As-prepared Hybrid Material Research Articles

One-pot synthesis of rod-like lignin@zeolitic imidazolate framework-8 with enhanced immobilization of β-glucosidase

Developing value-added lignin-based biomaterials for enzyme immobilization has drawn great attention. This study developed a cost-effective and eco-friendly one-pot strategy to synthesize the rod-like lignin@zeolitic imidazolate framework-8 (ZIF-8) hybrid nanomaterial by using lignin derived from lignocellulosic biofuel production. The incorporation of lignin into the ZIF-8 network not only altered the morphology, but also modified the surface properties of the material, making it an ideal support for enzyme immobilization. The synthesized nanoscale hybrid materials were used to immobilize beta-glucosidase (BG) with high immobilization capacity and about 92–166 mg/g of BG was immobilized through physical adsorption. The immobilized BG exhibited good stability, catalytic activity and recycling properties, and was reused under acidic conditions for more than 8 cycles with more than 60% activity kept. The as-prepared hybrid material can serve as a great carrier for immobilizing various biomolecules.

Free-standing hybrid material of Cu/Cu2O/CuO modified by graphene with commercial Cu foil using for non-enzymatic glucose detection

Free-standing Cu/Cu2O/CuO modified by graphene was formed through two steps: Firstly, the commercial Cu foil was thermal annealed to form Cu/Cu2O/CuO; Secondly, the Cu/Cu2O/CuO was modified by graphene through electrochemical exfoliated method. The SEM, XRD, TEM and XPS have been used to characterize the morphology, the crystalline phase, and the surface composition of the hybrid electrode as-prepared. The effects of Cu and its oxides on graphene has been uncovered by the Raman results. The sensitivity of the glucose sensor in 0.1 M NaOH by using the as-prepared hybrid material reaches 3102 μA·mM−1 cm−2 within a linear range of 0.002–2.88 mM, which is better than that of the Cu/graphene and the Cu/Cu2O/CuO prepared at the same conditions. The sensor also shows excellent anti-interference ability, good cycling stability and time stability. The advantage of the sensor is caused by the strengthened synergistic effects between the graphene and the Cu/Cu2O/CuO due to the alleviated detrimental effects of the metal on the property of the graphene through using oxides middle layer as well as the large active area that obtained. This work provides a new way to study the effects of graphene in improving the property of the metal oxide especially in using for glucose sensor.

Layered-structure N-doped expanded-graphite/boron nitride composites towards high performance of microwave absorption

High-efficiency microwave absorbers with broadband absorption are strongly desired for electromagnetic protection. Herein, we successfully synthesized a hybrid microwave absorbing material with two-dimensional layered structure, which consisted of expanded graphite (EG) and boron nitride (BN). The introduction of BN is to regulate the conductivity of EG and also to improve the thermal stability of the composite material. The ultrathin BN nano-sheets were uniformly wrapped on the EG sheets via chemical vapor deposition. Attributed to the dielectric loss and conductive loss, the as-prepared hybrid material exhibited high performance for microwave absorption. The effective absorbing bandwidth (reflection loss value < -10 dB) was achieved up to 9.37 GHz with the thickness of 2.4 mm in the frequency range of 5.75–6.98 GHz and 9.86–18 GHz. And the minimum reflection loss was -51.58 dB at the thickness of 3 mm. The excellent performance of microwave absorption was attributed to the dielectric loss, interfacial polarization loss and optimized impedance matching. Moreover, compared to pure EG, the thermal decomposition temperature of EG/BN composite materials had increased by about 100 °C which was up to 714 °C. Taking the advantages of high thermal stability of BN as well as the fine microwave absorbability of EG, the EG/BN composites would be applied in high-temperature microwave absorbing fields.

Superparamagnetic Iron Oxide Nanoparticle Nanodevices Based on Fe3O4 Coated by Megluminic Ligands for the Adsorption of Metal Anions from Water.

