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To fabricate high-performance polymer/clay nanocomposites, many efforts have been made on how to promote the complete exfoliation of clay in polymer matrix. Nevertheless, it is still unclear that how the topological structure of polymer chain influences the exfoliation of clay during annealing process. In this study, three types of polystyrene (PS) with linear, symmetric star and asymmetric star structure were synthesized; subsequently they were used to prepare PS/clay nanocomposites with two kinds of organic modified clays (OMC, with or without benzene group in its modifier molecules). Our results indicated that star PS (symmetric and asymmetric) could efficiently promote the exfoliation of OMC with benzene groups in its modifier. Moreover, the possible exfoliation mechanism for clay was discussed, which was attributed to the synergistic effect of PS topological structure and its attractive interaction with clay. Thus, our work provided useful guidelines to fabricate high-performnce polymer/clay nanocomposites and extend their applications.

This work demonstrates a catalytic activity of MXene materials in the isomerization of α-pinene. The temperature influence, catalyst content and reaction time on α-pinene conversion have been revealed. Furthermore, the selectivity of transformation to appropriate products have been investigated. The multilayered and exfoliated Ti3C2Tx have been examined. Both studied MXene materials were active in α-pinene isomerization. However, the exfoliated Ti3C2Tx increased the activity significantly. As a result, an outstanding 100 mol% conversion of α-pinene in 7 h was achieved. It was observed that at optimal operating conditions and catalyst content the selectivity resulted in ∼ 60 mol% toward camphene formation. Additionally, the kinetics of the process has been described. Here, the analysis indicates that the kinetics of α-pinene isomerization over MXene samples was described by first-order kinetics. To the best of our knowledge, it is the highest reported selectivity and conversion reported in the current state of the art.

To induce the water solubility of hexagonal boron nitride (h-BN), we exfoliated and functionalized bulk h-BN with hydroxyl groups (h-BN-OH-n). Short-term studies showed that h-BN-OH-n induced low cytotoxicity in different models: insect haemocytes (in vivo), human erythrocytes and mouse fibroblasts (in vitro). We also demonstrated that Alexa Fluor 647-h-BN-OH-n administered topically to the insects passed through the cuticle barrier and was phagocytosed by haemocytes. Nanoflakes did not affect the haemocyte cell membrane and did not interfere with the phagocytosis of latex beads. Long-term immunoassays showed that h-BN-OH-n, despite not inducing haemocytotoxicity, impaired nodulation, the most important cellular immune response in insects. The haemocytes exposed to h-BN-OH-n and then to bacteria differed in morphology and adhesiveness from the haemocytes exposed only to bacteria and exhibited the same morphology and adhesiveness as the control haemocytes. The h-BN-OH-n-induced decrease in nodulation can therefore result from the reduced ability of haemocytes to recognize bacteria, migrate to them or form microaggregates around them, which can lead to dysfunction of the immune system during pathogen infection. Long-term in vivo studies with animal models are still necessary to unambiguously confirm that h-BN is biocompatible and useful for application as a platform for drug delivery or for bioimaging.

In our study we prepared MOF-5 derived carbon to reveal the thermodynamics of CO

Oxygen evolution reaction (OER) via electrocatalytic water splitting is crucial for efficient electrochemical energy storage and conversion. Herein, we describe the preparation of the rod-like structure of tungsten disulphide (WS2) as efficient catalysts for OER. Exfoliated tungsten disulphide was used as a source of the rods. The reshaping process required high-temperature treatment with the assistance of hydrogen and ethylene. We propose a structure with novel morphology and promising performance as an electrocatalyst. The rod-like structure was manifested by high-resolution transmission electron microscopy measurements including HAADF intensity line profile. Further structural insights were obtained in X-ray diffraction and Raman spectroscopy. The structures exhibited apparent electrocatalytic activity toward OER overpotential =351 mV at 10 mA/cm2 which is superior in respect to exfoliated tungsten disulphide (overpotential =564 mV at 10 mA/cm2).

With the ever-increasing consumption of polyethylene terephthalate (PET) related products, how to recycle the waste PET still remains as a great challenge for the sustainable development. Converting waste PET into porous carbon material has been emerged as a promising way to address this issue. Recently, the microporous carbon derived from waste PET has drawn considerable attention in adsorption field, but its electrochemical application is still impeded by low specific surface area (SSA

Nitrogen-doped porous carbon materials with controllable pore sizes are selectively prepared via carbonization of banana sheets combined with KOH activation. The resulting carbon materials, featured with a well-designed pore size distribution, high specific surface area, exhibits excellent capacitive performance in aqueous electrolyte (264 F/g at 1 A/g). More importantly, the symmetric supercapacitor exhibited a maximum specific capacitance of 155 F/g and a corresponding energy density of 48.44 Wh/kg at a current density of 1 A/g in organic electrolyte. Further investigation revealed that the enhanced supercapacitance is attributed to the pore size (especially in the range of 0.9–1.2 nm) and N-doped. The prepared carbon also displays an excellent CO2 adsorption ability due to the suitable pore size distribution as high as 5.29 mmol/g and 4.16 mmol/g at 0 °C and 25 °C under 1 bar, respectively. The present investigation will provide a new avenue for the wide application of biomass-derived porous carbon in various fields.

