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

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

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

The one step hydrothermal synthesis of encapsulated ruthenium nanoparticles on carbon results in solids displaying high potential in photo‐thermal catalysis. The integration of ruthenium into the carbon matrix has a twofold effect: (i) enhanced stability through prevention of metal sintering and oxidation and (ii) improved photothermal response. As a result, high efficiencies are achieved in the photo‐thermal decomposition of ammonia. [ABSTRACT FROM AUTHOR]

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

Asphodelus-based CQDs were successfully synthesized in a single step by the hydrothermal synthesis method for detection of β-carotene. TEM, XRD, FTIR, XPS, Zeta potential, UV–Vis absorption and fluorescence measurements were taken to structurally and optically characterize the newly synthesized CQDs. It was determined that the characterized CQDs show high selectivity and sensitivity only to β-carotene among 11 different biomolecules. The detection limit of CQDs for β-carotene was calculated as 8.28 µM. It was determined that the new CQDs respond very quickly and stably without interfering with any other biomolecules. The studies in different pH environments exhibited that CQDs can detect β-carotene at all pH studied. Real sample experiments show that β-carotene can be determined accurately and reliably in practical applications with the novel CQDs. It was thought that the results obtained from this study will make significant contributions to the studies on β-carotene detection, which are limited in the literature. [ABSTRACT FROM AUTHOR]

In recent years, algae have emerged as a promising feedstock for biofuel production, due to their eco-friendly, sustainable, and renewable nature. Various methods, including chemical, biochemical, and thermochemical processes, are used to convert algal biomass into biofuels. Pyrolysis, a widely recognized thermochemical technique, involves high temperature and pressure to generate biochar and bio-oil from diverse algal sources. Various pyrolytic processes transform algal biomass into biochar and bio-oil, including low pyrolysis, fast pyrolysis, catalytic pyrolysis, microwave-assisted pyrolysis, and hydropyrolysis. These methods are utilized to convert a range of microalgae and cyanobacteria into biochar and bio-oil. In this publication, we will discuss catalytic pyrolysis using mesoporous materials, such as SBA-15. Mesoporous catalysts have earned significant attention for catalytic reactions, due to their high surface area, facilitating the better distribution of impregnated metal. Pyrolysis conducted in the presence of a mesoporous catalyst is viewed more as efficient, compared to reactions occurring within the smaller microporous cavities of traditional zeolites. SBA-15 supports with incorporated Zr and/or Ce were synthesized using the direct hydrothermal synthesis method. The catalyst was characterized using structural and morphological technical analysis and utilized for the pyrolysis reaction of the algal biomass. [ABSTRACT FROM AUTHOR]

This investigation explores the potential of enhancing aqueous zinc-ion batteries (AZIBs) through the introduction of a novel cathode material, NH4V4O10 (NVO), combined with reduced graphene oxide (rGO). Utilizing Density Functional Theory (DFT), it was hypothesized that the incorporation of rGO would increase the interlayer spacing of NVO and diminish the charge transfer interactions, thus promoting enhanced diffusion of Zn2+ ions. These theoretical predictions were substantiated by experimental data acquired from hydrothermal synthesis, which indicated a marked increase in interlayer spacing. Significantly, the NVO–rGO composite exhibits remarkable cyclic durability, maintaining 95% of its initial specific capacity of 507 mAh g−1 after 600 cycles at a current density of 5 A g−1. The electrochemical performance of NVO–rGO not only surpasses that of pristine NVO but also outperforms the majority of existing vanadium oxide cathode materials reported in the literature. This study underscores the effective integration of theoretical insights and experimental validation, contributing to the advancement of high-performance energy storage technologies. [ABSTRACT FROM AUTHOR]