The uptake ability toward arsenic(V), chromium(VI), and boron(III) ions of ad hoc functionalized magnetic nanostructured devices has been investigated. To this purpose, ligands based on meglumine have been synthesized and used to coat magnetite nanoparticles (Fe3O4) obtained by the co-precipitation methodology. The as-prepared hybrid material was characterized by infrared spectroscopy (IR), X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy combined with energy-dispersive X-ray analysis. Moreover, its magnetic hysteresis properties were measured to evaluate its magnetic properties, and the adsorption kinetics and isothermal models were applied to discern between the different adsorption phenomena. Specifically, the better fitting was observed by the Langmuir isotherm model for all metal ions tested, highlighting a higher uptake in arsenic (28.2 mg/g), chromium (12.3 mg/g), and boron (23.7 mg/g) sorption values if compared with other magnetic nanostructured materials. After adsorption, an external magnetic stimulus can be used to efficiently remove nanomaterials from the water. Finally the nanomaterial can be reused up to five cycles and regenerated for another three cycles.

Updated results on the integration of metal–organic framework with functional materials toward n-alkane for latent heat retention and reliability

Phase change composites are in high demand in thermal management systems. Various supporting materials, including nanocomposites, have been employed to develop shape-stable phase change materials (PCMs). As the reliability of most composite materials has mostly been studied right after the preparation with specific thermal cycling measurements, it is difficult to analyze the long-term leakage-resistance capability and energy retention capacity. Additionally, achieving multifunctional phase change composites is a significant challenge for single supporting materials. Herein, we provide a follow-up report on the thermal performance of hybrid material-supported n-alkane after a storage time of one year and 50 heating/cooling cycles. The interconnected hybrid material composed of a metal–organic framework (MOF) and graphite improved the shape/thermal stability of tetradecane (TD). The as-synthesized MOF/graphite/TD composites exhibited a high latent heat retention capacity of 84.2%, low leakage rate of 1.25%, and high PCM loading capacity, making them suitable for thermal management applications, such as industrial waste heat recovery systems. Furthermore, the intermolecular interactions and capillary forces between the hybrid materials and TD provided high stability and compatibility. Therefore, the as-prepared hybrid material fabricated in this study can be important in the development of multidirectional composite PCMs with comprehensive thermal characteristics.

Versatile nanoadsorbents based on magnetic mesostructured silica nanoparticles with tailored surface properties for organic pollutants removal

This paper addresses the development of new magnetic silica-based nanoadsorbents and evaluates their potential application in the removal of contaminants of emerging concern (CECs), polyaromatic hydrocarbons (PAHs) and aliphatic hydrocarbons. For this purpose, magnetic iron oxide nanoparticles were covered with a hybrid shell of silica and 3-(trimethoxysilyl)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as structure directing agent. The as-prepared hybrid material (MMST) was further modified with trimethoxyphenylsilane, obtaining a phenyl-functionalized nanoadsorbent (MMST-Ph). Both materials were thoroughly characterized with diverse physicochemical techniques, and batch sorption tests with single-contaminant and with mixtures of contaminants were performed. MMST-Ph proved to be more efficient for the adsorption of PAHs and aliphatic hydrocarbons. The presence of TPODAC and phenyl moieties anchored on the mesostructured silica frameworks resulted to be a key factor to obtain high PAHs uptakes from aqueous media. In the case of CECs, ibuprofen (IBU), diclofenac (DCF) and carbamazepine (CBZ) were tested. These experiments demonstrated that even though MMST possesses better adsorption capacities of CECs, MMST-Ph achieved high IBU and DCF uptakes. Regeneration and reuse experiments showed that MMST-Ph can be reused in eight cycles without losing the adsorption capacity of anthracene. In the case of MMST, there was a 42% drop in the adsorption capacity of ibuprofen in the second cycle, whereas in the next seven cycles the adsorption capacity remained constant.The promising results obtained in this work strengthen the potential application of surface-modified magnetic silica nanoparticles for the removal of different types of organic pollutants from waters.

