Morphology Of Nanocomposites Research Articles

Morphological studies of polypyrrole/silver nanocomposites

Polypyrrole/silver (PPy/Ag) nanocomposites of weight percentages (0.1%, 0.5%, 3%, 5% and 7% wt.) were synthesized via a chemical oxidation method. The AFM analysis is performed to study the surface roughness, morphology and size distribution of PPy particles and PPy-Ag nanocomposites. The results indicated that as the concentration of Ag in the nanocomposite increases, the roughness increases. The size of nanoparticles was also evaluated and found to be in the range of 15 nm to 125 nm. The PPy/Ag nanocomposites exhibited an effectiveness against Gram-negative Escherichia coli showing an inhibition zone of 4mm and displayed poor efficacy against Gram-positive Staphylococcus aureus. Based on given adequate antibacterial characteristics of PPy/Ag nanocomposites, it can be identified as a promising material in biomedical applications.

Fabrication of PES Modified by TiO2/Na2Ti3O7 Nanocomposite Mixed-Matrix Woven Membrane for Enhanced Performance of Forward Osmosis: Influence of Membrane Orientation and Feed Solutions.

Water treatment is regarded as one of the essential elements of sustainability. To lower the cost of treatment, the wastewater volume is reduced via the osmotic process. Here, mixed-matrix woven forward osmosis (MMWFO) PES membranes modified by a TiO2/Na2Ti3O7 (TNT) nanocomposite were fabricated for treating water from different sources. Various techniques were used to characterize the TNT nanocomposite. The crystal structure of TNT is a mix of monoclinic Na2Ti3O7 and anorthic TiO2 with a preferred orientation of (2-11). The SEM image shows that the surface morphology of the TNT nanocomposite is a forked nano-fur with varying sizes regularly distributed throughout the sample. The impact of TNT wt.% on membrane surface morphologies, functional groups, hydrophilicity, and performance was investigated. Additionally, using distilled water (DW) as the feed solution (FS), the effects of various NaCl concentrations, draw solutions, and membrane orientations on the performance of the mixed-matrix membranes were tested. Different water samples obtained from various sources were treated as the FS using the optimized PES/TNT (0.01 wt.%) MMWFO membrane. Using textile effluent as the FS, the impact of various NaCl DS concentrations on the permeated water volume was investigated. The results show that the MMWFO membrane generated with the TNT nanocomposite at a 0.01 wt.% ratio performed better in FO mode. After 30 min of use with 1 M NaCl and various sources of water as the FS, the optimized MMWFO membrane provided a steady water flow and exhibited antifouling behavior. DW performed better than other water types whenever it was used owing to its greater flow (136 LMH) and volume reduction (52%). Tap water (TW), textile industrial wastewater (TIWW), gray water (GW), and municipal wastewater (MW) showed volume reductions of 41%, 34%, 33%, and 31.9%, respectively. Additionally, when utilizing NaCl as the DS and TIWW as the FS, 1 M NaCl resulted in more permeated water than 0.25 M and 0.5 M, yet a higher volume reduction of 41% was obtained.

Microwave assisted synthesized graphene oxide nanocomposites for remediation of toxic metal ions

Here we report the eco-friendly synthesis of graphene magnetic and non-nonmagnetic nanocomposites, namely GO/Fe3O4 and GO-Ni(OH)2, by employing microwave energy. The nanocomposites were explored for the adsorption of toxic Pb2+ and Cd2+ ions. The characterization techniques of XRD, Raman, FESEM and HRTEM confirmed the structure quality and morphology of both nanocomposites. The adsorption studies were conducted using ICP-OES characterization data. The adsorption of Pb2+ and Cd2+ ions on the surface of the nanocomposites were described well by the Freundlich model. The results of the adsorption studies show that the GO/Fe3O4 nanocomposite shows a high adsorption of Cd2+ ions relative to Pb2+ ions due to the formation of a cadmium complex (CdOH +) in the solution which has a higher stability constant value as compared to the lead complex PbOH +. However, the nonmagnetic GO-Ni(OH)2 nanocomposite shows a higher adsorption of Pb2+ ions due to its high electronegativity relative to Cd2+ ions. It was found that the adsorption varies with the concentration of the metal ions.

