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Objectives. To examine the general principles and recent advances in the synthesis of high-purity and high-homogeneity barium titanate powders in the manufacture of electronic components.Results. The main publications regarding the synthesis of barium titanate powder, including the works of recent years, were analyzed. The technological advantages and disadvantages of various synthesis methods were identified. Groups of methods based on solid-state interaction of reagents and methods of “wet chemistry” were also considered. The possibilities of producing barium titanate particles of non-isometric shapes for creating textured ceramics were discussed separately.Conclusions. Barium titanate is a well-known ferroelectric with a high dielectric constant and low dielectric loss. It is used as a component in ceramic electronic products, for example, capacitors, memory devices, optoelectronic devices, and piezoelectric transducers. The possibilities of producing functional ceramics based on barium titanate powder largely depend on its state and morphological characteristics, determined during the synthesis stage. The most important factors affecting the functional characteristics of ceramics are the purity and morphology of the powder raw materials used.

Currently, the search for new types of carriers for low-molecular weight substances, as well as the development of optimal methods for the eff ective encapsulation of these substances are important tasks of modern chemistry and pharmacology. However, there are still limitations in this area, among which one of the most signifi cant is the lack of the optimal carrier capable of stably retaining a low-molecular weight substance. The work presents hybrid polymer structures obtained by in situ hydrothermal synthesis as an eff ective candidate for these purposes. The fl uorescent dye rhodamine B has been used as a model low-molecular weight substance for encapsulation into the structures. The resulting hybrid polymer structures demonstrated good stability when stored in an aqueous environment for 336 h with the release of the low-molecular weight dye rhodamine B no more than 2%. In addition, the infl uence of the conditions for obtaining hybrid carriers (including the composition of the carriers (thickness of the polymer shell and the presence of a calcium carbonate core) and synthesis temperature) on their physical-chemical characteristics has been studied. Thus, the optimal approach for obtaining fl uorescent hybrid polymer carriers with a set of desired properties has been revealed. In particular, it has been shown that the optimal production conditions are hydrothermal synthesis temperature of 180 °C and the absence of CaCO3 core inside the polyelectrolyte shell which allow us to obtain a stable hybrid polymer carrier with bright fl uorescence. The results presented in this study can be used to create functional platforms and systems with tunable fl uorescent properties and the ability to deliver low-molecular weight substances.

Calcination temperature is a crucial parameter that can be easily controlled to induce a change in material properties. Herein, iron tungstate (FeWO4) was synthesized via a hydrothermal method using iron(II) sulfate heptahydrate and sodium tungstate dihydrate as precursors and calcined at the temperature between 300 oC and 700 oC. With increasing calcination temperature, the saturation magnetization of FeWO4 nanoparticles decreased from 6.6 emu/g for FeWO4 to 0.4 emu/g for FeWO4_700, whereas their band gaps increased from 1.95 eV for FeWO4 to 2.20 eV for FeWO4_700. More crystallinity and crystal defects, and morphological changes at higher calcination temperatures contributed to varying magneto-optical properties of FeWO4 nanoparticles.

Abstract KAlPO4F was prepared hydrothermally at 453 K, a time-saving method using cheap reagents. The white solid was characterized by different methods such as powder X-ray diffraction, thermal analysis, SEM and UV–Vis diffuse reflectance. The compound was successfully tested for the removal of methyl violet (MV), a hazardous dye. Experiments were carried out as a function of contact time, initial concentration, temperature and pH. The amount of dye uptake was found to vary with increasing initial solution pH and maximum adsorption was observed at pH 10; the equilibrium was attained in 270 min. The amount of dye uptake (mg/g) was found to increase with increase in dye concentration and contact time. The pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models were applied to fit the experimental data to elucidate the kinetic adsorption. The pseudo-second-order model was the best to describe the adsorption process. Different models analyzed the equilibrium isotherms; the applicability for the experimental data follows the order: Freundlich > Langmuir > Temkin. The thermodynamic parameters: ΔH° (39.034 kJ mol−1), ΔS° (134 J K−1 mol−1) and ΔG° (− 367.01 J mol−1) indicated that the adsorption process is endothermic and spontaneous with increasing disorder at the solid–solution interface.

Developing advanced electrode materials for supercapacitors (SCs) has received incredible attention. The suitable electrode for high capacitance and energy density are significant challenges for SCs. This work reports an efficient hydrothermal synthesis of MoS2 nanosheets on carbon cloth (MoS2@CC). The large surface area of the binder-free MoS2@CC electrode provides rich active sites and an improved electrolyte ion diffusion rate. The MoS2@CC electrode exhibits good electrochemical performance by delivering a high specific capacitance of 947 F g−1 at the current density of 1.0 A g−1 and retains an excellent capacitance of 96.5% over 10 000 cycles. The high performance of the MoS2@CC electrode can be clarified through density functional theory (DFT) calculations. The DFT outcomes reveal that the electrode possesses favorable Li-ion intercalation and adsorption properties. The calculated adsorption energy of −0.352 eV at the hollow site shows the high stability of the system. The low energy barrier of path 1 (0.83 eV) easily facilitates Li-ions in the electrode material, which is beneficial for its fast electrochemical performance. The obtained results of the MoS2@CC electrode present improved pseudocapacitive performance, showing a significant possibility for high-performance SCs' application. [ABSTRACT FROM AUTHOR]

Mercury, emitted from various industries, is toxic and has devastating environmental consequences. Therefore, it becomes imperative to monitor the levels of mercury closely. This work mainly focuses on preparing inexpensive zeolite-coated kaolin membranes for separating Hg2+ from water. The membrane support was prepared using kaolin (50 wt%), quartz (25 wt%), and calcium carbonate (25 wt%). This mixture was blended with a 3 % hydroxypropyl methylcellulose (HPMC) solution and then passed through an extruder to obtain tubular support, which was further sintered at 950 °C. The zeolite-coated membrane (ZP membrane) was fabricated by subjecting the sintered support to a 48-h hydrothermal synthesis in 7 Na2O: 1 Al2O3: 10 SiO2: 205H2O gel at 90 °C. The isoelectric point of the ZP membrane was estimated to be 4.5. The zeolite-coated membrane displayed a pure-water permeability of 22.7 × 10−9 m3/m2 s kPa, a porosity of 31.72 ± 0.86 %, and a pore size of 90 nm. The performance of the ZP membrane in separating the Hg2+ ion from an aqueous solution was investigated by pressure variations (69–345 kPa) and feed concentration (0.5–10 ppm). The results clearly showed that in all cases, the zeolite-P membrane exhibited more than 99 % rejection of Hg2+ ions from aqueous solutions during the filtration experiments. Thus, the prepared ZP membrane can effectively be used for the separation of Hg2+ ions from wastewater.