Efficient photocatalysis of organic dyes under simulated sunlight irradiation by a novel magnetic CuFe2O4@porphyrin nanofiber hybrid material fabricated via self-assembly

The main aim of this study was to synthesize an innovative magnetic CuFe2O4@porphyrin nanofiber hybrid material via one-step re-precipitation self-assembly of freebase-tetracarboxy-porphyrin (TCPP), in the presence of CuFe2O4 nanoparticles. The resultant hybrid materials were thoroughly characterized using scanning electron microscopy, energy-dispersive X-ray mapping, X-ray diffractometry, and Fourier-transform infrared, and UV–vis spectroscopy. Results showed well-integration of CuFe2O4 nanoparticles into TCPP nanofiber network, with the average size of CuFe2O4 being less than 100 nm and diameter and length of TCPP aggregate being approximately 20 nm and several µm, respectively. The as-prepared hybrid material possessed strong magnetic properties with a saturated magnetization value of approximately 25 emu/g. This photocatalyst was highly efficient in the removal of rhodamine B (RhB) dye, with the rate constant reaching 2.1 × 10−2 min−1. This paper describes in detail a plausible photocatalytic mechanism for RhB removal by CuFe2O4@porphyrin nanofiber hybrid material.

Z-scheme heterostructure of Fe-doped SnO2 decorated layered g-C3N4 with enhanced photocatalytic activity under simulated solar light irradiation

A novel material Fe (1, 2 and 3 wt%) doped SnO2 decorated layered g-C3N4 was synthesized through a simple chemical precipitation method. The as-prepared hybrid material 1 wt%Fe– SnO2/g-C3N4 (1 wt%Fe–SCN) exhibited enhanced activity for both photodegradation of Rhodamine B (RhB) and Methylene blue (MB) under simulated solar light irradiation. The apparent rate constant, k, for MB degradation of 1 wt%Fe–SCN was 0.062min−1 (10.88 times and 7.56 times higher than that of pure SnO2 and pure g-C3N4) and RhB degradation of 1 wt%Fe–SCN was 0.043min−1 (10 times and 6.83 times higher than pure SnO2 and pure g-C3N4, respectively). It was found that Fe doping reduced the band gap of Fe–SnO2, and formed Z-scheme heterojunction between Fe doped SnO2 (Fe–SnO2) and g-C3N4, which effectively promoted the separation of photogenerated electrons and holes. Moreover, the 1 wt%Fe–SCN composite had a layered structure with large surface area, which increased the contact area with pollutants and improved the photocatalytic activity.

One-step formation of a hybrid material of graphene and porous Ni with highly active Ni(OH)2 used for glucose detection

A hybrid material of graphene and porous Ni with highly active Ni(OH)2 was formed through a one-step electrochemical exfoliation assisted method. The porous Ni with a pore size of 2–10 micrometers obtained by a hydrogen bubble template method was used as the cathode while the graphite foil was used as the anode with only (NH4)2SO4 as the electrolyte. Both the high surface areas of porous Ni and the oxygen radicals in graphene favored the formation of the Ni(OH)2. It is confirmed by energy dispersion spectrum, transmission electron microscope, Raman spectroscopy, x-ray diffraction and x-ray photoelectron spectroscopy analysis. Both the active area and the glucose sensing property of the as-prepared hybrid material were estimated by electrochemical methods of cyclic voltammetry with current-voltage (C-V) curve, chronoamperometry with current-time (I-t) curve and electrochemical impedance spectroscopy analysis, respectively. It shows an extraordinary active area as well as a low charge transfer resistance and absorption resistance. As a result, a high sensitivity of 6504 μA/mM−1 cm−2 within a linear range of 4 μM–1.0 mM was obtained for glucose detection.

Single-step grown boron doped nanocrystalline diamond-carbon nanograss hybrid as an efficient supercapacitor electrode.

Direct synthesis of a nano-structured carbon hybrid consisting of vertically aligned carbon nanograsses on top of boron-doped nanocrystalline diamond is demonstrated and the carbon hybrid is further applied as an electrode material for the fabrication of supercapacitors. The hybrid film combines the dual advantages of sp2 (carbon nanograss) and sp3 (nanocrystalline diamond) bonded carbon, possessing not only the excellent electrical characteristics of sp2 carbon but also the exceptional electrochemical stability of sp3 carbon. As a result, the specific capacitance of the as-prepared hybrid material reaches up to 0.4 F cm-2, one of the highest reported in diamond-based supercapacitors. The entire electrochemical results exhibit enhanced electron transfer efficiency with remarkable stability of 95% of capacitance retention even after 10 000 cycles.

