Search

The investigation of electrode materials for urea level determination (non-enzymatic) is advantageous to monitor patient's clinical health and prevention of milk adulteration. Chalcogenides have prospective applications in electrocatalysis because of their fast charge transfer and large specific surface area in terms of non-enzymatic sensing via redox reactions, which is of great significance. However, despite their tremendous relevance, they continue to present significant problems. To address this issue, a new parkerite-type compound, Ni3Bi2Se2, was synthesized using the capping agent sodium laurel sulfate through a hydrothermal process. The physical characterization of the ternary chalcogenide Ni3Bi2Se2 was done by X-ray photoelectron spectroscopy, scanning electron microscopy, powder X-ray diffraction, and photoluminescence. The analytical performances of the suggested sensor electrode, including sensitivity, the limit of detection (LOD), limit of quantification (LOQ), stability, and durability, were obtained by various electrochemical techniques. The lower limit of detection (LOD-6.05 µM), sensitivity (10.9 mA µM−1 cm−2) and lower limit of quantification (LOQ-18.35 µM) were derived using the calibration curve. Moreover, it provides accurate results when detecting urea in human urine samples. The prepared electrode shows outstanding sensitivity, selectivity, superior reproducibility, and long-term stability. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) have gained recognition as a promising indoor photovoltaic technology, drawing considerable attention for their ability to convert light into electricity. In this study, we present a straightforward one-step hydrothermal synthesis method for producing cobalt sulfide nanoparticles decorated with reduced graphene oxide (CoS2/RGO) nanocomposites, serving as an efficient counter electrode (CE) material for DSSCs. The CoS2/RGO nanocomposites exhibited a chain-like structure formed by RGO nanosheet-decorated spherical particles interconnected with CoS2. Demonstrating excellent electrocatalytic activity with a low Epp (peak-to-peak separation) value, the CoS2/RGO nanocomposites outperformed pristine CoS2 nanoparticles. Moreover, the power conversion efficiency of the CoS2/RGO hybrid structure-based CE surpassed that of the pristine CoS2 nanoparticles. These findings suggest that the facile synthesis of CoS2/RGO nanocomposites holds great promise as an electrode material for effective CEs in DSSC applications. [ABSTRACT FROM AUTHOR]

Citric acid mediated hydrothermal process was used to synthesise LaMn1−xFexO3 nanoparticles. The synthesised samples were characterised using TGA, XRD, FTIR, SEM, HRTEM, UV–Vis and XPS techniques. According to TGA study, 800 °C was considered to be the ideal temperature to ensure the crystallisation of LMO, LMFO, and LFO nanoparticles. XRD study shows that the impurity phase, La(OH)3 was disappeared when citric acid percentage is increased. The joint action of stretching vibrations of Mn–O and Fe–O was observed at 601 cm−1 for LaMn1−xFexO3 nanoparticles. SEM and TEM images show that Fe doping percentage over LaMnO3 influences the morphological features of LaMn1−xFexO3 nanoparticles. The bandgap energy of LaMn1−xFexO3 nanoparticles is between the bandgaps of LaMnO3 and LaFeO3, according to a UV–Vis spectroscopic investigation. The visible light photocatalytic activity of LaMn1−xFexO3, LaMnO3 and LaFeO3 nanoparticles was investigated. LaMn1−xFexO3 nanoparticles exhibited superior photodegradation of methyl orange (MO) dye compared to LaMnO3 and LaFeO3 nanoparticles. [ABSTRACT FROM AUTHOR]

The need for more efficient detection of toxic gas has driven the research and development of gas sensors. In this study, a NiCo2O4 nanocomposite gas sensor for n-butanol is synthesized by a hydrothermal route. Hydrothermally synthesized NiCo2O4 nanocomposites were characterized by analyzing their crystal structure, phase purity, morphology, and elemental and chemical composition using a wide range of state-of-the-art techniques. Compared to competing materials, the gas sensing properties of NiCo2O4 are improved by the influence of Ni with a 2:1 ratio on the crystal structure. At 303 K, the n-butanol measurement showed a sensitivity of around (250%) and a selectivity of to 50 ppm. Both the reaction and recovery times are very fast (65 and 108 s, respectively), and the stability over time is superb. As a result, NiCo2O4 is appealing as a sensor material for detecting n-butanol gas at low concentrations. Furthermore, the strategies for enhancing the detecting performance of NiCo2O4-based gas sensors are introduced. [ABSTRACT FROM AUTHOR]

Hydrotalcites are layered double metal hydroxides (LDH) that are widely used in many fields, owing to their large specific surface area, rich interface, and stable structure. Of these, NiFe-LDH is the most typical material used in the field of electromagnetic wave absorption. In this study, NiFe-LDH was synthesized by hydrothermal synthesis and subjected to liquid-phase shearing with graphite to synthesize the composite material C/NiFe-LDH. The results show that C/NiFe-LDH displays a strong electromagnetic wave absorption capacity, with a maximum reflection loss of − 51.8 dB at a thickness of 3.5 mm. The maximum effective absorption bandwidth is 4 GHz (10.8–14.8 GHz). Therefore, C/NiFe-LDH is expected to become a candidate material for efficient electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

ZnO nanoflowers-modified graphite screen-printed electrode had very good electrochemical catalytic activity toward sertraline and imipramine. Results showed significant decline in the oxidation overpotentials of sertraline and imipramine in comparison with the overpotential at the bare graphite screen-printed electrode. Moreover, differential pulse voltammetry has been utilized to simultaneously determine sertraline and imipramine in the ternary mixture. Based on the analyses, the peak separation between sertraline and imipramine was 200 mV. In addition, calibration curve for imipramine ranged from 0.1 to 550.0 μM. Furthermore, minimum limit of detection (S/N = 3) equaled 0.035 μM imipramine. Finally, this new procedure exhibited acceptable sensitivity and selectivity so that it could be utilized for determining sertraline and imipramine in the pharmaceutical medicines and urine samples. [ABSTRACT FROM AUTHOR]

Mesoporous TiO2 microspheres (MS) have been synthesized by a microwave-assisted hydrothermal technique. The samples were analyzed by XRD analysis, and it reveals the tetragonal phase of the TiO2 anatase with better crystallinity. The morphological characterization of TiO2 MS was investigated by FESEM and HRTEM. Bright spots observed from SAED analysis helped in determining the crystalline nature of the microspheres. The synthesized products have a surface area and average pore diameter of 89 m2g−1 and 11.28 nm. The power conversion efficiency of TiO2 MS-based device exhibits a higher PCE of 7.40% compared to commercial P25-based (4.48%) device. The enhanced performance of DSSC is due to its strong light-scattering ability and excellent dye loading capacity of TiO2 microspheres. Electrochemical impedance spectral analysis showed that TiO2 microspheres-based device contributes to a higher electron lifetime and increased efficiency. [ABSTRACT FROM AUTHOR]