ABSTRACTAn effective low-cost nano NiO-In2O3 electrode material for oxygen evolution (OER) is presented. Electrochemical studies uncovered electrocatalytic recital in Ascorbic Acid, Hydrogen Peroxide (H2O2), and ethanol. The cubic crystal structure of NiO-In2O3 was revealed by XRD. FT-IR, FE-SEM and HR-TEM studies exploit the structure and morphology of NiO-In2O3. Electrochemistry of NiO-In2O3 uncovered high current density (900mA/cm2) at substantially low overpotential (230mV), realizing its OER recital. On top, high mass activity and turnover frequency by NiO-In2O3 comprehend improved electrical and semiconductive properties in H2O2. The NiO-In2O3 durability beyond 90 hours was estimated by chronopotentiometry (CP). The Impedance analysis (EIS) revealed low charge transfer resistance and high exchange current density. Given electrocatalytic studies, we found a direct relationship between NiO-In2O3 nanocomposite and the degradation of H2O2 compared to its counterparts. Hence, this strategy can be an alternative and potential source of hydrogen and oxygen production at commercial scale.Highlights A facile and effectual low-cost NiO-In2O3 electrocatalyst is developed for efficient OER in aqueous hydrogen peroxide.NiO-In2O3 nanocomposite showed high current density (900mA/cm2) at low overpotential grasping its oxygen evolution reaction (OER) concert.NiO-In2O3 Impedance analysis revealed its low charge transfer resistance, high exchange current density (Jexc.), high mass Activity, and high turnover frequency (TOF) in hydrogen peroxide, advocating enhanced electrical and semiconductive properties.NiO-In2O3 showed long-term durability (>90 h) at varying current densities, fostering its application as a potential electrocatalyst for OER/HER reactions.

The examination of photocatalyst powders for the total removal of pollutants from aqueous solutions is a vital research subject within the realm of environmental preservation. The objective of this study is to develop a photocatalyst heterojunction consisting of Zingiber/ZnO-H for the degradation of both the reactive red dye (RR 141) and ofloxacin antibiotic in wastewater. The current investigation outlines the process of synthesising a composite material by combining Zingiber montanum extract with zinc oxide (ZnO) by a hydrothermal method. The synthesis was conducted at a temperature of 180°C for a period of 4 hours. Consequently. The photocatalyst with a constructed heterojunction shown a notable enhancement in its photocatalytic activity as a result of the improved efficiency in charge separation at the interface. The application of economically viable solar energy facilitated the complete eradication of harmful pollutants through the process of detoxification. The removal of impurities occurs by a process that follows a first-order kinetics. Among the pollutants, RR141 demonstrates the greatest rate constant at 0.02 min-1, while ofloxacin has a rate constant of 0.01 min-1. The assessment of the stability of the produced photocatalyst was conducted after undergoing five cycles. This study additionally investigated the influence of sunshine on degradation, uncovering degradation rates of 97% for RR141 and 99% for ofloxacin when exposed to UV Lamp, and degradation rates of 97% for RR141 and 95% for ofloxacin when exposed to Solar Light. [ABSTRACT FROM AUTHOR]

A new noncentrosymmetric strontium borate, P1‐Sr2[B5O8(OH)]2 ⋅ [B(OH)3] ⋅ H2O (1), has been synthesized under the hydrothermal condition. The P1‐Sr2[B5O8(OH)]2 ⋅ [B(OH)3] ⋅ H2O shows a layered B−O network with 9‐ring windows in the ab plane. Sr2+ cations, H3BO3, and H2O molecules are located in the voids of layers and interlayers, respectively. The P1‐Sr2[B5O8(OH)]2 ⋅ [B(OH)3] ⋅ H2O is the first synthetic phase of veatchite, while the other three polymorphs are found in different natural minerals. This strontium borate is a potential deep‐ultraviolet‐transparent nonlinear‐optical (NLO) crystal whose second‐harmonic‐generation (SHG) intensity is 1.7 times that of KH2PO4 (KDP) and is phase‐matchable. The short wavelength cutoff edge of compound 1 is below 190 nm. Density functional theory (DFT) calculations show that the B−O units are responsible for the nonlinear optical property. [ABSTRACT FROM AUTHOR]

X-ray detectors based on scintillators are widely used in the fields of medical imaging, high-energy physics, geological exploration, and industrial detection. The development of scintillation materials with different characteristics has become the focus of considerable research interest. Herein, we report a facile hydrothermal synthesis of Gd- and Eu-codoped LiLuF4 microcrystals (MCs), which exhibit strong luminescence of Eu3+ ion characteristic emission, characterized by distinct red fluorescence emission. The research shows that Gd3+ co-doping effectively improved the sensitivity and light yield of LiLuF4:Eu MCs by regulating the proportion of co-doping ions. In addition, the detection limit is 140.72 nGy s−1 for LiLuF4:Eu,Gd MCs, approximately 39 times lower than the dose requirement of medical diagnosis. Based on LiLuF4:Eu,Gd MCs with the superior scintillation properties, a MC-composited film with 250 μm thickness was prepared by a direct coating method. The uniform and high-loading scintillation film exhibits outstanding imaging performance with a high spatial resolution of 14.8 LP mm−1, which confirms the application potential of X-ray imaging. [ABSTRACT FROM AUTHOR]

To improve the complexity and low catalytic performance and reduce the high cost of the traditional electrode preparation process for the sodium borohydride electro-oxidation reaction (BOR), in this work, a self-supported and efficient electrode material grown on nickel foam (CoNi/Co3O4/NF) was successfully designed using a simple hydrothermal synthesis method accompanied by the electrodeposition process. Benefiting from the three-dimensional nanoarray structure of CoNi/Co3O4/NF and the uniform distribution of Co and Ni modulating active sites by electrodeposition, the catalytic activity towards NaBH4 exhibits high efficiency. CoNi/Co3O4 exhibits excellent catalytic performance (up to 2157 mA cm−2 in 2 mol L−1 NaOH and 0.3 mol L−1 NaBH4), a high electrochemically active surface area (62.5 cm−2), and a low activation energy (15.56 kJ mol−1). The CoNi/Co3O4/NF electrode was further investigated on a direct sodium borohydride–hydrogen peroxide fuel cell (DBHPFC), which exhibited a maximum power density of 108.5 mW cm−2 and excellent stability. The excellent performance is mainly due to its unique nanoarray structure and electrodeposition distribution of Co and Ni active sites, which increases the electrochemical surface area and enhances the contact between the electrode and the electrolyte. [ABSTRACT FROM AUTHOR]