The Addition of TiO2 Ratios in SiO2–TiO2 Nanocomposite by Sonochemical Process for the Enhancement in Self-cleaning Property

This research aims to study self-cleaning property for removing atmosphere pollutants on the substrate surface. Thus, the modification of nanocomposite material for self-cleaning property is an important challenge to solving the organic pollutants on various surfaces. Nanocomposite material in this work is focused on SiO2-TiO2 based metal oxide materials that synthesized by sonochemical process with the precursors of tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TTIP). The crucial parameter of different amount of titanium ratios in SiO2 matrix is related to the improvement on structural and self-cleaning properties. The ratios of Si:Ti precursor were varied at 1:0.1, 1:0.5, 1:1 and 0:1 (pure TiO2). The structural phase of SiO2-TiO2 nanocomposite powder was detected by X-ray diffraction technique (XRD). Chemical bonding structure in SiO2-TiO2 nanocomposite was analysed by Fourier transform infrared spectrophotometer (FTIR). Surface morphology of SiO2-TiO2 nanocomposite was monitored by field emission scanning electron microscope (FE-SEM). SiO2-TiO2 nanocomposites synthesized by sonochemical process were in form of composite powder with the spherical SiO2 particles and decorated TiO2 on its surface. After that, the products of SiO2-TiO2 nanocomposite with different TiO2 ratios were mixed with TES 40 WN solution and deposited on glass slides substrate by spray coating to study its hydrophilic property by contact angle method. The contact angle of SiO2-TiO2 nanocomposite film was reduced with the increase of Ti ratio in SiO2 matrix resulting to the development of hydrophilic surface on substrate. The influence of TiO2 in SiO2 matrix on self-cleaning and property would be improved by hydroxyl groups on the composite surface corresponding to Ti–O–Si linkages. For self-cleaning property, Si:Ti ratio at 1:1 in SiO2-TiO2 nanocomposite showed the optimized condition with decreasing contact angle at 28.97 degree in 60 min after UVA irradiation.

Enhancement photoactivity of CuO-doped YVO4 nanocomposites toward degradation of Atrazine herbicide under visible illumination

Herbicide photocatalytic oxidation across nanostructured semiconductor-based photocatalysts demonstrated an appropriate strategy for controlling the resulting environmental problems. Developing a recyclable and efficacious photocatalyst is a challenge to overcome the semiconductor defects like instability and quick recombination. A series of CuO-YVO4 nanocomposites with different concentrations of CuO were synthesized by the surfactant sol–gel method. The different characterization techniques approved the structures and morphology of the as-prepared nanocomposites. The Atrazine degradation in water under illumination with visible light was used to assess the photocatalytic performance of the as-synthesized CuO-YVO4 nanocomposites. It demonstrates that combining CuO nanoparticles (NPs) can significantly enhance the photocatalytic activity of YVO4. The full photooxidation of Atrazine was achieved over 1.6 g/L of 15 wt% CuO-YVO4 with an outstanding rate constant of 0.0518 min−1 about 51.8 times greater than that in pristine YVO4 (0.001 min−1) and keeping recyclability of 96.5%. The maximal photodegradation efficiency of 15 wt% CuO-YVO4 is likely relevant to suppressing charge recombination with enhanced light harvesting. The Atrazine photocatalytic degradation mechanism was suggested. The results of this research will pave the way for the widespread application of oxide-vanadate semiconductor photocatalysts for the photocatalytic oxidation of herbicide contaminates in water under visible illumination.

