Solution-based Chemical Method Research Articles

Processing and biomedical applications of novel eco-sustainable fluconazole–loaded zinc oxide (ZnO) encapsulated chitosan (CS) biopolymer nanocomposite by inhibiting microbe species against candidiasis

Drug resistance and a lack of effective antifungal treatments have spurred the research and development of novel therapeutics to combat the fungus Candida albicans. Candida is ubiquitous yeast that is often colonized on the skin and mucosal membranes and is implicated in opportunistic fungal disorders all over the globe. In particular, nanoparticles (NPs) made of metals and metal oxides are a novel kind of functional nanohybrids with fascinating physio-chemical characteristics that have potential uses in nanoscience and medicine. In this current novel research attempt, a decisive biocompatible nanocomposite material with conflation of organic and inorganic sources has been successfully developed using a bis-triazole antifungal agent, fluconazol (FCZ)-assimilated zinc oxide (ZnO) as filler, and chitosan (CS) as matrix by a solution-based chemical method for potent biomedical applications. The eco-sustainable biomaterial ZnO NPs has been synthesized with a simple in situ precipitation method, in which the potent antifungal drug FCZ was implemented into the system to improve its strength, and the system was further modified by employing CS biopolymer. CS is an amorphous, translucent organic biopolymer with a structure unit similar to the polysaccharide structure of the extracellular matrix. This may provide mechanical strength to the nanocomposite by creating interfacial bonding between them. Such a novel nanocomposite has been physicochemically characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Ultra violet (UV), Scanning electron microscope (SEM), and particle size distribution (PSD). Additionally, the well diffusion technique was used to evaluate the ZnO-NPs and to develop FCZ-ZnO-CS nanocomposite for antibacterial and antifungal activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and A. niger. The FCZ-ZnO-CS functionalized nanocomposite has excellent antifungal activity against Candida albicans and Aspergillus niger and optimum antibacterial activity against Escherichia coli and Staphylococcus aureus. Cytotoxicity studies demonstrated that the developed nanocomposite material FCZ-ZnO-CS has significant cytotoxicity against the mouse embryonic fibroblast (NIH-3T3) cell line. These results reveal that ZnO-incorporated fluconazole-chitosan (FCZ-ZnO-CS) could be used as an ideal material for candidiasis applications.

Ag nanoparticles decorated ZnSnO3 hollow cubes for enhanced formaldehyde sensing performance at low temperature

High power consumption is closely related to the high optimum operating temperature. Therefore, the exploration of sensors with excellent sensing performance at low temperature is essential in environment protection and daily life. Herein, the ZnSnO3 hollow cubes have been modified successfully by Ag nanoparticles (NPs) via a simple solution-based chemical method. A series of chemical states characterization and surface morphology analysis indicate that the Ag NPs are evenly dispersed on the surface of ZnSnO3 hollow cubes to generate the Schottky barrier-type junctions and enhance the sensing performance of sample. The gas-sensing results suggest that the sensor towards 50 ppm formaldehyde displays the excellent response value (26.7) at 100 °C, as well as fast response/recovery time (12/18 s), remarkable reproducibility and outstanding stability. Combined with ZnSnO3 hollow cubes structure and catalytic activity of Ag NPs loaded, the sensing mechanism was proposed. This work confirms that Ag NPs modification is an efficient strategy to improve the sensing propertied of ZnSnO3 based gas sensors.

