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In this work, an (NH4)0.5V2O5 nanobelt (NVO) was prepared by a facile hydrothermal reaction using NH4VO3 as the precursor and oxalic acid (C2H2O4) as the reducing agent. The crystal structure and quantity of NH4+ intercalated for NVO can be adjusted via postheat treatment, resulting in variable K+ storage property when utilized as a cathode for K-ion batteries (KIBs). Therein, NVO-150 °C obtained exhibits an optimal K+ storage capacity (86.8 mA h/g at the first discharge and 74.0 mA h/g at the 50th cycle under 50 mA/g between 1.5 and 3.8 V vs K/K+) and rate capability (58.4 mA h/g under 500 mA/g), which can be ascribed to the appropriate structural fine-tuning toward NVO, increasing its active sites for K+ storage. Furthermore, NVO was uniformly combined with rGO by a one-pot hydrothermal process through the bridging effect of cetyltrimethylammonium bromide. The acquired NVO-rGO also delivers a significantly improved K+ storage performance (89.7 mA h/g at the initial discharge and 71.9 mA h/g after 50 cycles; 56.5 mA h/g under 500 mA/g) compared to NVO, which benefits from the good conductivity and separation function of rGO, promoting the fast transport of electrons and K+. Both the postheat treatment and introduction of rGO are feasible to enhance K+ storage in NVO. This study proposed effective modification strategies to optimize K+ storage in a potential NVO cathode for KIB application. [ABSTRACT FROM AUTHOR]

Supercapacitors, in particular, are gaining popularity in electronic devices, electric vehicles, and emergency power supplies due to their safe operation, rapid charge/discharge rates, high power density, and extended lifespan compared with batteries and fuel cells. However, to further enhance the energy density, widening the operating voltage window through the design of asymmetric supercapacitors and increasing the capacitance of electrode materials have been explored. This study focuses on the development of a sea-urchin-like morphology composed of bimetallic copper–cobalt carbonate hydroxides (CCCOHs) by using a hydrothermal method to optimize the surface morphology and improve energy storage capabilities. The synthesized CCCOH-24 sample demonstrated an impressive specific capacitance of 675 C g–1 at a current density of 15 A g–1 and maintained 87% stability at 30 A g–1. When assembled into an asymmetric solid-state supercapacitor with activated carbon, the device achieved an energy density of 63 Wh kg–1 and a power density of 10.2 kW kg–1, retaining over 88% capacitance after 10000 cycles. This study highlights the potential of CCCOHs with tailored morphologies for advanced supercapacitor applications, offering a pathway to enhance the energy storage performance and stability. [ABSTRACT FROM AUTHOR]

Perovskite oxide has good sensitivity to VOCs gases, but its gas-sensitive properties are negatively affected by high humidity, thereby limiting its potential application in respiratory gas detection. This study focuses on synthesizing porous LaFeO3 of perovskite type used a dual-process method involved hydrothermal synthesis with thermal treatment. The morphology and evolution of porous LaFeO3 microspheres was studied. The LaFeO3 sensors exhibited p-type gas-sensitive behavior with notable selectivity for respiratory gases. The LaFeO3 sensor represented a significant response value of 9.7 to a 100 ppm C2H5OH concentration, with a rapid response/recovery time of 8 s/9 s at 300 °C. The sensor demonstrated a high response (S = 4.2) and a low detection limit of 100 ppb at 90% relative humidity. The superior sensor performance was due to the porous surface structure of LaFeO3 microspheres, which improved the gas diffusion channels and reaction sites with microspheres. The density of states map revealed a strong orbital hybridization between C2H5OH and LaFeO3, resulted in a calculated adsorption energy of − 1.18 eV, signified a strong adsorption affinity in line with the experimental results. [ABSTRACT FROM AUTHOR]

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

In this study, the photodegradation of cetirizine dihydrochloride (CET) by Bi2O3/TiO2 heterojunctions under simulated solar light irradiation (300-800nm) was examined in detail for the first time. A hydrothermal synthesis of the photocatalyst was carried out, and several analytical techniques were used to characterize the product. The resulting Bi2O3/TiO2 photocatalyst effectively removed CET from an aqueous solution. The Bi2O3/TiO2 (5.0%/95.0%) ratio exhibited the highest photocatalytic performance for CET degradation, degrading 75.85% of CET after 60 min of irradiation, with a high pseudo-first-order rate constant (kapp = 0.022 min−1; t1/2 = 31.50 min; natural pH). Moreover, TOC decreased by 40.45% after 420 min of irradiation. The Bi2O3/TiO2 photocatalyst has also been proven effective in degrading CET in different real aqueous matrices (Seawater (99.89%) > spring water (68.44%) > tap water (52.62%)), and the degradation under natural solar irradiation is more effective and faster than under artificial irradiation. Additionally, the Bi2O3/TiO2 photocatalyst demonstrated excellent photo-stability in a five-cycle photocatalytic experiment. The influence of various parameters showed that the removal of CET was heightened with a dose of 1 g/L of the Bi2O3/TiO2 and enhanced under acidic conditions (pH = 2.3). Moreover, the involvement of different reactive species was investigated by introducing diverse scavengers, revealing that hydroxyl radicals and photo-holes were the main reactive species involved in the CET photodegradation process over the Bi2O3/TiO2 photocatalyst. The primary photodegradation byproducts were identified using HPLC–MS analysis, and a possible mechanism was proposed. [ABSTRACT FROM AUTHOR]

A novel mineral-like phosphate hydrate Na6.9Ni2+0.9V3+4.3Al0.8(PO4)8(H2O)2 (Z = 2) was obtained under high-temperature hydrothermal conditions by modeling the chemistry of geothermal brines in natural geological solutions. The compound, characterized by scanning electron microscopy and microprobe analysis, possesses an orthorhombic symmetry with the Cccm space group; the unit cell parameters are a = 6.4082(8), b = 19.6813(19), c = 10.5035(11) Å. Here we report its crystal structure studied by low-temperature single crystal X-ray diffraction and discussed as derived from the α-CrPO4 archetype, known for a large range of compounds with promising properties. Three-dimensional continuous migration pathways for Na+ within the structure were found and confirmed by a bond valence energy landscape analysis. The migration barriers turned out to be ~0.44 eV along the a and b directions and ~0.42 eV along the c axis. These values suggest that the compound may be a potential electrode material for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

COx-free H2, along with uniform carbon nanotubes, can be achieved together in high yield by CH4 decomposition. It only needs a proper catalyst and reaction condition. Herein, Fe-based catalyst dispersed over titania-incorporated-alumina (Fe/Ti-Al), with the promotional addition of lanthanides, like CeO2 and La2O3, over it, is investigated for a methane decomposition reaction at 800 °C with GHSV 6 L/(g·h) in a fixed-bed reactor. The catalysts are characterized by temperature-programmed reduction (TPR), powder X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The promoted catalysts are facilitated with higher surface area and enhanced dispersion and concentration of active sites, resulting in higher H2 and carbon yields than unpromoted catalysts. Ceria-promoted 20Fe/Ti-Al catalyst had the highest concentration of active sites and always attained the highest activity in the initial hours. The 20Fe-2.5Ce/Ti-Al catalyst attains >90% CH4 conversion, >80% H2-yield, and 92% carbon yield up to 480 min time on stream. The carbon nanotube over this catalyst is highly uniform, consistent, and has the highest degree of crystallinity. The supremacy of ceria-promoted catalyst attained >90% CH4 conversion even after the second cycle of regeneration studies (against 87% in lanthanum-promoted catalyst), up to 240 min time on stream. This study plots the path of achieving catalytic and carbon excellence over Fe-based catalysts through CH4 decomposition. [ABSTRACT FROM AUTHOR]

