61 results
Search Results
Now showing 1 - 10 of 61
- Metal–organic ligands with mixed chalcogenides are potential compounds for the preparation of mixed anionic metal chalcogenide alloys. However, only a few of such ligands are known, and their complexes are not well explored. We have prepared homo- and hetero-dichalcogenoimidodiphosphinate [(EE′PiPr2NH)] (E, E′ = Se, Se; S, S; S, Se) complexes of manganese and copper through metathetical reactions. The X-ray single crystal structure of [Mn{(SePiPr2)2N}2] 1 revealed a triclinic crystal system, with a MnSe4 core unit, whereas the crystal structure determination of [Mn{(SPiPr2)(SePiPr2)N}2] 2 indicated a triclinic crystal system with a Mn(S/Se)2 unit. Both metal centres are tetrahedral, with two deprotonated bidentate ligands forming the coordination sphere. The free ligand was found to exhibit a gauche configuration in the solid state. The energies of the various rotamers of dithio-analogue were studied by DFT calculations. The decomposition behaviour of complexes with homo- and heterochalcogenides was investigated, and the complexes were employed as single-source precursors to generate manganese and copper chalcogenides through solvent-less melt reactions between 500 and 550 °C. The deposited powders were characterized by powder X-ray diffraction (p-XRD), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX), transmission electron microscopy (TEM), and elemental mapping. MnS, MnSe2, and MnSSe phases were obtained from the decomposition of respective manganese complexes. In contrast, the decomposition of copper-based complexes yielded Cu2–xSe and the sulphur-doped Cu3Se2 phase from seleno- and mixed thio/seleno-complexes of Cu, respectively. The morphology ranged from random sheet-like structures to agglomerated platelets, while the selected area electron diffraction (SAED) revealed the crystalline nature of the materials. Depending on the nature of the complex and the temperature, different amounts of phosphorus were present as an impurity in the synthesized products.
- 0
- 2
- 0
- The smart design of nanoparticles with varying surfaces may open a new avenue for potential biomedical applications. Consequently, several approaches have been established for controlled synthesis to develop the unique physicochemical properties of nanoparticles. However, many of the synthesis and functionalization methods are chemical-based and might be toxic to limit the full potential of nanoparticles. Here, curcumin (a plant-derived material) based synthesis of gold (Au) nanoparticles, followed by the development of a suitable exterior corona using isoniazid (INH, antibiotic), tyrosine (Tyr, amino acid), and quercetin (Qrc, antioxidant), is reported. All these nanoparticles (Cur-Au, Cur-AuINH, Cur-AuTyr, and Cur-AuQrc) possess inherent peroxidase-mimicking natures depending on the surface corona of respective nanoparticles, and they are found to be excellent candidates for free radical scavenging action. The peroxidase-mimicking nanoparticle interactions with red blood cells and mouse macrophages confirmed their hemo- and biocompatible nature. Moreover, these surface-engineered Au nanoparticles were found to be suitable in subsiding key pro-inflammatory cytokines such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). The inherent peroxidase-mimicking behavior and anti-inflammatory potential without any significant toxicity of these nanoparticles may open new prospects for nanomedicine.
- 0
- 1
- 0
- Mixed metal sulfides are increasingly being investigated because of their prospective applications for electrochemical energy storage and conversion. Their high electronic conductivity and high density of redox sites result in significant improvement of their electrochemical properties. Herein, the composition-dependent supercapacitive and water splitting performance of a series of Ni(1−x)CuxCo2S4 (0.2 ≤ x ≤ 0.8) solid solutions prepared via solvent-less pyrolysis of a mixture of respective metal ethyl xanthate precursors is reported. The use of xanthate precursors resulted in the formation of surface clean nanomaterials at low-temperature. Their structural, compositional, and morphological features were examined by p-XRD, SEM, and EDX analyses. Both supercapacitive and electrocatalytic (HER, OER) properties of the synthesized materials significantly vary with composition (Ni/Cu molar content). However, the optimal composition depends on the application. The highest specific capacitance of 770 F g−1 at a current density of 1 A g−1 was achieved for Ni0.6Cu0.4Co2S4 (NCCS-2). This electrode exhibits capacitance retention (CR) of 67% at 30 A g−1, which is higher than that observed for pristine NiCo2S4 (838 F g−1 at 1 A g−1, 47% CR at 30 A g−1). On the contrary, Ni0.4Cu0.6Co2S4 (NCCS-3) exhibits the lowest overpotential of 124 mV to deliver a current density of 10 mA cm−2. Finally, the best OER activity with an overpotential of 268 mV at 10 mA cm−2 was displayed by Ni0.8Cu0.2Co2S4 (NCCS-1). The prepared electrodes exhibit high stability, as well as durability.