Simple preparation of Si/CNTs/C composite derived from photovoltaic waste silicon powder as high-performance anode material for Li-ion batteries

Currently, with the rise of the photovoltaic industry, how to effectively treat waste silicon powder from an environmentally friendly and economic point of view becomes significant. We reported a simple method to prepare the “core-shell” structure of silicon/carbon nanotubes/carbon (Si/CNTs/C) composite by ball-milling using waste silicon powder. Specifically, The synergistic effect of CNTs and amorphous carbon matrix is beneficial to improving the transmission rate of Li-ions and electrons, and facilitating the reaction kinetics of Li-ions in the process of lithiation/de-lithiation. Meanwhile, the carbon coating layer reduces the direct contact between silicon and the electrolyte, which greatly alleviates the volume expansion of silicon in cycling. With these merits, Si/CNTs/C anode shows high rate performance and outstanding cycling stability up to 300 cycles at 0.2C. Furthermore, full cells assembled with pre-lithiated Si/CNTs/C anodes and commercial NCM811 cathodes deliver considerable initial coulombic efficiency (84.4%) and high energy density (502 Wh kg −1 ). Si/CNTs/C composites prepared by ball-milling show excellent long-cycle stability and rate performance. • Industrial waste silicon is used to prepare silicon-based anodes. • Two-step ball milling method to prepare Si/CNTs/C composite. • A solution-based chemical prelithiation method is proposed. • Si/CNTs/C anode exhibits excellent long-cycle stability and good rate performance. • A full cell shows an improved ICE (84.4%) and a higher energy density (502 Wh kg −1 ).

Chemically Integrating MXene Nanosheets with N-Doped C-Coated Si Nanoparticles for Enhanced Li Storage Performance

Herein, ternary composite composed of Si@N-doped C coupled with 2D MXene nanosheets (Si@NC/MX) is synthesized by a facile solution-based chemical method followed by thermal treatment. In the aqueous solution, polydopamine (PDA)-coated Si nanoparticles were strongly coupled with MXene nanosheets via chemical interactions. Subsequently, the PDA layers were transformed into N-doped amorphous C during the annealing process. As anodes for Li-ion batteries (LIBs), the rational architecture of composites can effectively prevent particle aggregation and restacking between MXene nanosheets during cycling. Also, the dual protection by the C layer and MXene can alleviate the large volume expansion of the Si anode and provide conductive pathways. Accordingly, the Si@NC/MX composites exhibited a high reversible capacity of 953 mA h g−1 after 300 cycles at 1 A g−1. In addition, the electrode exerted a high reversible capacity of 849 mA h g−1 even at a high current density of 10 A g−1.

Investigation of metal-insulator transition temperature and magnetic properties of NdNiO3 nanoparticles

The control of metal–insulator transition (MIT) and magnetic properties of rare-earth nickelates remains a fundamental problem in material science. Here, we report a possible way to tune the MIT as well as the magnetic properties of NdNiO3 by reducing the crystalline size to the nanoscale. NdNiO3 nanoparticles of different sizes have been synthesized by a simple aqueous solution-based chemical method in the atmospheric pressure under oxygen. The x-ray diffraction study shows the formation of orthorhombic nanocrystals of NdNiO3 with Pbnm space group, presence of oxygen vacancies and higher octahedral distortion. The morphology and the particle size distribution have been evaluated by FESEM and TEM. The temperature dependent resistivity measurement shows the metal to insulator transition, which depends on the particle size; lower the particle size, higher the MIT temperature (TMI). Further study on the temperature dependent magnetic susceptibility shows the signature of magnetic phase transition at a temperature (Néel temperature TN), lower than the TMI, which indicates the existence of second order magnetic phase transition in our NdNiO3 nanoparticles. We have attributed the higher TMI and the origin of second order magnetic phase transition predominantly to the higher NiO6 octahedral distortion and the narrowing of bandwidth of the nanocrystalline NdNiO3, which leads to the opening of the charge transfer gap at the temperature higher than the bulk.