In this work, few-layered molybdenum disulfide (MoS2) was functionalized with metal oxide (MxOy) nanoparticles which served as a catalyst for carbon nanotubes (CNT) growth in the chemical vapour deposition (CVD) process. The resulting MoS2/MxOy/CNT functionalized nanomaterials were used for flame retarding application in poly(lactic acid) (PLA). The composites were extruded with a twin-screw extruder with different wt% loading of the nanomaterial. Full morphology characterization was performed, as well as detailed analysis of fire performance of the obtained composites in relation to pristine PLA and PLA containing an addition of the composites. The samples containing the addition of MoS2/MxOy/CNT displayed up to over 90% decrease in carbon oxide (CO) emission during pyrolysis in respect to pristine PLA. Microscale combustion calorimetry testing revealed reduction of key parameters in comparison to pristine PLA. Laser flash analysis revealed an increase in thermal conductivity of composite samples reaching up to 65% over pristine PLA. These results prove that few-layered 2D nanomaterials such as MoS2 functionalized with CNT can be effectively used as flame retardance of PLA.

The versatility of nanomaterials allows their use in multiple applications. Their properties can be used in cementitious composites in order to mitigate the problem of microbiologically induced deterioration. Nevertheless, incorporating nanomaterials to such composites is associated with the agglomeration of nanoparticles and their release to the natural environment. There are multiple methods to assess the toxicity of nanomaterials, where microorganisms are used as model for studies. Even though microbial models are advisable, their use should be adjusted to the conditions in which the nanomaterial will be present. This includes a careful selection of test microorganisms that requires the description of their properties and environmental meaning. Current studies are focused on the toxicity, although metabolic characteristics, such as the possible stimulation of metabolism caused by the contact with a nanomaterial, are often omitted. This chapter describes issues associated with studying nanosized cement admixtures on microbiological models with indication on microorganisms that could be used for that purpose along with some of their characteristics.

Polymeric carbon nitride (PCN) has been found as a promising photocatalyst for hydrogen evolution from water splitting. However, disadvantages limit its commercial applications. Therefore, modification of PCN in order to increase the hydrogen evolution rate and stability of the photocatalyst are extensively studied. In this contribution, we compare the influence of oxidation and the number of walls in carbon nanotubes (SWCNT and MWCNT) on the photocatalytic performance of PCN. It was found that oxidation of both types of CNT enhanced a photocurrent response, interfacial charge transfer and separation properties leading to the enhanced hydrogen evolution rate. Interestingly, MWCNT were found to enhance the charge transfer and separation properties more significantly. However, this material affected inferior co-catalytic behavior. We suggest it was related to the lower number of reactive electrons migrating to the surface reaction sites because of transferring to the inner tubes. SWCNT influence ~12-fold increase in H2 evolution rate, while MWCNT influenced ~8-fold enhancement in comparison to pristine PCN.

Carbon nanotubes (CNTs) have been of great interest because of their unique electrical, structural, and mechanical properties. Many methods for obtaining CNTs are known. Chemical vapor deposition (CVD) has been recognized as the most popular and practical synthetic method for obtaining CNTs, with high purity, high yield, and low cost. Catalyst components are usually transient metals such as Fe, Co, and Ni, and hydrocarbons are used as a feedstock for the CNT synthesis. The metal particles are supported on the inorganic porous materials, such as alumina (Al2O3), silica (SiO2), magnesia (MgO), zeolite, and mesoporous silica. In this work, we propose a new platform for the deposition of metal nanoparticles and the growth of CTs. Molybdenum disulfide (MoS2) has gained much attention in the material fields. The principal aim of the present work is to compare the synergetic effect of MoS2 and CTs and to investigate the possibility of using the material in various fields. The obtained material was tested for its use in fire retardation. We compared the effect of adding bulk MoS2 and MoS2/CTs into the polymer matrix.

Nitrogen-doped hierarchical porous carbon (CNx-Co) samples embedded with cobalt nanoparticles are selectively prepared with polyethylenimine (PEI) as both the carbon and nitrogen sources. By processing at different temperature, CNx-Co-800 and CNx-Co-1000 are selectively prepared and the materials exhibit excellent electrocatalytic activity in the oxygen reduction reaction (ORR). The ORR measurements show that sample processed at the higher temperature delivers better performance due to the larger Co and graphitic nitrogen concentrations. CNx-Co-1000 also shows more tolerance against methanol crossover and outstanding durability towards ORR, making it a promising Pt-free electrocatalyst for ORR under alkaline conditions. The method demonstrated here is a general strategy to prepare other metal or metal alloy/porous carbon hybrid materials.

Functional carbon materials have been fabricated through simple and effective catalytic carbonization with waste coffee grounds (CGs) as carbon precursor and FeCl3 as catalyst. The effect of FeCl3 loading and carbonization temperature on carbon yield was investigated. The morphology and structure of as-synthesized carbons was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and nitrogen isothermal adsorption/desorption measurement, respectively. Furthermore, the carbon materials showed high efficiency for the removal of methylene blue (MB, 653.6 mg g−1), methyl orange (MO, 465.8 mg g−1) and rhodamine B (RB, 366.1 mg g−1). More importantly, the carbon was magnetic, so it can be easily separated by a magnet and reused multiple times. This work not only exploited a low–cost and large-scale preparation method to synthesize functional carbon materials from bioresources, but also provided an eco-friendly and effective adsorbent in water purification applications.