Recently, layered rare-earth hydroxides (LRHs) have received growing attention in the field of theranostics. We have previously reported the hydrothermal synthesis of layered terbium hydroxide (LTbH), which exhibited high biocompatibility, reversible uptake of a range of model drugs, and release-sensitive phosphorescence. Despite these favourable properties, LTbH particles produced by the reported method suffered from poor size-uniformity (670 ± 564 nm), and are thus not suitable for therapeutic applications. To ameliorate this issue, we first derive an optimised hydrothermal synthesis method to generate LTbH particles with a high degree of homogeneity and reproducibility, within a size range appropriate for in vivo applications (152 ± 59 nm, n = 6). Subsequently, we apply this optimised method to synthesise a selected range of LRH materials (R = Pr, Nd, Gd, Dy, Er, Yb), four of which produced particles with an average size under 200 nm (Pr, Nd, Gd, and Dy) without the need for further optimisation. Finally, we incorporate Gd and Tb into LRHs in varying molar ratios (1 : 3, 1 : 1, and 3 : 1) and assess the combined magnetic relaxivity and phosphorescence properties of the resultant LRH materials. The lead formulation, LGd1.41Tb0.59H, was demonstrated to significantly shorten the T2 relaxation time of water (r2 = 52.06 mM−1 s−1), in addition to exhibiting a strong phosphorescence signal (over twice that of the other LRH formulations, including previously reported LTbH), therefore holding great promise as a potential multi-modal medical imaging probe. [ABSTRACT FROM AUTHOR]

Hydrogen is known as the fuel for 21st century, the best and clean method to produce hydrogen is electrolysis of water. The oxygen evolution reaction (OER) is of vital position in water splitting, enabling the production of clean hydrogen fuel and contributing to renewable energy solutions. However, the inherently sluggish nature of the OER presents a major challenge for practical water electrolysis but at the same time electrocatalysts play a pivotal role by overcoming this challenge through accelerating the reaction kinetics and reducing the energy requirements. In the realm of electrocatalysts for OER, cobalt-based materials have gained significant attention due to their low overpotential and cost-effectiveness. Among prepared catalysts, the CoSe/CoO heterostructure has emerged as a standout performer, offering an optimal balance of efficiency and minimal overpotential. This electrocatalyst exhibits exceptional electrochemical performance, featuring a low 1.31 V onset potential (vs. RHE) and a mere 170 mV overpotential at a current density of 40 mA/cm2 for OER, setting a new standard for Co-based catalysts. Moreover, the CoSe/CoO heterostructure surpasses Co based bench mark electrocatalysts by displaying the lowest overpotential. Moreover, when subjected to controlled potential electrolysis at 1.65 V (vs. RHE) with a stable current density of 60 mA/cm2, it showcases remarkable electrochemical stability, affirming its practicality for real-world applications. The hydrothermal synthesis of CoSe, CoO, and their heterostructure (CoSe/CoO) represents a straightforward and accessible approach, rendering them as promising candidates for water splitting, specifically in the context of oxygen evolution. These outstanding results achieved with non-precious metal electrocatalysts open new avenues for practical OER applications, providing a platform for the scientific community to advance the development of effective electrocatalysts using non-noble metals in the field of electrochemical water splitting. • The prepared CoSe/CoO demonstrates remarkable OER activity compared to benchmark Co-based electrocatalysts. • The CoSe/CoO reveals excellent durability and stability which demonstrate it as a stable and efficient OER catalyst. • The CoSe/CoO illustrates competitive OER activity, with low overpotentials (η) of 170 mV at 40 mAcm−2 current density. • Results highlight its standing as cost effective, alternative and highly efficient electrocatalyst for OER. [ABSTRACT FROM AUTHOR]

A hydrothermal synthesis method was developed to produce high crystallinity ZSM-5 zeolite using coal gasification coarse slag (CGCS) as the raw material. Instead of the expensive NaOH(s.), Na2SiO3(s.) was utilized to activate, depolymerize, and recombine Si and Al elements in the CGCS. The mother liquor circulation technology was employed to recover and reuse raw materials and residual reagents (Na2SiO3(aq.) and TPABr), reducing waste emissions and enhancing resource utilization efficiency. The synthesized ZSM-5 had a specific surface area of 455.675 m2 g−1, pore volume of 0.284 cm3 g−1, and pore diameter of 2.496 nm. The influence of various factors on the morphology and crystallinity of ZSM-5 was investigated, resulting in the production of ZSM-5 with higher specific surface area and pore volume. Adsorption experiments showed that WU-ZSM-5 exhibited a removal efficiency of 85% for ammonia nitrogen (NH4+-N(aq.)), validating its effectiveness in coal chemical wastewater purification. The mother liquor recycling technology enabled zero-emission utilization of solid waste resources and improved the utilization rate of alkali and template to 90%. These results demonstrate the potential application of the developed method in the efficient treatment of coal chemical wastewater. [ABSTRACT FROM AUTHOR]

AbstractTwo novel Olefin-copper(I) coordination polymers, whose are named [Cu3(DADMP)Cl4]n (1) and [Cu2(DADMP)Br2]n (2) (DADMP = 1,4-Diallyl-2,5-Dimethyl-piperazine), were synthesized through the solvothermal reactions of CuCl, CuBr and 2,5-dimethyl-piperazine and further characterized by powder and single crystal X-ray diffraction, as well as elemental analysis and TGA. The title polymers crystallized in the monoclinic P21/C space, both featuring two-dimensional network structure. Their fluorescent properties were also investigated. [ABSTRACT FROM AUTHOR]

As the Brønsted acid sites in the 8-membered ring (8-MR) of mordenite (MOR) are reported to be the active center for dimethyl ether (DME) carbonylation reaction, it is of great importance to selectively increase the Brønsted acid amount in the 8-MR. Herein, a series of Fe-HMOR was prepared through one-pot hydrothermal synthesis by adding the EDTA–Fe complex into the gel. By combining XRD, FTIR, UV–Vis, Raman and XPS, it was found that the Fe atoms selectively substituted for the Al atoms in the 12-MR channels because of the large size of the EDTA–Fe complex. The NH3-TPD and Py-IR results showed that with the increase in Fe addition from Fe/Si = 0 to 0.02, the Brønsted acid sites derived from Si-OH-Al in the 8-MR first increased and then decreased, with the maximum at Fe/Si = 0.01. The Fe-modified MOR with Fe/Si = 0.01 showed the highest activity in DME carbonylation, which was three times that of HMOR. The TG/DTG results indicated that the carbon deposition and heavy coke formation in the spent Fe-HMOR catalysts were inhibited due to Fe addition. This work provides a practical way to design a catalyst with enhanced catalytic performance. [ABSTRACT FROM AUTHOR]