MWCNT/Fe3O4/Si3N4 composite was synthesized via hydrothermal synthesis. The morphology and structure of MWCNT/Fe3O4/Si3N4 were investigated by means of SEM, XPS, XRD, and FT-IR. Their electromagnetic parameters were measured by a vector network analyzer. The microwave attenuation properties of as-synthesized composite could be modulated by regulating the feed ratio of MWCNT, Fe3O4, and Si3N4. According to the different amounts of modified nano Fe3O4 added, they are labelled as S1-S3. When the feed ratio is 3:15:20, the maximum reflection loss value of the sample is −23.3 dB at 14.4 GHz, the corresponding thickness is 2.5 mm, and the corresponding effective absorption bandwidth is 5.36 GHz. Moreover, the test results of the thermogravimetric analyzer show that the composite material has excellent heat resistance. Our research results provide a reference value for the development of excellent heat resistance and high-performance MWCNT-based microwave absorption composite materials. [ABSTRACT FROM AUTHOR]

The compound {[Cd (H2IDC) 2 (H2O) 2]·2H2O}n (1) was synthesized via a hydrothermal method, utilizing 4,5-imidazoledicarboxylic acid (H3IDC) and Cd (NO3) 2·4H2O as raw materials. Single crystal X-ray diffraction (SXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and fluorescence spectroscopy (FL) were employed to ascertain and elucidate the structure of compound 1. SXRD analysis reveals that compound 1 categorized under the P21/n space group of monoclinic crystal system. In compound 1, Cd (Ⅱ) ions coordinate with H2IDC- anions and water molecules to form a six-coordinated octahedral configuration, which is further extended into a three-dimensional structure through hydrogen bonding. Fluorescence spectrum analysis at room temperature indicates that compound 1 exhibits the most intense emission peak at 598 nm when excited at a wavelength of 296 nm.  [ABSTRACT FROM AUTHOR]

In recent years, research on pure ZnO, Ni-doped ZnO, Mg-doped ZnO, and Fe-doped ZnO nanostructures has been gradually progressing to create more effective materials that may be applied in a variety of applications. In this investigation, hydrothermal synthesis was used to create both pure ZnO nanoparticles and ZnO that had been doped with Ni, Mg, and Fe at a concentration of 7%. Before testing the nanostructures' ability to inhibit harmful bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterobacter sp.), they were shown to have antibacterial activity. With the use of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and ultraviolet–visible (UV–Vis), their physicochemical characteristics were initially determined. When Ni, Mg, and Fe are inserted into ZnO, XRD measurements show that the particle size decreases from 28.94 nm to 19.96 nm. The optical bandgap decreases from 3.17 eV to 3.08 eV with the least value for Fe/ZnO NPs, according to UV–Vis spectral data, which also shows that the absorption edge changes to higher wavelengths (redshift). This research has produced nanoparticle samples of Ni/ZnO, Mg/ZnO, and Fe/ZnO that, when compared to the pure ZnO sample, show intriguing antibacterial activity. [ABSTRACT FROM AUTHOR]

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

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

Purpose: The study aims to develop an inexpensive metal oxide semiconductor gas sensor with high sensitivity, excellent selectivity for a specific gas and rapid response time. Design/methodology/approach: This study synthesized Zn2SnO4 nanostructures using a hydrothermal method with a 1 M concentration of zinc chloride (ZnCl2) as the zinc source and a 0.7 M concentration of tin chloride (SnCl4) as the tin source. Thick films of nanostructured Zn2SnO4 were then produced using screen printing. The structural properties of Zn2SnO4 were confirmed using X-ray diffraction, and the formation of Zn2SnO4 nanoparticles was verified by transmission electron microscopy. Scanning electron microscopy was used to analyse the surface morphology of the fabricated material, while energy dispersive spectroscopy provided insight into the chemical composition of the thick film. These fabricated thick films underwent testing for various hazardous gases, including nitrogen dioxide, ammonia, hydrogen sulphide (H2S), ethanol and methanol. Findings: The nanostructured Zn2SnO4 thick film sensor demonstrates a notable sensitivity to H2S gas at a concentration of 500 ppm when operated at 160°C. Its selectivity, response time and recovery time were assessed and documented. Research limitations/implications: The primary limitations of this research on metal oxide semiconductor gas sensors include poor selectivity to specific gases, limited durability and challenges in achieving detection at room temperature. Practical implications: The nanostructured Zn2SnO4 thick film sensor demonstrates a strong response to H2S gas, making it a promising candidate for commercial production. The detection of H2S is crucial in various sectors, including industries and sewage plants, where monitoring this gas is essential. Social implications: Currently, heightened global apprehension about atmospheric pollution stems from the existence of perilous toxic and flammable gases. This underscores the imperative need for monitoring such gases. Toxic and flammable gases are frequently encountered in both residential and industrial environments, posing substantial hazards to human health. Noteworthy accidents involving flammable gases have occurred in recent years. It is crucial to comprehend the presence and composition of these gases in the surroundings for precise detection, measurement and control. Thus, there has been a significant push for extensive research and development in diverse sensor technologies using various materials and methodologies to monitor and regulate these gases effectively. Originality/value: In this research, Zn2SnO4 nanostructures were synthesized using a hydrothermal method with ZnCl2 at a concentration of 1 M for zinc and SnCl4 at a concentration of 0.7 M for tin. Thick films of nanostructured Zn2SnO4 were then fabricated via screen printing technique. Following fabrication, all thick films were subjected to testing with various toxic gases, and the results were compared to previously published data. The analysis indicated that the nanostructured Zn2SnO4 thick film sensor demonstrated outstanding performance concerning gas response, gas concentration, selectivity and response time, particularly towards H2S gas. [ABSTRACT FROM AUTHOR]