Two synthesis methods (reflux and impregnation) have been compared for the preparation of Pd supported OMHCS. The hydrogen storage properties of OMHCS and OMHCS@Pd were studied. OMHCS@Pd samples exhibited enhanced hydrogen storage capacity in respect to the pristine OMHCS. The significant differences between the hydrogen storage capacities of OMHCS@Pd produced via reflux and impregnation routes were observed. It was found that among OMHCS@Pd samples, the one with higher surface area and broader Pd particle distribution showed the highest hydrogen sorption properties. The results indicated that reflux doping method is more appropriate for the preparation of OMHCS@Pd with high hydrogen capacity.

The effect of hybrid material—graphene flakes with Fe3O4 nanospheres (GO-Fe3O4), graphene oxide (GO) and magnetite nanospheres (Fe3O4) in rotating magnetic field on mammalian cells metabolism has been studied. Several reports shown that exposure to magnetic field may have influence on cellular membrane permeability. Thus, the aim of presented study was to determine the cellular response of L929 fibroblast cells to nanomaterials and rotating magnetic field for 8-h exposure experiment. The GO had tendency to adsorb proteins, thus cell metabolism was decreased and the effect of that mechanism was enhanced by impact of nanospheres and rotating magnetic field. The highest reduction of cellular metabolism was recorded for WST-1 and NR assays at concentration 100 µg/mL of all tested nanomaterials and magnetic induction value 10.06 mT. The lactate dehydrogenase leakage assay has shown significant changes in membrane permeability. Further studies need to be carried out to precisely determine the mechanism of that process.

Graphene – novel 2D material, which possesses variety of fascinating properties, can be considered as a convenient support material for the nanoparticles. In this work various methods of synthesis of reduced graphene oxide with metal or metal oxide nanoparticles will be presented. The hydrothermal approach for deposition of platinum, palladium and zirconium dioxide nanoparticles in ethylene glycol/water solution was applied. Here, platinum/reduced graphene oxide (Pt/RGO), palladium/reduced graphene oxide (Pd/RGO) and zirconium dioxide/reduced graphene oxide (ZrO2/RGO) nanocomposites were prepared. Additionally, manganese dioxide/reduced graphene oxide nanocomposite (MnO2/RGO) was synthesized in an oleic-water interface. The obtained nanocomposites were investigated by transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Raman spectroscopy and thermogravimetric analysis (TGA). The results shows that GO can be successfully used as a template for direct synthesis of metal or metal oxide nanoparticles on its surface with a homogenous distribution.

This paper reports on the fabrication and characterization of glucose oxidase (GOx) immobilized onto a glassy carbon electrode (GCE) modified with reduced graphene oxide/palladium nanocomposite (RGO–Pd). Characterization tools showed well dispersed uniform Pd nanoparticles on a partly reduced graphene oxide surface. Cyclic voltammetry demonstrated successful immobilization of GOx on RGO–Pd modified GCE (GCE–RGO–Pd) using covalent bonding of GOx with RGO–Pd (RGO–Pd–GOx). Therefore, it was used as an electrochemical biosensor of glucose. RGO–Pd–GOx exhibited good electrocatalysis toward glucose in different glucose concentrations (from 2 to 10 mM, which includes the blood glucose levels of both normal and diabetic persons) with O 2 saturated phosphate buffer solution (PBS) at pH 7.4. The system showed a linear increase in current at potential −0.085 V in the concentration range examined, with a correlation coefficient of 0.996. The sensitivity of the biosensor was 41.3 μA cm −2 mM −1 , suggesting that RGO–Pd–GOx-modified GCE could be a potential candidate as a glucose sensor.

We report a facile strategy to synthesize carbon nanotubes decorated by mesoporous cobalt oxide (CNT@Co3O4). The mesoporous nature of the nanocomposite is confirmed by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The data imply 41 wt% mesoporous Co3O4 spheres in the as-prepared material with mean diameters ∼12 nm. The nanospheres are embedded in an interconnected network of carbon nanotubes. The specific surface area of CNT@Co3O4 amounts to 463 m2/g. Cyclic voltammetry studies show a high activity of the Co2+/Co0 and Co3+/Co2+ redox couples. The conversion reaction is observed and full theoretical capacity is found in the 2nd cycle while significant capacity fading appears upon further cycling. Decorating mesoporous metal oxide nanospheres onto the interconnected electrically conducting network of carbon nanotubes therefore provides a first step towards an electrochemically active material promising for lithium-ion batteries.

The application of nanomaterials in construction is a new alternative to enhance the mechanical properties of the traditional materials, e.g., cement mortars and concretes. One of the most interesting nanomaterials which still requires detailed investigation is graphene and graphene oxide. The study presented in this paper aims at assessing how 3 wt% of graphene oxide incorporated into the cement can affect the microstructure and physical–mechanical properties of the cement composite. Therefore, here we present study on early age mechanical response of the cement mortar modified with graphene oxide using atomic force microscopy (AFM). The kinetics of the hydration process was investigated by Infrared, Raman, X-ray diffraction (XRD) techniques. The morphology of the nanocomposite was revealed by the scanning electron microscopy (SEM).