Bio-evaluation of doxorubicin (DOX)-incorporated hydroxyapatite (HAp)-chitosan (CS) nanocomposite triggered on osteosarcoma cells

A new strategic nanostructure consisting inorganic–organic combination for cancer dominancy has been successfully developed using doxorubicin (DOX)-assimilated hydroxyapatite (HAp) as filler and chitosan (CS) as matrix by a solution-based chemical method to access a new window in the field of drug delivery systems (DDS). In this research attempt, we have focussed to fetch an anticancer efficacy from a nanoassembly consisting of DOX-coated nanosized HAp and CS. Basically, HAp is a progressive ceramic biomaterial and has been synthesized by a simple in situ precipitation method, in which the reputed anticancer drug DOX was incorporated and the system was further modified by an extensively used polymer CS. CS is an organic polymer that can be obtained from different organic sources, which may provide mechanical strength to the nanocomposite by making interfacial bonding between them. Such a novel nanocomposite has been physicochemically characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and particle size distribution (PSD). Also, the in vitro biocompatible assistance of the synthesized HAp and the anticancer activity of the newly derived nanocomposite were evaluated through a colorimetric assay (MTT assay). HAp remains biocompatible to osteosarcoma cells, whereas the DOX-HAp-CS nanocomposite produces a remarkable cytotoxicity towards cultured osteosarcoma cells. The prepared DOX-HAp-CS nanocomposite may be potentially used as an anticancer agent for osteosarcoma inhibition.

A conductive polymer derived N-doped carbon nanofiber supported Li2S coating layer for Li–S batteries with high mass loading

The commercialization of Li2S as a potential candidate for lithium-sulfur cathode material is hampered due to its low electronic conductivity, the “shuttle effect” and the initial energy barrier. In this work, nanosized Li2S particles coated carbon nanofibers are prepared via a solution-based chemical method. Benefiting from this synthetic method, a uniform Li2S layer can be obtained without any agglomeration. Due to the small size of Li2S particles, a smaller energy barrier is observed in the first charging process, which means it is easier to activate the Li2S with a smaller cut-off voltage. In addition, the carbon nanofibers as matrixes could enhance the conductivity of cathode. Moreover, to verify the potential practical application of prepared materials, Li2S cathodes with high loading amount of active materials (∼3 mg cm−2) are prepared, which show excellent cycling and rate performance, delivering an initial specific capacity of 916.2 mA h g−1 at 0.1C, and 321 mA h g−1 capacity still can be reached at 2 C. This good performance can be attributed to the unique solution-based synthesis method, resulting in small and uniform Li2S particles coated on carbon nanofibers.

The Role of Solvent Environment on the Optical Behavior of Chemically Synthesized Silicon Nanoparticles

Silicon nanoparticles (Si-NPs) were prepared by solution-based chemical etching method. Optical characteristics of the as-prepared Si-NPs were investigated in different polar and nonpolar organic solvents. The emission and absorption properties of Si-NPs were tuned by altering the environment (solvents). The variation in absorption coefficient was observed because of the solvent interaction nature of Si-NPs. Si-NPs in polar aprotic and nonpolar solvents manifested good luminescence under UV excitation. PL intensities were observed to be depending on etched cross-section area on wafer surface. The results show a linear dependence of the refractive index (n) on wavelength (λ). The nature of solvents altered the luminescence efficiency of Si-NPs when examining under UV lamp. The emission and absorption properties of Si-NPs were tuned by altering the environment (solvents) through electrostatic interaction of various organic solvents with the Si-NPs. The band shapes of the Si-NPs show remarkable changes in passing from noncoordinating solvent (chloroform) to various coordinating solvents, which was the result of change in the environment around Si-NPs in various solutions.

Hydroxyapatite-chitosan based bioactive hybrid biomaterials with improved mechanical strength

Composites consisting of hydroxyapatite (HA) and chitosan (CTS) have recently been intensively studied. In this work, a novel inorganic-organic (I/O) HA/CTS materials in the form of granules were prepared through a simple solution-based chemical method. During the synthesis of these hybrids, the electrostatic complexes between positively charged, protonated amine groups of chitosan and the negative phosphate species (HPO42− and H2PO4−) were formed. Our biocomposites belong to the class I of hybrids, which was confirmed by FTIR studies. XRD analysis revealed that the obtained materials consisted of hydroxyapatite as the only crystalline phase. Homogeneous dispersion of the components in HA/CTS composites was confirmed. The use of 17wt% and 23wt% of chitosan resulted in approximately 12-fold and 16-fold increase in the compressive strength of HA/CTS as compared to the non-modified HA material. During incubation of the studied materials in SBF, pH of the solution remained close to the physiological one. Formation of apatite layer on their surfaces indicated bioactive nature of the developed biomaterials.