Choosing suitable photoanode materials is the most critical aspect for photoelectrochemical (PEC) water splitting. The low efficiency of PEC water splitting photoanodes restricts their widespread application for large-scale H2 production. Herein, we prepared WO3 photoanodes with controllable structures via hydrothermal-electrophoretic deposition and seed-mediated hydrothermal synthesis, achieving ex situ assembly and in situ growth on FTO glass substrates. Under simulated sunlight irradiation, the photoelectric current density of the WO3 photoanode prepared by in situ hydrothermal synthesis exceeds 1.0 mA/cm² (at 1.23 V vs. RHE), significantly higher than that of the WO3 photoanode prepared by ex situ assembly (which is less than 0.3 mA/cm² at 1.23 V vs. RHE). By contrast, the in situ preparation of the WO3 photoanode using tungsten powder and H2O2 as raw materials exhibits the enhanced photocurrent density of 1.27 mA/cm² at 1.23 V vs. RHE. The excellent PEC performance of the resulting sample could be attributed to the ordered charge transport channels from the two-dimensional (2D) nanoplates structure, the enhanced electron-hole pairs separation from the superior crystallinity of WO3 and the strong binding between the WO3 nanoplates and the FTO substrate. Additionally, the effect of calcination temperature on the PEC performance of the prepared WO3 was further investigated. This work provides a way for the synthesis of environmentally friendly and cost-effective photoanodes for efficient photoelectrochemical water splitting. [ABSTRACT FROM AUTHOR]

MIL‐53(Fe) is a novel photocatalytic material that has been developed over the past decade; however, significant efforts are still required to fully optimize its photocatalytic performance in order to meet the requirements of practical applications. In this paper, we investigated the effects of size and crystallinity on the photocatalytic performance of MIL‐53(Fe) and its composites x‐MIL‐53(Fe)/g‐C3N4 (x‐MIL‐Fe/CN). During the hydrothermal synthesis process, the control over particle size was achieved by adjusting the amount of acetic acid (HAc). Ball milling was utilized to manipulate both the size and crystallinity of MIL‐53(Fe). Photocatalytic experiments demonstrated that MIL‐53(Fe) and 15‐MIL‐Fe/CN, characterized by the smallest particle sizes and great crystallinity, exhibited the highest photocatalytic activity. This enhancement in photocatalytic activity can be attributed to the reduced band gap and lower recombination rate of photogenerated carriers. Notably, the hydrogen evolution rate for 15‐MIL‐Fe/CN reached up to 4950 μmol·g−1·h−1, but MIL‐53(Fe) achieved a 98% degradation of methyl orange within 60 min. [ABSTRACT FROM AUTHOR]

Highlights This study aims to investigate the electric, dielectric poperies, and the charge transport mechanism in Polyaniline/Tin disulfide (PANI/SnS2) nanocomposites. SnS2 nanoflowers were synthesized using the hydrothermal method and were utilized to synthesize PANI/SnS2 nanocomposites by in‐situ polymerization of the aniline. PANI/SnS2 nanocomposites were composed of hexagonal nanoflowers and amorphous PANI. The charge transport mechanism was investigated by using DC and AC conductivities. DC conductivity increased and reached a maximum value at 5 wt. % sample and then it decreased indicating the percolation effect. To understand the charge transfer mechanism in the PANI/SnS2 composites, AC conductivity, dielectric properties, and impedance characteristics were investigated in the frequency range of 20 Hz to 2 MHz. PANI/SnS2 nanocomposites follow Jonscher's Power Law of disordered materials with an exponent value ranging from 0.8 to 0.9. The Havriliak – Negami model confirmed that the samples display a non‐Debye relaxation mechanism. The dielectric constant value increases with an increase in the SnS2 content. These enhanced properties of PANI/SnS2 nanocomposites suggest that the proposed PANI/SnS2 nanocomposites are the potential materials for multifunctional applications, especially in nano‐electronic devices. Hydrothermal synthesis of SnS2 Nano flowers. SnS2/PANI composites were synthesized by the in situ polymerization method. The DC conductivity of 5 wt. % sample shows Percolation threshold. Jonscher's & Havriliak–Negami fittings suggest non‐Debye dielectric relaxation. Charge transfer mechanisms in the composites were studied using Nyquist plots. [ABSTRACT FROM AUTHOR]

In order to photocatalytic degradation of ethylene in environmental pollution, TiO2 (B) featuring a multiphase crystal structure was first synthesized via hydrothermal synthesis method. The efficiency of photocatalytic degradation of ethylene and methyl orange by TiO2 (B) was up to 49.23% and 60%, respectively, and the specific surface area of TiO2 (B) was as large as 277.69 m2/g. Subsequently, photocatalytic films loaded with the TiO2 (B) were produced using an extrusion casting machine coupled with a twin-screw extruder. The mechanical properties and barrier property to oxygen were enhanced by adding 1% TiO2 (B) to photocatalytic films. The hydrophilicity of the photocatalytic films and the decrease in contact angle confirmed the existence of the 'Honda-Fujishima effect'. The highest degradation efficiency of methyl orange and ethylene by the photocatalytic film could reach 9% and 7.79%, respectively. Both TiO2 (B) and photocatalytic films showed good antibacterial properties against Escherichia coli and Staphylococcus aureus. TiO2 (B) and photocatalytic films have been shown to have excellent photocatalytic degradation performance of organic compounds. [ABSTRACT FROM AUTHOR]

A conceptually new approach is developed for hydrothermal synthesis of nanostructured iron oxides for energy storage in anodes of supercapacitors. The use of biocompatible organic additives facilitates the fabrication of electrodes with enhanced capacitance. The use of amino acids, such as L-histidine (HS), L-lysine (LS) and L-arginine (AR), as capping agents results in the crystallization of antiferromagnetic α-Fe2O3 phases, which show higher capacitance than that of α-Fe2O3 formed without additives using NaOH for pH modification. Surprisingly, the use of meglumine (ML) as an alkalizer–capping agent instead of NaOH results in the fabrication of a ferrimagnetic γ-Fe2O3 phase. The γ-Fe2O3 electrodes prepared using ML show a capacitance of 2.97 F cm−2 from cyclic voltammetry data at 2 mV s−1 and 3.22 F cm−2 from galvanostatic charge–discharge data at 3 mA cm−2 in a potential window of −0.8–0 V in 0.5 M Na2SO4 electrolyte. The high active mass γ-Fe2O3 electrodes, prepared using ML show higher capacitance and lower resistance, compared to the α-Fe2O3 electrodes, prepared using HS, LS and AR. Moreover, the γ-Fe2O3 electrodes prepared using ML exhibit higher capacitance, compared to the literature data for γ-Fe2O3 electrodes, prepared by other methods. The particle size, magnetization and capacitance of the γ-Fe2O3 electrodes can be varied by the variation in synthesis temperature. The obtained γ-Fe2O3 is a promising magnetically ordered pseudocapacitive material for energy storage and other applications based on magnetocapacitive properties. The synthesis method developed in this investigation can be used for the fabrication of other functional nanomaterials. [ABSTRACT FROM AUTHOR]