Reduced graphene oxide sheets (RGO) with different number of graphene layers were used as platforms for TiO2 nanoparticles deposited using hydrothermal process. The nanomaterials were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy (PL) and diffuse reflectance UV–vis spectroscopy (DR-UV-vis). The photocatalytic activity of the nanocomposites was investigated in a model reaction of phenol decomposition under visible light irradiation. Here, the influence of graphene thickness on its photoactivity was explored. It was found that the highest photocatalytic activity was observed for the catalyst composed of single layer graphene and decreased when a number of graphene layers was higher. This might be related to the surface and electronic properties of reduced graphene oxide arising from different number of graphene layers and its interaction with titanium dioxide: (i) higher interfacial area of TiO2-RGO with lower thickness of RGO, which could influence in enhanced transferring of photoinduced electron–hole pairs between TiO2 and RGO, hence improving their separation; (ii) variations in excitations lifetime relating to the diverse surface quality and density of trap sites of reduced graphene oxide; (iii) higher charge carriers mobility in 1-layer RGO compared to 2- and few-layers.

In this study, the efficiency of the adsorption of anionic dye Direct Red 23 (DR23), nonionic dye Direct Green 97 (DG97) and cationic dye Basic Yellow 28 (BY28) from aqueous solutions onto hollow mesoporous carbon nanospheres (HMCN) was investigated. The adsorbent was characterized by means of XRD, HRTEM, TGA, Raman spectroscopy, FTIR, BET and zeta potential measurements. The influence of dye initial concentration, temperature and pH on DR23, DG97 and BY28 adsorption onto HMCN was investigated. Equilibrium data were analyzed by model equations such as Langmuir and Freundlich isotherms and were best represented by Langmuir isotherm model showing maximum monolayer adsorption capacity 769.2 mg g−1, 312.5 mg g−1 and 909.1 mg g−1 for the DR23, DG97 and BY28, respectively. The experimental kinetic data were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models. The adsorption kinetics was best fitted to the pseudo-second-order kinetic model. Thermodynamic parameters, change in free energy ΔG°, enthalpy ΔH°, and entropy ΔS° were also evaluated, indicating that the adsorption of DR23, DG97 and BY28 was spontaneous and endothermic in nature.

In the last decade nanomaterials due to their unique physical and chemical properties, have attracted the interest of researchers to fabricate new building materials with novel functions. One of the most referred to and used cementitious nanosized materials is nanosilica (nSiO 2 ). Although the number of publications devoted to the influence of nanosilica on the properties of cementitious composites has increased over the course of the last decade, the field of polymer-cement composites (PCC) has remained under-studied. Therefore, this paper will deal with the potential application and the influence of nanosilica (nSiO 2 ) on the mechanical properties of PCC. In this study the influence of diameter (100 nm and 250 nm) and quantity (1%, 3%, 5% by weight of cement) of nSiO 2 on the consistency and mechanical properties of polymer-cement mortars (PCC) have been examined. Moreover, the hydration of cement compounds was followed by X-ray diffraction (XRD). Studies have shown that the addition of nanosilica has great potential to accelerate the pozzolanic reaction, thus reacting more with the CH and increasing conversion of C-S-H, and having the potential to improve mechanical properties of PCC. The obstacle overcome is the high water demand of nanosilica particles, leading to significant deterioration of consistency. Finer particles of nSiO 2 seem to be more effective and cause fewer problems with the consistency of fresh mortars.

The present paper reports a facile method to synthesize CNT-Fe2O3 and CNTs-Fe3O4@C beaded structures by deposition of Fe2O3 and carbon layers on CNTs, which integrate both electronic conductivity and buffering matrix design strategies. The CNT-Fe2O3 and CNTs-Fe3O4@C were tested as anode materials for lithium-ion batteries, CNT-Fe2O3 showed excellent cycling performance, the reversible capacity retention after 80 cycles is stable at 410 mA h g−1. However, CNTs-Fe3O4@C exhibited improved reversible capacity and better cycling performance when compared to CNT and CNTs-Fe2O3. The highly improved reversible capacities are attributed to the combination of (a) the network structured CNTs, which improve the matrix electrical conductivity, (b) the mesopores created by the carbon coating on Fe3O4 nanoparticles and CNTs, which increases lithium-ion mobility and storage, and (c) the Fe3O4 nanoparticles attached to the CNTs facilitate the transport of electrons and shorten the distance for Li+ diffusion. This study provides a cost-effective, highly efficient method to fabricate nanomaterials which combines carbon nanotubes with iron oxide nanoparticles for the development of lithium ion batteries with high-performance.

CFs and CNTs showed a synergistic effect on significantly improving the thermal stability and flame retardancy of PP.

Catalytic conversion of waste plastics into high value-added carbon nanomaterials (CNMs) has attracted increasing attention; however, the role of lattice oxygen in the carbonization of plastics still remains ambiguous. In this work, firstly, a nickel catalyst with different content of lattice oxygen was prepared by the sol–gel combustion synthesis method. Subsequently, the effect of lattice oxygen in the nickel catalyst on the catalytic carbonization of polypropylene (PP, an example of plastics) into CNMs was investigated. It was found that the yield of CNMs increased dramatically with the increasing content of lattice oxygen. Large and short platelet-like carbon fibers were obtained when the content of lattice oxygen was low. With the increasing content of lattice oxygen, small, winding and short carbon nanofibers were produced. When the content of lattice oxygen further increased, long, small and straight cup-stacked carbon nanotubes were formed. Besides, it was demonstrated that lattice oxygen not only prevented the coalescence of nickel catalyst nanoparticles into large particles and promoted their reconstruction into rhombic shape, but also facilitated the catalytic carbonization of PP degradation products. This work provides new insights into the carbonization mechanism of plastics and puts forward a novel chemical method to prepare CNMs with diverse morphologies by controlling the content of lattice oxygen in the catalyst.