In this work, we explored the hydrothermal synthesize and crystallization process of SAPO‐34 zeolites from two‐dimensional layered silicate magadiite by using tetraethylammonium hydroxide (TEAOH) as a templating agent. Comprehensive characterization was conducted by XRD, SEM, FTIR, Raman, and BET. Time‐resolved PXRD analysis revealed that SAPO‐34 zeolite exhibited a steep growth curve when the crystallization time was 30 h, and the crystallinity reached 98.65 % at 48 h. Specifically, the disruption of the magadiite layer exposed charged silanol groups on the surface, fostering an affinity for AlO4 and PO4 species, thereby initiating the nucleation process. Under the guidance of TEAOH, these nucleation sites transformed into SAPO‐34 nuclei, gradually advancing towards crystallization. FTIR and Raman analyses affirmed the presence of 6Rs, followed by D6R and 4Rs SBUs, along with the characteristic CHA structure. Combined with 29Si NMR established that disaggregated silicate minerals served as zeolite synthesis "seeds", enhancing nucleation sites and overall crystallization efficiency. [ABSTRACT FROM AUTHOR]

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

In this study, a trisodium citrate (TSC)-assisted hydrothermal method is utilized to prepare three-dimensional hydroxyapatite (3D HA). Understanding the role of TSC in the preparation of 3D HA crystals may provide valuable methods to design advanced biomaterials. As one of the indexes of solution supersaturation, the initial pH (ipH) value can not only directly affect the nucleation rate, but also affect the growth of HA crystals. In this work, the effect of the ipH on the microstructure, particle size distribution, and specific surface area of the 3D HA is explored. Results showed that the morphology of 3D HA transformed from a bundle to a dumbbell ball and then a dumbbell with an increase in the ipH. A corresponding mechanism of such a structural evolution was proposed, providing inspiration for the fabrication of innovative 3D HA structures with enhanced biological functionality and performance. [ABSTRACT FROM AUTHOR]

In this work, β-NiS nanoparticles (NPs) were efficiently prepared by a straightforward hydrothermal process. The difference in morphology between these NiS NPs was produced by adding different amounts of thiourea, and the corresponding products were denoted as NiS-15 and NiS-5. Through electrochemical tests, the specific capacity (Cs) of NiS-15 was determined to be 638.34 C g−1 at 1 A g−1, compared to 558.17 C g−1 for NiS-5. To explore the practical application potential of such β-NiS NPs in supercapacitors, a hybrid supercapacitor (HSC) device was assembled with activated carbon (AC) as an anode. Benefitting from the high capacity of the NiS cathode and the large voltage window of the device, the NiS-15//AC HSC showed a high energy density (Ed) of 43.57 W h kg−1 at 936.92 W kg−1, and the NiS-5//AC HSC provided an inferior Ed of 37.89 W h kg−1 at 954.79 W kg−1. Both HSCs showed excellent cycling performance over 6000 cycles at 10 A g−1. The experimental findings suggest that both NiS-15 and NiS-5 in this study can serve as potential cathodes for high-performance supercapacitors. This current synthesis method is simple and can be extended to the preparation of other transition metal sulfide (TMS)-based electrode materials with exceptional electrochemical properties. [ABSTRACT FROM AUTHOR]

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

This work presents the formation of a stable 3D monolith based on manganese oxide for the adsorption of lithium from brine. The precursor phase was prepared by microwave‐assisted hydrothermal synthesis and a subsequent calcination process to achieve the desired crystalline phase LiMn2O4. The monolith was formed using additive manufacturing, which allowed its size and shape to be controlled. Subsequently, this monolith was washed with a HCl solution to generate adsorption sites for lithium. The prepared materials were characterized by XRD, FTIR, TGA, N2 physisorption, and SEM‐EDS. Analysis confirmed that the 3D monolith retained its crystalline structure throughout the process. The kinetic characteristics of the adsorption process were evaluated using pseudo‐first and pseudo‐second order equations, as well as Freundlich and Langmuir equations, to describe thermodynamic equilibrium. Monoliths were able to capture lithium up to 13.84 mg/g and the Freundlich equation described the equilibrium (R2=0.9751), while the second‐order equation better described the kinetic behavior (R2=0.9130). Results showed that monoliths are selective towards lithium in the presence of competing cations. The stability of the materials was evaluated in adsorption‐desorption cycles, demonstrating a competitive reuse after five cycles. This research presents a promising new approach for developing efficient lithium extraction methods from brine. [ABSTRACT FROM AUTHOR]