This study novelly investigates the influence of saline water sources in the ecofriendly synthesis of zeolites, employing economical materials like aluminum scraps, and commercial sodium silicate, within an organic-template-free crystallization system. The type of dissolved anions significantly influences the crystallographic and morphological properties of zeolites. Initially, mordenite forms in distilled water, then transforms into P zeolite and eventually the more stable analcime phase. Saline waters significantly slowed down the phase transformation of the zeolites. At prolonged reaction time, pure analcime, exhibiting varying degrees of aggregation, was observed using distilled, tap, and synthetic saline waters containing Cl− or CO32−. However, mixtures of well-defined crystals consisting of 82.3% P zeolite and 17.7% analcime, or 65.3% P zeolite and 34.7% mordenite, were obtained using waters containing SO42− or HCO3−, respectively. When Mediterranean seawater was utilized, a mixture comprising 30.9% mordenite and 69.1% analcime was produced. Conversely, the high salinity of the Red seawater impeded zeolite formation. While distilled water follows classical nucleation and layer-by-layer deposition, saline waters influenced crystallography and morphology, with anions playing a pivotal role. HCO3− suppressed transformation, while surface-adsorbed Cl− and SO42− ions facilitated reverse crystal growth mechanism akin to organic-directing agents. Preliminary tests reveal zeolites' affinity for removing Cu2⁺ and Fe3⁺ ions, warranting further research. This study opens new avenues for sustainable materials and environmental remediation. [ABSTRACT FROM AUTHOR]

This paper presents the laboratory study results of the hydrothermal synthesis of compounds structurally related to the jarosite group, which is characterized by basic iron sulfate AFe3(SO4)2(OH)6 as the main structural component containing A+ cations such as K+, Ag+, and NH4+. The synthesis process involves preparing the initial model solution using soluble salts of the studied metals, either jointly or individually. The resulting solution is then processed in a sealed vessel (autoclave) at a temperature exceeding 100 °C. This study was conducted within a temperature range of 105–200 °C, with experiment durations varying and a maximum dwell time of 300 min. The zero-time value was defined as the moment the autoclave reached the required temperature. It was observed that adding potassium salts to the solution during hydrothermal synthesis reduced the amount of silver precipitated as argentojarosite. An increase in process temperature from 105 °C to 200 °C resulted in a rise in silver precipitation, from 35% to 69%. The equilibrium constants of the reactions involved in the precipitation of specific jarosite group compounds were calculated, and the reaction order was determined. [ABSTRACT FROM AUTHOR]

Layered inorganic materials are widely used as fillers in nanocomposites due to their unique properties such as mechanical performance, thermal properties, flame resistance, barrier properties, corrosion resistance, catalytic activity, and multifunctionality. Among them, layered α-zirconium phosphate (α-ZrP: Zr(HPO4)2H2O) is one of the representative inorganic materials and unique properties with P–O–H groups that can exchange inorganic and organic cations and intercalate basic molecules. This paper deals with the use of this compound as an adsorbent for heavy metal cations in wastewater. Samples were prepared by hydrothermal treatment at various Zr/P ratio, water amounts, and temperatures. Furthermore, an attempt was made to widen the interlayer distance of the sample using n-butylamine. The α- zirconium phosphate prepared at 160°C for 20 h with Zr/P = 1/2 adsorbed the most amount of metal ions. Furthermore, interlayer amine modification was effective. Then, the behaviour of the adsorption process was observed by varying the time of adsorption from 1 h to 50 h, in order to clarify the change in adsorption of the samples over time. [ABSTRACT FROM AUTHOR]

In this study, the potential to modify the phase structure and morphology of manganese dioxide synthesized via the hydrothermal route was explored. A series of samples were prepared at different synthesis temperatures (100, 120, 140, and 160 °C) using KMnO4 and MnSO4·H2O as precursors. The phase composition and morphology of the materials were analyzed using various physicochemical methods. The results showed that, at the lowest synthesis temperature (100 °C), an intercalation compound with composition K1.39Mn3O6 and a very small amount of α-MnO2 was formed. At higher temperatures (120–160 °C), the amount of α-MnO2 increased, indicating the formation of two clearly distinguished crystal structures. The sample obtained at 160 °C exhibited the highest specific surface area (approximately 157 m2/g). These two-phase (α-MnO2/K1.39Mn3O6) materials, synthesized at the lowest and highest temperatures, respectively, and containing an appropriate amount of carbon xerogel, were tested as active mass for positive electrodes in a solid-state supercapacitor, using a Na+-form Aquivion® membrane as the polymer electrolyte. The electrochemical evaluation showed that the composite with the higher specific surface area, containing 75% manganese dioxide, demonstrated improved characteristics, including 96% capacitance retention after 5000 charge/discharge cycles and high energy efficiency (approximately 99%). These properties highlight its potential for application in solid-state supercapacitors. [ABSTRACT FROM AUTHOR]

This study investigates the magnetic and dielectric properties of cobalt–zirconium co-doped iron oxide nanoparticles synthesized via the hydrothermal method. The synthesis was conducted at 150 °C, with reaction times of 4, 6, 8, 10, and 12 h. Co-doping with cobalt and zirconium significantly influenced the magnetic phase formation of iron oxide. Magnetic properties were characterized using a Vibrating Sample Magnetometer (VSM), revealing ferromagnetic behavior with a maximum saturation magnetization of 45 emu/g for the 8 h sample. The dielectric properties were analyzed through impedance spectroscopy across a wide frequency range, and the results were interpreted using Maxwell–Wagner's model and Koop's theory. The dielectric constant reached its maximum value of approximately 58 at a logarithmic frequency of 1.5 Hz for the sample synthesized for 8 h. This study highlights the importance of synthesis time in optimizing both the magnetic and dielectric properties of (Co, Zr) co-doped iron oxide nanoparticles. [ABSTRACT FROM AUTHOR]

A cost-effective industrial TiOSO4 solution was employed to fabricate visible light active sulfur-doped titanium dioxide (S-TiO2) via a facile hydrothermal method. The effect of calcination temperature on morphology, particle size, crystallinity, and photocatalytic property of S-TiO2 was systematically investigated. Successful incorporation of sulfur into TiO2 was confirmed by carbon-sulfur analysis, X-ray photoelectron spectroscopy (XPS), and Energy dispersive spectrometer (EDS). The research results demonstrated that calcination temperature significantly impacted the crystallinity, specific surface area, sulfur content, and light absorption properties of S-TiO2. The catalyst calcined at 400 °C revealed the highest photocatalytic activity, with a rate constant of 0.02408 min−1, approximately 25 times higher than commercial P25 catalyst. The higher activity was attributed to the synergistic effect of well-crystallized anatase phase, specific surface area, and red shift of spectral absorption. [ABSTRACT FROM AUTHOR]

The liquid-phase selective oxidation of benzyl alcohol is a sustainable route for the synthesis of benzaldehyde. Wherein, the exploration of heterogeneous and cheap metal oxide catalysts instead of noble metal catalysts is of interest in both practical implementation and green chemistry. Herein, vanadium dioxide (VO2) nanosheets were prepared via a one-step hydrothermal reduction of V2O5 by citric acid. The hydrothermal temperature and time played important roles in determining the crystalline structure, morphology, and distribution of V valences of VO2 materials. In the selective oxidation of benzyl alcohol by atmospheric O2, VO2 materials as heterogeneous catalysts showed catalytic activity. Based on XPS and O2-TPD analysis, the catalytically active sites were proposed as V4+ species. At a reaction temperature of 95 °C, the maximum yield of benzaldehyde was up to 91.6% after 6 h, and the VO2-140-5 catalyst can be recycled at least five times without any obvious loss in activity. [ABSTRACT FROM AUTHOR]