One-Pot Fast Synthesis of Leaf-Like CuO Nanostructures and CuO/Ag Microspheres with Photocatalytic Application

A time- and energy- saving solution-based chemical precipitation method was developed to synthesize leaf-like CuO nanostructures. The morphology and size of the leaf-like CuO nanostructures could be simply manipulated by controlling the type and concentration of precursors, and the oriented attachment mechanism is responsible for the formation of leaf-like shape. With the concurrent reduction reaction and at appropriate concentration, CuO/Ag microspheres could be prepared and the growth mechanism is proposed. These two structures could serve as effective photocatalyst for the degradation of rhodamine B under visible light irradiation in the presence of hydrogen peroxide. Moreover, compared to pure CuO nanostructures, the photodecomposition activity of CuO/Ag microspheres increases by 42.9% due to plasmon-enhanced light absorption.

Fabrication of 1,4-bis(aminomethyl)benzene and cobalt hydroxide @ graphene oxide for selective detection of dopamine in the presence of ascorbic acid and serotonin

A simple electrochemical sensor for detecting dopamine was fabricated using 1,4-bis(aminomethyl)benzene (BAMB) and cobalt hydroxide (Co(OH)2) at graphene oxide (GO) surface using a simple solution-based chemical reduction method. The successful formation of GO-BAMB-Co(OH)2 was confirmed by transmission electron microscopy and X-ray photoelectron spectroscopy, while the electrochemical performance of the material was studied using different techniques, including cyclic voltammetry, differential pulse voltammetry, linear sweep voltammetry, and chronoamperometry in 0.1M PBS at pH 7.4. The GO-BAMB-Co(OH)2-modified electrode showed an excellent electrochemical response with a broad linear range (3–20 and 25–100μM) and low limit of detection (0.4μM). Furthermore, efficient selective detection of dopamine in the presence of a 10-fold excess concentration of bio-interfering species, such as ascorbic acid and serotonin, was remarkable. The practical feasibility of the sensor was checked using urine samples, which showed appreciable recovery results. The main advantages of this sensor are its simple electrode fabrication procedure, rapid sensing response, remarkable selectivity, repeatability, and stability.

Facile and template-free synthesis of spherical Cu2O as anode materials for lithium-ion batteries

In this work, we report the synthesis of spherical Cu2O through a facile and template-free solution-based chemical precipitation method at 60 °C. The crystal structure, surface morphology, and electrochemical performance of spherical Cu2O were investigated using X-ray diffraction, scanning electron microscopy, galvanostatic charge/discharge and cyclic voltammetry techniques, respectively. As anode materials for lithium-ion batteries, spherical Cu2O not only exhibits high cycling stability but also excellent reversibility.

Improving the Electrochemical Performance of Si Nanoparticle Anode Material by Synergistic Strategies of Polydopamine and Graphene Oxide Coatings

Graphene oxide/polydopamine-coated Si nanocomposite (GO/PDA-Si) was synthesized by a novel facile solution-based chemical method at room temperature. The nanocomposite with a PDA coating layer of ∼1.5 nm exhibits a high reversible specific capacity and excellent cycling stability (1074 mAh g–1 after 300 cycles at 2100 mA g–1) as an anode material for lithium ion batteries. The synergistic effect of the PDA coating layer and GO plays an important role in improving the electrochemical lithium storage performances. Both of them can serve as a cushion to buffer the volume change of Si nanoparticles (NPs) during the charge/discharge process and prevent Si NPs from direct contact with a liquid electrolyte. The surface property of Si NPs was also modified by introducing secondary amine groups, which can form amide groups with carboxyl groups and hydrogen bonds with hydroxyl/carboxyl groups on GO. These chemical interactions firmly anchor Si NPs to GO so that aggregation of Si NPs can be mostly prevented. Moreover, the good lithium ion conductivity of PDA is beneficial for rate performance. The experimental results should be very useful in guiding the preparation of long-cycle-life Si-based anode materials with good rate performance using a simple surface-modification process.