In this work, a simple one-step hydrothermal synthesis of La doped SnO 2 nanocomposites was studied. The structure, morphology, specific surface area, and chemical composition were determined by XRD, SEM, BET, and XPS techniques. The gas sensing performance of SnO 2 and La/SnO 2 nanocomposites with varied La doping dosages on n-butanol gas was systematically investigated. The results manifested that under the testing environment (50 % relative humidity and 30 °C), La doped SnO 2 nanocomposite sensor presented high response (69), excellent selectivity, good repeatability and long-time stability to n-butanol gas at 160 °C. Especially, the 7 mol% La doped SnO 2 sensor displayed a 5.9 times higher response to 50 ppm n-butanol than the SnO 2 sensor. In comparison with bare SnO 2 , La doping increased the band gap value of 7 mol% La/SnO 2 nanocomposite by 6.23 %, decreased particle size by 11.83 %, and increased the oxygen defect concentration by 6.07 %. Due to the synergistic effect of the above factors, the gas sensing performance of La doped SnO 2 nanocomposites towards n-butanol gas was enhanced. Therefore, La doped SnO 2 nanocomposites might be a potential gas sensing material for monitoring n-butanol gas at relatively high humidity. [ABSTRACT FROM AUTHOR]

Zinc indihuhium sulfide (ZIS), among various semiconductor materials, shows considerable potential due to its simplicity, low cost, and environmental compatibility. However, the influence of precursor anions on ZIS properties remains unclear. In this study, we synthesized ZIS via a hydrothermal method using four different anionic precursors (ZnCl2/InCl3, Zn(NO3)2/In(NO3)3, Zn(CH3CO2)2/In(CH3CO2)3, and Zn(CH3CO2)2/In2(SO4)3), resulting in distinct morphologies and crystal structures. Our findings reveal that ZIS produced from Zn(CH3CO2)2/In2(SO4)3 (ZIS-AceSO4) exhibited the highest photocatalytic CO2 reduction efficiency, achieving a CO production yield of 134 μmol g−1h−1. This enhanced performance is attributed to the formation of more zinc and indium vacancy defects, as confirmed by EDS analysis. Additionally, we determined the energy levels of the valence band maximum (VBM) and the conduction band minimum (CBM) via UPS and absorption spectra, providing insights into the band alignment essential for photocatalytic processes. These findings not only deepen our understanding of the anionic precursor's impact on ZIS properties but also offer new avenues for optimizing photocatalytic CO2 reduction, marking a significant advancement over previous studies. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (MoO3) is an attractive semiconductor. Thus, bandgap engineering toward photoelectronic applications is appealing yet not well studied. Here, we report the incorporation of sulfur atoms into MoO3, using sulfur powder as a source of sulfur, via a self-developed hydrothermal synthesis approach. The formation of Mo-S bonds in the MoO3 material with the synergistic effect of sulfur doping and oxygen vacancies (designated as S-MoO3−x) is confirmed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The bandgap is tuned from 2.68 eV to 2.57 eV upon sulfur doping, as confirmed by UV-VIS DRS spectra. Some MoS2 phase is identified with sulfur doping by referring to the photoluminescence (PL) spectra and electrochemical impedance spectroscopy (EIS), allowing significantly improved charge carrier separation and electron transfer efficiency. Therefore, the as-prepared S-MoO3−x delivers a sensitive photocurrent response and splendid cycling stability. This study on the synergistic effect of sulfur doping and oxygen vacancies provides key insights into the impact of doping strategies on MoO3 performance, paving new pathways for its optimization and development in relevant fields. [ABSTRACT FROM AUTHOR]

Resource saving and creation of environmentally safe environment are the guidelines of modern world policy in the field of waste management. This paper considers a possible method of utilization of a by-product of aluminum fluoride production—silica gel—as an alternative high-silica raw material for hydrothermal synthesis of LTA-type zeolites. To obtain synthetic zeolites, industrial silica gel was subjected to sulfuric acid purification and used to obtain one of the hydrogel components—sodium silicate. As a result of investigation of the influence of hydrogel molar composition on the phase composition of the obtained samples, the optimal molar ratios of SiO2:Al2O3, Na2O:Al2O3 and H2O:SiO2 were identified. The phase composition of the obtained samples and morphological pattern were evaluated using X-ray diffraction and scanning electron microscopy techniques. According to the obtained results, the use of hydrogel of composition 1.8SiO2:Al2O3:4Na2O:28H2O allows to obtain a monophase of LTA type zeolite with high ion exchange capacity, the particles of which have a regular cubic shape with the size of the main fraction up to 10 μm. [ABSTRACT FROM AUTHOR]