Metal chalcogenides are regarded as favorable H 2 -evolution photocatalysts, however, reasonably constructing and synthesizing metal sulphides catalysts with high activity, stability, and cost-effectiveness still faces great challenges. Herein, a novel P-doped hexagonal NiS 2 /ZnS photocatalyst (P–Ni–ZnS) is facilely obtained using a one-step hydrothermal method. Its photocatalytic hydrogen evolution performance is prominently better than those of pure ZnS, P- M -ZnS (M = Cu, Co, and Mn) synthesized under the same conditions and most reported ZnS-based photocatalysts. The optimized P–Ni–ZnS-2 has the highest H 2 production rate of 26.24 mmol g−1 h−1, approximately 3, 2 and 1.5 times higher than ZnS, P–ZnS and NiS 2 /ZnS (Ni–ZnS), highlighting that the synergistic effect of P-doping and NiS 2 cocatalyst results in excellent catalytic efficiency of P–Ni–ZnS-2. Further mechanism studies have shown that P doping and NiS 2 cocatalyst significantly enhance the light capture capability, separation and migration rate of photoinduced carriers. Our work provides a simple and effective method for preparing efficient and stable metal sulfur-based photocatalysts. • One step hydrothermal synthesis of P-doped hexagonal NiS 2 /ZnS composite. • P doping and NiS 2 cocatalyst enhance the photocatalytic activity of hexagonal ZnS. • The optimized P–Ni–ZnS-2 exhibits superior HER photocatalytic activity. [ABSTRACT FROM AUTHOR]

The liquid-phase selective oxidation of benzyl alcohol is a sustainable route for the synthesis of benzaldehyde. Wherein, the exploration of heterogeneous and cheap metal oxide catalysts instead of noble metal catalysts is of interest in both practical implementation and green chemistry. Herein, vanadium dioxide (VO2) nanosheets were prepared via a one-step hydrothermal reduction of V2O5 by citric acid. The hydrothermal temperature and time played important roles in determining the crystalline structure, morphology, and distribution of V valences of VO2 materials. In the selective oxidation of benzyl alcohol by atmospheric O2, VO2 materials as heterogeneous catalysts showed catalytic activity. Based on XPS and O2-TPD analysis, the catalytically active sites were proposed as V4+ species. At a reaction temperature of 95 °C, the maximum yield of benzaldehyde was up to 91.6% after 6 h, and the VO2-140-5 catalyst can be recycled at least five times without any obvious loss in activity. [ABSTRACT FROM AUTHOR]

The development of advanced photocatalyst for the complete and sustainable removal of emerging organic pollutants such as pharmaceuticals in wastewater is still challenging. Thus, a new three-dimensional cauliflower of TiO2 immobilised on a bio sourced activated carbon (AC/3D-TiO2) was successfully synthesised by a hydrothermal method. Its morphological and physicochemical properties were well-characterised with a pure 3D-TiO2 anatase phase, a high surface area (763 m2.g−1) and a cauliflower-shaped morphology composed of TiO2 tubes in a radial direction at a micrometric scale. 3D-TiO2-AC photocatalytic activity on carbamazepine (CBZ), in water showed that around 90% of CBZ elimination is obtained after 4 h of exposure, that is 1.5 times more efficient than commercial TiO2 P25. This was confirmed on five pharmaceuticals (CBZ, ketoprofen, sulfamethoxazole, ciprofloxacin and diclofenac) by measuring their adsorption, elimination, and mineralisation in wastewater highlighting the promising application of AC/3D-TiO2 in the treatment of wastewaters. [ABSTRACT FROM AUTHOR]

In recent years, carbon dots (CDs), a type of new carbon nanomaterial, have been widely used. In this study, new fluorescent CDs were synthesized via a one-step hydrothermal synthesis using 2,3-dihydroxynaphthalene and sodium citrate as the carbon source. The results showed that the prepared CDs were significantly quenched by Fe3+ in aqueous environments, and a good linear relationship between the fluorescence intensity of the CDs and a low concentration of Fe3+ was observed. The detection limit of Fe3+ was 0.12 μM, the linear range was 0–4.69 μM and the recovery range of the sample detection was 84–111%. The new fluorescent CDs showed high sensitivity to Fe3+ in the presence of various metal ions and anions. These excellent characteristics promise extensive potential applications for our fluorescent CDs in aqueous environmental monitoring. [ABSTRACT FROM AUTHOR]

Hydrogen is an emerging alternative green fuel for global decarbonization with a high energy density and zero‐emission. Developing electrocatalysts with strong adhesion, active, and highly efficient that can be operated at high current densities is vital to producing green hydrogen at a large scale via electrocatalytic water splitting (EWS). The sputtering technique is an innovative and prospective alternative to fabricate electrodes for EWS due to its scalability, purity, strong adhesion, chemical‐, solvent‐, and waste‐free catalyst preparation. This review article provides an overview of recent electrocatalyst advances for EWS made by the sputtering technique, emphasizing its distinct advantages over other methods, such as hydrothermal synthesis and drop‐casting. We also provide the recent difficulties associated with the scale‐up issue and outlook to overcome those difficulties, as well as the future direction of the electrocatalysts to meet industrial needs. [ABSTRACT FROM AUTHOR]

Zinc ion batteries (ZIBs) are increasingly prominent due to their cost-effectiveness, abundance, environmental safety, mature processing methods, high volumetric energy density, and compatibility with aqueous electrolytes. However, a significant challenge lies in finding a suitable cathode material with high capacity and structural stability. Manganese dioxide (MnO 2) is a promising candidate for ZIB cathodes in aqueous systems, surpassing other metal oxides in potential. However, MnO 2 cathodes encounter challenges, including rapid capacity degradation and limited cyclic stability. Enhancing the structural stability of host materials during intercalation presents a significant avenue for increasing cathode capacity. In this study, we employed a hydrothermal method to synthesize MnO 2 , followed by annealing in an argon atmosphere at 300 °C for 4 h for MnO 2 -300 and 400 °C for 2 h for MnO 2 -400 to bolster its structural integrity. The properties of annealed samples MnO 2 -300 and MnO 2 -400 are compared with pristine samples (MnO 2 -P). Initially, XRD analysis is conducted to compare their structures, followed by a comparison of electrochemical properties, including Cyclic Voltammetry (CV) and charge-discharge analysis. MnO 2 -400 exhibits a higher initial capacity (149.3 mAhg−1 at 0.1 Ag-1) than MnO 2 -300 (129.0 mAhg−1 at 0.1 Ag-1) and MnO 2 -P (107.9 mAhg−1 at 0.1 Ag-1). An extended cycling test of up to 500 cycles also indicates that annealing MnO 2 in an Ar atmosphere enhances structural stability and capacity compared to the unannealed sample. [ABSTRACT FROM AUTHOR]