ZnONPs/covalent triazine frameworks nanocomposite as high-performance photocatalysts for degradation of Congo red under visible light

Herein, we report the construction of novel zinc oxide nanoparticles/covalent triazine frameworks (ZnONPs/CTFs) as a new and active photocatalyst for Congo red degradation under visible light. The deposition of ZnONPs into the CTFs extends the absorption spectrum into the visible range, allowing for photocatalytic degradation of Congo red even with low-energy light under mild conditions. Various amounts of ZnONPs were loaded on as-prepared CTFs, and the photocatalytic effect of ZnONPs/CTFs was studied on Congo red degradation. The deposition of appropriate contents of ZnONPs (0.3 g) on CTFs had the lowest band gap (1.8 eV) and highest photocatalytic activity compared to other ZnONPs/CTFs. The morphology and structure of nanocomposite were characterized by XRD, FTIR, UV–Vis DRS, FESEM, EDS/Map, TEM, TGA, XPS, PL, and BET techniques. Box-Behnken design (BBD) was used to optimize the operating parameters based on response surface methodology (RSM) with design expert software. The highest degradation efficiency (99.97%) of Congo red was achieved according to the optimum conditions as follows: pH 4.03, catalyst mass 0.08 (g), reaction time 149.15 (min), and loading of ZnONPs (0.3g) on CTFs. In addition, ZnONPs/CTFs can be reused six times (6 continuous runs) without an apparent reduction in the photocatalytic operation.

Synthesis of calcium carbonate-loaded mesoporous SBA-15 nanocomposites for removal of phosphate from solution.

Removal of phosphate from water is very crucial for protecting the ecological environment since massive phosphorus fertilizers have been widely used and caused serious water deterioration. Thus, we fabricated a series of calcium carbonate-loaded mesoporous SBA-15 nanocomposites with different Ca:Si molar ratio (CaAS-x) as phosphorus adsorbents via a simple wet-impregnation method. The multiply approaches including X-ray diffraction (XRD), N2 physisorption, thermogravimetric mass spectrometry (TG-MS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) were used to characterize the structure, morphology, and composition of mesoporous CaAS-x nanocomposites. The phosphate adsorption efficiency of the CaAS-x nanocomposites was studied through adsorption and desorption batch tests. Results showed that the increases of Ca:Si molar ratio (rCa:Si) improved the phosphate removal capacity of CaAS nanocomposites, especially CaAS with the optimum synthesis molar ratio of Ca:Si as 0.55 showed the high adsorption capacity of 92.0 mg·g-1 to high concentration of phosphate (> 200 mg·L-1). Note that the CaAS-0.55 had a fast exponentially increased adsorption capacity with increasing the phosphate concentration and correspondingly showed a much faster phosphate removal rate than pristine CaCO3. Apparently, mesoporous structure of SBA-15 contributed to high disperse of CaCO3 nanoparticles leading to the monolayer chemical adsorption complexation formation of phosphate calcium (i.e., =SPO4Ca, =CaHPO4-, and =CaPO4Ca0). Therefore, mesoporous CaAS-0.55 nanocomposite is an environmental-friendly adsorbent for effective removal of high concentration of phosphate in neutral contaminated wastewater.

A comparative analysis of dry sliding wear characterization of textile wastes (cotton/jute fabrics) reinforced nano fly ash filled epoxy based hybrid composites

PurposeThe purpose of current study deals with the development and wear testing of jute and cotton fiber reinforced with nano fly ash-based epoxy composites. Performance of waste cotton fabric nano hybrid composites are compared with waste jute fabric nano hybrid composites.Design/methodology/approachBasic hand layup technique was used to develop composites. To optimize the parameters and design of experiments, Taguchi design was implemented to test wear rate and co-efficient of friction as per ASTM standards. Performance of waste cotton fabric nano hybrid composites is compared with waste jute fabric nano hybrid composites.FindingsResult shows that nano fly ash lowers the wear rate and co-efficient of friction in developed composites. Findings reveals that hybrid composites of waste jute Fabric with 3 Wt.% of nano fly ash performed best amongst all composites developed. Morphology of nano composites worn out surfaces are also analyzed through SEM.Practical implicationsPractically, textile waste, i.e. jute, cotton and nano fly ash (thermal power plant) all wastes, is used to develop composites for multi-function application.Social implicationsWastes are reused and recycled to develop epoxy-based composites for sustainable structures in aviation.Originality/valueTo the best of the authors’ knowledge, nano fly ash and jute, cotton combination is used for the first time to develop and test for wear application.