The dye-sensitized solar cells (DSSCs) were assembled using counter electrodes (CEs) constructed of carbonized yogurt/PEDOT:PSS composites and evaluated for their efficiency. The influences of two different crucible materials used during the pyrolysis of hydrothermally treated nonfat yogurt on the structures and properties of derived carbons were compared. Carbons denoted by Aa and Ab were pyrolyzed on an aluminum alloy boat and an alumina one, respectively. Hydrophobic carbon/nano-Whitlockite (WH) composites were obtained for both crucible materials. The carbon features are primarily made up of nanocarbons, micronized carbon spheres, and carbyne nanowires. Aa and Ab have surface areas (SBET) of 1060 and 289.7 m2 g−1, respectively. Moreover, the Aa carbon has a lower degree of oxidation than the Ab sample. The electrocatalytic activity of Aa carbon is higher than that of Ab carbon but Aa is less hydrophobic than Ab. Whitelockites were also prepared from hydrothermal synthesis and oxidation of Aa and Ab samples. Notably, the electrocatalytic activities of Whitlockites/PEDOT:PSS are as good as that of Pt but it is still lower than Aa/PEDOT:PSS and Ab/PEDOT:PSS electrodes. The DSSC with an Aa/PEDOT:PSS CE has a slightly higher efficiency (7.40%) than the DSSC with an Ab/PEDOT:PSS CE (7.05%) and the one with a Pt CE (7.01%) because Aa DSSC has a slightly higher fill factor (FF) and short-circuit current density (Jsc). Note that the Whitelockites/PEDOT: PSS can not be used as counter electrodes since these films swell excessively, resulting in a short circuit. Carbon in Aa and Ab plays a very important role in preventing such swelling incidence. [ABSTRACT FROM AUTHOR]

CuMn2O4 with spinel structure was synthesized on a flexible stainless steel mesh by a one-pot hydrothermal method and evaluated as a supercapacitor electrode. The stainless steel mesh is used as an alternative to nickel foam. X-ray diffraction analysis was used to determine the crystal structure, revealing the presence of a major cubic spinel phase. The hydrothermal technique resulted in an average crystallite size of 12.174 nm. Functional groups present in the samples were confirmed using Fourier transform infrared spectroscopy. The results showed two bands, at 760.62 cm−1 and 555.64 cm−1, relative to stretching vibrations of the tetrahedral and octahedral groups, respectively. Scanning electron microscopy analysis shows a surface microstructure in the shape of flat sheets. Energy-dispersive X-ray spectroscopy analysis displays the material's elemental composition, with atomic ratios of 0.8 for Cu:Mn and 0.27 for Cu:O. Cyclic voltammetry and electrochemical impedance spectroscopy were implemented to assess the electrochemical performance of the electrode. The as-obtained CuMn2O4 exhibited excellent electrochemical properties. It delivered a low electrolyte solution resistance Rs (5.5 Ω) and a high specific capacity of 1169.3 F/g for 1.15 × 10–3 g of active material at a low scan rate of 1 mV/s. [ABSTRACT FROM AUTHOR]

Transition metal chalcogenides have fascinating characteristics are considered as electrode materials for high-performance energy storage devices. Herein, we report the CoS/G nanocomposite was successfully synthesized by a simple one-pot hydrothermal method. The phase formation and morphology of the obtained materials were analyzed by various techniques. The electrochemical properties of the prepared electrode materials were assessed from cyclic voltammetry in a three-electrode system. The obtained cyclic voltammetry curves demonstrate pseudocapacitive behavior for prepared materials due to the synergistic effect between Cobalt and sulfur. The Galvanometric Charge Discharge (GCD) profile of the materials confirms the pseudocapacitive nature and specific capacitance calculated from these curves. The CoS/G nanocomposite delivered high specific capacitance 739.83 Fg−1 compared to the pure CoS nanospheres 390 Fg−1 and prolonged cyclic stability with 91.2% capacity retention after 3000 cycles. Overall, these excellent electrochemical performances indicate the CoS/G nanocomposite as a desirable electrode material for commercial supercapacitor applications. [ABSTRACT FROM AUTHOR]

We developed an improved hexagonal wurtzite ZnO and ZnO/C microflowers through the facile hydrothermal technique. The obtained nanostructures were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX) and UV–visible diffuse reflectance spectroscopy (UV–Vis DRS). The formation of flower-like material is confirmed using SEM and TEM analysis with an average diameter of about 2 µm composed of several plate-like nanostructures. The optical analysis results show that the presence of carbon particles with ZnO structures has significantly increased the light absorption ability of nanocomposite. The photocatalytic degradation ability of prepared nanostructures was examined using methylene blue as a model pollutant. The obtained results show that the photocatalytic degradation ability of ZnO/C nanostructures is approximately two times higher than the pristine ZnO microflowers. Based on the investigation, an enhancement of the photocatalytic ability of ZnO/C nanocomposite is achieved due to the synergistic effect between carbon particles and flower-like ZnO nanostructures. [ABSTRACT FROM AUTHOR]

In this work, a flexible ZnO-based gas sensor is developed for room-temperature detection of nitrogen oxide (NO2). The sensor is fabricated on polyimide (PI) substrate by highly efficient and scalable laser micro-processing techniques, including laser direct writing of carbonized electrode on PI and laser-localized hydrothermal synthesis of ZnO on the electrode. The gas sensing characteristics of the device, such as response, stability, and repeatability, are systematically investigated. The ZnO-based sensor shows a response of 0.71% for NO2 in room temperature, a good stability (30 days), and repeatability with the substrate curvatures bent from 22.34 to 4.16 mm in 1000 ppm NO2 at room temperature (25 °C). Unlike the traditional ZnO-based gas sensor, the device we made presents the characteristics of p-type semiconductor through gas sensing tests, which could be attributed to the possible doping of C and low performing temperature. [ABSTRACT FROM AUTHOR]

It is well known that the intelligent hybridization of active materials and the controllable recombination of nanostructures can significantly improve the electrochemical performance of pseudocapacitor electrodes. In this work, a NiO/NiCo2O4 needle/sphere nanostructure was synthesized on the hydrochloric acid-activated Nickel foam by a simple hydrothermal method and measured the performance of it as an electrode material for supercapacitors. Field emission scanning electron microscope, transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterize the morphology and composition of the samples. The electrodes display a prominent specific capacitance (2447 F/g at the ampere density of 2 A/g) and remarkable cycling stability (85.2% capacity remained after 3000 cycles), owing to the unique needle/sphere composite architecture and the rational combination of active materials. The results demonstrate that the three-dimensional composite structure of NiO/NiCo2O4 nanomaterials provides a large specific surface area for the electrode, which promotes the penetration of electrolyte ions and the transmission of electrons. This novel structured material will be promising in the application of supercapacitor electrode materials. [ABSTRACT FROM AUTHOR]