Co3 O4 @Cu-Based Conductive Metal-Organic Framework Core-Shell Nanowire Electrocatalysts Enable Efficient Low-Overall-Potential Water Splitting.

In the work reported herein, the electrocatalytic properties of Co3 O4 in hydrogen and oxygen evolution reactions have been significantly enhanced by coating a shell layer of a copper-based metal-organic framework on Co3 O4 porous nanowire arrays and using the products as high-performance bifunctional electrocatalysts for overall water splitting. The coating of the copper-based metal-organic framework resulted in the hybridization of the copper-embedded protective carbon shell layer with Co3 O4 to create a strong Cu-O-Co bonding interaction for efficient hydrogen adsorption. The hybridization also led to electronically induced oxygen defects and nitrogen doping to effectively enhance the electrical conductivity of Co3 O4 . The optimal as-prepared core-shell hybrid material displayed excellent overall-water-splitting catalytic activity that required overall voltages of 1.45 and 1.57 V to reach onset and a current density of 10 mA cm-2 , respectively. This is the first report to highlight the relevance of hybridizing MOF-based co-catalysts to boost the electrocatalytic performance of nonprecious transition-metal oxides.

In situ synthesis of open hollow tubular MnO/C with high performance anode materials for lithium ion batteries using kapok fiber as carbon matrix

MnO/C materials with a long lifetime and high rate performance via a biomass template strategy for the lithium ion battery (LIB) market are indispensable. Therefore, novel and efficient ways for their synthesis are urgently required to greatly alleviate the pressure of consuming nonrenewable resources. Herein, we fabricate an open hollow tubular MnO/C hybrid based on the transformation of a natural kapok fiber by hydrothermal and thermal treatment. The as-prepared hybrid material was obtained with high synthesis efficiency and exhibited an extremely stable structure attributed to the in situ growth strategy, overcoming volumetric expansion and self-aggregation of MnO. As an anode material for LIBs, this typical MnO/C electrode demonstrated a high reversible capacity of 1917 mAh · g–1 at 300 mA · g–1 and an excellent rate performance of 693.1 mAh · g–1 at 5000 mA · g–1. More importantly, this biomass carbon-based material demonstrates a superior cycling stability of 1433.1 mAh · g–1 at a high current density of 5000 mA · g–1 after 1000 cycles. The significant electrical performance of this new type of green material is promising for the development of LIBs.

Efficient Photocatalytic Degradation of Malachite Green in Seawater by the Hybrid of Zinc-Oxide Nanorods Grown on Three-Dimensional (3D) Reduced Graphene Oxide(RGO)/Ni Foam.

A hybrid of ZnO nanorods grown onto three-dimensional (3D) reduced graphene oxide (RGO)@Ni foam (ZnO/RGO@NF) is synthesized by a facile hydrothermal method. The as-prepared hybrid material is physically characterized by SEM, XRD, Raman, and X-ray photoelectron spectroscopy (XPS). When the as-prepared 3D hybrid is investigated as a photocatalyst, it demonstrates significant high photocatalytic activity for the degradation of methylene blue (MB), rhodamine (RhB), and mixed MB/RhB as organic dye pollutants. In addition, the practical application and the durability of the as-prepared catalyst to degradation of malachite green (MG) in seawater are firstly assessed in a continuous flow system. The catalyst shows a high degradation efficiency and stable photocatalytic activity for 5 h continuous operation, which should be a promising catalyst for the degradation of organic dyes in seawater.

Bentonite-decorated calix [4] arene: A new, promising hybrid material for heavy-metal removal

There is global concern about the contamination of ground, river, and tap waters as well as soil contamination with heavy metal ions; these chemical species are known to not degrade and to cause severe health problems if ingested by humans and animals. Such environmental and health concerns necessitate the development of ultrasensitive sensors and high-capacity adsorbents. This study demonstrates for the first time the potential of organophilic bentonite combined with tetra(2-pyridylmethyl)amide calix [4] arene as a high-performance hybrid material for the removal of toxic heavy metals. After consecutive synthesis steps, the modified bentonites were thoroughly characterized by FT-IR, XRD, UV spectroscopy, and TEM. In particular, the XRD analysis showed strong supporting evidence for intercalation in the clay following each modification step. The salient feature of the newly prepared hybrid material is its high extraction capacity for Cd(II) and Zn(II) metals, as determined by atomic absorption spectrometry and UV spectrometry. Different preparation methods, with respect to the quantity of the added cationic surfactant, were investigated to determine the optimal conditions for synthesis. The extraction percentage for the as-prepared hybrid material was measured to be as high as 97.4% and 94.2% for Cd(II) and Zn(II), respectively.