Organic pollutants such as dyes and pharmaceutical drugs have become a significant environmental problem due to their unrestricted discharge, especially in water bodies. As a result, an economically viable and environmentally friendly approach to their degradation in water bodies is required and the incorporation of metal tungstate with single metal oxide has attracted attention due to its potential ability towards the photocatalytic degradation of pollutants. The work demonstrates a WO3/g-C3N4/V2O5 nanocomposite synthesized using a facile route wet impregnation method. The results revealed that WO3/g-C3N4/V2O5 nanocomposites are suitable, mainly for their better surface properties, enhanced visible-light absorption, and preferred band positions. Besides that, the degradation of methylene blue (MB) dye is carried out and demonstrated that the complete degradation occurs over 120 min using 10 mg L−1 of WO3/g-C3N4/V2O5 nanocomposite under UV–visible-light irradiation. The scavenger experimental result implies that the photogenerated free electrons and superoxide radials are important role in MB dye degradation. In addition, a possible mechanism is proposed for the photocatalytic activity of WO3/g-C3N4/V2O5 nanocomposite. Moreover, the stability analysis demonstrated that the WO3/g-C3N4/V2O5 nanocomposite can be recycled multiple times. [ABSTRACT FROM AUTHOR]

LiFeOHS is a material with Li2(OH)2 layers intercalated between Fe2S2 planes. Its hydrothermal synthesis in various concentrations of LiOH yields materials with a high non-stoichiometry of the Li/Fe ratio which can be explained by partial substitution of Li+ for Fe2+ in the Li2(OH)2 layers. Thermogravimetry, X-ray diffraction and Mössbauer studies indicate that the charge balance is obtained by substitution of hydroxyl ions OH− by oxide ions O2−. This material has been tested as an electrode for lithium-ion batteries against lithium metal. Specific capacities above 200 mA h g−1 at C/10 are achieved, involving 1 lithium per chemical formula when cycled between 1 V and 3 V vs. lithium. The first irreversible discharge leads to the insertion of one lithium atom and the evolution of hydrogen gas while iron remains in its +2-oxidation state. An original Li2OFeS oxysulfide is formed. The following reversible oxidation/reduction cycles involve the Fe3+/Fe2+ redox couple between the two limiting compositions: Li2OFeIIS and LiOFeIIIS. [ABSTRACT FROM AUTHOR]

This study explores the synthesis of cyclopenta‐fused polyaromatic hydrocarbons (CP‐PAHs) via Pt‐catalyzed cyclization in water, focusing on the formation of fused pentagonal rings within heavily fused PAH frameworks. Utilizing platinum catalysts at lower temperatures (200‐260 °C) in water, led to the successful synthesis of singly cyclized CP‐PAHs. The reaction conditions facilitated the mono‐cyclization of substrates such as dibenzo[g,p]chrysene and its isomers, yielding the desired products while suppressing the formation of bis‐cyclized compounds. The use of Fe2O3 as an additive in conjunction with PtO2 was effective to suppress hydrogenation of the substrates and products. The products exhibited a redshift in UV‐visible absorption and photoluminescence bands due to a decrease in the HOMO−LUMO energy gap. These findings highlight the potential of Pt‐catalyzed cyclization for the controlled synthesis of CP‐PAHs, with implications for various applications in materials science. [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]

