorhombic space group Cmcm (No. 63) reveals a 3D framework structure with a 1D channel consisting of Te/InO6 octahedra and TeO4 polyhedra. An interesting transition reaction from KIn0.33Te2.67O7 to KIn(TeO3)2 under hydrothermal conditions at 230 °C is discussed.

We report the hydrothermal syntheses of three uranyl oxide hydroxy-hydrate (UOH) materials containing Sm(III) ions (UOH-Sm) by controlling the solution pH and a new way to make Sm-doped porous uranium oxides with different U-to-Sm atomic ratios via their thermal decompositions. While layer-structured UOH-Sm phases with U-to-Sm atomic ratios of 1 (UOH-Sm1) and 4 (UOH-Sm2) were obtained from the reaction of schoepite and samarium nitrate with final solution pH values of over 4, similar reactions without pH adjustment with final solution pH values of less than 4 led to the formation of a uranyl oxide framework (UOF-Sm) with a U-to-Sm atomic ratio of 5.5. The crystal structure of compound UOF-Sm was revealed with synchrotron single-crystal X-ray diffraction and confirmed with transmission electron microscopy. The two-dimensional uranyl oxide hydroxide layers, similar to that for β-U3O8, are linked by double pentagonal uranyl polyhedra to form a three-dimensional framework with Sm(III) ions in the channels. Scanning electron microscopy characterization revealed nanoplate crystal morphologies for the two UOH-Sm phases, in contrast to the needle morphology for UOF-Sm. Subsequent thermal treatments led to the formation of Sm-doped uranium oxides, maintaining the original crystal shapes and U-to-Sm ratios but with nanopores. This work demonstrated that the hydrothermal synthesis conditions, especially fine-tuning of the solution pH, have a significant impact on the uranium hydrolysis, thus leading to well-defined products. This will facilitate the targeted syntheses of UOH phases with lanthanide (Ln) ions and explore the subsequent applications of these materials and Ln-doped porous uranium oxides as potential nuclear or functional materials.

A facile “green chemistry” hydrothermal method of chitosan-Ag nanoparticles (NPs) synthesis has been proposed. Chitosans of different molecular weight (from 20 to 1200 kDa) have been used as reducing agents and particle stabilizers. The obtained chitosan–Ag nanocomposites have been studied by UV–Vis and IR spectroscopy, X-ray powder diffraction analysis, and transmission electron microscopy. Nanocomposites have a “core-shell” structure, spherical shape with size up to 60.0 nm and the surface ξ-potential value >40.0 mV. Optimal parameters of synthesis (time, temperature, molecular weight of chitosan) of chitosan–Ag nanoparticles with highest antimicrobial activity against gram-positive and gram-negative bacteria and fungi have been found.

In this paper, a hydrothermal synthesis method synthesized a foamed nickel (NF)-supported Ag-doped Ag2S@MoS2 hydrogen evolution catalyst. Silver doping can improve the conductivity of MoS2, thereby improving the hydrogen evolution activity of MoS2. Compared with a single MoS2, the Ag2S@MoS2 electrode has a larger specific surface area and has many highly catalytic S edges. In 1 M KOH, the overpotential of Ag2S@Ag0.33MoS2/NF electrode at 10 mA cm−2 is approximately 188 mV. Comparing with the overpotential of NF (391 mV) and MoS2/NF (290 mV), it is much lower. Further changing the amount of silver added, the overpotential of Ag2S@Ag0.5MoS 2/NF is further reduced to 165 mV at a current density of 10 mA cm−2. When the voltage is 0.35 V, the current densities of Ag2S@Ag0.33MoS2/NF (42.45 mA cm−2) and Ag2S@Ag0.5MoS2/NF (55.5 mA cm−2) are higher than those of NF (4.91 mA cm−2) and MoS2/NF (20.51 mA cm−2).