MoS2 nanosheets direct supported on reduced graphene oxide: An advanced electrocatalyst for hydrogen evolution reaction.

Molybdenum disulfide nanosheets/reduced graphene oxide (MoS2 NSs/rGO) nanohybrid as a highly effective catalyst for hydrogen evolution reaction (HER) have been successfully synthesized by a facile microwave-assisted method. The results clearly reveal that direct grown of MoS2 NSs on rGO have been achieved. Electrochemical tests show that the as-prepared hybrid material exhibited excellent HER activity, with a small Tafel slope of 57 mV dec-1, an overpotential of 130 mV and remarkable cycling stability. After analysis, the observed outstanding catalytic performance can be attributed to the uniform distribution of the MoS2 NSs, which are characterized by the presence of multiple active sites as well as the effective electron transport route provided by the conductive rGO substrate. Moreover, according to the classic theory, the mechanism governing of the catalytic HER on the MoS2 NSs/rGO nanohybrid has been clarified.

Co(II) ethylene glycol carboxylates for Co3O4 nanoparticle and nanocomposite formation

Ethylene glycol-functionalized Co(II) carboxylates [Co(CO2CH2(OC2H4) n OMe)2] (2a, n = 1; 2b, n = 2), [Co(CO2CHPh(OC2H4)2OMe)2] (2c) and [Co(CO2CMe2(O–C2H4)2OMe)2] (2d) have been synthesized by the reaction of [Co(OAc)2·4H2O] with the corresponding acids MeO(C2H4O) n CRR′CO2H (n = 1, 2; R=H, R′=Me; R=H, R′=Ph). Based on the IR spectroscopic studies, the binding motif of the carboxylato ligands to cobalt is discussed. Thermogravimetry and mass spectrometry studies were carried out in order to investigate the thermal decomposition mechanism of 2a–2d in the solid state. Based on the result obtained, complex 2b was chosen as single-source precursor for the generation and stabilization of Co3O4 nanoparticles (NPs) by solid-state thermal decomposition in air. Depending on the decomposition time, NPs with different chemical composition (consisting of Co3O4, CoO and Co) and with crystallite sizes ranging from 9 to 18 nm were obtained. Furthermore, the preparation of cobalt oxide-based nanocomposites by twin polymerization of 2,2′-spirobi[4H-1,3,2-benzodioxasiline] (3) in the presence of 2b is reported. After treatment of the as-prepared hybrid material by either oxidation or etching, the respective mesoporous carbon/silica (IUPAC type IV isotherms) matrices were obtained. Quenched solid and nonlinear density functional theory calculations gave a surface area of 1040 cm2 g−1 for the respective carbon and 336 cm2 g−1 for the appropriate silica material. Powder X-ray diffraction measurements confirm the formation of Co3O4 NPs in both components. High-angle annular dark field scanning transmission electron microscopy revealed well-distributed particles within the silica matrix, whereas no particles were found in the carbon material. The electrochemical properties of the composite materials have been investigated by cyclic voltammetry. The respective silica material shows five reduction events (Co3O4 to CoO, CoO to Co), while no redox potentials occurred for the Co3O4 NPs embedded in the carbon matrix.

A versatile and efficient approach to separate both surfactant-stabilized water-in-oil and oil-in-water emulsions

Oil/water separation is an important field aiming to resolve industrial oily wastewater and oil-spill pollution, as well as environmental protection. However, the separation of oil-water mixtures, especially surfactant-stabilized oil-water emulsions, is a worldwide challenge. To this end, we developed a versatile and efficient approach to separate various highly stable emulsions including both surfactant-stabilized W/O emulsions and O/W emulsions with high separation efficiency using nanoporous divinylbenzene (DVB)/SiO2 hybrid material. The highly effective separation property of the hybrid material is attributed to its superhydrophobicity, high specific surface area and nanopore size distribution. Therefore, the versatile emulsion separation of hybrid material shows obvious advantage over most superwetting surfaces that only have effect on free oil-water mixtures or one form emulsion (W/O emulsions or O/W emulsions). Besides, the as-prepared hybrid material can rapidly swell various organic solvents from water selectively with high absorption capacity because of the present multi-level nanopores which can enhance adsorption performance for their improved accessibility and high surface area. Moreover, the hierarchical nanoporous structure of hybrid material still remained even after repeated separation procedures indicating the outstanding fouling resistance and good reusability. (C) 2016 Elsevier B.V. All rights reserved.