One-step hydrothermal method has been used to synthesize YMnO3@NiO (YMO@NO) photocatalysts with high photocatalytic activity for the degradation of oil and gas field wastewater under simulated solar irradiation. Through various characterization methods, it has been confirmed that the YMO@ NO photocatalyst comprises only YMO and NO, without any other impurities. The microstructure characterization confirmed that the YMO@NO photocatalyst was composed of large squares and fine particles, and heterojunction was formed at the interface of YMO and NO. The optical properties confirm that the YMO@NO photocatalyst has high UV-vis optical absorption coefficient, suggesting that it has high UV-vis photocatalytic activity. Taking oil and gas field wastewater as degradation object, YMO@NO photocatalyst showed the highest photocatalytic activity (98%) when the catalyst content was 1.5 g/L, the mass percentage of NO was 3%, and the irradiation time was 60 min. Capture and stability experiments confirm that the YMO@NO photocatalyst is recyclable and electrons, holes, hydroxyl radicals and superoxide radicals play major roles in the photocatalysis process. Based on experiments and theoretical calculations, a reasonable photocatalytic mechanism of the YMO@NO photocatalyst is proposed. [ABSTRACT FROM AUTHOR]

The supercritical hydrothermal synthesis of nanomaterials has gained significant attention due to its straightforward operation and the excellent performance of the resulting products. In this study, the supercritical hydrothermal method was used with Zn(CH3COO)2·2H2O as the precursor and deionized water and ethanol as the solvent. Nano-ZnO was synthesized under different reaction temperatures (300~500 °C), reaction times (5~15 min), reaction pressures (22~30 MPa), precursor concentrations (0.1~0.5 mol/L), and ratios of precursor to organic solvent (C2H5OH) (2:1~1:4). The effects of synthesis conditions on the morphology and size of ZnO were studied. It was found that properly increasing hydrothermal temperature and pressure and extending the hydrothermal time are conducive to the more regular morphology and smaller size of ZnO particles, which is mainly achieved through the change of reaction conditions affecting the hydrothermal reaction rate. Moreover, the addition of ethanol makes the morphology of nano-zno more regular and significantly inhibits the agglomeration phenomenon. In addition to the change in physical properties of the solvent, this may also be related to the chemical bond established between ethanol and ZnO. The results show that the optimum synthesis conditions of ZnO are 450 °C, 26 MPa, 0.3 mol/L, 10 min, and the molar ratio of precursor to ethanol is 1:3. [ABSTRACT FROM AUTHOR]

Binary transition metal oxide complexes (BTMOCs) in three-dimensional (3D) layered structures show great promise as electrodes for supercapacitors (SCs) due to their diverse oxidation states, which contribute to high specific capacitance. However, the synthesis of BTMOCs with 3D structures remains challenging yet crucial for their application. In this study, we present a novel approach utilizing a single-step hydrothermal technique to fabricate flower-shaped microspheres composed of a NiCo-based complex. Each microsphere consists of nanosheets with a mesoporous structure, enhancing the specific surface area to 23.66 m2 g−1 and facilitating efficient redox reactions. When employed as the working electrode for supercapacitors, the composite exhibits remarkable specific capacitance, achieving 888.8 F g−1 at 1 A g−1. Furthermore, it demonstrates notable electrochemical stability, retaining 52.08% capacitance after 10,000 cycles, and offers a high-power density of 225 W·kg−1, along with an energy density of 25 Wh·kg−1, showcasing its potential for energy storage applications. Additionally, an aqueous asymmetric supercapacitor (ASC) was assembled using NiCo microspheres-based complex and activated carbon (AC). Remarkably, the NiCo microspheres complex/AC configuration delivers a high specific capacitance of 250 F g−1 at 1 A g−1, with a high energy density of 88 Wh kg−1, for a power density of 800 W kg−1. The ASC also exhibits excellent long-term cyclability with 69% retention over 10,000 charge–discharge cycles. Furthermore, a series of two ASC devices demonstrated the capability to power commercial blue LEDs for a duration of at least 40 s. The simplicity of the synthesis process and the exceptional performance exhibited by the developed electrode materials hold considerable promise for applications in energy storage. [ABSTRACT FROM AUTHOR]

A novel porous Ni matrix with optimal pore structure and adequate mechanical property is successfully prepared by a modified spark plasma sintering progress, while a self-supporting HER electrode of Ni 3 Se 2 @Porous Ni is subsequently obtained via a facile one-step hydrothermal synthesis. Such the Ni 3 Se 2 @Porous Ni electrode has performed a superior conductivity, excellent catalytic activity and robust durability, which can be attributed to the strong covalent bonding between Ni 3 Se 2 and Ni matrix, abundant active sites of the vertically arranged nanosheets, as well as the metallurgically bonded metal skeleton, exhibiting a fascinating potential for the industrial application. [Display omitted] Developing efficient and durable self-supporting catalytic electrodes is an important way for industrial applications of hydrogen evolution reaction. Currently, commercial nickel foam (NF)-based electrode has been widely used due to its good catalytic performance. However, the NF consisting of smooth skeleton surface and large pores not only exhibits poor conductivity but also provides insufficient space for catalyst decoration and sufficient adhesion, resulting in inadequate catalytic performance and poor durability of NF-based electrodes. In this paper, a novel three-dimensional porous Ni substrate with multangular skeleton surface and small pore structure was prepared by a modified spark plasma sintering technique, and subsequently Ni 3 Se 2 @Porous Ni electrode with a large number of Ni 3 Se 2 nanosheets uniformly distributed on the surface was obtained by one-step in-situ selenization. The electrode exhibits outstanding conductivity and catalytic hydrogen evolution reaction, providing a low overpotential of 183 mV at a current density of 100 mA cm−2. Due to the strong interfacial bonding between Ni and Ni 3 Se 2 , the Ni 3 Se 2 @Porous Ni electrode shows strong durability, which can work stably at 85 mA cm−2 for more than 200 h. This work provides an effective strategy for the rational preparation of metal substrates for efficient and durable self-supporting catalytic electrodes. [ABSTRACT FROM AUTHOR]