A facile hydrothermal method was used for fabricating phase-pure Bi1−xCexFe1−xZrxO3 (x = 0.00, 0.03, 0.06) multiferroic ferrites, and the dependence of structural, optical, and magnetic properties on the composition have been investigated. The samples were investigated by X-ray diffraction, Raman and Fourier transform infrared spectroscopies, scanning electron microscopy, UV–Vis spectroscopy, and vibrating sample magnetometer at room temperature. Structural results show that the structure of Bi1−xCexFe1−xZrxO3 ferrites is indexed to a rhombohedral structure with the R3c space group. However, the weakening in the intensity, the expansion of the line-width of all bands, and some band shifts observed in Raman spectra indicate a structural transition from rhombohedral (R3c) to pseudo-tetragonal (P4mm) phase as the content of Ce/Zr increases. Also, a significantly enhanced intensity of the A1–2 mode in Raman spectra means that there is a novel behavior of magnetic anisotropy in the Ce/Zr co-substituted samples. A significant increase in optical bandgap with increasing of the Ce/Zr co-substitution suggests that the materials are suitable for technological applications. Magnetic properties of the samples show a magnetic transition from antiferromagnetic to ferromagnetic phase due to the presence of the rhombohedral to the tetragonal phase transition, and exchange interaction between the 4f orbitals of the Ce3+/Ce4+ and the 3d orbitals of the Fe3+/Fe2+. [ABSTRACT FROM AUTHOR]

With the advantages of high power density, long cycle life, and fast charging, supercapacitor has become a research hotspot in recent decades. Graphene is considered as an ideal electrode material for supercapacitors because of its special electrical and mechanical properties. In order to prepare graphene that can be used as supercapacitor electrode materials, various methods are proposed, among which hydrothermal method is mostly used, but graphene prepared using this method always agglomerates seriously and rarely have pores that might be helpful for the increase of electrochemical performance. Therefore, sodium alginate, which has strong hydrogen bonding with graphene oxide and might be helpful to optimize the structure of graphene in the reduction process, should be considered. In this paper, by optimizing the ratio of reducing agent and graphene oxide in hydrothermal reaction, two samples that exhibit better performance were obtained. On this basis, sodium alginate was added in the process of hydrothermal reduction of graphene oxide, and the effect of it on the structure and properties of graphene was explored. The results demonstrate that pore structure is formed and the rate performance is improved obviously by adding sodium alginate. [ABSTRACT FROM AUTHOR]

Exploring lightweight electromagnetic wave absorption materials is urgently needed to satisfy the miniaturization and integration of artificial intelligence and 5G technologies. Herein, nitrogen-doped graphene (N-GN) is successfully fabricated through a simple hydrothermal method, which can float in the water. Except for keeping the sheet-like structure of GO, nitrogen-doped graphene shows a reticular-like structure with more wrinkles and crinkles, which is crossed and interconnected to each other. The introduced nitrogen heteroatoms may induce dipole polarization, and the special interconnected reticular-like structure may improve the energy dissipation capacity. These features make nitrogen-doped graphene process improved dielectric loss and enhanced electromagnetic wave absorption performance. When the mass fraction of N-GN is only 10 wt%, N-GN shows a maximum reflection loss value of − 21.7 dB at 14.3 GHz with an absorber thickness of only 1.78 mm. This work indicates that nitrogen-doped graphene is a good candidate of lightweight dielectric materials. [ABSTRACT FROM AUTHOR]

The research on the best technology of large-scale hydrothermal preparation of Co–Mn–Fe–Zn–O (CMFZ) material will provide reference for its industrial production. The CMFZ nanopowders were prepared on a large scale by hydrothermal method to explore the optimal process to obtain NTC ceramic materials with high consistency. The precursor morphology showed that their grain sizes were small, and with the increase of reaction temperature, reaction time, and stirring speed, the grain size of the powder first decreased to 20.01 nm and then increased to 36.56 nm, and the grain size of the corresponding ceramic samples also decreased and then increased. The optimum preparation conditions at 150 °C for 9 h and stirring speed of 200 rpm resulted in the smallest precursor grain size of 20.01 nm and the highest room-temperature resistivity ρ25 and material constant B25/50 of 1.44 kΩ cm and 3953 K, respectively, with average deviations of 0.089 and 0.237, indicating that the consistency of electrical properties were better. The study of the optimum technique for the large-scale hydrothermal preparation of CMFZ materials will provide a reference for their industrial production. [ABSTRACT FROM AUTHOR]

Nowadays, sensing and detection of ethanol is paramount one for numerous applications including production of ethanol, fuel processing, chemical processing in industry, traffic management, food package testing for safety and medical applications. On the other hand, the rapid growth of nanotechnology paves the way to develop highly sensitive, portable and low-cost sensors with less power consumption. In line with this fact, a cladding modified fiber optic ethanol sensor using CdS nanoflower has been reported in the present study. CdS nanoflower was prepared by one step hydrothermal synthesis and subjected for various characterization techniques to investigate the material properties. The sensor probe was developed viz cladding modification technology followed by dip coating of CdS nanoflower over an unclad section of an optical fiber. The potency of CdS nanoflower has been probed for 0–300 ppm of acetone, ethanol, methanol and isopropanol at ambient environment. The sensing results demonstrates that the sensor coated with CdS nanoflower manifested better sensing performances towards ethanol (~ 4.6% at 300 ppm) with response/recovery of 90 s and 100 s than other gases. The unique sensing feature complied that CdS nanoflower is desirable candidate in effective quantification of ethanol. [ABSTRACT FROM AUTHOR]

Ti3+/N-co-doped TiO2 was successfully synthesized in situ by one-step hydrothermal method using tetrabutyl titanate (TBOT) as the titanium source and hydrazine hydrate as the reducing agent and nitrogen source. Afterward, the microstructure and physicochemical properties of the catalysts were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, and photoluminescence spectroscopy. Results indicated that nitrogen was effectively doped into the lattice of TiO2 and Ti3+ was stably presented in the prepared TiO2, which reduced the band-gap TiO2 (2.96–2.75 eV) and enhanced photo-induced charge separation efficiency under visible light. In addition, the photocatalytic activity was evaluated by degradation of rhodamine B under xenon lamp with 420 nm filter. With the amount of hydrazine hydrate increased, the photocatalytic degradation performance of the sample increased first and then decreased. When the volume ratio of hydrazine hydrate to TBOT was 1:5, the sample showed the best photocatalytic performance. [ABSTRACT FROM AUTHOR]