A novel sodium bismuth oxo-cuprate phosphate chloride, Na6Cu7BiO4(PO4)4[Cl2.23(OH)0.77], containing square-kagome layers of Cu2+ has been synthesized by hydrothermal techniques. The compound crystallizes in the tetragonal space group P4/nmm, a = 10.0176(4), c = 10.8545(6), Z = 2, V = 1089.3(1) A3, R1 = 0.021, wR = 0.053, S = 1.32. Its composite crystal structure includes [O4Cu6Bi]7+ layers, which are formed by the clusters of oxygen-centered tetrahedra [OCu3Bi]. These positively charged two periodic fragments are intercalated in a negatively charged [CuNa6Cl3(PO4)4]7- matrix built by Na-centered polyhedra, PO4 tetrahedra, and CuO4Cl pyramids. The composite character of the crystal structure of Na6Cu7BiO4(PO4)4[Cl2.23(OH)0.77], as well as the way of its self-assembly, are discussed in close connection with the sulfohalite Na6ClF(SO4)2 salt. It is shown that the "host-guest" model of the formation of the tetragonal Na6Cu7BiO4(PO4)4[Cl2.23(OH)0.77] phase is due to the group-subgroup symmetry relation with the cubic crystal structure of mineral sulfohalite and is also supported by the crystallization condition in excess sodium chloride. The magnetic subsystem of Na6Cu7BiO4(PO4)4[Cl2.23(OH)0.77] is represented by a dense square-kagome network of 2Cu1 and 4Cu2 ions, decorated with weakly bonded Cu3 ions. Measurements of magnetization and heat capacity indicate the absence of long-range order up to 2 K, which makes this compound a candidate for a highly demanded spin liquid.

A tetraimidazole-decorating tetraphenylpyrazine has been designed and utilized for the fabrication of a novel metal-organic framework (MOF), denoted as {Mn(Tipp)(A)2}n·2H2O (TippMn, where Tipp = 2,3,5,6-tetrakis[4-[(1H-imidazol-1-yl)methyl]phenyl]pyrazine and A = deprotonation of 1,4-naphthalenedicarboxylic acid), through hydrothermal synthesis. Structural analysis reveals that TippMn possesses a 2-fold-interpenetrated 4,8-connected three-dimensional (3D) network with an unprecedented {416·612}{44·62} topology. Fluorescent spectral investigations indicate that TippMn shows discriminative fluorescence when treated by Cr3+ and Cu2+, giving an INHIBIT logical gate performance. Meanwhile, TippMn can be further used as a sensor for MnO4- and 2,4,6-trinitrophenol (TNP) by fluorescence quenching. Notably, the sensing processes toward Cu2+, Cr3+, MnO4-, and TNP are labeled with high selectivity and sensitivity, quick response, and good recyclability. It is anticipated that this MOF-based versatile sensor could shed light on the exploration of MOFs for fluorescent sensors, optical switches, etc.

The rapid deactivation caused by coke deposits is the major obstacle to the ethane aromatization of Zn-based catalysts. We have successfully synthesized a Zn-embedded inside HZSM-5 crystal catalyst (Zn@HZSM-5) by hydrothermal synthesis using preformed Zn/SiO2 as the only silicone source. Based on various characterization results, including in situ etching XPS, operando DRIFTS, as well as NMR, it is found that Zn(OH)+ and [Zn–O–Zn]2+ species are active sites for ethane aromatization for zinc-based catalysts, and their dynamic transformation significantly changes reaction performance of ethane dehydrogenation. For the Zn/HZSM-5 catalyst, the existence of a large number of [Zn–O–Zn]2+ species causes higher initial ethane conversion and higher selectivity of aromatics, resulting in a large amount of coke deposits. Moreover, [Zn–O–Zn]2+ species on the Zn/HZSM-5 catalyst fast transit to Zn(OH)+ species and subsequently form the sintered ZnO species, leading to rapid deactivation. For the Zn@HZSM-5 catalyst, the embedded structure contributes to forming more Zn(OH)+ species and delays the transformation of the Zn(OH)+ species to [Zn–O–Zn]2+ species, resulting in slowly increased selectivity of aromatics during the reaction. Therefore, the Zn@HZSM-5 catalyst realizes stable ethane conversion with dynamic selectivity.

Hydroxyapatite (HAp) of different morphologies was prepared by the direct decomposition of calcium lactate pentahydrate chelates using dipotassium hydrogen phosphate under hydrothermal conditions. The proposed technique allows for precise control of the HAp crystals morphology and product purity, which are necessary for biomedical applications. The synthesis parameters such as reagent concentrations, pH, reaction time, temperature, pressure, and stirring rate were optimized in order to produce calcium phosphates (CaPs) ceramics with restricted morphologies and composition. As a result, we obtained hydroxyapatite in the form of whiskers, hexagonal rods, nano particles, flowers, and cylinders. The products were characterized according to their structure (FTIR and XRD), morphology (SEM), and functional properties, i.e., the specific surface area. The obtained results indicate that the reagent concentration and pH values have the greatest impact on the HAp properties; however, the proper combination of all the mentioned parameters should be considered when there is a need for a bioceramic with defined physicochemical properties and an appropriate morphology.