This review article summarises decades of research on nickel hydroxide. Nickel hydroxide is an important material in both physics and chemistry, especially in technical applications such as batteries. First, the structures of two known polymorphs, α-Ni(OH)2 and β-Ni(OH)2, are described. The article also examines common types of disorder in nickel hydroxide, such as hydration, stacking faults, mechanical stresses and the presence of ionic impurities. Related materials such as intercalated α-derivatives and basic nickel salts are also discussed. Various synthetic methods of nickel hydroxide synthesis are reviewed, including chemical and electrochemical precipitation, sol-gel synthesis, chemical ageing, hydrothermal and solvothermal processes, electrochemical oxidation, microwave-assisted techniques and sonochemical methods. The article discusses the physical properties of nickel hydroxide, including its magnetic, vibrational, optical, electrical and mechanical properties. Finally, the article highlights the promising properties of these materials and approaches for the identification and characterization of unknown nickel hydroxide-based samples. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and characterization of La0.5Sr0.5MnO3 (LSMO) perovskite nanostructures via the hydrothermal method and their catalytic performance evaluation in CO oxidation. Structural analysis using techniques like XRD, FE-SEM, FTIR, and Raman spectroscopy analysis verified the development of LSMO nanostructures exhibiting a rhombohedral phase configuration. The catalytic activity of the annealed LSMO nanostructures was assessed, demonstrating significant CO conversion efficiency attributed to structural modifications enhancing catalytic performance. These findings highlight the potential of LSMO perovskite nanostructures as efficient catalysts for CO oxidation. [ABSTRACT FROM AUTHOR]

A method for the formation of nanostractured coatings from ZnO nanorods for use in adsorption gas sensors is presented. It has been shown that ultrasonic spray pyrolysis provides the formation of local growth centers for the formation of ZnO nanorods by the low-temperature hydrothermal synthesis. The obtained ZnO nanorods with a small diameter demonstrate a high concentration of oxygen vacancies in the near-surface region of the nanorods and a high surface concentration of hydroxyl groups. An additional method is proposed for testing seed layers by resistance using a liquid probe based on an indium-gallium melt without the need to apply top contacts. The presented technique is suitable for mass production of sensor coatings. The obtained nanostructured coatings from ZnO nanorods demonstrate a high gas analytical response. [ABSTRACT FROM AUTHOR]

The present research is devoted to the investigation of a nanosystem including gold nanoparticles in an aqueous solution of sodium sulfacetamide in order to determine the nature and efficiency of their interaction depending on the concentration and pH of the medium. Sodium sulfacetamide is of interest due to the possibility of its use in the composition of new hydrogel materials with incorporated gold nanoparticles for the development of ophthalmic implants. Gold nanoparticles with an average size of 20 nm, obtained by hydrothermal synthesis, were used. The study of the cytotoxicity of sodium sulfacetamide based on the integral index of the metabolic activity of MA-104 cells established concentrations that are the basis for explaining the possible toxic effect of materials impregnated with sodium sulfacetamide solutions. The concentration of 0.1 % sodium sulfacetamide solution after 24 hours of contact with cells and 0.05 % after 48 hours of contact should be considered as indifferent. The effectiveness of the interaction of sodium sulfacetamide and gold nanoparticles was evaluated by UV-Vis spectroscopy, electrokinetic measurements and scanning electron microscopy. Spectral studies of a suspension of gold nanoparticles in sodium sulfacetamide solutions in the range of therapeutic concentrations of 5.0÷30.0 % revealed a non-monotonic concentration-dependent effect of the sulfonamide medicine on the absorption intensity in the visible and ultraviolet ranges. The broadening of the spectral band of the surface plasmon resonance of gold nanoparticles in the presence of increasing concentrations of sulfacetamide and the appearance of an absorption band in the long-wave region were found. The peak shifts in the UV spectra after the addition of gold nanoparticles to sodium sulfacetamide were estimated. An increase in the negative value of the electrokinetic potential of gold nanoparticles under the influence of sulfacetamide from –26.2 mV to –41.4 mV was found. The data obtained indicate the existence of a chemical interaction between gold nanoparticles and sodium sulfacetamide solutions, which makes it possible to determine the conditions of their use in composite materials for biomedical purposes to reduce toxicity and leaching rate. [ABSTRACT FROM AUTHOR]