Effect of Thermal Treatment on Morphology and Acetone Gas Sensing Properties of Fe3O4-C Nanocomposites Prepared via Green Synthesis

Fe3O4-C nanostructured composites were used for the fabrication of thin films as active layers in resistive chemical sensors. Nearly spherical and porous structures were obtained via green method using olive leaf extract (OLE) followed by thermal process at 300 °C and 550 °C, respectively, for high-performance gas sensing applications. The prepared sensors were measured with various concentrations of toxic gases such as acetone (C3H6O), ethanol (C2H5OH), and carbon dioxide (CO2) at different operating temperatures. The gas sensing results illustrated that the porous structure of Fe3O4-C nanocomposite exhibited high response of 15.71, 225.35 and 3141.66 toward 20, 100 and 1000 ppm of acetone gas at 300 °C. The sensor based on porous structure of Fe3O4-C nanocomposite also indicated fast response and recovery time as well as higher response to acetone compared to ethanol and CO2 gases. The better gas-sensing properties of the porous nanostructures can be attributed to the higher surface area of porous compared with the nearly spherical structure which is confirmed using BET analysis. The gas sensing performance of porous Fe3O4-C nanocomposite reveals that it can be a good sensing material for the fabrication of acetone gas sensors.

개질된 Nanographene Oxide기반의 실리콘 고무 복합체의 기계적 물성 및 Swelling 거동 연구

Nanocomposites were created by using nanographene oxide (GO) as a reinforcing filler into silicone rubber and evaluating the materials’ mechanical and abrasion resistance properties. GO was treated with 4,4’-diphenylmethane diisocyanate (MDI), then mixed with phenyl silicone rubber (PSR) at different concentrations (2-10 phr) and vulcanised. It was investigated the impact of MDI modified GO concentration on the morphology of PSR nanocomposites. The swelling properties of silicone rubber/MDI modified GO nanocomposites were also investigated in relation to penetrants (aromatic, aliphatic, and chlorinated solvents) and nanofiller concentrations (0-10 phr). Due to greater dispersion and reinforcing impact, mechanical parameters (tensile strength and modulus), and swelling resistance of silicone nanocomposites improve with MDI-GO concentration. The rate of rise is constant up to a concentration of 6 phr MDI-GO, after which it drops, confirming the formation of agglomeration. The MDI modification of GO improves the dispersion of MDI-GO in silicone rubber considerably, according to FESEM analysis. Because of its strong contact with the polymer matrix, GO serves as reinforcement. This research expands the range of applications for GO in the silicone rubber sector.

Facile synthesis and physicochemical characterization of κ-Carrageenan-silver-bentonite based nanocatalytic platform for efficient degradation of anionic azo dyes

Water pollution due to textile industry effluents is a global concern that warrants versatile research solutions for degrading them, and for a sustainable environment. In the present work, by using the imperative role of nanotechnology, a facile one-pot synthesis has been devised to generate κ-carrageenan capped silver nanocatalyst (CSNC), and was immobilized on 2D bentonite (BT) sheets to generate nanocatalytic platform (BTCSNC) for the degradation of anionic azo dyes. The nanocomposite(s) were physicochemically characterized using UV–Vis, DLS, TEM, FESEM, PXRD, ATR-FTIR, TGA, BET and XPS etc., to obtain insights into the nanocomposite composition, structure, stability, morphology and mechanism of interaction. The obtained CNSC are monodispersed, spherical with a size of 4 ± 2 nm, and were stabilized by the functional groups (-OH, COO‾, and SO3‾) of κ-Crg. The broadening of peak corresponding to basal plane (001) of BT montmorillonite in PXRD spectra established its exfoliation upon addition of CSNC. XPS and ATR-FTIR data evidenced the absence of covalent interactions between CSNC and BT. The catalytic efficiency of CSNC and BTCSNC composites were compared for the degradation of methyl orange (MO) and congo red (CR). The reaction followed a pseudo first order kinetics, and immobilization of CSNC on BT resulted in a 3–4 fold enhancement in degradation rates. The rates achieved for the degradation kinetics are: MO degradation within 14 s (Ka 9.86 ± 2.00 min−1), and CR degradation within 120 s (Ka of 1.24 ± 0.13 min−1). Further, a degradation mechanism has been proposed by analyzing the products identified through LC-MS. The reusability studies of the BTCSNC evidenced the complete activity of the nanocatalytic platform for six cycles, and gravitational separation method for catalyst recycling. In a nutshell, the current study provided an environmentally friendly, sizable, and sustainable nano catalytic platform” for the remediation of industrial wastewater contaminated with hazardous azo dyes”.