BACKGROUND With the increasing environmental pollution issues arising from NOx, the low-temperature selective catalytic reduction (LT-SCR) of NOx by NH3 is becoming more important. Mn/Fe mixed oxides type catalysts have been proven to be particularly effective at low temperature reactions; however, the synthesis method can be a key factor determining the SCR activities. RESULTS A comprehensive study of LT-SCR was carried out on a series of Mn/Fe mixed oxides catalysts prepared using diverse synthesis methods, namely, sonication assisted continuous coprecipitation (SACP), equilibrium adsorption (EA), precipitation method using either NaOH (P-OH) or Na2CO3 (P-CO) as precipitant, and one pot hydrothermal synthesis (CA). The morphology, composition, crystal property, oxidation status, and surface property were systematically characterised. LT-SCR of the NOx performance of prepared Mn/Fe catalysts was conducted in temperatures from 75 to 225 °C. It was demonstrated that, at reaction temperatures under 125 °C, LT-SCR performance showed the trend of P-OH > SACP > EA ~ CA > P-CO; meanwhile, the trend was CA > SACP > P-OH ~ EA > P-CO at temperatures over 125 °C. However, N2 selectivity showed the trend SACP > CA > P-OH overall. CONCLUSION The characterisation results suggested that NOx conversion performance is controlled by several parameters, especially uniformity of materials, high surface area, Mn crystallinity, surface oxygen defects, Fe (III) on the surface; these are important parameters to achieve high denitrification performance as shown by P-OH and SACP under low temperature. At higher temperatures, the stability of materials and high Bronsted acid sites on the surface are important, leading to better performance by CA and SACP.

Our previous work reported a new strategy based on a P excess reaction system to hydrothermally synthesize lithium transition metal phosphates (LiMPO4), and herein the effect of P excess on the synthesis and property of LiMPO4 is investigated in detail by taking the multi-component LiMn0.8Fe0.19Mg0.01PO4 as a case. The results show that a proper degree of P excess is fairly profitable for hydrothermal synthesis including the effect on suppressing the occurrence of undesired Fe2+ oxidation during synthesis and improving the particle dispersion of hydrothermal product, and thus the obtained samples have enhanced electrochemical performance. These effects of P excess should be general and applicable to hydrothermal synthesis of other lithium transition metal phosphates.

A novel modification of the KCoPO4, δ-phase has been prepared by hydrothermal synthesis at 553 K. The compound crystallizes in the orthorhombic system with the unit-cell parameters a = 8.5031(8), b = 10.2830(5), c = 54.170(4) A. The crystal structure was determined based on synchrotron low-temperature single-crystal X-ray diffraction data obtained from an inversion twin in the space group P212121 and refined to R = 0.077 for 5156 reflections with I > 3σ(I). The δ-KCoPO4 possesses a new structure type which is based on a framework built from sharing vertices Co- and P-centered tetrahedra. The {CoPO4-}∞ construction of tetrahedra may be described as assembled from networks formed by two topologically diverse six-membered rings of tetrahedra stacked together through vertex-bridging contacts along the a axis. The ratio of the (UUUDDD) and (UUDUDD) rings, where (U) and (D) denote the orientation of the tetrahedra in the six-membered rings up and down relative to the plane grids, is equal to 5:1. The (UUDUDD) rings form bands parallel to the [010] direction each surrounded from both sides along the c axis by slabs of five ribbons width having alternative (UUUDDD) topology. Open in the [100] direction channels incorporate K+ ions; this structural feature permits to suppose ion-conductive and/or electrochemical properties of the title compound. The possible mechanism of the δ → γ phase transition is discussed on the basis of the crystal chemical analysis of the KCoPO4 polymorphs. The title compound orders magnetically at TN = 24.8 K.