This study presents a method for enhancing the photocatalytic properties of strontium oxide (SrO) nanoparticles (NPs) through doping with Iron (Fe) and titanium (Ti) ions using hydrothermal synthesis. The materials were characterized using a range of spectroscopic and microscopic techniques to ensure accurate analysis of their structure and composition. Photocatalytic efficiencies of the as-synthesized materials were evaluated against the degradation of methyl orange dye, achieving about 98 % removal in 90 min with 3 % doped material. The degradation efficiency was found to be dependent on several factors including pH, initial dye concentration, and catalyst dosage. Optimal conditions were determined to be a pH of 4, an initial dye concentration of 20 mg/L, and a catalyst dosage of 150 mg. These findings suggest that the Fe/Ti-codoped SrO nanoparticles hold significant potential for applications in environmental cleanup processes, particularly in the degradation of organic pollutants. The study provides valuable insights into the synthesis and application of doped nanoparticles in photocatalysis, highlighting their efficiency and the importance of optimizing reaction conditions to maximize performance. [ABSTRACT FROM AUTHOR]

MoS2 nanosheets consist of multiple S-Mo-S trilayers with large interlayer spacing, which could allow facile Li-ion insertion/extraction. However, MoS2 nanosheets are easily curled and randomly stacked due to high surface energy of 2D nanosheets, which hinders fast ion transportation. In addition, intrinsic electronic conductivity of MoS2 is limited. Therefore, enhancements of both ionic and electronic conductivity of MoS2 are greatly demanded for its application in Li-ion batteries. Here, we report a cost-effective and facile hydrothermal synthesis of 3D nanoflower-like MoS2/C anode materials, which avoids random stacking of nanosheets and improves the electronic conductivity of MoS2. The nanoflower-like MoS2/C exhibits large reversible specific capacity (724 mAh g−1) and high initial coulombic efficiency (79.82%). Moreover, excellent capacity retention (97.98%) after 500-cycle charge/discharge has been achieved at 1 A g−1. [ABSTRACT FROM AUTHOR]

This work describes the comparison of the catalytic performances of α‐MnO2 nanorods synthesized by a facile hydrothermal approach at varying temperatures (140–200 °C). The structure and morphology of these nanorods were analyzed by XRD, N2‐physisorption, NH3‐TPD, Raman, SEM, HRTEM, and XPS. The prepared α‐MnO2 nanorods also performed exceptionally well in the catalytic oxidation of cyclohexanone to dicarboxylic acids under mild reaction conditions. The characterization results conferred that there is a significant influence of hydrothermal temperatures on the textural properties, morphology, and catalytic activity. Notably, the α‐MnO2 nanorods obtained from 180 °C hydrothermal conditions outperformed other catalysts with 77.3 % cyclohexanone conversion and 99 % selectivity towards acid products such as adipic acid (AA), glutaric acid (GA) and succinic acid (SA). The improved catalytic activity may be attributed to the interaction of the bifunctional Mn3+/4+ redox metal centres and surface acidic sites. The present oxidation reaction was found to be a promising eco‐benign process with high selectivity for the production of commercially significant carboxylic acids from cyclohexanone. [ABSTRACT FROM AUTHOR]

Aiming at the problems of the large storage, complex composition, low comprehensive utilization rate, and high environmental impact of coal gangue, this paper carried out experimental research on the preparation of iron oxide red from high-iron gangue by calcination activation, acid leaching, extraction, and the hydrothermal synthesis of coal gangue. The experimental results show that when the calcination temperature of coal gangue is 500 °C, the calcination time is 1.5 h, the optimal concentration of iron removal is 6 mol/L, the acid leaching temperature is 80 °C, the acid leaching time is 1 h, and the liquid——solid mass ratio is 4:1; the iron dissolution rate can reach 87.64%. A solvent extraction method (TBP-SK–hydrochloric acid system) was used to extract the leachate, and a solution with iron content up to 99.21% was obtained. By controlling the optimum hydrothermal conditions (pH = 9, temperature 170 °C, reaction time 5 h), high-purity iron oxide red product can be prepared; the yield is 80.07%. The red iron oxide was characterized by XRD, SEM-EDS, particle-size analysis, and ICP-OES. The results show that the red iron oxide peak has a cubic microstructure, an average particle size of 167.16 μm, and a purity of 99.16%. The quality of the prepared iron oxide red product meets the requirement of 98.5% of the "YHT4 Iron oxide Standard for ferrite". It can be used as a raw material to produce high-performance soft magnetic ferrite. In summary, this experimental study on the preparation of iron oxide red from coal gangue is of great significance for the comprehensive utilization of coal gangue to realize the sustainable development of the environment and economy. [ABSTRACT FROM AUTHOR]