We report the hydrothermal synthesis of visible light absorbing and direct energy bandgap kesterite-structured Cu2ZnSnS4 (CZTS) nanoparticles (NP) for photocatalytic and photoelectrochemical (PEC) applications. The crystal structure, morphology, composition, and optical properties of CZTS nanoparticles were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis microscopy techniques. The tetragonal kesterite phase CZTS nanoparticles with compact spherical morphology with an energy bandgap of about 1.51 eV have been synthesized. The CZTS nanoparticles were employed as a photocatalyst for the degradation of Rhodamine B (RhB) dye. The study reveals that the CZTS photocatalysts with compact spherical shape showed photoactivity around 55% under indoor visible light illumination. The CZTS photoelectrodes were fabricated on fluorine-doped tin oxide (FTO) substrate using a doctor blade coating method. The detailed photoelectrochemical (PEC) studies demonstrate that CZTS photoelectrode showed 2.98% of photoconversion efficiency. [ABSTRACT FROM AUTHOR]

This study reports that the novel binary g-C3N4@NiFe-LDH heterostructured photocatalysts were simply prepared by loading well-dispersed g-C3N4 nanosheets on the surface of NiFe-LDH precursor via the hydrothermal synthesis process. The morphologic structure, chemical composition and optical properties of the as-prepared nanocomposites were clearly characterized by using XRD, SEM, FT-IR, UV–Vis DRS, XPS and N2 adsorption–desorption techniques. In the photocatalytical degradation experiments, it can be seen that the optimal g-C3N4@NiFe-LDH nanocomposites can achieve the highest degradation efficiency (99%) for rhodamine B (RhB) within 240 min under visible light irradiation, and the corresponding pseudo-first-order rated constant is 0.912 h−1. The improvement of photocatalytical performance can be attributed to the enhanced visible light absorption and fast separation of the photo-generated electron–hole pairs. Besides, the degradation efficiency can still remain more than 80% via four cycle processes, demonstrating its remarkable stability and reusability. More importantly, a possible Z-scheme photocatalytic mechanism was proposed according to the analysis of energy band structure and the radicals trapping experiments. This study will be beneficial for the design and research of Z-scheme g-C3N4-based heterojunction photocatalysts in the environmental remediation field. [ABSTRACT FROM AUTHOR]

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

The prompt recombination between photogenerated electrons and holes is the common problem for improving the hydrogen evolution performance of a photocatalyst, which could be solved greatly by composite co-catalysis. Herein, a simple hydrothermal reaction was utilized to prepare g-C3N4/Ni9S8 composite photocatalysts. Through electroless nickel plating, Ni9S8 nanostructure was homogeneously grown onto the g-C3N4 surface by using sodium hypophosphite as reducing agent. With the optimum loading amount of Ni9S8, the acquired composite, compared with the raw g-C3N4, presented a significant increase in hydrogen evolution rate under visible light irradiation, which was measured as 355.7 μmol g−1 h−1 at 7 °C, being 21.2 times that of raw g-C3N4. The mechanism for the hydrogen evolution reaction over the present g-C3N4/Ni9S8 composite photocatalysts was discussed in detail. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4) is a promising photocatalyst material for photocatalytic degradation of organic pollutions. However, the fast recombination of photo-induced charge and insufficient light absorption often lead to poor photocatalytic performance. Herein, novel fibrous BiVO4/CdS (BVO/CdS) heterostructures are constructed by uniformly modifying caterpillar shaped electrospun BiVO4 nanofibers with controllable quantity of CdS nanoparticles through hydrothermal reaction. The absorption of visible light and separation efficiency of photo-generated charge of BiVO4 are significantly promoted after the decoration of CdS nanoparticles. As a result, the photocatalytic efficiency of the optimized BVO/CdS sample (BVO/CdS-2 stands for the sample synthesized with 0.05 mmol Cd(CH3COO)2 and CH4N2S) is 90.43%, which is 3.3 times as high as that of pure BiVO4 after 180 min irradiation under visible light, respectively. Moreover, the.O2− and.OH are the predominant active species for the degradation process indicated by scavengers added photocatalytic experiments. Due to the simple, low-cost and controllable synthetic process, the BVO/CdS heterojunctions are suitable for practical usage. [ABSTRACT FROM AUTHOR]

The bismuth tungstate with different morphologies was controllably synthesized by simple hydrothermal synthesis under different pH and different hydrothermal reaction time (HRT). Under the influence of these two conditions, the results show that with the increase of pH, the sample gradually changed from orthogonal phase Bi2WO6 to cubic Bi3.84W0.16O6.24 and the morphology changed from lamellas composed of nanorods to octahedral particles, as well as the photo-catalytic activity of Bi3.84W0.16O6.24 was far less than that of Bi2WO6. Additionally, with the increase of HRT, the thickness of flaky Bi2WO6 is thinner, the crystallinity is more stable, and the direction of growth is changed from lamellar to flower buds. The photo-catalytic activity of lamellar BWO-8/BWO-T-10 (prepared in lower pH and lower HRT) is the best. After radiation of 2 h, the degradation efficiency of tetracycline is 85% and the kinetic reaction rate constant is 0.0135 min−1. After three cycles of reusing, it still maintains high stability. The catalytic mechanism analysis shows that the active particle.OH produced by the photoelectron hole to the reaction has strong oxidizing property, which can quickly decompose tetracycline. [ABSTRACT FROM AUTHOR]

The cubic spinel ZnCo2O4 nanostructures with different novel shapes have been purposefully fabricated in an efficient hydrothermal synthetic platform by just tuning reaction temperature. XRD, FTIR, SEM, Raman scattering, and M–H curves were used to analyze the samples. With the decrease of hydrothermal temperature, the morphology has an obvious transformation from hierarchical microsphere to finally loosened nanosphere, an obvious blue shifting of Raman spectrum happened and the samples transform from paramagnetic behavior to ferromagnetic. The elevated Hc may be attributed to the size effect, surface spin disorder, and shape anisotropy. [ABSTRACT FROM AUTHOR]

In the current study, we have explored the consequences of synthesis conditions on optical, morphological, and photoluminescence characteristics of hybridized ZnO nanocomposites. The photodegradation kinetics of Triclopyr, a pesticide, using hydrothermally synthesized ZnO/CuO materials at various synthesis conditions were also studied. The prepared samples were characterized by various techniques such as UV-vis spectrophotometer, field emission scanning electron microscopy (FESEM), elemental dispersive X-ray analysis, and photoluminescence spectrometer. From FESEM images, it was revealed that the synthesis conditions greatly influence the morphology of nanomaterials, particle size, nucleation, and crystal growth. To evaluate the percentage composition of elements present in synthesized materials, elemental analysis with mapping was performed. The band gap values were calculated using Kubelka Munk's plot. The band gap values decrease on CuO incorporation and lie near infrared region. Effect of scavengers and pH on degradation kinetics were also explored. The complete mineralization of Triclopyr was achieved in 100 min. The synthesized materials are found energy efficient and helpful in environmental purification. [ABSTRACT FROM AUTHOR]