ABSTRACT The thermal characteristics of zirconyl and hafnium hydrogentellurates, ZrO(HTeO4)2 × 4H2O (ZrOTe) and Hf(HTeO4)4 × 8H2O (HfTe), were investigated via non‐isothermal decomposition kinetics in this paper for the first time. Important kinetic parameters such as activation energy (EA), pre‐exponential factor (A) and g(α) function were determined using Coats‐Redfern integral method. The latter was verified by means of z(α) master plots. In addition, plausible decomposition mechanisms for the title compounds were offered. Based on the EA values, less thermal stability for ZrOTe (633.69 kJ/mol) with respect to HfTe (872.24 kJ/mol) was observed. Thermodynamic functions (ΔS≠, ΔH≠, and ΔG≠) of the activated complexes generated during the thermal decomposition steps were studied as well. A high positive ΔH≠ value (855.70 kJ/mol) for the thermal decomposition of HfTe indicated formation of high‐ordered activated complexes. In contrast, lower ΔH≠ (612.50 kJ/mol) for ZrOTe suggested easier formation the transition states in that case. [ABSTRACT FROM AUTHOR]

Lithium‐rich manganese‐based layered oxide cathode materials (LLOs) have always been considered as the most promising cathode materials for achieving high energy density lithium‐ion batteries (LIBs). However, in practical applications, LLOs often face some key problems, such as low initial coulombic efficiency, capacity/voltage decay, poor rate performance and poor cycle stability. It seriously shortens the lifespan of lithium‐ion batteries and hinder the large‐scale commercial application of LLOs. Herein, firstly, the basic theories of LLOs were systematically reviewed, including the structural characteristics, the working mechanism of LLOs, the preparation methods of LLOs (liquid phase co‐precipitate method, sol‐gel method, hydrothermal synthesis method, solid phase method, low heat solid‐phase method, high temperature solid‐state method etc.), and electrochemical characteristics of LLOs (first charge discharge characteristics and reversible efficiency, cycling performance, high and low temperature performance and thermal stability etc.). Then, key challenges faced by LLOs were systematically discussed. Finally, the LLOs modification strategies used to address these challenges (element doping, surface modification, defect engineering, structural and morphological control etc.) were elaborated in detail. This important review provides potential insights and directions for further improving the electrochemical performance of LLOs, and provides a necessary theoretical basis for accelerating the large‐scale commercial application of LLOs. It possesses important scientific research value and far‐reaching social significance. [ABSTRACT FROM AUTHOR]

When developing gas sensors, selecting a suitable gas-sensing material is of great importance. Currently, there is great interest in the development of new gas-sensitive layers based on molybdenum oxide MoO3 and improvement of their sensor characteristics. In the work, a MoO3 gas-sensitive layer is obtained by the hydrothermal method followed by annealing at a temperature of 400°C for 2 hours. The elemental composition of the surface of the obtained sample is analyzed using X-ray photoelectron spectroscopy. Studies of the sensor response, response time, and recovery time of the gas-sensitive layer to isopropyl-alcohol vapors at different operating temperatures are carried out. The chemical composition is shown to be consistent with MoO3, but adsorbed hydroxyl groups are also observed on the surface. Analysis of the sensor properties shows that the sensitivity at temperatures of 250°C and 150°C is 13.3 and 5.5, respectively. It is found that layers based on MoO3 nanoparticles synthesized by the hydrothermal method exhibit sensitivity to isopropyl-alcohol vapors even at a temperature of 150°C. [ABSTRACT FROM AUTHOR]

In this study, a nanowire network-based V 2 O 5 nanostructure, designed as the active surface in H 2 S gas sensors, was produced using an environmentally friendly method known as hydrothermal synthesis. The morphological, structural, and electrical properties of the produced nanostructure were characterized using various measurement techniques. XRD, SEM, and EDX analyses confirmed that the nanostructure was in a pure monoclinic phase, had a two-dimensional (2-D) nanowire network morphology, and was deposited stoichiometrically. From UV–Vis analysis, the energy band gap value of the nanostructure was calculated to be 2.65 eV. In gas sensing measurements conducted between 27 °C and 102 °C, the optimal operating temperature of the fabricated sensor was determined to be 42 °C. At this temperature, which is close to room temperature, the sensor exhibited a high sensitivity of 21.16 % for 50 ppm H 2 S gas, along with good selectivity, stable repeatability, and baseline stability. Moreover, for 2 ppm H 2 S gas, the response and recovery times were 39 s and 58 s, respectively. A comprehensive electrical analysis of the sensor was carried out through impedance spectroscopy measurements over a wide temperature range. Our findings indicate that the 2-D V 2 O 5 nanowire network structure (NNS) results in several notable effects, including low operating temperature, high selectivity, and stability for H 2 S gas, demonstrating considerable potential for industrial applications. [ABSTRACT FROM AUTHOR]

Spinel oxides still exhibit unsatisfactory electrocatalytic performance toward oxygen evolution reaction (OER) given their low intrinsic activity, poor electronic conductivity, and limited exposure of reaction sites. Defect engineering has garnered intensive attention and become a promising strategy to enhance the reaction kinetics. In this work, spinel NiFe2O4 nanospheres with rich nickel vacancies are prepared via simple one‐pot hydrothermal synthesis. Combined electrochemical measurements and in situ Raman characterization prove that a relatively higher degree of electrochemical surface reconstruction is realized after the introduction of nickel vacancies in NiFe2O4, in addition to boosted OER electrocatalytic performance. Further theoretical calculations also reveal that the cation‐vacancy‐induced effect can reduce the difficulty for surface reconstruction by increasing the octahedral nickel‐oxygen covalency in nickel ferrite. Contributed to the great structural flexibility and optimized electronic structure of the pre‐catalyst, the reconstructed electrocatalyst presents desirable OER performance, accompanied by long durability in alkaline solution. This work provides a sound strategy to intensify surface reconstruction on spinel oxides and design electrocatalysts with high efficiency toward water oxidation. [ABSTRACT FROM AUTHOR]

Two rare earth isonicotinic acid compounds [Y(HIA)2(H2O)4(NO3)](2NO3) ((1); HIA = isonicotinic acid) and [LaHg3Cl8(HIA)4]nnCl (2) were reported. Compound one features an isolated (0-D) structure, while compound two has a two-dimensional (2-D) structure. The rare earth ions are coordinated by eight oxygen atoms to display a square antiprismatic REO8 geometry. Compound one shows blue photoluminescence and it has CIE chromaticity coordinates of 0.2332 and 0.3104. The CCT of compound 1 is 13755 K. Compound two exhibits green photoluminescence and it has CIE chromaticity coordinates of 0.3663 and 0.6184. The CCT is 4997 K. Their band gaps are 2.86 and 3.12 eV. [ABSTRACT FROM AUTHOR]