Two modifications of Te2MoO7 oxide have been prepared by different synthetic methods. The crystal structure and composition have been studied by X‐ray diffraction analysis and X‐ray microanalysis. The phase of α‐Te2MoO7 has been synthesized by solid‐state reaction from ammonium salts and characterized by monoclinic structure with P21/c. The β‐Te2MoO7 compound has been formed in hydrothermal conditions and has amorphous nature. The thermal behavior of β‐Te2MoO7 modification is characterized by the phase transition into α‐form, however after melting the amorphous state has restored. The electron structure has been investigated experimentally by X‐ray photoelectron spectroscopy and UV‐vis diffusion reflectance spectra and theoretically by approximation using atomic electronegativity. Despite the same composition, the band gap of β‐Te2MoO7 corresponds to visible light, whereas α‐Te2MoO7 adsorbs light in UV region. The both modifications are able to generate superoxide radicals in vacuum or air and hydroxyl radicals in water under irradiation. The HPLC‐MS analysis has shown the quite deep decomposition of dye and antibiotics by α‐Te2MoO7, whereas amorphous phase almost does not lead to any oxidation. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) has almost become synonymous with greenhouse gases. Neither improvement of energy efficiency nor the application of alternative energy can reduce the concentration of CO2 to the allowable concentration. Therefore, CO2 must be captured to prevent its escape into the atmosphere. CO2 is commonly adsorbed by activated carbon because of the good affinity between them. In this study, to enhance the CO2 adsorption performance of this material, activated carbon was modified by two ways, synthesis and grafting with chitosan, to examine how the adsorption performance was affected by the different modifications. The experimental results showed that the adsorption performances of activated carbon with grafted chitosan and synthesized with chitosan were better than that of activated carbon. Although the nitrogen content was higher in the activated carbon synthesized with chitosan than in the carbon grafted with chitosan, the adsorption enhancements were similar due to the reduced surface area of the former. In addition, the results of the multi adsorption-desorption processes showed that the adsorption performance of the activated carbon grafted with chitosan slightly decreased, while that of the activated carbon synthesized with chitosan was almost unchanged. As the heterogeneous adsorption was modeled well by the Toth adsorption isotherm model, this isotherm model was used to model the experimental data for comparison with the Freundlich adsorption isotherm model. The average deviation of adsorption uptake fitted by the Toth adsorption isotherm model was about 3.07%, in comparison with 12.71% fitted by the Freundlich adsorption isotherm model. [ABSTRACT FROM AUTHOR]

Two zinc complexes [Zn(LH)2(phen)] (1) and [Zn(L)(H2O)]n (2) (LH− = 2-hydroxy-5-((3-nitrophenyl)azo)-benzoate, phen = 1,10-phenanthroline) were synthesized by hydrothermal methods and characterized by elemental analysis and IR spectroscopy. Complexes 1 and 2 crystallize in mononuclear and polymeric structures, respectively, where ligands L2− are coordinated to the zinc ions via their carboxylate and phenolate groups in η2,μ2,κ2 and η2,μ2,κ1 mode, respectively. Introduction of the auxiliary chelating phen ligand results in the chelation of the zinc ions in 1 through both the phen ligand and the carboxylate group of the first LH− anion assisted further by the monodentate carboxylate group of the second LH− anion. In complex 2 the L2− anions act as tridentate ligands utilizing their carboxylate and phenolate groups to coordinate to three zinc ions. The phenolate oxygen atom bridges two zinc ions resulting in the generation of a layer structure. Fluorescence measurements have indicated that complexes 1 and 2 exhibit similar luminescence emissions around 393 and 387 nm, respectively, which originate from intra-ligand π-π* transitions. The emission intensities were strengthened relative to the sodium complex NaLH owing to the enhancement of the rigidity of the aromatic system through the coordination interactions of the ligands with the more tightly bound zinc ions. Furthermore, the suspension of complex 2 can be used to selectively detect Fe3+ cations via the luminescence quenching process. [ABSTRACT FROM AUTHOR]