After 3 h of irradiation, the H 2 O 2 accumulation of BiPO 4 nanocrystals (BIP NCs) reaches 30.44 mM·g−1, which is 3.13 times higher compared to bulk BiPO 4 (BIP-B) synthesized through hydrothermal synthesis. This significant increase can be attributed to the nanocrystal structure, which shortens charge migration distance. Consequently, the path of H 2 O 2 production is altered from a two-step one-electron pathway to a more efficient one-step two-electron pathway. [Display omitted] The photocatalytic production of H 2 O 2 has gained recognition as an economical and eco-friendly technology, but it suffers from limitations such as low production rates and difficulty in achieving high concentrations. This study was designed to overcome these limitations by preparing BiPO 4 nanocrystals (BIP NCs) via high-temperature hydrolysis, and X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that BIP NCs with particle sizes of 8.5 ± 3 nm were synthesized. In a photocatalytic performance test, only H 2 O and O 2 were used to produce H 2 O 2 , resulting in an accumulation of H 2 O 2 of up to 30.44 mM·g−1, as measured with the potassium titanium oxalate method; this value was 3.13 times greater than that of bulk BiPO 4 (BIP-B). The resulting nanocrystals demonstrated superior electron-hole transport and separation efficiency compared to those of BIP-B, and H 2 O 2 was formed in a one-step two-electron process. Furthermore, a film composed of a gas diffusion layer (GDL) and BIP NCs provided continuous accumulation of H 2 O 2 ; a concentration of 7.23 mM was achieved after 96 h of reaction, and the stability of the film was confirmed by comparing scanning electron microscopy (SEM) images obtained before and after the reaction. Construction of a nanocrystalline structure to enhance the activities of photocatalysts and films and achieve continuous accumulation of H 2 O 2 will provide insights into the photocatalytic production of highly concentrated H 2 O 2. [ABSTRACT FROM AUTHOR]

This work presents for the first time one-step ultrafast (precursor-free) synthesis of 1D MnFe 2 O 4 (MFO) nanorods and soft magnetic colloidal nanoparticles (NPs) using microwave-assisted hydrothermal (MAH) methods, with or without citric acid (CA) as a surfactant (in situ synthesis), respectively. The mechanism of growth of spinel MFO nanostructures during the MAH synthesis was studied by varying synthesis duration (3–6 h) and temperature (180–200 °C). An increase in both the duration and temperature improved the purity of the samples, up to 97%. On the other hand, a temperature increase by 20 °C notably shortened the formation time of MFO nanorods, which have an average diameter and length of less than 20 nm and 350 nm, respectively, as observed at 200 °C after 6 h. All the fabricated MFO NPs with spherical and rod-like morphologies manifested high saturation magnetization in the range of 54–64 emu/g. The chelation of lattice metal ions by CA resulted in the formation of a stable colloid comprising 100% pure spinel MFO NPs with a size of ≤32 ± 10 nm (mean ± SD) and featuring very soft magnetic properties. This colloid was generated by the MAH synthesis at 175 °C within 30 min. Notably, an increase in synthesis duration from 30 min to 3 h diminished MFO phase purity from 100% to 52% and saturation magnetization from 43.4 ± 0.7 to 33.9 ± 2.0 emu/g for CA-functionalized MFO NPs owing to CA degradation increasing during the in situ MAH synthesis with longer duration. This study indicates good potential of ultrafast MAH synthesis for the development of 1D magnetic spinel nanostructures with controllable morphology, size, magnetic properties, and colloidal stability, thereby offering a wide range of applications within the fields of adsorption, catalysis, electronics, and biomedicine. [ABSTRACT FROM AUTHOR]

In the last decade, mesoporous hydroxyapatite (HA) materials have received much attention regarding environmental applications (including adsorption of soil and water contaminants, films for lithium batteries, catalysts, and support systems for catalysis) and open up ample opportunities regarding biomedical devices and structures. Molybdenum ions may strongly influence catalytic and sorption properties of materials. The present study shows an influence of hydrothermal-synthesis conditions (including temperature and duration of the treatment) on phase composition, textural properties, and morphology of molybdate-containing HA. Powders with high crystallinity manifested Brunauer–Emmett–Teller specific surface area up to 55 m2/g with a pore volume of 0.33 cm3/g. The molybdate-containing HA powders were investigated by chemical analysis, X-ray diffraction, Fourier-transform IR spectroscopy, and transmission electron microscopy. Their specific surface area, pore volume, and pore size distributions were determined by low-temperature nitrogen adsorption measurements, zeta potential was quantified, and electron paramagnetic resonance spectroscopy was performed. The concentration of MoO 4 2− preserving the one-phase state was found, and the impact of hydrothermal treatment mode was analyzed by machine learning using artificial neural networks. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) are a type of carbon‐based nanoparticles that are typically smaller than 10 nanometres in size. In this study, L‐tryptophan‐mediated CQDs were synthesized using the hydrothermal carbonization (HTC) technique, which is known for its non‐toxic, environmentally friendly, and cost‐effective nature. The synthesized carbon quntum dot was successfully characterized. The HR‐TEM analysis clearly revealed the formation of specific aggregates with a size distribution ranging from 3.0 to 5.1 nm. These L‐tryptophan‐mediated CQDs exhibited remarkable emission behaviour, displaying strong and stable blue fluorescence. Moreover, they were utilized as a sensor for the sensitive detection of Fe3+ and Hg2+ ions in an aqueous solution, employing a fluorescence quenching mechanism. The limit of detection for Fe3+ sensing was determined to be 1.2×10−5 M, while for Hg2+ sensing, it was found to be 1.9×10−5 M. The sensing of Fe3+ and Hg2+ ions was also confirmed through visual eye detection, as a significant color change of the CQDs was observed. Additionally, a competitive study was conducted to verify the selectivity of the L‐tryptophan‐mediated CQDs towards Fe3+ and Hg2+ metal ions. [ABSTRACT FROM AUTHOR]

This study presents the synthesis and characterization of Copper Oxide/Tungsten Oxide (CuO/WO3) hybrid bifunctional composites using a hydrothermal approach. X‐ray diffraction (XRD) analysis confirms the successful synthesis of CuO/WO3 hybrids, exhibiting additional peaks corresponding to WO3 phases. Scanning electron microscopy (SEM) images reveal well‐defined, aggregated particles with a nanoscale pattern and uniform distribution of CuO and WO3 throughout the composite. Energy‐dispersive X‐ray spectroscopy (EDX) confirms the stoichiometric composition of CuO/WO3 hybrids. Evaluation of dark adsorption and sunlight‐assisted photocatalysis using methylene blue (MB) dyes shows a remarkable enhancement in efficiency compared to pristine CuO. The CuO/WO3 hybrids exhibit a dark adsorption capacity of 87 % and a photocatalytic degradation efficiency of 95 % under sunlight illumination, outperforming pure CuO. These results underscore the synergistic interaction between CuO and WO3, facilitating efficient pollutant removal. The study elucidates the structural properties and mechanistic insights driving the superior performance of CuO/WO3 hybrid composites, offering promising prospects for advanced water treatment technologies. [ABSTRACT FROM AUTHOR]