Developing and implementing technologies that can significantly reduce food loss during storage and transport are of paramount importance. Ozone synergistic catalytic oxidation (OSCO) technology has been developed, which sterilizes bacteria and viruses on the surface of food and degrades ethylene released during fruit storage through the active oxygen produced by the catalytic decomposition of ozone. Herein, we report the hydrothermal synthesis of MnO2 with distinct phase compositions and nanostructures through simply varying the reaction temperatures. Optimized copper-doped α-MnO2 nanorods exhibited remarkable efficacy in activating ozone at a concentration of 40 ppb, and this activation resulted in the complete eradication of indicator bacteria on food surfaces within a 24 h period. Moreover, these nanorods demonstrated high effectiveness in decomposing more than 80% of the ethylene molecules emitted by apples and bananas during the preservation period. The high concentration of surface oxygen vacancies is believed to contribute to the enhanced catalytic activity of the Cu-doped α-MnO2 catalyst in the OSCO procedure by reducing ethylene production and maintaining the fruit quality during the preservation period. [ABSTRACT FROM AUTHOR]

Utilization of fluoride-containing waste from aluminium fluoride production is an important strategic issue. Here, we use technogenic silica gel containing about 30 wt. % of fluoride and aluminum for zeolite NaA (LTA) synthesis. The process consists of two steps: silica gel acid purification up to a silica content of 95 wt. % and hydrothermal synthesis. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy were used for phase identification and synthesis conditions optimization. As a result, we determined that hydrothermal synthesis from aluminosilicate gel with molar ratios SiO2:Al2O3 = 1.8, Na2O:Al2O3 = 4.0, and H2O:SiO2 = 50 at 95 °C for 60 min with vigorous stirring yields zeolite NaA with Ca2+ and Mg2+ ion exchange capacities of 562.6 and 187.5 mEq/100 g respectively and water vapor capacity of 25.8 g/100 g. Thus, the developed process offers waste silica gel utilization and production of zeolite NaA, which is as good as commercial analogs. [ABSTRACT FROM AUTHOR]

It has generally been believed that the performance of ultra‐thin multilayer ceramic capacitors (MLCCs) are mainly controlled by doping elements and the contribution of synthesis approaches of BaTiO3 (BT) powders can be neglected. However, in this study, we demonstrate that the solid‐state powders exhibit a heterogeneous distribution of residual BaCO3 (BC), TiO2, or Ti‐rich phases, whereas hydrothermal powders are characterized by a BC surface layer, which can be characterized by nanoinfrared (AFM‐IR), and the divergent approaches play an important role in the “core–shell” structure. The BC layer in hydrothermal BT contributes to Ti vacancies during sintering, increasing the “core–shell” ratio in MLCCs. This results in augmented capacitance but reduced performance at elevated temperatures. Conversely, the presence of a Ti‐rich phase in solid‐state powders induces Ba vacancies, leading to decreased “core–shell” ratios and dielectric constants. [ABSTRACT FROM AUTHOR]

We revealed the reaction pathway in the hydrothermal synthesis of Cu nanoparticles from an aqueous solution of copper formate at relatively low temperatures up to 573 K by in situ synchrotron X-ray diffraction. The two possible pathways were reduction reaction caused by (i) formic acid adsorption on an intermediate oxide and (ii) hydrogen gas generated through the water-catalyzed decomposition of formic acid under hydrothermal conditions. We observed the formation of intermediate Cu2O under all conditions within the temperature range of 473–673 K and pressure range of 5–30 MPa, despite rapid heating within a few seconds. The induction time of Cu formation decreased exponentially with increasing temperature. The pressure-independent activation energy of 0.87(7) eV was estimated for Cu formation between 498 and 573 K from the Arrhenius plot of induction time. Compared with the reported values, the pressure-independent activation energy was attributed to reduction reaction (i). In addition, we suggest that reaction (i) may also dominate in the supercritical and subcritical hydrothermal synthesis, which was originally designed with reaction (ii). This is due to the observation of intermediate Cu2O and the fact that particle growth and induction time can be explained by reaction (i) continuously from lower temperatures. While further investigation is necessary to confirm the reaction pathway under supercritical and subcritical conditions, the present findings can change a synthesis strategy from suppressing to utilizing the intermediate. [ABSTRACT FROM AUTHOR]

Efficient water‐splitting is severely limited by the anodic oxygen evolution reaction (OER). Iridium oxides remain one of the only viable catalysts under acidic conditions due to their corrosion resistance. We have previously shown that heat‐treating high‐activity amorphous iridium oxyhydroxide in the presence of residual lithium carbonate leads to the formation of lithium‐layered iridium oxide, suppressing the formation of low‐activity crystalline rutile IrO2. We now report the synthesis of Na‐IrOx and K‐IrOx featuring similarly layered crystalline structures. Electrocatalytic tests confirm Li‐IrOx retains similar electrocatalytic activity to commercial amorphous IrO2 ⋅ 2H2O and with increasing size of the intercalated cation, the activity towards the OER decreases. However, the synthesised electrocatalysts that contain layers show greater stability than crystalline rutile IrO2 and amorphous IrO2 ⋅ 2H2O, suggesting these compounds could be viable alternatives for industrial PEM electrolysers where durability is a key performance measure. [ABSTRACT FROM AUTHOR]

In order to improve the electrochemical performance of NiCo‐based layered double hydroxide (NiCoLDH), the synthesis of low‐crystallinity NiCoLDH was induced by the adsorption of glucose and NiCoLDH. The results showed that glucose could not only effectively regulate the pore structure and morphology of NiCoLDH, but also had a regular effect on crystallinity. Pure phase NiCoLDH had higher crystallinity. When the mass of glucose is 0.05 g, the prepared NiCoLDH‐0.05 is a short‐range ordered structure embedded in the amorphous matrix. The crystallinity of the product decreases further with the further increase of glucose mass. Since the ordered structures have higher electrical conductivity, and amorphous structures have more defects and active sites, the structure of NiCoLDH‐0.05 is conducive to achieving the best electrochemical performance. Electrochemical test results show that NiCoLDH‐0.05 has a high specific capacitance, about 12 times that of the pure phase NiCoLDH, the mass of glucose is higher than or below 0.05 g, the specific capacitance will be further reduced. NiCoLDH‐0.05 and activated carbon assembled into an asymmetric supercapacitor have a power density of 400 W kg−1 at an energy density of 32.7 Wh kg−1. This study provides a new idea for obtaining excellent electrochemical properties by adjusting LDH crystallinity. [ABSTRACT FROM AUTHOR]

Oxide zeolites are synthesized from aqueous solutions in an established way employing hydrothermal synthesis. Transferring this approach to nitride zeolites requires a solvent providing nitrogen for which ammonia has proven to be particularly suitable. We present the successful ammonothermal synthesis of the (oxo)nitridosilicate compounds Ce3[Si6N11], Li2RE4[Si4N8]O3 (RE=La, Ce) and K1.25Ce7.75[Si11N21O2]O0.75. Within this procedure, the usage of supercritical ammonia as a solvent as well as the utilization of the mineralizers NaN3, Li3N and KN3, respectively, allowed the targeted synthesis of large single crystals. Formation of these (oxo)nitridosilicates depends mainly on the employed mineralizer despite their similar degree of condensation. The three compounds were structurally characterized using X‐ray diffraction and their crystal structures contain a wide range of different ring sizes within their tetrahedra networks. The zeolite(‐like) crystal structures are elucidated and compared to known nitridosilicate representatives of the respective structure types. Their elemental composition was investigated using energy‐dispersive X‐ray (EDX) spectroscopy and incorporation of the O rather than N−H functionality was confirmed by Fourier‐Transform infrared (FTIR) spectroscopy as well as by charge distribution (CHARDI) and bond valence sum (BVS) calculations. The presented examples demonstrate that ammonothermal synthesis provides a one‐step access from elemental starting materials towards nitride zeolites. [ABSTRACT FROM AUTHOR]