Synthesis, structural characterization and photocatalytic application of ZnO@ZnS core–shell nanoparticles

ZnO nanoparticles were synthesized by co-precipitation with no capping agent followed by covering with ZnS using a solution-based chemical method at low temperature. By variation of the solution concentrations it was found that the fully-covering ZnS shell forms by a reaction of Na2S with ZnO NPs followed by the formation of ZnS nano-crystals by the reaction of Na2S with ZnCl2. The mechanism that led to full coverage of the ZnO core is proposed to be the addition of ZnCl2 at a later stage of the growth which guarantees a continuous supply of Zn ions to the core surface. Moreover, the ZnS nanocrystals that uniformly cover the ZnO NPs show no epitaxial relationship between the ZnO core and ZnS shell. The slow atomic mobility at the low reaction temperature is attributed to the non-epitaxial uniform ZnS shell growth. The rough surface of the ZnO grains provides initial nucleation positions for the growth of the ZnS shell nano-crystals. The low growth temperature also inhibits the abnormal growth of ZnS grains and results in the homogeneous coverage of ZnS nano-crystals on the ZnO core surface. The as-synthesized ZnO@ZnS core–shell nanoparticles were used as a photocatalyst to decompose Rose Bengal dye at three different pH values. ZnO@ZnS core–shell nanoparticles perform as a more active photocatalyst at a pH of 4, while pure ZnO nanoparticles are more efficient at a pH of 7.

Tunable Photoluminescence of Monolayer MoS2 via Chemical Doping

We demonstrate the tunability of the photoluminescence (PL) properties of monolayer (1L)-MoS2 via chemical doping. The PL intensity of 1L-MoS2 was drastically enhanced by the adsorption of p-type dopants with high electron affinity, but reduced by the adsorption of n-type dopants. This PL modulation results from switching between exciton PL and trion PL depending on carrier density in 1L-MoS2. Achievement of the extraction and injection of carriers in 1L-MoS2 by this solution-based chemical doping method enables convenient control of optical and electrical properties of atomically thin MoS2.

In situ and room-temperature synthesis of ultra-long Ag nanoparticles-decorated Ag molybdate nanowires as high-sensitivity SERS substrates

We report on room-temperature synthesis of Ag nanoparticles (NPs) decorated silver molybdate nanowires (SMNs) using a solution-based chemical reaction method. We show that AgxMoyOz (Ag2Mo2O7, Ag2MoO4 and Ag6Mo10O33) nanomaterials can be selectively synthesized by altering the pH value of the reaction media in the presence of silicotungstic acid at room temperature. This reaction process uses isopropyl alcohol as a free radical scavenger and occurs over a short reaction time compared to the traditional hydrothermal method. Moreover, we demonstrate that under UV-light illumination of different periods, Ag NPs of controllable distribution densities are formed in situ on the surface of SMNs in tungstosilicate acid environment. We show that the SERS sensitivity of such Ag NP–SMN complex depends on the distribution density of Ag NPs, with the best structure capable of detecting the p-aminothiophenol at a concentration as low as 1.0×10−11M. The same substrate is further used to enhance the Raman signal from 2-mercaptopyridine from which a quantitative relationship between the analyte concentration and its corresponding Raman intensity can be established.