Waste plastic utilization and wastewater treatment are the two most serious challenges on the path to urbanization and industrialization, due to the limited fossil fuel resources, ever-increasing energy demands, and severe environmental pollution. The conversion of waste plastics into high value-added carbon nanomaterials has become a promising way to utilize waste plastics; however, most current studies are limited to single component waste plastic; besides, little attention has been paid to porous carbon nanosheets (PCNSs). Herein, a facile approach was established to prepare PCNSs by the carbonization of real-world mixed waste plastics on organically-modified montmorillonite and subsequent KOH activation. The morphology, microstructure, textural property, phase structure, surface element composition, and thermal stability of the PCNSs were investigated. The PCNSs showed high specific surface area (2315 m2 g−1) and large pore volume (3.319 cm3 g−1) with high purity (>99.6%). More importantly, the PCNSs exhibited fast adsorption (about 95% of methylene blue (MB) was removed during the first 10 min of adsorption), an unprecedented adsorption capacity of 769.2 mg g−1 (higher than most of reported adsorbents), and excellent recyclability (after ten cycles, an adsorption capacity of 692.0 mg g−1 remained and 90 wt% of the PCNS was reclaimed) for MB from wastewater. This was attributed to the high specific surface area and large pore volume of the PCNS, and due to multiple adsorption mechanisms, including pore filling, hydrogen bonding, and π–π and electrostatic interactions between MB and the PCNS. It is believed that this work not only provides a novel potential way to utilize waste plastics, but also presents a facile sustainable approach to synthesize PCNSs, which will be an ideal candidate for various applications.

In this contribution the results on the development of a novel measurement system for electrochemical biosensing are presented. It covers the most important work on innovative graphene-based nanocomposites used in preparation of biosensing electrodes, design of different electrode types and a specialized flow chamber, specialized hardware and software for two versions (mobile and laboratory) of the electronic control and read-out system. The results of lab tests performed with the prototype system GruntMaster 6001 are shown in comparison to the measurements obtained by means of commercially available professional platforms used as a reference. The prototype is currently in the process of commercialization.

Multifunctional polymer nanocomposites are one of the hottest topics in the field of materials science. Herein nanosized carbon black (CB) was functionalized by H2O2 hydroxylation and chemical grafting of phosphorous flame retardant. The obtained nanofiller hybrids (CB-g-DOPO) presented a high grafting degree to 37.89 wt%, and remained large numbers of active hydroxyl groups (CH–OH), which could covalently react with adscititious compatibilizer to promote its dispersion and interaction with poly( l -lactide) (PLA) matrix. The resultant PLA nanocomposites showed remarkably improved flame retardancy, electrical conductivity and mechanical properties. The limited oxygen index (LOI) was 29.3%; the UL-94 rating reached to V0; and the peak of heat release rate (PHRR) was decreased by 50% in cone calorimeter testing. Outstanding electrical conductivity was present with more than 4 wt% CB-g-DOPO. Besides, the nanocomposites displayed a good balance on stiffness and toughness, especially 8.7 and 2.5 times improvement on elongation at break and impact strength, respectively. The enhancement mechanism was discussed on the basis of the unique structure and surface composition of CB-g-DOPO. This work will be favorable to the designation and application of multifunctional polymer nanocomposites with high performances.

It is a great challenge to fabricate polymer nanocomposites with synchronously improved comprehensive performances. Herein fullerene (C60) and nickel hydroxide (Ni(OH)2) were reactively modified by grafting of polypropylene (PP) chains, then they were added into PP matrix to construct a catalytic carbonization system. The resultant PP nanocomposites exhibited simultaneous improvements on thermal stability, flame retardancy and mechanical properties. The enhanced mechanism on thermal properties was mainly ascribed to the synergistically catalytic carbonization effect of C60/Ni(OH)2 on delaying the thermal decomposition of PP and forming better carbon layer during combustion. Besides, the trapping radicals of C60 and 3D network structure of nanofillers also were helpful to improve their flame retardancy. Moreover, the improvement on mechanical performances with balanced stiffness and toughness resulted from good dispersion of nanofillers and strong interfacial adhesion between nanofillers and polymer matrix. This work provided a facile and efficient strategy for designing and fabricating high-performance polymer nanocomposites.

Present study reports a facile sol-gel approach enabling to obtain nanomaterial based on ordered mesoporous carbon spheres functionalized by titanium dioxide. The content of TiO2 was controlled in a facile step of isopropanol washing. The hybrid containing 36 wt% of TiO2 exhibited superior photocatalytic performance in Rhodamine B decomposition under UV light irradiation. Moreover, the presence of carbon in the composite induced the enhancement of the absorption in visible region and thus the catalyst displayed also improved photocatalytic activity in this process under solar light illumination. The photocatalytic activity of the hybrid was ~4 times higher under UV light and 2.5-times higher under solar light irradiation in comparison to the reference samples. The observed phenomena can be explained by (1) high surface area, (2) suitably adjusted core/shell providing greater contact surface between hybrid ingredients and (3) phase composition which is favorable for the efficient photogenerated carrier separation. Here, it was proved that formation of stable mesoporous carbon/titanium dioxide spheres allows to create the efficient photocatalyst, which is active, both, under solar and ultraviolet light irradiation.