Fluorescent nanostructures based on carbon, or carbon dots, are attracting much attention and interest because of their diverse properties which can be applied in several fields of knowledge, such as optics, biomedicine, environmental research, among others. Such properties are in part, derived from its intrinsic luminescence from tunable functional groups. In this work, we produced carbon nanodots (CND) using agro-industrial residues, such as Lolium perenne and malt bagasse. The methods used were conventional hydrothermal syntheses and microwave-assisted hydrothermal synthesis. To the best of our knowledge, this is the first time that carbon dots synthesized from this ryegrass type are reported. The synthesis methods were one step (no catalyst, base, or acid were added for passivation), and the functional groups responsible for the luminescence and high solubility in water were identified by infrared spectroscopy, being mainly C=O, C–OH, C–N, and N–H. According to our theoretical studies, the C=O group introduced a new energy level for electronic transitions that can affect the emission properties. Fluorescence images of osteoblasts using CNDs were acquired and their chelating property towards Pb2+ and Cr6+ detection was tested.

In order to improve the current environmental pollution caused by discarded pesticide packages in rural areas, and raise awareness of agricultural ecological environmental protection. Rare earth ions (RE3+ = Ce3+, Sm3+, Pr3+, La3+) doped titanium dioxide (TiO2) catalysts were prepared by sol-hydrothermal method and characterized by XRD, SEM, TEM, XPS, BET, UV–vis DRS, PL, EPR, and density functional theory (DFT) calculations. The characterization results showed that the doped rare earth ions replace Ti4+ into the titania lattice. The activity of the RE3+-doped TiO2 photocatalyst was evaluated by degrading methyl orange (MO) and mixed pesticides (also containing pirimicarb, fenthiophos, triadimefon and deltamethrin) under ultraviolet light. Compared with pure TiO2, RE3+-doped TiO2 has significantly improved photocatalytic activity for the degradation of MO and carbamate pesticides. The degradation rate of Sm-TiO2 sample to degrade MO reached 100% within 60 min, and the degradation rate of degrading aphicarb, fenthion, triadimefon and deltamethrin reached more than 90% within 180 min. Sm-TiO2 is the best catalyst. This can be attributed to a synergistic effect of the doping of Sm3+ introduces impurity energy levels and a large number of oxygen vacancies (OVs), which can more effectively capture photogenerated electrons and reduce the recombination rate of photogenerated electrons-holes. In this study, the sol-hydrothermal method was used to develop a high-efficiency catalyst for simultaneous photocatalytic degradation of various organic pollutants in aqueous solutions.

Polyimide is one of the most important high-performance polymers, which is widely used due to its excellent mechanical performance and thermal stability. Unlike the conventional synthetic approach, hydrothermal polymerization enables the synthesis of polyimides without any toxic solvent and catalyst. Herein, we report the synthesis of polyimide-based microparticles (PIMs) through one-pot hydrothermal polymerization using precursors of mellitic acid (MA) and three isomers of phenylenediamine (PDA) (o-, m-, and p-PDA). Interestingly, the chemical composition of PIMs was highly tunable with the choice of the PDA isomers, leading to considerable morphological differences between PIMs. The molecular dynamics simulation and density functional theory calculation of the polymeric segment of the respective PIMs suggested that the relative ratio of amide to imide influenced the rotational freedom of the polymeric chains and number of hydrogen bonds, resulting in the well-defined structures of respective PIMs. Consi...

Ultraviolet (UV) photodetectors have attracted increasing attention in military and civilian fields.In this work, the prepared TiO2-graphene composite was fabricated by hydrothermal synthesis metho...

The transformation of gibbsite into boehmite upon hydrothermal treatment at 200°C in 1.5 wt % NaOH have been studied by X-ray powder diffraction, IR spectroscopy, Brunauer–Emmett–Teller, differential scanning calorimetry, and scanning electron microscopy. The stages of the process have been determined. The transformation of gibbsite into boehmite in an alkaline medium takes 1 h and is accompanied by the splitting of gibbsite into boehmite plates with an average particle size of ~1 μm. It has been shown that, upon hydrothermal treatment of gibbsite in a 1.5 wt % NaOH solution, lamellar boehmite particles are formed for 24 h. This makes it possible to recommend the synthesized powder boehmite to be used as an additive to oils, in the production of concrete, fire retardants, and as an intermediate phase in the synthesis of α‑Al2O3 powders

To deal with rapid depletion of fossil fuels and increasing demand of energy, development of highly efficient non-noble metal based catalyst has attracted much attention. Therefore, in this study r...