In this work, MoS2 nanosheets with diverse morphologies and their nanocomposites with PEDOT:PSS are synthesized at relatively low temperature via a hydrothermal process using ammonium heptamolybdate tetrahydrate (AHT), thiourea (Th), and citric acid as precursors. The study investigates the effects of varying concentrations of AHT and Th in acidic condition on the growth, morphology, and optical properties of MoS2 nanosheets and their nanocomposites with PEDOT:PSS. Morphology, chemical composition, and optical properties of the MoS2/PEDOT:PSS nanocomposites are studied using Field Emission Scanning Electron Microscopy(FESEM), FTIR, UV–Vis, and photoluminescence spectroscopy. The FESEM images indicate that the MoS2 nanosheets exhibited large, uniform rectangular and leaf-like structures formed through the stacking of multiple nanosheets. Moreover, the concentration of the PEDOT:PSS polymer is found to have a significant impact on the morphological and optical properties of the MoS2/PEDOT:PSS nanocomposites. [ABSTRACT FROM AUTHOR]

SnS nanoparticles (NPs) were synthesized at different reaction temperatures in the range of 150℃-180℃ (in step size of 10℃) via hydrothermal method using Urea as complexing agent. The structural, morphological, and optical properties of the synthesized nanoparticles were investigated using X-ray diffraction analysis (XRD), Energy-dispersive X-Ray analysis (EDS), and UV–VIS by diffuse reflectance spectroscopy. Analysis of the XRD spectra for synthesized SnS nanoparticles at different reaction temperature are in good agreement with JCPDS card number 001–0984 with preferred orientation of grains along (0 1 3) plane. The EDS analysis suggests that SnS nanoparticles are tin deficient. The energy band gap estimated for SnS nanoparticles synthesized at different reaction temperature are in the range of 1.24 eV to 1.27 eV. Synthesized SnS nanoparticles prepared at reaction temperature of 170℃ were used for photocatalytic degradation of methylene blue (MB) dye under visible light irradiation. The Average photo degradation efficiencies of the SnS NPs for MB dye were found to be 72% for an irradiation time of 150 min. The higher efficiency of SnS nanoparticles may be due to deficiency of tin that is capable of enhanced adsorption sites for photocatalytic oxidation of MB. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable zinc ion batteries (ARZIBs) represent a cheaper and more environmentally friendly alternative to lithium-ion batteries (LIBs) in energy storage systems. Vanadium oxide is one of the most attractive materials to be used as a cathode in ARZIBs because it has multiple oxidation states that grant high specific capacity. This work employed an alternative synthetic route to obtain VO 2 with varied morphology and structural properties utilizing vanadyl acetylacetonate as a precursor by tuning the temperature during two-step solvothermal/hydrothermal treatment. When highly crystalline VO 2 (B) with rod morphology is obtained, the electrode exhibits the best electrochemical response, with the most significant contribution of surface-confined redox processes to the charge stored. The ARZIB assembled with VO 2 rod showed an initial capacity of up to ∼300 mA h g−1 (2.4 mA h cm−2) at 0.1 A g−1, delivering a specific energy of up to 168 W h kg−1 at a specific power of 65 W kg−1. It exhibits outstanding stability after 2000 GCD cycles at 2.5 A g−1. Ex-situ structural and spectroscopic characterization showed that Zn2+ storage causes an expansion and contraction of the lattice without evidence of crystalline phase transformations. [ABSTRACT FROM AUTHOR]

To synthesize high-quality TS-1 zeolites with enhanced catalytic performance for 1-hexene epoxidation is highly attractive for meeting the increased need for sustainable chemistry. Herein, we report that a series of framework Ti-enriched TS-1 zeolites with high crystallinity can be effectively synthesized by the hydrothermal crystallization of a composite precursor composed of diol-based polymer (containing titanium and silicon) and tetrapropylammonium bromide (TPABr). The pre-addition of a certain amount of TPABr into the polymer-based precursor plays a very positive role in maintaining the high crystallinity and framework Ti incorporation rate of TS-1 zeolites under the premise that a relatively low concentration of tetrapropylammonium hydroxide (TPAOH) template is adopted in the following hydrothermal crystallization process. The condition-optimized TS-1 zeolite with a smaller particle size (300–500 nm) shows excellent catalytic activity, selectivity, and recyclability for the epoxidation of 1-hexene with H2O2 as an oxidant, which can achieve a 75.4% conversion of 1-hexene and a 99% selectivity of epoxide at a reaction temperature of 60 °C, which is much better than the TS-1 zeolites reported in the previous literature. The relatively small particle size of the resultant TS-1 crystals may enhance the accessibility of the catalytically active framework Ti species to reagents, and the absence of non-framework Ti species, like anatase TiO2, and low polymerized six-coordinated Ti species could effectively inhibit the ineffective decomposition of H2O2 and the occurrence of side reactions, leading to an improvement in the catalytic efficiency for the epoxidation of 1-hexente with H2O2. [ABSTRACT FROM AUTHOR]

Zeolites are a class of porous aluminosilicates possessing high surface area, good hydrothermal stability, strong sorption, and high ion-exchanging potential, and which frequently serve as efficient catalytic materials. The composites which integrate zeolite with alternative substances like metal oxides or carbon-based materials steadily outperform individual constituents. Recently, the application of zeolite-based composites in the field of photocatalytic oxidation and electrocatalytic oxidation/reduction, which is mainly focused on pollution treatment in sewage and air, have garnered significant attention. Several synthesis strategies for zeolite-based composites including post-treatment and in situ hydrothermal synthesis methods are explicated. Meanwhile, multifarious types of zeolite-based photoelectric catalytic composites are also summarized. Finally, we highlight the advancements improving the performance of zeolite-based composites in the photocatalytic treatment of organic pollutants in wastewater and the electrocatalytic reduction of CO2 and organics. [ABSTRACT FROM AUTHOR]

This study investigates the application of robocasting technology for fabricating high-density yttria-stabilized zirconia (8YSZ) electrolytes used in solid oxide fuel cells (SOFCs). The primary goal is to overcome the limitations of traditional manufacturing techniques, such as low density and poor microstructural control. Using a combination of hydrothermal synthesis, rheological testing, and robocasting, we achieved dense 8YSZ structures (over 95% density) with minimal porosity. The fabricated electrolytes underwent sintering and debinding processes, with thermal treatment profiles optimized for structural integrity. A microstructural analysis through SEM and XRD confirmed the formation of stable crystalline phase. This research opens new avenues for the use of additive manufacturing in electrochemical applications, particularly for producing complex ceramic components with superior characteristics. [ABSTRACT FROM AUTHOR]