Supercapacitors are regarded as promising electrochemical energy storage solutions due to their multiple advantages. In this study, we report simple hydrothermal synthesis of nanostructured MnMoO4 (MMO) using CTAB and PVA as structure-directing agents, which is then employed as an electrode material in high-performance asymmetric supercapacitors. This resulted in the formation of morphologies analogous to nanoflakes (for CTAB; MMO-C), nanosheets (for PVA; MMO-P), and nanobundles (without a surfactant; MMO). MMO-C has a nanoflake-like structure with a large surface area, and an increasing number of electroactive surface sites and contact areas at the electrode–electrolyte interface. This results in a higher specific capacitance than other electrodes, measuring 919.6 F g−1 and 505 F g−1 at 1 A g−1 and 10 A g−1, respectively. It also exhibits extended cycling performance, with 94.1% retention after 10 000 cycles. The fabricated MMO-C//activated carbon (AC) asymmetric supercapacitor (ASC) device achieved a high specific capacitance of 111.9 F g−1 at 1 A g−1 in an operational potential window of 0–1.5 V. The ASC also has a high specific energy of 39.45 W h kg−1 at a specific power of 837.66 W kg−1 while retaining 90.3% of its initial capacitance after 10 000 cycles. A red LED was also turned on for 120 seconds when two ASCs were connected in series. [ABSTRACT FROM AUTHOR]

The employment of biomass waste for the fabrication of carbon quantum dots (CQDs), as a novel fluorescent material with high photoluminescence (PL) activity, has gained intense interest for the last decade. However, the fabrication of CQD from biomass waste encounters challenges including low fluorescence yield, reproducibility, and stability. Therefore, the novel, simple, flexible fabrication routes for CQDs using biomass waste as a precursor are still essential for practical applications. In this study, we reported the employment of human urine (U), sour whey (W), and their mixture (U/W) as precursors for the hydrothermal green synthesis approach. For all cases, CQDs with an excitation‐dependent emission nature were obtained with a quantum yield (QY) value of 48 %, 28 %, and 39 % for U, W, and U/W, respectively. For each case, doping of various heteroatoms such as N, P, S, etc., in the structure of CQDs contributed PL characteristics with high QY, reasonably low cytotoxicity, and, robust pH and storage stability which indicate their high potential in various biomedical applications such as bioimaging and pH sensors. This study proves the utilization of human urine and whey as the precursors for the fabrication of CQDs through a low‐cost, flexible, and eco‐friendly green synthesis procedure. [ABSTRACT FROM AUTHOR]

Here in the present work, simple, eco-friendly and economical method of synthesis has been approached known as hydrothermal synthesis that allowed easy doping of Fe ions into the ZnS host lattice. A unique approach was adopted for the first time to prepare ZnS material where thioglycolic acid (TGA) was used as a source for sulfur in addition to a reducing and capping agent. Properties of the nanostructures were explored using different techniques. The X-ray diffraction (XRD) results indicated formation of single phase hexagonal ZnS material where inclusion of Fe2+ ions into the ZnS lattice have no influence on the crystal phase of the material. Probably almost identical sizes of Zn2+ and Fe2+ ions made this possible that indicated Fe2+ ions take Zn2+ vacant sites by substitution of Zn2+ ions by Fe2+ ions. Chemical analysis (X-ray photoelectron spectroscopy) performed discovered that Zn and Fe ions were present in +2 oxidation states whereas S is in −2 state. Anisotropic growth of the nanostructures is reported where irregular shaped nanostructures of varying dimensions were formed that agglomerated as doping concentration was increased to form spherical microstructures. Inclusion of Fe ions into the host material modified magnetic behavior of the nanostructures converting diamagnetic ZnS into a ferromagnetic material. Optical properties were also influence by the doping resulting in photon absorption at different wavelengths. The band gap got reduced from 3.2 eV to 2.7 eV making the ZnS nanostructures visible light active. The nanostructures with band gap 2.7 eV exhibited good photocatalytic activity against methylene blue (MB) dye under visible light illumination degrading 94% of the dye in just 2 h. The scavenging experiments performed showed hydroxyl free radicals play an active role in mineralizing the dye. Reusability and post photocatalytic properties of the photocatalysts determined their stability and potential ability for possible commercialization. [ABSTRACT FROM AUTHOR]

In this study, we report on the electrochemical properties of hydrothermally synthesized MoS2 composites for use in lithium-ion batteries. A widespread method was modified for facile synthesis of pristine MoS2 and its composites with PEDOT:PSS, rGO, or both. The electrochemical performance of the materials was investigated using cyclic voltammetry and galvanostatic charge-discharge measurements. The addition of rGO significantly enhances the specific capacity and stability of MoS2, with the MoS2/rGO composite exhibiting specific capacity in the second cycle of 748 mA·h·g−1 and a capacity retention of 63% through the 400th cycle. The composites exhibited a phenomenon of capacity increase after reaching a minimum, with this effect being most pronounced in the case of MoS2/rGO. This composite reached its lower capacity value at the 143rd cycle (211 mA·h·g−1), and then recovered to 224% of the minimum capacity (472 mA·h·g−1). We attribute this behavior to an increase in the availability of active particles over the course of cycling by milling the active components into smaller and thus more accessible species of Li2S and S. The intensity of the effect of rGO is due to its intrinsically large surface area and two-dimensional layered structure, which enhances the distribution of redox-active particles within the material layers and prevents agglomeration. Our results contribute to the existing evidence of the improved electrochemical performance of MoS2 in Li-ion batteries with layered graphitic compounds and provide promising avenues for further research of the unique behavior of conversion materials. [ABSTRACT FROM AUTHOR]

Levofloxacin (LFX), which is difficult to degrade effectively due to its molecular stability, has become an problem that needs to be solved urgently. The advanced oxidation technology of persulfate has received increasing attention from researchers. In this study, a Ce-MOF derivative (Ce-MOF-T) was prepared by hydrothermal synthesis and calcination, which synergistically responded to electroactivation to generate sulfate radicals for the efficient degradation of LFX. It has been proven that electrical activation and the Ce-MOF derivatives work together to generate sulfate radicals and effectively degrade LFX. Ce-MOF-550-modified carbon cloth was used as the cathode and a platinum electrode as the anode, the concentration of LFX was 20 mg·L−1, the loading of Ce-MOF-550 was 15 mg, pH = 5, the concentration of sodium persulfate (PMS) was 0.3 g·L−1, the current density was 100 A·m−2, and the degradation rate was 82.05% after 1 h of reaction and 95% after 3 h of reaction. After five cycle tests, the degradation rate was still higher than 75.00%, indicating that the material had good stability. In addition, the degradation of LFX was consistent with a quasi-primary kinetic reaction with apparent rate constants of 2.26 × 10−2 min−1. [ABSTRACT FROM AUTHOR]