In this study, CuO and CeO2/CuO nanostructures were successfully synthesized via a hydrothermal route. The structure, morphology, composition and optical properties of these nanostructures have been studied using various techniques. X-ray diffraction (XRD) analysis showed the formation of monoclinic crystalline phase of CuO with a decrease in the crystallinity of the samples as the Ce content increased. Scanning electron microscopy (SEM) acquired images showing that increased Ce incorporation induces transformation of morphology from spherical to rod-like nanostructures. Energy-dispersive X-ray spectroscopy (EDS) mapping showed that Ce was homogeneously distributed onto the CuO matrix. UV/Vis/NIR spectrophotometer measurements depicted a blue shift in the bandgap from 2.0 to 3.5 eV for 0%-6% Ce and then 3.2 eV for 8% Ce. Brunauer Emmett Teller (BET) analysis revealed enhanced porosity with the incorporation of cerium. Raman spectroscopy results confirmed the presence of the A g (296 cm−1), B g (346 cm−1) and B g (631 cm−1) modes belonging to CuO. The F2g Raman active mode observed at 454 cm−1 belongs to CeO2. Fourier transform infra-red (FTIR) measurements showed stretching vibrations of Cu–O. The CeO2/CuO samples exhibited enhanced temperature-controlled Dc conductivity with the 4% Ce sample showing the lowest activation energy, lowest Tmax (peak value of (dσ/dT)) and consequently the maximum conductivity peaking at a temperature of 503 K. The nature of conductivity was elucidated on the basis of the carrier hopping model. [ABSTRACT FROM AUTHOR]

Intermetallic compounds are commonly used in semiconductor, shape memory materials, hydrogen storage materials and magnetic materials due to their unique physical and chemical properties. In this study, the FeNi3/rGO (rGO: reduced graphene oxide) composite was prepared by one-step hydrothermal method using water-soluble nickel and iron salts as metal sources and hydrazine hydrate as reducing agent in alkaline solution. The structure of the composites are characterized by XRD, FTIR, XPS and Raman spectroscopy. The micromorphology of the samples is observed by SEM and TEM. The electrochemical performance of the FeNi3/rGO composite is evaluated by electrochemical impedance spectroscopy (EIS), galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV). The results indicate that when the scan rate is 10 mV s−1 in 4 M KOH electrolyte solution, the specific capacitance of the FeNi3/rGO composite is 169.42 F g−1. At a current density of 1 A g−1, the specific capacitance of the FeNi3/rGO composite remains 82.72% of the original energy after 3000 cycles. Therefore, the FeNi3/rGO composite has excellent capacitance performance and is expected to be applied in supercapacitors and nanodevices in the future. [ABSTRACT FROM AUTHOR]

In this study, we report ZnO and Bismuth-doped ZnO (rBi/Zn) (r = 3, 6, 9 wt%) nanoparticles through the hydrothermal synthesis method. Different characterization techniques such as XRD, TGA, FTIR, XPS, FESEM, EDX analysis, UV spectroscopy, and PL spectroscopy have been used to investigate the influence of Bi+3 doping over the synthesized rBi/Zn nanoparticles. XRD result reveals a reduction of average particle size from 30 to 21 nm with the increment of Bi+3 (3 → 9 wt%) concentration. The mass variation in rBi/Zn was found more than the pure ZnO sample which reveals in TGA results. The material rBi/Zn exhibits a single-stage to multi-stage decomposition with the enhancement of Bi+3 (3 → 9 wt%) concentration while the XPS result indicates that the reduction of binding energy with increasing Bi+3 doping. UV analysis shows that as the concentration of Bi+3 increases the band gap of the material rBi/Zn reduces from 3.217 to 2.901 eV. However, the conductivity analysis shows the enhancement in the conductivity of rBi/Zn (0 → 6 wt%) but decreases from 6 → 9 wt%. Furthermore, the morphology of rBi/Zn also changes as the doping of Bi+3 increases which is possibly due to the enhancement of lattice mismatch, and pH variation. Such a kind of rBi/Zn nanocomposite material could be used in optoelectronic devices or fiber optics-based gas-sensing applications. [ABSTRACT FROM AUTHOR]

NO2 gas-sensitive and hydrophobic zinc oxide (ZnO) thin films were synthesized through a simple, economical and eco-friendly hydrothermal route. The synthesized material of varying precursor concentrations was deposited on a non-conducting glass substrate. The precursor concentration can tune the morphology of ZnO and, subsequently, sensitivity towards NO2 gas under study. Once the material gets synthesized, it was annealed at 450 °C and characterized with advanced techniques like X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Visible spectroscopy, photoluminescence and water contact angle measurements which ensures the synthesis of material and reveals morphology and other characteristics of the material. The XRD patterns explore the crystallinity as a revealed the hexagonal wurtzite crystal structure. SEM image analysis reveals that with an increase in precursor concentration the size of the ZnO rod also gets increased. The highest gas response (%) = 557.62% is observed at an operating temperature of 200 °C for NO2 gas at 100 ppm. The response and recovery times are 11.3 s and 126.9 s, respectively, for the optimized sample. Also, the contact angle analysis reveals that hydrophobicity increases with increase in the concentration of precursor. [ABSTRACT FROM AUTHOR]

SnS2/CdS composites with different mole ratios were prepared by hydrothermal methods. The effects of different ratios on the microstructure, morphology, optical, photo-electrochemical, and photocatalytic properties of SnS2/CdS samples were studied. The photocatalytic activity of SnS2/CdS composites was evaluated by simulating visible light degradation of methyl orange (MO) dye. Experimental results demonstrate that hexagonal pencil-shaped nanorod CdS and flower-like morphology SnS2 are wurtzite structures. SnS2/CdS nanocomposites showed excellent visible light absorption. Nyquist EIS and transient photocurrent density showed that the composites exhibit more effective electron–hole separation and faster interface charge transfer under simulated sunlight. Within 120 min, the degradation rate of SnS2/CdS photocatalyst reached 85.3%, and its reaction rate constant is the largest, which is 9.2 times and 5.32 times that of pure CdS and SnS2 samples, respectively. Also, it has good photocatalytic recyclability, the photocatalytic degradation rate of the fifth cycle can still reach 80%. [ABSTRACT FROM AUTHOR]