Conversion of waste plastics into high value-added carbon nanomaterials has gained wide research interest due to the requirement of sustainable development and the ever-increasing generation of waste plastics. However, most of studies are limited to single component plastic; besides, little attention has been paid to carbon nanosheets (CNS). Herein, CNS were prepared by catalytic carbonization of mixed plastics consisting of polypropylene, polyethylene, polystyrene, poly(ethylene terephthalate), and polyvinyl chloride on organically modified montmorillonite. After KOH activation, porous CNS (PCNS) were produced. The morphology, microstructure, phase structure, textural property, surface element composition, and thermal stability of PCNS were investigated. PCNS contained randomly oriented lattice fringes and showed a layered morphology consisting of thin, leaf-like, agglomerated nanosheets ranging from hundreds of nanometers to several micrometers in length. Besides, PCNS exhibited high specific surface ar...

In situ synthesis of Pd nanoparticles supported on multiwalled CNT (carbon nanotubes) is reported. The size of the nanoparticles can be easily tuned via application of different experimental conditions. The hydrogen storage properties of Pd supported on CNT at room temperature were examined in the pressure range of 0–50 bar. Carbon material with palladium particles of 3 nm diameter exhibits the highest hydrogen capacity at low moderate pressure than the raw materials and CNT with larger particles size of 17 and 9 nm, respectively. We also propose the mechanism of hydrogen storage in the studied samples.

TiO2-reduced graphene oxide nanocomposites with different diameters and crystallinity of titania nanoparticles were synthesized via the sol-gel method followed by calcination in air or treatment under vacuum. The materials were characterized with transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, photoluminescence spectroscopy and diffuse-reflectance UV–vis spectroscopy. The photocatalytic activity of the resulting materials was examined in the process of phenol decomposition under UV–vis light irradiation. The influences of TiO2 loading and calcination treatment on photocatalytic activity of the composites were investigated. It was found that higher TiO2 concentrations resulted in higher photocatalytic activity. This is in agreement with the band gap energy values, as lower visible light absorption and higher E g values were obtained for the samples prepared with higher TiO2 loading. Furthermore, photoactivity was affected by the calcination treatment. Higher activity under UV–vis was shown by the samples calcinated under vacuum, which was attributed to the better crystallinity compared to the samples treated with air.

Magnetic nanoreactors based on Pd nanoparticles supported on magnetic carbon nanotubes that are coated by a mesoporous silica layer, (Fe3O4-CNT-Pd)@m-SiO2, have been selectively synthesized by facile steps. The prepared system exhibits high catalytic efficiency in Suzuki-coupling reactions because of the Pd nanoparticles supported on carbon nanotubes (CNT-Pd). Most importantly, induced magnetic properties make the separation of the catalyst easy from the reaction media, which can be re-used several times with significant activity. Moreover, the existence of a mesoporous silica layer makes the Pd catalyst very stable and does not allow the Pd nanoparticles to get detached from the CNT supports. The above-mentioned observations make the obtained catalyst a great candidate for future applications.

Recent research is focused on the enhancement in photoactivity of titanium dioxide/carbon nanotubes through formation of novel nanocomposites that exhibit a high specific surface area, remarkable electron transfer and biocompatibility. Here, we explore a new synthesis route in the system composed of nanocrystalline titanium dioxide supported on external walls and inner space of multiwalled carbon nanotubes (MWCNT). The advantages of this method are: its simplicity, direct fusion of titanium dioxide particles on the carbon material, and formation of chemical bond Ti–O–C between TiO 2 and MWCNT. Photocatalytic performance of this system has been compared to a commercial catalyst (Degussa P25) in a model reaction of phenol decomposition in/under UV light. The efficiency of the process increased by the factor of 2.5 when the TiO 2 –MWCNT photocatalyst was utilized. Further, the photoactive nanocomposite was analysed towards its biocompatibility in order to establish a safe dose of the catalyst. Its influence on the cells viability was studied on mouse fibroblasts and human liver tissue cells, in the range from 0 to 100 μg/mL. This has revealed that the composite in concentrations up to 25 μg/mL exerted low toxicity, which allowed for finding a compromise between the highest safe dose and acceptable photoactivity of the catalyst.

A one-pot approach was demonstrated to effectively synthesize cup-stacked carbon nanotubes (CS-CNTs) through carbonization of polypropylene (PP) under the combined catalysis of halogenated compound and NiO at 700 °C. The effect of halogenated compound on the morphology, microstructure, phase structure and thermal stability of the resultant CS-CNTs was studied by scanning electron microscope, transmission electron microscope (TEM), high-resolution TEM, X-ray diffraction, Raman spectroscopy and thermal gravimetric analysis. Long, straight and surface-smooth CS-CNTs with graphene nanosheets oblique to CS-CNT axis at the angle of 21–25° were obtained when a low content of halogenated compound was added. The synergetic catalytic efficiency of combined catalysts in the carbonization of PP into CS-CNTs followed in the sequence: fluorinated compound/NiO ≪ chlorinated compound/NiO

The removal of Ni2+ from aqueous solution by magnetic multiwalled carbon nanotube nanocomposite (MMWCNTs-C) was investigated. MMWCNTs-C was characterized by X-ray Diffraction method (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), surface area (BET), and Fourier Transform-Infrared Spectroscopy (FTIR). The effects of initial concentration, contact time, solution pH, and temperature on the Ni2+ adsorption onto MMWCNTs-C were studied. The Langmuir and Freundlich isotherm models were applied to fit the adsorption data. The results showed that the adsorption isotherm data were fitted well to the Langmuir isotherm model with the maximum monolayer adsorption capacity of 2.11 mg g–1. The adsorption kinetics was best described by the pseudo-second-order model. The thermodynamic parameters, such as ΔHo, ΔGo and ΔSo, were also determined and evaluated. The adsorption of Ni2+ is generally spontaneous and thermodynamically favorable. The values of ΔHo and ΔGo indicate that the adsorption of Ni2+ onto MMWCNTs-C was a physisorption process.