Free MoS2 Nanoflowers Grown on Graphene by Microwave-Assisted Synthesis as Highly Efficient Non-Noble-Metal Electrocatalysts for the Hydrogen Evolution Reaction.

Advanced approaches to preparing non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER) are considered to be a significant breakthrough in promoting the exploration of renewable resources. In this work, a hybrid material of MoS2 nanoflowers (NFs) on reduced graphene oxide (rGO) was synthesized as a HER catalyst via an environmentally friendly, efficient approach that is also suitable for mass production. Small-sized MoS2 NFs with a diameter of ca. 190 nm and an abundance of exposed edges were prepared by a hydrothermal method and were subsequently supported on rGO by microwave-assisted synthesis. The results show that MoS2 NFs were distributed uniformly on the remarkably reduced GO and preserved the outstanding original structural features perfectly. Electrochemical tests show that the as-prepared hybrid material exhibited excellent HER activity, with a small Tafel slope of 80 mV/decade and a low overpotential of 170 mV.

Sol-gel Preparation and Optical Properties of TiO2/Organically Modified Silane Hybrid Material Containing DR13

Disperse red 13 (DR13) azoaromatic chromophores were incorporated into sol-gel derived TiO2/organically modified silane matrix to achieve a hybrid material doped with dye molecules. Nonlinear optical properties of the asprepared hybrid material were investigated by an optical Kerr shutter technique with an 800-nm femtosecond laser. It is obtained that the response time of the bulk sample doped with 0.1% DR13 molecules is less than 208 fs and the third-order nonlinear refractive index is estimated at about 1.141×10-15 cm2/W. It is also found that the sample of material with higher DR13 content could be with higher third-order nonlinear susceptibility. The linear refractive index and the thickness of the hybrid films derived by a spin-coating process were also studied by a prism coupling technique. It is found that with an increasing of the baking temperature, both the refractive index and the thickness of the hybrid films decrease. Absorption spectra, microstructural and morphological properties of the hybrid films were also characterized by UV–Vis absorption spectroscopy, thermal gravimetric analysis, Fourier-transform infrared spectroscopy and atomic force microscopy. Results indicate that the as-prepared hybrid material is expected to be potential in ultrafast photonic applications.

Propylsulfonic acid and methyl bifunctionalized TiSBA-15 silica as an efficient heterogeneous acid catalyst for esterification and transesterification

Propylsulfonic acid and methyl bifunctionalized TiSBA-15 silica material, TiSBA-15-Me-PrSO3H, is prepared by a direct nonionic surfactant-templated sol–gel co-condensation approach combined with low-temperature hydrothermal treatment. The structural integrity of the incorporated propylsulfonic acid groups and terminally bonding methyl groups are studied by 13C CP-MAS NMR and 29Si MAS NMR spectroscopy, while the chemical state of Ti(IV) species in the hybrid material is tested by XPS and UV–Vis/DRS. The ordered mesostructure, morphology and porosity of as-prepared hybrid material are characterized by low-angle XRD measurements, TEM observations and nitrogen gas porosimetry measurements. As the efficient solid acid catalyst, the heterogeneous acid catalytic activity and stability of the TiSBA-15-Me-PrSO3H are evaluated by esterification of palmitic acid and transesterification of yellow horn oil with methanol under refluxing temperature (65°C) and atmospheric pressure. Based on the physicochemical properties and catalytic testing results, the excellent heterogeneous acid catalytic behaviors of as-prepared hybrid catalyst are explained by the contribution of their strong Brönsted and Lewis acidity, excellent porosity properties as well as surface hydrophobicity.