A series of Zn1−xCrxS powder with (x = 0–0.18) has been obtained by hydrothermal synthesis. Hexagonal phase nanocrystalline structure of powder samples has been emphasized by X-ray diffraction (XRD) showing particle size ranging from ~ 7 to 11 nm. FE-SEM confirms the nanostructure nature of samples. Elemental compositional analysis confirmed the accurate atomic percentage of existing elements using EDX technique. FTIR spectra of Zn1−xCrxS powder samples indicate different bands corresponding to their structure. The fundamental optical bandgap transition observed at 3.36 eV and additional transitions exist for Cr-doped ZnS samples. Photoluminescence (PL) emission spectra of Zn0.82Cr0.18S nanoparticle powder pumped with different excitation wavelengths (200–290 nm) showed different emission peaks, the highest intensity peak at 398 nm is due to fundamental transition of bandgap which agree with the optical results. The sample with x = 0.11 displays the most intense PL signal. Diamagnetic behavior was observed for ZnS compound whereas ferromagnetic behavior was observed for ZnS-doped with Cr. [ABSTRACT FROM AUTHOR]

Herein, we report a facile hydrothermal synthesis of MoSe2 nanoflowers composed of several MoSe2 nanosheets for electrochemical energy storage. As an electrode material of supercapacitor, MoSe2 nanoflower exhibits high specific capacitance (95 Fg−1) and excellent cycling stability (90% after 10,000 cycles) due to their porous morphology, indicating their applicability as a potential electrode material for energy storage devices. [ABSTRACT FROM AUTHOR]

Nanostructured CuO/ZnO composite has been prepared by hydrothermal method. The prepared nanocomposite has been investigated by various characterization techniques such as PXRD, FTIR, SEM with EDAX, UV and electrochemical workstation. Structural analysis shows the arrangement of CuO/ZnO, composition of monoclinic CuO with space group of C2/c, and hexagonal ZnO with space group of P63mc. The nanorods like morphology of the nanocomposite have been confirmed by SEM analysis. Optical bandgap of the material has been calculated by Tauc's plot and obtained bandgap values are 2.83 eV and 2.68 eV, respectively. In GCD analysis, maximum specific capacitance is observed in modified working electrode at scan rate of 1 mA, which continues remarkable cycling stability within the retention ratio of 40.86% after 1000 cycles. [ABSTRACT FROM AUTHOR]

In this study, a series of spindle-like Na3Y1−x(PO4)2: xTb3+ phosphors have been controllably synthesized by an ionic liquid-assisted hydrothermal route. The structures and morphologies of the as-synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Photoluminescence spectroscopy (PL), fluorescence decay, and temperature-dependent emission spectroscopy were adopted to characterized the luminescence properties of the samples. The excitation spectra of Na3Y1−x(PO4)2: xTb3+ comprised several well-resolved absorption bands at 273, 285, 304, 318, 340, 352, 368, and 378 nm. When excited at 368 nm, Na3Y1−x(PO4)2: xTb3+ phosphors could exhibit emission bands at 490 nm (5D4 → 7F6), 545 nm (5D4 → 7F5), 586 nm (5D4 → 7F4), and 624 nm (5D4 → 7F3), respectively. The concentration quenching occurred when x is beyond 0.22. The decay time of the photoluminescence of Na3Y1−x(PO4)2: xTb3+ decreased with the increase of Tb3+ doping, which demonstrated the existence of energy transfer among Tb3+ ions. The Commission Internationale de L'Eclairage (CIE) chromaticity coordinates of Na3Y0.78(PO4)2: 0.22Tb3+ were (0.3273, 0.5199) at 273 K, which located in the green region. The temperature dependence experiments revealed that the title material had excellent luminescence thermal stability. The luminescence intensity of Na3Y0.78(PO4)2: 0.22Tb3+ phosphor at 473 K declined 22.1% to its initial intensity. The title material could be used as green light-emitting phosphor for cold white LED applications. [ABSTRACT FROM AUTHOR]

In this work, we used two simple and inexpensive hydrothermal steps to synthesize Bi2S3 nanoflowers branched on TiO2 nanorod heterostructure. The nanoscale morphology of Bi2S3 deposited on TiO2 nanorods was optimized by controlling the hydrothermal growth temperature of bare Bi2S3 nanoparticles. Under solar lighting, the structural and optical properties, also the photocatalytic performance was systematically evaluated for the bare Bi2S3, bare TiO2 and Bi2S3/TiO2 heterostructures synthesized under optimized conditions. The Bi2S3/TiO2 heterostructures showed an enhanced visible-light absorption ability and photocatalytic efficiency comparing to bare TiO2. Photoluminescence and electrochemical impedance spectroscopy measurements suggest that Bi2S3/TiO2 heterostructures promoted the separation of electron-hole pairs and then enhanced the photocatalytic degradation performance for organic pollutant. The prepared heterostructures showed great stability and reusability. It also displayed enhanced photocatalytic performance for MB degradation, presenting 90% removal efficiency for 240 min, under solar light irradiation. The improved photocatalytic performance was attributed to the large Bi2S3 nanowires branched like nanoflowers structure on TiO2 nanorod arrays. This performance has obviously led to a better separation of electron-hole pair and an improvement in the absorption of light in the visible-light region. [ABSTRACT FROM AUTHOR]

A series of Ba1−xLaxTiO3 (x = 0.2, 0.4, 0.6, & 0.8) nanorods were synthesized through hydrothermal method. The X-ray diffraction patterns indicated the cubic phases for x = 0.2 – 0.8 contents. The TEM pictures revealed the formation of nanorods of high length. The Tauc's plots showed the wide band gap (Eg) for x = 0.2 & 0.6 compositions while the narrow band gap was noticed for x = 0.4 & 0.8 contents. At low-frequency (dielectric constant = − 1051.4 at log ω = 2.4627) values, the negative dielectric constant and dielectric loss were observed at x = 0.2. This behavior was similar to the metamaterial. At 8 MHz frequency, the high dielectric constant of 35.7 was noticed for x = 0.2. In addition, the frequency dependence of ac-electrical conductivity was also studied. [ABSTRACT FROM AUTHOR]

Low cost and efficient one-step facile hydrothermal synthesis was used to synthesis CoS@WS2 composite on the surface of nickel foam and evaluated as an electrode material for high-performance supercapacitors. Electrochemical impedance spectroscopy, galvanostatic charge–discharge tests, and cyclic voltammetry were used to evaluate the electrochemical characteristics of the CoS@WS2 electrode. A high-specific capacitance of 2442.32 F g−1 at a current density of 4.28 A g−1 was noted for CoS@WS2. The fabricated CoS@WS2 electrode material displayed acceptable rate capability (97.1% capacitance retention at a current density of 4.28 A g−1) and good cycling stability over 3000 charge–discharge cycles. The advanced electrochemical characteristics of CoS@WS2 were contributed to the synergistic effect and high surface area. The greater electrochemical performance of nanoparticles-like CoS@WS2 composite attracts their capacity to meet the requirements of applied electrochemical energy-loading applications. Over all, these results demonstrate that the synthesis of layered CoS@WS2 could be a promising for applied electrochemical energy-loading applications. [ABSTRACT FROM AUTHOR]