The combination of fumed silica (SiO2) with carbon black (CB) for improving thermal stability, flame retardancy and mechanical properties of linear low density polyethylene (LLDPE) was investigated. The temperature at the maximum weight loss rate of LLDPE was dramatically increased by 92 degrees C, and the peak value of heat release rate measured by cone calorimeter was significantly reduced by 80.7%. The improved thermal stability and flame retardancy of LLDPE were partially attributed to the formation of a percolated network structure in LLDPE matrix, and partially to the accelerated oxidation crosslinking reaction of LLDPE or other radicals by CB and SiO2. More importantly, although both SiO2 and CB were used without any pre-treatment, ternary LLDPE nanocomposites showed much higher mechanical properties compared to those of neat LLDPE. This was ascribed to good dispersions of two kinds of nanoparticles and strorig matrix-nanoparticle interfacial interactions with LLDPE matrix. (C) 2014 Elsevier Ltd. All rights reserved.

A novel combined catalyst of fumed silica (SiO 2 ) with Ni 2 O 3 was demonstrated to be more efficient than SiO 2 or Ni 2 O 3 alone in enhancing the char yield of poly(lactic acid) (PLA) and improving its char layer structure, which greatly enhanced the flame retardancy of PLA. The results of field-emission scanning electron microscope, transmission electron microscope, X-ray diffraction, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the residual chars mainly consisted of block-like carbon and carbon nanotubes with some surface functional groups. The flame retardancy of PLA and its composites was studied by cone calorimeter test. The heat release rate and total heat release of PLA composites containing both SiO 2 and Ni 2 O 3 decreased significantly in comparison with those of neat PLA. The investigation of the synergetic mechanism showed that in the presence of both SiO 2 and Ni 2 O 3 , a large amount of chars were in situ formed from the catalytic carbonization of degradation products of PLA by Ni 2 O 3 during combustion. This not only reduced the release of flammable degradation products, but also acted as an insulating barrier to prohibit the oxygen and feedback of heat from reaching the underlying substrate. On the other hand, the formation of a percolated network structure of SiO 2 and Ni 2 O 3 particles in PLA matrix increased the melt viscosity of PLA and facilitated the formation of a more compacted protective layer, which promoted the flame retardancy of PLA.

Upcycling waste plastics into high value-added carbon nanomaterials has been a hot topic due to everincreasing generation of waste plastics, however, little attention has been paid to valuable hollow carbon spheres (HCSs). Herein, uniform mesoporous HCSs with controllable diameter and high surface area were efficiently prepared through the carbonization of mixed plastics consisting of polypropylene, polyethylene and polystyrene under the combined catalysis of organically-modified montmorillonite (OMMT)/Co3O4 at 700 degrees C. The morphology, microstructure, phase structure, textural property, surface element composition and thermal stability of HCSs were investigated by Scanning electron microscope, transmission electron microscope (TEM), high-resolution TEM, X-ray diffraction, Raman spectroscopy, N-2 sorption, X-ray photoelectron spectroscopy and thermal gravimetric analysis. The effects of OMMT on the dispersion of Co3O4 in the mixed plastics and the degradation of mixed plastics were studied. It was found that OMMT not only promoted the dispersion of Co3O4 in the mixed plastics, which favored to control the diameter of HCSs, but also promoted the degradation of mixed plastics into light hydrocarbons and aromatics, which facilitated the growth of HCSs. Finally, a possible mechanism was proposed to explain the growth of uniform HCSs with controllable diameter. This facile method provides a novel potential way to convert waste plastics into valuable HCSs, which can be used as catalyst support, adsorbent, storage medium and template for the synthesis of other useful hollow materials, etc. (C) 2014 Elsevier B.V. All rights reserved.

A one-pot approach was used to convert polyethylene (PE) with different chain structures into carbon nanomaterials (CNMs) under the combined catalysis of CuBr and NiO at 700 °C, including linear low density polyethylene (LLDPE), low density polyethylene (LDPE) and high density polyethylene (HDPE). The effect of chain structure of PE on the yield, morphology, microstructure, phase structure and thermal stability of CNMs, including cup-stacked carbon nanotubes (CS-CNTs) and carbon nanofibers (CNFs), were investigated by scanning electron microscope, transmission electron microscope (TEM), high-resolution TEM, X-ray diffraction, Raman spectroscopy and thermal gravimetric analysis. In addition, the degradation products from different chain structures of PE under the catalysis of CuBr were analyzed by gas chromatography and gas chromatography–mass spectrometry. It was demonstrated that the branched structure played an important effect in the degradation products of PE. The dehydrogenation and aromatization of LLDPE were remarkably promoted by Br radicals from the decomposition of CuBr to form a large amount of light hydrocarbons and a relatively small amount of aromatics, favoring the formation of long and straight CS-CNTs. However, the degradation of LDPE was not obviously influenced by Br radicals due to its high extent of branched structure, while the random cleavage of HDPE was accelerated with the formation of a lot of olefins with long chains, resulting in the formation of short and winding CNFs. This work will contribute to the conversion of mixed waste polyolefin into high value-added CNMs.