Efficiency evaluation of titanium oxide nanocomposite membrane in adsorption of chromium from oil effluents.

Reverse osmosis and nanofiltration (NF) are the essential physical separation technologies used to remove contaminants from liquid streams. A hybrid of nanofiltration and forward osmosis (FO) was used to increase the removal efficiency of heavy metals in synthesized oil effluents. Thin-film nanocomposite (TFN) membranes were synthesized by applying surface polymerization on a polysulfone substrate to use in the forward osmosis process. The impact of different membrane fabrication conditions such as time, temperature, and pressure on effluent flux, the effect of different concentrations of the heavy metal solution on adsorption rate and sedimentation rate, the impact of TiO2 nanoparticles on the performance and structure of forward osmosis membranes were investigated. The morphology, composition, and properties of TiO2 nanocomposites made by the infrared spectrometer and X-ray diffraction (XRD) were studied. Kinetic modeling and Langmuir, Freundlich, and Tamkin relationships were used to draw adsorption isotherms and evaluate adsorption equilibrium data. The results indicated that pressure and temperature directly affect water outlet flux, and time affects it indirectly. Evaluating the isothermal relationships revealed that chromium adsorption from the TFN 0.05ppm membrane and thin-film composite (TFC) membrane follows the Langmuir model with correlation coefficients of 0.996 and 0.995, respectively. The significant removal of heavy metals and the acceptable amount of water flux demonstrated the appropriate potential of the titanium oxide nanocomposite membrane, which can be used as an effective adsorbent to remove chromium from aqueous solutions.

Effects of graphene oxide concentration and frequency on morphology, mechanical and rheological studies of fluoroelastomer nanocomposites

Fluoroelastomer nanocomposites have been prepared using different concentrations (1-5 wt%) of graphene oxide (GO) nanoparticles through mechanical mixing and compression molding. The surface morphology of prepared fluoroelastomer/GO nanocomposites has been studied by scanning electron microscopy (SEM). The mechanical properties of fluoroelastomer nanocomposites show increase in hardness, tensile strength, modulus, toughness and decrease in elongation at break with the increasing of GO’s concentration. This can be attributed towards excellent distribution of GO nanoparticles in the fluoroelastomer matrix. The effect of GO nanoparticle concentration on rheological properties of fluoroelastomer nanocomposites like: loss factor, storage modulus, loss modulus and complex viscosity have been studied as a function of temperature (5-100°C) and at different frequency 1, 10, and 100 Hz. The non-linear relationship between storage and loss moduli have been observed through Cole-Cole plots of fluoroelastomer/GO nanocomposites. The linear relationship of loss factor and storage modulus plots was explained on the basis of fluoroelastomer/GO interactions. The visco-elastic properties show increase in loss modulus, storage modulus, complex viscosity and decrease in loss factor with GO concentration, which can be attributed towards better fluoroelastomer-nanoparticle interactions.

Reactive Oxygen Species (ROS) Are Generated as Organic Contaminants Are Broken Down: SnO2-Doped Graphene Oxide Nanocomposites Are Investigated Under Visible Light Illumination for their Photocatalytic Activity

Our aim is to establish a more efficient and reliable method for the bio-fabrication of pure SnO2 and SnO2-doped graphene oxide nanocomposites through a green chelating agent called Moringa Oleifera extract by sol-gel method. A sintered SnO2-doped GO nanocomposite exhibited increased crystallinity and size with increasing temperature, as determined by XRD studies. An FTIR investigation shows that the SnO2-doped GO nanocomposite exhibits two distinct bands at 733 cm−1 and 438 cm−1 due to terminal oxygen vibrations, while samples treated with G-O-Sn-O exhibit bands at 733 cm−1 due to antisymmetric stretching. By increasing the SnO2 peak, SnO2 nanoparticle sizes decrease, which results in a broadened GO, as well as a reduced IR intensity. By SEM and EDAX, the size and morphology of SnO2-doped GO nanocomposites were clearly observed. It was calculated that the optical bandgap of SnO2-doped GO nanostructures is 4.48 eV. It has been demonstrated that SnO2-doped GO nanocomposite can be used as an organic photocatalyst against organic pollutants methyl orange (MO) dye; despite its fast charge recombination when illuminated with visible light, these findings have been reported in detail.

