Mesoporous Carbon Composites Research Articles

Synthesis and Electrochemical Performance of Ni/Ordered Mesoporous Carbon Composites with High Surface Areas

Ni/ordered mesoporous carbon composites with high surface areas were successfully fabricated via a facile one-step template method using the self-assembly of phenolic resin and triblock copolymers (F127) under acidic condition, tetraethylorthosilicate (TEOS) as a structural strengthening agent, carbamide as an additive and nickel as catalyst. Transmission electron microscope, small-angle X-ray diffraction and N2 sorption analysis demonstrate that Ni/ordered mesoporous carbon composites have a 2D hexagonal ordered mesostructure, which couples with uniform mesopores (about 5.3 nm). Maximum specific surface area and pore volume can be up to 2800 m2/g and 3.80 cm3/g respectively after carbonization at 850°C, and all BET surface areas result from mesopores. Wide-angle X-ray diffraction patterns illustrate that the presence of Ni catalyst and an obvious enhancement of graphitic degree in the skeleton structure. Electrochemical measurements performed on Ni/ordered mesoporous carbon composites display that cyclic voltammetry curves present as approximately rectangular at different scanning rates, including 100 mV/s, and the samples display large capacitance (210 F/g) in KOH electrolyte. The findings above indicate that Ni/ordered mesoporous carbon composites can be used as electrode material for an electrochemical double layer capacitor.

Three-dimensional graphene aerogel–mesoporous carbon composites as novel coatings for solid-phase microextraction for the efficient enrichment of brominated flame retardants

Graphene aerogel–mesoporous carbon composites with hierarchical nanostructures were synthesized via a facile, environmentally friendly nanocasting technique for SPME coatings.

CoO@Co and N-doped mesoporous carbon composites derived from ionic liquids as cathode catalysts for rechargeable lithium–oxygen batteries

N-Doped mesoporous carbon-supported CoO@Co nanoparticles using an ionic liquid as the precursor show superior catalytic activity for Li–O2batteries.

Synthesis and electrochemical performances of mixed-valence vanadium oxide/ordered mesoporous carbon composites for supercapacitors

The highly ordered CMK-3 with short-rod like morphology significantly enhance the electrochemical performance of VOx.

Cu-Containing Carbon Nanocomposites Based on Cellulose

Structural transitions of Fe-containing fibrous and microcrystalline flax and hemp cellulose during heat treatment in an inert medium were studied using IR spectroscopy, x-ray diffraction, electron microscopy, thermogravimetric analysis, and N2 adsorption. Mesoporous ferromagnetic graphitecontaining carbon composites with specific surface area 280-550 m2/g were produced. The nature and shape of the cellulose matrix and the iron-salt anion were found to affect the composition, shape, and size of metal particles and the catalytic graphitization process.

The p-type MoS2 nanocube modified poly(diallyl dimethyl ammonium chloride)-mesoporous carbon composites as a catalytic amplification platform for electrochemical detection of l-cysteine

Molybdenum-sulfur nanocube/poly(diallyl dimethyl ammonium chloride)-mesoporous carbon (MoS2/PDDA-MC) composites was synthesized via a convenient and low-cost synthesis approach, which was proposed for the development of a simple and novel sensitive electrochemical sensor for the determination of l-cysteine. The as-synthesized MoS2 nanoparticles shows a nanocube structure with a uniform size of about 20nm. The photocurrent sign indicates that the MoS2 is the p-type compound. Due to large surface-to-volume ratio, high conductivity of mesoporous carbon, and good biocompatibility of MoS2, the MoS2/PDDA-MC based sensor exhibited excellent electrocatalytic activity for the detection of l-cysteine with a wide linear range from 0.45μM to 155μM and a low detection limit of 0.090μM (S/N=3). This work opens a new way to functionalized MC with good biocompatibility and solubility in sensors.