Exploiting high-performance and cost-effective non-noble metal catalysts for oxygen reduction reaction (ORR) is still greatly important for energy storage devices such as metal-air batteries and fuel cells. In this work, CeO2, NiCo2O4, and NiCo2O4/CeO2 were synthetized by facile hydrothermal method and used as an ORR catalyst. The as-prepared CeO2, NiCo2O4, and NiCo2O4/CeO2 samples were measured by XRD, XPS, SEM, and TEM. Electrochemical characterization tests exhibit that the ORR activity of NiCo2O4 is evidently enhanced by blending with CeO2 nanoparticles. The NiCo2O4/CeO2 composite exhibits more superior electrocatalytic performances and stability in alkaline solution as compared to the pure CeO2 and NiCo2O4. The electrochemical performance of composite is very near to that of 20 wt% Pt/C. Owing to the synergistic interactions, NiCo2O4/CeO2 favors a four-electron pathway in ORR and exhibits a higher ORR activity than CeO2 and NiCo2O4. The outstanding performance confirms the NiCo2O4/CeO2 composite as a promising efficient ORR catalyst in metal-air batteries and fuel cells. [ABSTRACT FROM AUTHOR]

CuO–CoO/TiO2 has been prepared using TiO2-P-25, Cu(acac)2/Co(acac)3 (sample 1) and Cu(NO3)2/Co (NO3)2 (sample 2) by hydrothermal method. DRS, CV, EDX, XRD, XPS, Raman, FE-SEM, and TEM have been used for structural, optical, and morphological analyses of the samples. The anatase phase formation of the samples has been identified by powder X-ray diffraction and Raman spectroscopy. Cu and Co metals were present as CuO and CoO in both samples, according to XPS and Raman spectroscopy data. UV–Vis–NIR reflectance and cyclic voltammetry analysis were used to determine the absorption nature of the samples. Through these techniques, the band gap values of samples 1 and 2 were determined as 2.0 and 2.5 eV, respectively. Nanotube/nanosheet and nanoparticle morphologies were shown by samples 1 and 2, respectively, based on transmission electron microscopy (TEM) results. The synthesized nanomaterials were applied in the degradation of methylene blue (MB) under visible light. The photocatalytic activity of the samples was studied in the presence and absence of H2O2. Degradation time was 4–40 min in the presence of 2 mg of the catalyst. In addition, the samples were used as catalysts in the reduction of P-nitrophenol (PNP) by NaBH4. UV–Vis spectroscopy was used to monitor the progress of the catalytic and photocatalytic degradation reactions. Furthermore, the catalyst samples were removed and recycled several times. The photocatalytic degradation reaction was carried out in the presence of various free radical scavengers and hydroxyl radical and hole were determined as the main active species for samples 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

This paper reports the development of a facile hydrothermal approach to grow pure BiFeO3 (BFO) films on BFO seed-layer-coated indium tin oxide/glass substrates in mild conditions. The results indicate that the seed layer and no involvement of complex agents were crucial for the mild condition [small amount of NaOH (approximately 1 g); 180 °C] because of homogeneous nucleation and growth of the BFO films. The phase and crystallinity of the BFO films were studied through X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction. The stoichiometric BFO films were ascertained using electron-probe energy-dispersive spectroscopy. The band gap of the BFO films was approximately 2.6 eV. The induced piezopotential of approximately 2.0 mV at a stress of approximately 0.6 GPa indicated the piezoelectric property of the obtained BFO films. The associated piezotronic properties were determined from the asymmetric current–voltage characteristics. The piezophotocatalytic efficiency for methylene blue degradation under visible light irradiation was approximately three times higher than for photocatalysis without stress. [ABSTRACT FROM AUTHOR]

Nickel-doped vanadium pentoxide (Ni-doped V2O5) photocatalyst is prepared through facile hydrothermal method to investigate its performance as photocatalyst in degradation of Rhodamine B (RhB) dye. Different characterization tools are employed for the investigation of structural, morphological and optical characteristics of Ni-doped V2O5. X-ray Diffraction technique confirms the formation of orthorhombic V2O5 and shows stable phase upon doping. The rod-like layer structure morphology is presented through Scanning Electron Microscopy. Energy Dispersive X-ray Spectroscopy confirms the purity of the prepared samples. The optical characteristics are evaluated through UV–Visible spectroscopy which reveals that bandgap of the material is decreased with increasing doping of Ni. The emission spectra of Ni-doped V2O5 is obtained through Photoluminescence Spectroscopy which confirms that the synthesized material is visible light-driven. The photocatalytic activity of optimized samples is evaluated through studying its potential in degradation of RhB dye. The influence of different parameters, i.e., light irradiation time, temperature of solution, pH of solution, amount of catalyst, etc., on the performance of photocatalyst is also studied. The degradation of RhB follows the pseudo first-order linear kinetics with degradation rate of 0.144 min−1. The stability experiment ensures that Ni-doped V2O5 has potential to degrade the organic pollutants and dyes polluted wastewater for a number of cycles. [ABSTRACT FROM AUTHOR]

The minerals such as the CoCO3 can be utilized for the fabrication of lithium-grafted batteries and for a variety of food applications. In this study, we have successfully synthesized Cobalt carbonate crystals (CoCO3) using hydrothermal synthesis method. The synthesized micro-crystals consist of hexagonal structure symmetry. The XRD shows the single-phase hexagonal (R-3c) crystal with lattice constants a = 4.661 Å, b = 4.661 Å, and c = 14.96 Å. EDAX spectroscopy analysis confirms the presence of all the elements of sample. FE-SEM analysis suggests nearly rod-shaped crystals with ~ 29 µm average crystalline size. The Fourier Transform Infrared spectrum suggested existence of O–H, C–O etc. bonding. The TGA is carried out to study the thermal stability. The dielectric relaxation is well studied over large angular frequency range. Complex impedance spectrum of the synthesized microcrystals consists of single semi-circular arc due to the presence of grain only. The magnetic study has suggested paramagnetic nature of the sample. The theoretical study such as the density function theory has been carried out using the Quantum ESPRESSO. A reasonably good agreement is observed between experimentally obtained data and DFT data for optimized structures. [ABSTRACT FROM AUTHOR]