- 1
- 15
- 0
- Canfieldite Ag8SnS6 (STS) nanocubes were prepared by the solution decomposition of precursors using heat-up and hot injection protocols employing coordinating solvents (oleylamine - OLA and dodecanethiol - DT) to afford monodispersed silver tin sulfide (STS) nanoparticles. The phase and shape of nanoparticles were tuned by varying reactants' temperature and mole ratios. The powder X-ray diffraction (p-XRD) and transmission electron microscopy (TEM) analysis indicate phase pure orthorhombic Ag8SnS6 nanocrystals with nearly monodispersed particles ranging between 12 and 50 nm. The p-XRD patterns for the STS nanoparticles obtained by the heat-up method exhibited enhanced peak broadening than the hot injection route, accounting for the corresponding quantum confinement effects. Likewise, the (124), (227) and (266) planes of the reflections in OLA/DT capped STS crystals appeared well resolved, indicating that seed growth of a transitional Ag2S might be involved in the formation of the ternary chalcogenides. The values of the energy bandgap (Eg) were found in the range of 1.16–2.60 eV. At the same time, the STS nanoparticles exhibited high photon absorption and low quantum yield potentials, making them a possible candidate for photovoltaic cells and enhanced photoelectrochemical performance.
- 1
- 16
- 0
- 2025| ElsevierThe use of surfactants in catalyst synthesis is essential for controlling particle dimensions but often hinders catalytic performance by blocking active sites. To overcome this challenge, this study investigates a solvent-free solid-state pyrolysis approach as an alternative to colloidal synthesis with surfactants. Nickel selenobenzoate was employed as a metal-organic precursor to synthesize NiSe2 nanosheets, aiming to avoid surfactants while preserving active surface sites for catalysis. However, results indicate that merely eliminating surfactants in solvent-free synthesis is insufficient, as the decomposition of the metal-organic precursor leads to an amorphous carbonaceous residue, which negatively impacts electrochemical performance. To understand these effects, NiSe2 nanosheets synthesized via solid-state pyrolysis were compared with those produced using a conventional oleylamine-assisted colloidal approach. Electrochemical tests revealed that oleylamine-capped NiSe2 exhibited superior performance in both supercapacitance and hydrogen/oxygen evolution reactions (HER/OER), highlighting the adverse effects of carbon residue in the solid-state route. Further optimization of solid-state pyrolysis enabled controlled surface and structural modifications, leading to the formation of a NiSe2/Ni0.85Se heterostructure via gradual selenium loss, which improved HER activity. At higher temperatures, further Se loss resulted in a phase transformation from NiSe2 to Ni0.85Se while preserving the nanosheet morphology. Notably, this Ni0.85Se phase exhibited the best HER and OER performance, attributed to enhanced conductivity and the partial conversion of residual carbon into crystalline graphitic carbon at elevated temperatures. These findings underscore the need for careful precursor and method selection in solvent-free synthesis to optimize catalytic material performance, offering valuable insights for the design of next-generation electrocatalysts.
- 1
- 1
- 0
- Cytotoxicity and in vitro evaluation of whey protein-based hydrogels for diabetes mellitus treatment2019| Springer NatureObesity is the accumulation of excess body fat and the hallmark of type II diabetes mellitus, characterized by hyperglycemia. Glycemic control is very critical to reduce long-term vascular complications resulting from the progressive nature of hyperglycemia. In previous studies, thermally reduced graphene oxide (rGO)-based hydrogel biocomposites were prepared and in vitro drug release studies confirmed their potential as a biodegradable-targeted drug delivery system. Thus, the in vitro biological evaluation of these rGO-based hydrogels was investigated. The hydrogels were encapsulated with chloroquine diphosphate (CQ) and proguanil (P) drugs to investigate potential of combination therapy. The non-toxic nature of the hydrogels was investigated by the use of the MTT assay against 3T3-L1 and c2c12 cell lines. 3T3-L1 pre-adipocytes were grown, differentiated and treated with the drug-encapsulated hydrogels to detect the effect on the adipose tissue cells by quantitative real-time polymerase chain reaction (qPCR) identifying gene expression levels by utilizing gene markers specific for diabetes and obesity: cpt-1, glut-4, acc1, pgc-1, mef2a and nrf-1 with comparison to positive control metformin. The cytoxicity studies confirmed non-toxic nature of the hydrogels; identified dosage of drugs encapsulated were effective within investigated treatment time and qPCR revealed an upregulation of CPT-1, GLUT-4, PGC-1, MEF2A and NRF-1 marker genes, but a downregulation of ACC-1 marker gene. The results from the expression of investigated genes suggest the anti-obesity potential of drugs released from the hydrogels. There were identified positive effects employing combination therapy, but further studies are required to ascertain the actual effect of the drugs in combination, by further varying the ratios of drugs (instead of the presented 1:1 ratio) employed. Statistically, the results from the individual drug release treatments were not significantly different from positive control metformin treatments, but the combination therapy investigation showed more promise.