A series of nanoporous activated biocarbons have been successfully obtained from novel carbon precursor - lumpy bracket. The textural properties of the biocarbons were tailored towards microporosity suitable for high CO2 adsorption. Outstanding CO2 adsorption up to 1.67 mmol/g at the temperature of 298 K and at the pressure of 0.15 bar was achieved. The performance of biocarbons in the absorption/regeneration cycles towards CO2 adsorption remained stable. The selectivity of CO2 over N2 calculated on the basis of Ideal Adsorbed Solution Theory was excellent (33.9–130.2). To the best to our knowledge, the prepared activated carbon labelled as 850_1 is one of the most promising sorbents tested in CO2 post-combustion capturing and pre-combustion capturing. Furthermore, the electrochemical properties of this sample were also evaluated. The specific capacitance reached over 220 F/g with excellent retention (~92% of the original capacitance) after 5000 cycles. These results clearly indicate that activated carbons obtained from lumpy bracket can be used for the production of low cost and, more importantly, highly efficient electrode in supercapacitors as well. In this way, simple and efficient direct conversion of the lumpy bracket into highly valuable multifunctional system is proposed.

Spherical photocatalyst based on ordered mesoporous carbon and graphitic carbon nitride with core/shell structure (CS/GCN) was successfully synthesized via facile electrostatic self-assembly strategy. The photocatalytic properties of the hybrid were evaluated by the decomposition of Acid Red 18 under simulated solar light irradiation in comparison to the bulk graphitic carbon nitride (GCN). The results clearly revealed that coupling of carbon nitride with mesoporous carbon allows the catalyst to form with superior photocatalytic performance. The photoactivity of CS/GCN was over nine times higher than that of pristine GCN. Introducing mesoporous carbon into GCN induced higher surface area of the heterojunction and also facilitated the contact surface between the two phases. The synergistic effect between those two components enhanced the visible light-harvesting efficiency and improved photoinduced charge carrier generation, and consequently their proper separation. The electrochemical behavior of the obtained composite was also evaluated by electrochemical impedance, transient photocurrent response and linear sweep potentiometry measurements. The results confirmed that transport and separation of charge carriers in the hybrid was enhanced in comparison to the reference bulk graphitic carbon nitride. Detailed electrochemical, photoluminescence and radical scavenger tests enabled determination of the possible mechanism of photocatalytic process. This work presents new insights to design a core/shell hybrid through the simple preparation process, which can be successfully used as an efficient photocatalyst for the treatment of wastewater containing dyes under solar light irradiation.

It is a great challenge to improve the flame retardancy of polymer materials by adding eco-friendly magnesium hydroxide (Mg(OH)2) but simultaneously maintain satisfied mechanical performances. In this study, expanded graphite (EG) as a synergist was introduced into poly(butylene succinate) (PBS)/Mg(OH)2 system to investigate the effect of EG on their flame retardancy, thermal stability and mechanical properties. The results showed that only addition of 5 wt% EG into PBS/20 wt%Mg(OH)2 resulted in excellent flame retardancy, including that the LOI was 29.4%, the UL-94 rating reached to V0, and the PHRR decreased by 73%. These flame retarded parameters were comparable or even better than that of PBS/40 wt%Mg(OH)2 composites. More importantly, PBS/20 Mg(OH)2/5 EG presented much better thermal stability and mechanical properties than PBS/40 wt%Mg(OH)2, indicating a balanced improvement on comprehensive performances of PBS. Based on the comparison with PBS/20 Mg(OH)2/5Graphene(Gr) system and the structure analysis for residual chars, the mechanism for improved flame retardancy was attributed to the formation of gradient-structured char layer due to the helpful thermal expansion process of EG together with the decomposition of Mg(OH)2 during combustion, resulting in better barrier action to heat, oxygen and flammable gases via “labyrinth effect”. As far as we know, it is the first report that gradient-structured char layer was discussed in flame retarded polymer systems. Hence, this work provides not only a high-efficient synergist to improve the flame retardant efficiency of Mg(OH)2, but also useful guidelines to design polymer composites with balanced comprehensive performances.

Graphitic carbon nitride (gCN) exhibits outstanding photocatalytic performances toward H2 evolution. However, it can be further improved by overcoming its disadvantages such fast recombination of pohotogenerated electron-hole pairs. Here, we propose an efficient photocatalysts based on three components: (i) gCN modified with (ii) cadmium compounds (CdX: Cd(OH)2, CdS, CdO) and (iii) nanoporous carbon flakes (NPC) derived from Al-metal organic framework. The fabrication method was focused on finding the optimal hybrid composition dispalying the most powerful performance. Three main aspects were revealed: (i) band gap of gCN narrowing from 2.70 eV to 2.32 eV, (ii) reduction of overpotential for H2 evolution, as conduction band minimum (CBM) moved from −1.07 V vs. NHE to −0.63 V vs. NHE and (iii) enhanced charge separation, since CdX and NPC acted as electron acceptors. These factors had an effect on ˜60-fold enhancement of the photocatalytic efficiency. The mechanism of the photocatalytic process was discussed.