Process intensification of uniform loading of SnO2 nanoparticles on graphene oxide nanosheets using a novel ultrasound assisted in situ chemical precipitation method

In this paper, a novel ultrasound assisted, solution-based chemical synthesis method for the preparation of SnO2–graphene nanocomposite is presented. Graphene oxide (GO) was prepared by the modified Hummers–Offeman method in presence of ultrasonic irradiation. Further loading of SnO2 on GO was carried out with an ultrasound assisted solution-based synthesis route. The prepared GO and SnO2–graphene nanocomposite were characterized by XRD, TEM, FTIR spectra, TGA and DTA analysis in order to confirm the formation of graphene–SnO2 nanocomposite. TEM analysis of ultrasonically prepared graphene–SnO2 composite shows the uniform and fine loading of SnO2 particles (3–5nm) on graphene nanosheets. However agglomerated morphology was observed in case of conventionally prepared graphene–SnO2 composite. The cavitational effects generated due to the ultrasonic irradiations during the synthesis of graphene–SnO2 composite improve the fine and uniform loading of SnO2 on graphene nanosheets by oxidation–reduction reaction between GO and SnCl2·2H2O compared to conventional synthesis methods. The formed material was used for the preparation of anode in lithium ion batteries and its electrochemical performance was characterized by cyclic voltammetry and charge/discharge cycles. It is found that the capacity of SnO2–graphene nanocomposite based Li-battery is stable for around 120 cycles, and the battery could repeat stable charge–discharge reaction.

High-Density Chemical Intercalation of Zero-Valent Copper into Bi2Se3 Nanoribbons

A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi(2)Se(3) nanoribbons. Up to 60 atom % copper (Cu(7.5)Bi(2)Se(3)) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction.

Preparation of TiO2, Ag-doped TiO2 nanoparticle and TiO2–SBA-15 nanocomposites using simple aqueous solution-based chemical method and study of their photocatalytical activity

Nanocrystalline TiO2, Ag-doped TiO2 and TiO2–SBA-15 nanocomposites have been synthesised using a simple aqueous solution-based chemical method. Nanocrystalline TiO2 was synthesised by calcining the precursor prepared by using ethylenediamine tetraacetic acid and TiCl3 in aqueous medium. Formation of crystalline phase (anatase, rutile or mixed phase) and crystallite size were found to be dependent on calcination temperature. To enhance the photocatalytic activity, Ag-doped TiO2 was synthesised by doping of Ag during the synthesis step of TiO2. TiO2–SBA-15 nanocomposites were synthesised by impregnation method. Pure anatase TiO2 nanoparticle was formed in the amorphous matrix of the silicate SBA-15, even though the loading of the TiO2 in the silicate matrix was as low as 5 wt%. The synthesised materials were characterised using thermal analysis, powder X-ray diffraction method, surface area and porosimetry analysis, diffuse reflectance analysis and transmission electron microscopy. The photocatalytic property of the synthesised materials was investigated towards the degradation of methyl orange under sunlight exposure and monitored by UV–visible spectrophotometer. Ag-doped TiO2 exhibited enhanced photocatalytic activity than undoped TiO2. TiO2–SBA-15 nanocomposites showed impressive photocatalytic activity even with 10 wt% TiO2 loading.

Effect of Fe doping concentration on optical and magnetic properties of ZnO nanorods

Herein, a facile low temperature, aqueous solution-based chemical method has been demonstrated for large-scale fabrication of Fe doped ZnO nanorods (ZnO:Fe) with a series percentage of Fe dopant. Interestingly, the SEM results reveal a uniform well dispersed synthesis of ZnO:Fe nanorods throughout the substrate. The x-ray diffraction result suggests that Fe substitutes Zn in the ZnO matrix and rules out the formation of any secondary phase. Selected area electron diffraction investigation verifies the single crystal, hexagonal wurtzite structure of the ZnO:Fe nanorods. Energy dispersive spectroscopy data confirm Fe doping of the ZnO nanorods with a concentration ranging from 0.9 to 2.2 at.%. The photoluminescence spectrum reveals a continuous suppression of defect related broad-band emission (ID/IUV = 1–0.11) by increasing the concentration of the dopant ion, which produces the quenching of surface defects present in the nanostructures. An enhancement in ferromagnetism (M = 0.15 × 10−2–0.24 × 10−1 emu g−1 at 2000 Oe) is found in doped ZnO nanorods.