Recently, titanate nanotubes (TNTs) have been receiving more attention and becoming an attractive candidate for use in several disciplines. With their promising results and outstanding performance, they bring added value to any field using them, such as green chemistry, engineering, and medicine. Their good biocompatibility, high resistance, and special physicochemical properties also provide a wide spectrum of advantages that could be of crucial importance for investment in different platforms, especially medical and pharmaceutical ones. Hydrothermal treatment is one of the most popular methods for TNT preparation because it is a simple, cost-effective, and environmentally friendly water-based procedure. It is also considered as a strong candidate for large-scale production intended for biomedical application because of its high yield and the special properties of the resulting nanotubes, especially their small diameters, which are more appropriate for drug delivery and long circulation. TNTs' properties highly differ according to the preparation conditions, which would later affect their subsequent application field. The aim of this review is to discuss the factors that could possibly affect their synthesis and determine the transformations that could happen according to the variation of factors. To fulfil this aim, relevant scientific databases (Web of Science, Scopus, PubMed, etc.) were searched using the keywords titanate nanotubes, hydrothermal treatment, synthesis, temperature, time, alkaline medium, post treatment, acid washing, calcination, pharmaceutical applications, drug delivery, etc. The articles discussing TNTs preparation by hydrothermal synthesis were selected, and papers discussing other preparation methods were excluded; then, the results were evaluated based on a careful reading of the selected articles. This investigation and comprehensive review of different parameters could be the answer to several problems concerning establishing a producible method of TNTs production, and it might also help to optimize their characteristics and then extend their application limits to further domains that are not yet totally revealed, especially the pharmaceutical industry and drug delivery. [ABSTRACT FROM AUTHOR]

The layered double hydroxides (LDHs) of transition metals are of great interest as building blocks for the creation of composite photocatalytic materials for hydrogen production, environmental remediation and other applications. However, the synthesis of most LDHs is reported only by the conventional coprecipitation method, which makes it difficult to control the catalyst's crystallinity. In the present study, ZnCr- and NiCr-LDHs have been successfully prepared using a facile hydrothermal approach. Varying the hydrothermal synthesis conditions allowed us to obtain target products with a controllable crystallite size in the range of 2–26 nm and a specific surface area of 45–83 m2∙g−1. The LDHs synthesized were investigated as photocatalysts of hydrogen generation from aqueous methanol. It was revealed that the photocatalytic activity of ZnCr-LDH samples grows monotonically with the increase in their average crystallite size, while that of NiCr-LDH ones reaches a maximum with intermediate-sized crystallites and then decreases due to the specific surface area reduction. The concentration dependence of the hydrogen evolution activity is generally consistent with the standard Langmuir–Hinshelwood model for heterogeneous catalysis. At a methanol content of 50 mol. %, the rate of hydrogen generation over ZnCr- and NiCr-LDHs reaches 88 and 41 μmol∙h−1∙g−1, respectively. The hydrothermally synthesized LDHs with enhanced crystallinity may be of interest for further fabrication of their nanosheets being promising components of new composite photocatalysts. [ABSTRACT FROM AUTHOR]

Nanoparticles of spinel ferrites with a composition of Co0.9Cu0.1Fe2O4 (AM NPs) were effectively synthesized via a hydrothermal route. The structure of ferrite nanoparticles was characterized with X-ray diffraction, which showed a single cubic spinel phase. Energy-dispersive X-ray (EDX) spectroscopy and field emission-scanning electron microscopy (FE-SEM) were employed to analyse elemental composition and surface morphology, respectively. Moreover, the effects of the Co0.9Cu0.1Fe2O4 on the morphology of [PLA = polylactic acid] nanocomposites were examined through polarized light optical microscopy (POM) and X-ray diffraction (XRD). The thermal behaviours for tested samples were studied through [DSC = differential scanning calorimetry] and [TGA = thermal gravimetric analysis]. A great number of minor PLA spherulites were detected using POM in the presence of the Co0.9Cu0.1Fe2O4 ceramic magnetic nanoparticles (AM), increasing with AM nanoparticle contents. X-ray diffraction (XRD) analysis showed that the presence of nanoparticles led to an increase in the intensity of diffraction peaks. The DSC findings implied that the crystallization behaviours for the efficient PLA as well as its nanocomposites were affected by the addition of AM nanoparticles. They act as efficient nucleating agents because they shift the temperature of crystallization to a lower value. The Avrami models were used to analyse kinetics data. The experimental data were well described using the Avrami method for all samples tested. The addition of AM to the PLA matrix resulted in a decrease in the crystallization half-time t1/2 values, indicating a faster crystallization rate. TGA data showed that the occurrence of AM nanoparticles decreased the thermal stability of PLA. [ABSTRACT FROM AUTHOR]

This current study assessed the impacts of morphology adjustment of perovskite BiFeO3 (BFO) on the construction and photocatalytic activity of P-infused g-C3N4/U-BiFeO3 (U-BFO/PCN) heterostructured composite photocatalysts. Favorable formation of U-BFO/PCN composites was attained via urea-aided morphology-controlled hydrothermal synthesis of BFO followed by solvosonication-mediated fusion with already synthesized P-g-C3N4 to form U-BFO/PCN composites. The prepared bare and composite photocatalysts' morphological, textural, structural, optical, and photocatalytic performance were meticulously examined through various analytical characterization techniques and photodegradation of aqueous rhodamine B (RhB). Ellipsoids and flakes morphological structures were obtained for U-BFO and BFO, and their effects on the successful fabrication of the heterojunctions were also established. The U-BFO/PCN composite exhibits 99.2% efficiency within 20 min of visible-light irradiation, surpassing BFO/PCN (88.5%), PCN (66.8%), and U-BFO (26.1%). The pseudo-first-order kinetics of U-BFO/PCN composites is 2.41 × 10−1 min−1, equivalent to 2.2 times, 57 times, and 4.3 times of BFO/PCN (1.08 × 10−1 min−1), U-BFO, (4.20 × 10−3 min−1), and PCN, (5.60 × 10−2 min−1), respectively. The recyclability test demonstrates an outstanding photostability for U-BFO/PCN after four cyclic runs. This improved photocatalytic activity exhibited by the composites can be attributed to enhanced visible-light utilization and additional accessible active sites due to surface and electronic band modification of CN via P-doping and effective charge separation achieved via successful composites formation. [ABSTRACT FROM AUTHOR]

Design of experiments is a powerful planning technique that optimizes processes and reduces experimental variability. This research aims to optimize the hydrothermal synthesis of TiO2 nanotubes with a high specific surface area (SSA). A 22 factorial design was applied to investigate the influence of temperature and time on nanotube formation, achieving SSA above 350 m2 g−1. A Doehlert design combining SSA with morphology reveals closely related responses and a defined maximum surface. Microscopy shows that nanotube formation is favored at lower temperatures and longer treatment times, with the optimal condition at 120 °C for 36 h. Higher temperatures yield cauliflower-like nanostructures and provide insight into how synthesis conditions affect the morphology and nanoparticle properties. XRD and Raman spectroscopy analysis revealed that, although the anatase phase played a vital role in nanotube formation, the materials exhibited a combination of crystalline phases, including the discovery of an unidentified phase. [ABSTRACT FROM AUTHOR]