Multifunctional dual Z-scheme heterostructured Sm2O3-WO3-La2O3 nanocomposite: Enhanced electrochemical, photocatalytic, and antibacterial properties

In this study, heterostructured dual Z-scheme Sm2O3-WO3-La2O3 nanocomposite (NC) and bare Sm2O3, WO3, and La2O3 nanostructured (NSs) were prepared using a co-precipitation approach. The comparative electrochemical, photocatalytic, and antimicrobial properties of NC and NSs were studied. The XRD spectrum exhibits the formation of bare NSs and NC having cubic-Sm2O3, monoclinic-WO3, and hexagonal-La2O3 phases. FESEM results showed mesoporous morphology of NC. The higher electrical conductivity 261.33 mho-cm−1 and lower optical energy bandgap 2.55 eV were obtained for NC. The photodegradation tests exhibited that NC photocatalyst has degraded 99% (methylene blue), 96% (Methyl orange), 99% (safranin-O), 48% (p-nitroaniline), and 98% (methyl red) dyes pollutants in 40 min sunlight radiation and showed strong inhibition activity against E. coli, K. pneumoniae, S. aureus, P. Vulgaris, and P. aeruginosa bacterial strains with zones of inhibition (ZOI) 31 mm, 30 mm, 30 mm, 28 mm, and 31 mm, respectively. Electrochemical studies revealed the excellent capacitive characteristics of NC with a specific capacitance 532F/g at a scan rate 5 mV/s, energy density 48.0278 W h Kg−1, and power density 0.3782 KW Kg−1 at 0.006 A/cm2 current density. Furthermore, the present study revealed a novel composition for environmental remediation and energy storage applications.

Morphology, structure and optical properties of PVA nanocomposites reinforced with bismuth oxide nanoparticles and carbon quantum dots

Morphology, structure and optical properties of PVA nanocomposites reinforced with bismuth oxide nanoparticles and carbon quantum dots

Compatibilization of Immiscible PA6/PLA Nanocomposites Using Graphene Oxide and PTW Compatibilizer for High Thermal and Mechanical Applications

The aim of this work is synthesis a novel nanocomposite containing Polylactide (PLA) and polyamide 6 (PA6) reinforced with graphene oxide (GO) and poly ethylene-butyl acrylate-glycidyl methacrylate) (PTW) compatibilizer during solvent-based method. For this purpose, GO was added to the nanocomposite with 0.1, 0.3, 0.5, 0.7 and 1 phr. Morphology, rheology and mechanical properties of nanocomposites were studied with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and (DMTA) which showed rougher fracture surface due to the presence of compatibilizer and an increase in the amount of graphene oxide and better dispersion of graphene oxide. The results of experimental and theoretical studies of mechanical properties showed that increasing the concentration of graphene oxide in the presence of PTW improved the tensile strength, impact strength and tensile modulus in the PA6/PTW/PLA system. The study of rheological properties showed an increase in storage modulus and complex viscosity, which also confirmed the role of PTW compatibilizer in better GO dispersion. So, PA6/PTW/PLA is a good candidate for mechanical and high thermal applications.