This work reports single-step deposition of Cu2ZnSn(S,Se)4 (CZTSSe) nanocrystalline film via simple and non-toxic hydrothermal route. The hydrothermal growth of CZTSSe multinary nanocrystalline film formation based on Ostwald ripening law which results in highly oriented nanocrystalline nanoflakes. The UV–Vis spectroscopy illustrates that maximum absorption was observed in the range of 650–700 nm with band gap energy of 1.48 eV. Structural studies confirm the formation of pure-phase kesterite crystal structure. Further, Raman shift at 174 cm−1, 196 cm−1 and 236 cm−1 shows A1 mode of vibration corresponding to kesterite structure. Densely packed and compact nanoflake formation was observed in SEM studies. Compositional analysis confirms the stoichiometric film formation with expected valence states of CZTSSe stoichiometry: Cu+, Zn2+, Sn4+, S2− and Se2−. The photoelectrochemical cell performance of CZTSSe film photoelectrode was investigated using simple two-electrode system. In dark condition, J–V measurement demonstrates semiconductor behavior and under illumination shows generation of photocurrent of 3.64 mA/cm2 at a photovoltage of 400 mV. The CZTSSe films show photoconversion efficiency (η) of 3.41%, indicating that the hydrothermally grown CZTSSe photocathode is a promising material for film solar cell technology. Electron impedance spectroscopy illustrated generation of charge transport resistance of 465 Ω. [ABSTRACT FROM AUTHOR]

Magnetic recoverable MnFe2O4/rGO nanocomposites were synthesized via a facile one-pot hydrothermal method. The microstructure, morphology, optical and magnetic property were characterized by X-ray diffraction, high-resolution transmission electron microscope, ultraviolet–visible spectroscopy, N2 adsorption–desorption technique, photoluminescence spectroscopy and vibrating sample magnetometer. The photo-Fenton degradation activity of the MnFe2O4/rGO composites was investigated using the methylene blue (MB) in aqueous solution under the simulated sunlight. The results show that MnFe2O4 nanoparticles with cubic spinel structure were loaded on the surface of rGO, possessing irregular ellipsoid with uniform particle size and good dispersion. The band gap of MnFe2O4/rGO is narrower than that of pure MnFe2O4 and exhibits redshift. The weak luminescence of MnFe2O4/rGO nanocomposites indicates the efficient separation of photoexcited electron/hole pairs. MnFe2O4/rGO nanocomposites display superior photo-Fenton degradation efficiency of MB, exhibit obvious room temperature ferromagnetism and can be readily recovered by external magnetic field. MnFe2O4/rGO nanocomposites exhibit the best degradation efficiency under the condition of pH 9, 0.5 mL H2O2 and 0.06 g mass fraction in photo-Fenton degradation of MB dye. The radical scavenger tests demonstrate that ·OH, e− and h+ are the main active species and play a decisive role, and rGO plays a vital role in synergistic enhancement of photo-Fenton degradation. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide-incorporated cadmium zinc sulphide (rGO–CZS) thin films were synthesised on glass substrates by hydrothermal-assisted chemical bath deposition. The effect of the rGO concentration (0.5–2 wt%) on the photosensitivity of the films was established along with the structural, morphological and optical properties of the composite films. The structural investigations by XRD analysis ensured that the prepared samples are nanocrystalline with hexagonal structure of cadmium zinc sulphide. Scanning electron microscopy showed aggregated sphere-like CZS nanoparticles enveloped with rGO flakes. The average particle size attained from TEM image is approximately 8 nm. The presence of various functional groups was scanned by FTIR analysis. Further, we established the characteristics of the rGO–CZS nanocomposite films as visible-light photodetectors. The photosensitivity, photo response and detectivity of the devices were found to increase with rGO concentration. (2 wt%) rGO–CZS detector exhibits highest photosensitivity of the order of 106, photoresponse of 18.5 mA/W and specific detectivity of 2.08 × 1012 Jones. This work demonstrates fast and simple preparation process of rGO–CZS visible-light detectors with high sensitivity, responsivity and good stability. The enhancement of sensitivity and responsivity can be attributed to the excellent electron conductivity and mobility due to the warm interfacial contact between CZS nanoparticles and the rGO sheet. [ABSTRACT FROM AUTHOR]

Herein, the Nd(OH)3-NiTe2 nanoparticles were synthesized by hydrothermal synthesis. The crystal structure, morphology and surface element composition were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. At the same time, the electrocatalytic performance of Nd(OH)3-NiTe2 for glucose oxidation in alkaline electrolyte was determined by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy (EIS). It exhibits a high peak current density of about 21.09 mA/cm2 for glucose oxidation. The low semicircle diameter of 8000 Ω means fast electron transfer of Nd(OH)3-NiTe2. The oxidation signal of glucose at 0.5 V tends to be constant within 36000 s. Electrochemical experiments show that Nd(OH)3-NiTe2 nanoparticles exhibit good electrocatalytic activity and stability for the oxidation of glucose, which proves their potential application in the field of fuel cells. [ABSTRACT FROM AUTHOR]

A novel magnetic Ag2S/Fe3O4/MoS2 hybrid nanostructure was facilely fabricated by one-step hydrothermal synthesis of MoS2 in the presence of satellite structured Ag/Fe3O4 nanoparticles (NPs), in which process Ag was vulcanized into Ag2S NPs concurrent with the production of MoS2. As a result, flower-like MoS2 nanostructures with only several layers in thickness uniformly attached with high-crystallized Ag2S and Fe3O4 NPs were synthesized from the X-ray diffraction (XRD) and transmission electron microscopy (TEM) results. The Ag2S/Fe3O4/MoS2 hybrids exhibit stronger visible light absorption due to the narrow band gaps of Ag2S and MoS2 component. The obtained Ag2S/Fe3O4/MoS2 hybrid nanostructures can be collected and separated with a magnet conveniently. Moreover, the catalytic performance toward decomposition of Rhodamine B (RhB) can be remarkably improved to 73.3% by Ag2S/Fe3O4/MoS2-1 hybrids compared with the Fe3O4/MoS2-1 of 39.9% within 120 min visible light illumination due to the formation of semiconductor interface. [ABSTRACT FROM AUTHOR]

In this study, a CoS/NiMoO4 composite catalyst with good TYPE-II heterojunction was prepared by hydrothermal method with NiMoO4 nanorods, with water as a medium to load small amount of amorphous CoS, by changing the loading amounts of amorphous CoS. X-ray diffraction, UV–Visible diffuse reflection and other characteristics indicate that doped amorphous CoS can significantly improve the photocatalytic performance of NiMoO4, and the charge separation and electron transfer efficiency of composite catalysts detected by photoelectric chemistry are also significantly improved compared with NiMoO4. The photocatalytic activity and stability of the composite catalyst were studied by hydrogen evolution experiment. The hydrogen production rate of the composite catalyst can reach 338 μmol, which is 3.23 times higher than pure NiMoO4. This simple hydrothermal synthesis of photocatalytic materials provides new ideas and methods for the design and development of new composite photocatalysts. [ABSTRACT FROM AUTHOR]