- 1
- 1
- 0
- This study optimised a novel autoclave-assisted Fe3O4 nanoparticle pre-treatment (NAAP) for the improvement of reducing sugar (RS) recovery from potato peel waste. The optimised NAAP was further assessed for other lignocellulosic substrates, recyclability, animal feed and bioethanol production. Maximum RS yield of 0.324 g/g was obtained with the optimised NAAP conditions. Recyclability resulted in an average RS yield of 0.254 g/g over three pre-treatment cycles. Moreover, the optimised NAAP for the pre-treatment of corn cob (0.021 g/g), cassava peels (0.242 g/g), bamboo stem (0.357 g/g), Amaranthus (0.428 g/g), sorghum leaves (0.867) and banana pseudostem (1.392 g/g) demonstrated its versatility. Furthermore, the potential of the optimised pre-treated biomass for animal feed waste valorisation and bioethanol production (22.82 g/L) was achieved. The present NAAP pre-treatment provides novel insights on the application of nanotechnology in lignocellulosic bioprocessing, which could eliminate chemical and enzyme usage, while reducing the process costs and its associated negative environmental impact.
- 1
- 14
- 0
- 2023| ElsevierThe synthesis of photocatalysts with a suitable bandgap that could speed up the rate of oxidation of chemical effluent is of utmost importance to material chemists. It has been observed that chalcogenide nanostructures research continues to dominate scientific work over the last few years based on their exciting bandgap within the semiconductor bandgap range. In this research work, novel class I2-II-IV-VI4 quaternary chalcogenides nanoparticles were synthesised using co-precipitation by varying the reaction conditions of temperature (200 °C and 250 °C) and, essentially, capping agents (citric acid and glycerol) and the mole ratio of precursors. The resulting nanoparticles were purified and vacuum dried to give a black crystalline solid. The Powder-X-ray Diffraction analysis of the as-synthesised heterostructure chalcogenides showed novel pure phase materials that exhibited the orthorhombic and cubic Ag2FeSnS4 crystal systems reminiscent of the parent compounds Ag8SnS6 and AgSnS2 under different experimented reaction conditions. The morphological characterisation of the HC chalcogenides by Transmission Electron Microscope revealed that the nanomaterials formed were predominantly nanocubes, with particle diameters ranging from 22.98 ± 1.67 to 57.26 ± 12.93 nm. Further elucidation of the optical property of the HC nanoparticles by Tauc's plot based on the data derived from UV-Vis spectrophotometry measurement revealed that the bandgap ranged from 1.58 to 1.99 eV. The FTIR absorption character of the as-synthesised HC nanoparticles provided evidence for the surface functionalisation, confirming the presence of moieties like the hydroxyl (O-H) at 3396.16 cm−1 and carbonyl group (C=O) at 1712.31 cm−1. At the same time, the UV-Visible spectrophotometry, measured over a range of 250 to 1000 nm, showed broad absorbance between 420 and 800 nm, confirming the optical property of the nanoparticles. The result showed that heterostructure chalcogenide nanoparticles would have an excellent photocatalytic application.
- 1
- 16
- 0
- In this study, a facile and potentially scalable synthesis of AgBiS2 (schapbachite) using melts of metal xanthates is presented; AgBiS2 is both a significant mineral and a technologically important material. This ternary material was synthesized by a novel and low-cost solventless route using simple ethyl xanthate complexes of silver and bismuth. p-XRD analysis indicates that the synthesized ternary material is highly crystalline and belongs to the cubic phase (schapbachite). The electrochemical properties of the material were tested; the potential of the synthesized material for application in charge storage shows a high specific capacitance of 460 F g−1 at 2 mV s−1. A capacitance retention of 83% with a 100% coulombic efficiency was observed after 3000 cycles. The charge storage potential, analysed by fabricating actual symmetrical devices, shows a specific capacitance of 14 F g−1 at 2 mV s−1. An energy density of 26 W h kg−1 and a power density of 3.6 kW kg−1 were observed. Besides, the potential for the oxygen evolution reaction was also studied. An overpotential of 414 mV and a Tafel slope of 134 mV dec−1 were obtained for water oxidation. The fabrication of an electrolyzer cell using the synthesized material as the cathode indicates that a current of 10 mA cm−2 can be achieved at a potential of 1.63 V.
- 1
- 3
- 0
- 2020| Springer NatureInorganic two-dimensional semiconductor indium sulfide (In2S3) has recently attracted considerable attention as a buffer material in the field of thin-film photovoltaics, photo electrochemical cells and other energy-related applications. Compared with this growing interest, however, detailed characterizations of the commercial material are not done. The present investigation deals with the systematic investigation of the physical properties of powdered β-indium sulfide (In2S3). The crystalline structure, the composition, and the morphological properties of the samples were characterized using a range of techniques such as X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). X-ray diffraction patterns revealed mixed peaks of In2S3 and In2O3 for the sample annealed at 400 °C. The In2O3 peaks were crystalline with a cubic phase with a (222) preferential orientation. These results were supported by the FTIR, and XPS studies. Thus, a significant correlation was established between the annealing tem perature and the TEM images. The main conclusion of the paper opens the possibility of using In2S3 layers for solar cells.
- 1
- 10
- 0