Engineering of a Hybrid g-C3N4/ZnO-W/Cox Heterojunction Photocatalyst for the Removal of Methylene Blue Dye

Robust hybrid g-C3N4/ZnO-W/Cox heterojunction composites were synthesized using graphitic carbon nitride (g-C3N4) and ZnO-W nanoparticles (NPs) and different concentrations of Co dopant. The hybrid heterojunction composites were prepared by simple and low-cost coprecipitation methods. The fabricated catalyst was explored and investigated using various characterization techniques such as FTIR, XRD, FESEM and EDX. The surface morphology of the as-prepared hybrid nanocomposites with particle sizes in the range of 15–16 nm was validated by SEM analysis. The elemental composition of the synthesized composites was confirmed by EDS analysis. Photocatalysis using a photon as the sole energy source is considered a challenging approach for organic transformations under ambient conditions. The photocatalytic activity of the heterojunctions was tested by photodegrading methylene blue (MB) dye in the presence of sunlight. The reduced band gap of the heterojunction composite of 3.22–2.28 eV revealed that the incorporation of metal ions played an imperative role in modulating the light absorption range for photocatalytic applications. The as-synthesized g-C3N4/ZnO-W/Co0.010 composite suppressed the charge recombination ability during the photocatalytic degradation of methylene blue (MB) dye. The ternary heterojunction C3N4/ZnO-W/Co0.010 composite showed an impressive photocatalytic performance with 90% degradation of MB under visible light within 90 min of irradiation, compared to the outcomes achieved with the other compositions. Lastly, the synthesized composites showed good recyclability and mechanical stability over five cycles, confirming them as promising photocatalyst options in the future.

Preparation of thermally stable organic-inorganic hybrid nanocomposites from chemically functionalized oxidized graphite by in situ catalytic oxidative decarboxylation

ABSTRACT In this study, the preparation of thermally stable organic-inorganic hybrid nanocomposites from chemically functionalized oxidized graphite is carried out by in-situ catalytic oxidative decarboxylation of 3,5-dinitrobenzoic acid (reactant) in the presence of potassium persulfate (oxidant), silver nitrate (catalyst) and graphite (support) under thermal or microwave conditions. The effects of heat transfer and dosages of reactant, catalyst and oxidant on the crystalline structure and the morphology of nanocomposites are studied in detail. The prepared nanocomposites are characterized by EDS, elemental mapping, FE-SEM, FT-IR and XRD. The thermal stability of nanocomposites is examined by TGA and DSC. EDS shows that nanocomposites are composed of C, O, N, S, K and Ag elements. FT-IR exhibits that the graphitic layers in nanocomposites are mainly oxidized and functionalized with carboxyl, carbonyl, hydroxyl, epoxy, sulfate, nitrate and nitroaryl groups. Addition of nitroaryl groups to nanocomposites is also supported by an increase found in their C and N contents. XRD demonstrates the coexistence of both oxidized amorphous carbon and graphite in combination with different levels of organic and inorganic phases. The prepared nanocomposites show good thermal stability. The total area of the DSC curve in these nanocomposites compared to graphite is enhanced.

Molecular simulation of crystal nucleation and growth of structurally restricted polymer nanocomposites

This study reveals important features of crystal nucleation and growth in coarse-grained structurally restricted polymer systems (i.e., one end of the chain is grafted on the surface of one-dimensional filler) based on the Monte Carlo simulation on cubic lattice. The structurally restricted polymer system includes two kinds of polymers: terminally grafted and free chains. The existence of more grafted chains increases the crystal nuclei number in the structurally restricted polymer systems, which shortens the nucleation induction time and accelerates crystallization. Intramolecular nucleation occurs when the chain structure is limited. Then, with the increase of restricted chains, the nucleation mechanism changes to intermolecular nucleation. When the interface interaction is introduced into the system, the change of crystallization rate is the result of the competition between conformation entropy and chain mobility. The chain elongation increases with the enhancement of interface interaction, which leads to the increase of the loss of conformational entropy and is conducive to the formation of crystal nucleus. However, the chain mobility slows down with the enhancement of interface interaction, which will hinder the formation of crystal nucleus. By tailoring the interface interaction, the crystal morphologies of polymer nanocomposites can be adjusted to form the unique nanohybrid shish-kebab structures, that is, the filler is used as shish, the crystal regions generated by free chains are attached to the outside of crystal regions generated by restricted chains to form kebabs. Furthermore, the length of grafted chains has different effect on the crystallization depending on the concentration of grafted chains.