Simple hydrothermal method can be applied for synthesizing rod shape Gd2O3:Eu3+ phosphors. X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy are used for the characterizations of samples. Increase of Eu3+ concentration in Gd2O3:Eu3+ can cause red shift in the charge transfer band (CTB) of Eu – O. The nature of Eu3+ surroundings is asymmetric. It is ascertained from PL emission studies. The calculation of second order crystal field parameter from PL spectra corroborates the asymmetric environment of Eu3+. PL emission and decay lifetime studies confirm the existence of quenching due cross-relaxation. The quantum yield for Y2O3:Eu3+ (19 at.%) under 265 nm excitation is found to be 7%. [ABSTRACT FROM AUTHOR]

We report on Ru-doped self-supported honeycomb nickel molybdate nanoflakes (Ru-NiMoO 4 /NF) with abundant OV on Ni foam and its application in both electrocatalytic NO 2 –RR and Zn-NO 2 – battery. The catalytic activity of Ru-NiMoO 4 /NF was significantly enhanced due to the Ru doping and the existence of oxygen vacancies, achieving high Faraday efficiency of 95.56 ± 0.72% and large ammonia yield of 17192.52 ± 1136.64 μg h−1 cm−2 at –0.6V vs. RHE in 0.5 M Na 2 SO 4 and 0.1 M NO 2 – solution, as well as preferable long-term stability. In addition, it was verified that Zn-NO 2 – battery with Ru-NiMoO 4 /NF as cathode delivers a good energy supply (13.87 mW cm−2), as well as simultaneously ammonium yield of 1524.74 μg h−1 cm−2 and Faradaic efficiency of 96.15% at 15 mA cm−2. [Display omitted] The electrocatalytic reduction of nitrite to recyclable ammonia (NH 3) is essential to maintain nitrogen balance and meet growing energy requirements. Herein, we report that Ru doped honeycomb NiMoO 4 nanosheet with copious oxygen vacancies grown on nickel foam substrate has been prepared by a facile hydrothermal synthesis and immersion process, which can act as an efficient electrocatalyst for NH 3 synthesis by reduction of nitrite. By optimizing the concentration of RuCl 3 solution, 0.01Ru-NiMoO 4 /NF possesses excellent NO 2 −RR performance with NH 3 yield of 20249.17 ± 637.42 μg h−1 cm−2 at −0.7 V and FE of 95.56 ± 0.72 % at −0.6 V. When assembled into a Zn–NO 2 − battery, it provides a remarkable level of power density of 13.89 mW cm−2, outperforming the performance of virtually all previous reports. The efficient adsorption and activation of NO 2 − over Ru-doped NiMoO 4 with oxygen vacancy have been verified by density functional theory calculations, as well as the possible reaction pathway. [ABSTRACT FROM AUTHOR]

Usage of cost effective synthesis methods are inevitable due to increasing economic conditions worldwide. In this study, zinc oxide nano-structures were synthesized by low cost chemical methods. Outcomes of X-ray diffraction analysis revealed dominating plane was c-axis for ZnO seed layer and nano-rods deposited by sol–gel spin coating and chemical bath deposition method (CBD), respectively. However, a-axis plane dominance was observed for ZnO nano-rods prepared by hydrothermal method. Scanning electron microscopy offered the surface morphology of granular structure and well aligned compact ZnO nano-rods by sol–gel and CBD, respectively. Conversely, randomly oriented ZnO nano-rods were found by hydrothermal method. Presence of zinc and oxygen in the samples was confirmed by EDS results. Optical band gap of 3.29 eV, 3.25 eV and 3.21 eV were obtained by sol–gel, CBD and hydrothermal method, respectively. Likewise, photoluminescence results were also analyzed for all the samples. The super-hydrophobic state with water contact angle (WCA) of 150° was observed for ZnO nano-rods by CBD. However, hydrophilic and hydrophobic state was detected for ZnO seed layer and nano-rods with WCA of 70° and 118°, respectively. The super-hydrophilic state was also noticed after the induction of Ultra-Violet (UV) light. The WCA reduction rate of the values 0.067 and 0.17 were estimated for ZnO nano-rods. Furthermore, CA recovery time was also measured. The UV sensing photo-response was evaluated among seed layer and nano-rods, and better result was produced by ZnO nano-rods by CBD. [ABSTRACT FROM AUTHOR]

In this work, distinct-morphological Co 3 O 4 /Nickel foams were prepared through a simple hydrothermal method and a subsequent heat treatment process. The morphology of Co 3 O 4 can be efficiently modulated from hexagonal nanosheets to nanobunches and urchin-like microspheres by manipulating the NH 4 F concentration. For the urchin-like Co 3 O 4 /Nickel foam composites, the minimum reflection loss (RL min) value can reach −42.53 dB at a matching thickness of 2.7 mm. Theoretical analysis shows that the enhanced microwave absorption intensity is mainly originated from dielectric losses including significant interfacial polarization of the abundant interfaces, intrinsic dipoles of Co 3 O 4 and magnetic losses containing natural resonance and eddy current loss are favorable for the impedance matching. Simultaneously, multiple scattering occurring within the 3D Ni network skeleton are considered to promote the microwave absorption performance. Furthermore, a quadrilateral cone array of the resultant urchin-like Co 3 O 4 /Nickel foam composites has a RL min of −56.7 dB and an effective absorption bandwidth can achieve 9.44 GHz. This work could be beneficial for exploiting high-efficient magnetic-dielectric microwave absorption materials via the microstructural design. [ABSTRACT FROM AUTHOR]

Metallogenic models of polyphase mountain belts critically rely on robust geochronology. We combine petrology with Rb--Sr and U--Th--Pb in situ geochronology, paired at thin-section scale, to date mineralization in deformed hydrothermal Pb--Zn--Ag deposits along an east-west transect in the Western Alps, France. The Pb--Zn--Ag veins occur in shear zones with kinematic structures consistent with the mylonitized host rocks. The ore consists mainly of galena in a quartz-phengite gangue. The paragenesis can be related to hydrothermal crystallization during periods of variable strain. Both isotope systems yield only Cenozoic ages (ca. 35 Ma and 15-20 Ma) without any pre-Alpine inheritance, clearly indicating orogenic mineralization. The metallogenic model proposed here includes significant fluid circulation along major tectonic contacts between basement and sedimentary cover during Alpine convergence. [ABSTRACT FROM AUTHOR]