In this work we have narrowed the band gap of orthorhombic sodium tantalate by doping the perovskite structure with 5 and 10% of iron. The hydrothermal method was used in the preparation of the samples. Moreover, the evolution of hydrogen by photocatalytic water splitting is reported for first time for orthorhombic NaTaO3 mono-doped with Fe. The band gap was reduced from 4.08 to 3.24 eV for sodium tantalate doped with 5% of Fe, and up to 2.05 eV for the perovskite doped with 10% of Fe. The highest photocatalytic activity was obtained with the semiconductor that had 5% of Fe. Which was attributable to its smaller particle size, larger specific surface area and lower recombination of electron–hole pairs in contrast with the sample that had 10% of Fe. X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy, nitrogen physisorption, ultraviolet–visible diffuse reflectance and photoluminescence spectroscopies were used to analyze the perovskite materials. [ABSTRACT FROM AUTHOR]

A solid-liquid composite lubrication coating capable of controlling friction and wear has received widespread attention among researchers. Here, a novel self-lubricating ceramic coating was created through a combination of thermal spraying, hydrothermal reactions, and vacuum impregnation. Its mechanical properties, tribological performance, and self-lubrication mechanism were thoroughly analyzed. The results indicate that the thermally sprayed ceramic coating contained carbon spheres and perfluoropolyether. As a result of the in-situ synthesis of carbon spheres, the coating exhibited enhanced mechanical properties. Compared to the single solid lubricant coating, the solid-liquid composite coating decreased the coefficient of friction by 46.7% to 0.112 and decreased the wear rate from 1.25 × 10−6 mm3/m N to 3.70 × 10−7 mm3/m N. It is proposed in this work that solid-liquid composite coatings can be prepared by utilizing the defects such as pores and microcracks inherent in thermal spray coatings for introducing solid lubricating phases and liquid lubricating phases. This strategy addresses the issue of degradation of the mechanical properties of conventional ceramic-based self-lubricating coatings due to their tribological design. [ABSTRACT FROM AUTHOR]

The direct synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO2) and methanol (MeOH) is a DMC preparation route that meets the requirements of green chemistry and can realize the resource utilization of CO2. Cerium oxide (CeO2) based catalysts are widely used in this reaction. The current researches focus on the effects of morphology regulation and heteroatom doping on the catalytic performance of the catalysts. The rod-shaped CeO2 precursor was prepared by hydrothermal synthesis method, and then the corresponding catalysts were obtained by calcining the precursor in different atmospheres (H2, N2, air and O2, respectively). Then the catalysts were applied to the direct synthesis of DMC from CO2 and MeOH with 2-cyanopyridine (2-cp) as dehydrating agent (adding 0.10 mol MeOH, 0.05 mol 2-cp and 0.32 g catalyst, reaction at the conditions of 120 °C and 5 MPa for 2 h). The effects of calcination atmospheres on the catalytic performance of catalysts were studied. The crystal structures, texture properties and morphologies of the catalysts were characterized by XRD, N2 absorption/desorption, SEM, etc. The results show that the four catalysts show no significant differences in structural properties and morphologies, and the valence of Ce on the catalysts surface is closely related to acid-base sites. The abundant defect sites on the catalysts surface enable them to have large specific surface areas and average pore sizes (specific surface area and average pore size of CeO2-air are 65.44 m²/g and 30.06 nm, respectively). The main exposed CeO2(111) crystal surface of the catalysts can promote the formation of DMC. Compared with the other three catalysts, CeO2-air exhibits the best catalytic performance due to its highest concentration of medium and strong acid-base sites and total acid-base sites, as well as the enhancement of weak acid acidity. The DMC yield and DMC selectivity of CeO2-air are 83.2% and 99.3%, respectively. [ABSTRACT FROM AUTHOR]