Facile synthesis and enhanced electromagnetic wave absorption of thorny-like Fe–Ni alloy/ordered mesoporous carbon composite

Ordered mesoporous carbon (OMC) coated with thorny-like Fe–Ni alloy composites have been successfully synthesized. The electromagnetic (EM) parameters of Fe–Ni alloy/OMC/paraffin wax composites were measured. Interestingly, the μ″ values of Fe–Ni(0.2)/OMC were very negative from ∼7 to 18GHz and the minimum value was −0.7, which are mainly caused by the eddy current. The reflection loss (RL) values were calculated with the measured EM parameters based on the transmission line theory. Results showed that the effective absorption bandwidth (<−10dB) of Fe–Ni(0.2)/OMC/paraffin wax composites with the thickness of 2.00mm could reach up to 4.8GHz. The enhanced EM wave-absorbing properties of the composites could be attributed to well impedance matching between the absorber and air. Moreover, the enhanced dielectric loss and magnetic loss induced by Fe–Ni alloy also played a crucial role in the EM wave-absorbing process.

V2O5/Mesoporous Carbon Composite as a Cathode Material for Lithium-ion Batteries

ABSTRACT V 2 O 5 /mesoporous carbon composite has been prepared by an ultrasonically assisted method followed by a sintering process. The as-prepared V 2 O 5 /mesoporous carbon material containing 90 wt% V 2 O 5 shows better electrochemical performance, with capacity of 163 mA h g −1 after 100 cycles at the current density of 500 mA g −1 , as well as better charge/discharge rate capability for lithium storage than V 2 O 5 nanoparticles. The improved electrochemical performance indicates that the V 2 O 5 /mesoporous carbon composite could be used as a promising cathode material for lithium ion batteries.

A Facile Preparation of Mesoporous Carbon Composites with Well-Dispersed Pd Nanoparticles and Their Utilization as Supports for Pt Catalysts

Palladium-introduced ordered mesoporous carbon (Pd-C) composite materials were prepared through a facile co-assembly process by employing nonionic block copolymers (Pluronic F127) as a structure-directing agent, low-molecular weight phenolic resin (resol) as a carbon precursor and tetraethyl orthosilicate and palladium chloride as additives. The addition of Pd nanoparticles (less than 9wt.%) were well-dispersed throughout the Pd-C frameworks without destroying the ordered tubular mesochannels. Layered graphitic sheets were readily formed due to the catalytic graphitization of amorphous carbon by Pd nanoparticles, leading to an increased crystallinity and electronic conductivity of carbon support (Pd-C). The Pt/Pd-C catalysts were prepared by loading Pt nanoparticles onto the Pd-C supports. Abundant Pt nanoparticles with an average size of 3nm were well-deposited onto the Pd-C framework by the means of the distributed anchor sites of Pd nanoparticles, finally increasing the utilization of Pt catalyst. Herein, the Pt catalyst supported on Pd-C composite materials exhibited much higher electrochemical active surface areas compared to Pt catalysts supported on pure ordered mesoporous carbon because of its increased electronic conductivity, active anchor sites and electrocatalytic active Pd nanoparticles.

Magnetic mesoporous carbon: efficiently reusable adsorbent for ionic liquid [Bmim]Cl from aqueous solution

Magnetic mesoporous carbon composite (Fe/OMC) was synthesized and as an adsorbent for removal of ionic liquid, 1-butyl-3-methyl imidazolium chloride ([Bmim]Cl), from aqueous solution. X-ray diffraction, transmission electron microscopy analyses and nitrogen adsorption measurements revealed that the synthesized Fe/OMC composite retained ordered mesoporous structure. Meanwhile, nitrogen adsorption measurements indicated that the Fe/OMC possess relatively high surface areas (up to 651 m2 g−1), pore volumes (up to 0.66 cm3 g−1) and multimodal mesopore (3.48 and 4.85 nm) and micropore (1.47 and 1.85 nm) distributions of pore sizes. Magnetic measurement revealed the ferromagnetic property of Fe/OMC at room temperature with saturation magnetization value at 26.11 emu g−1 which implies that Fe/OMC composite could be separated by ferromagnet. Results of adsorption experiment showed that Fe/OMC composite was high-performance, easily recyclable adsorbent for ionic liquid, [Bmim]Cl, from aqueous solution. In addition, the Langmuir adsorption isotherm was applicable to the removal process; the maximum adsorption capacity value is 238.32 mg g−1. After eight recycle runs, the adsorption capacity was almost at the same value (238.32 mg g−1 for the first sorption and 228.21 mg g−1 for the eighth times sorption). An efficient magnetically separable sorbent for wastewater treatments was prepared and can be used to remove the ILs, [Bmim]Cl, from aqueous solution. Adsorption capacity of Fe/OMC adsorbent is good for adsorbing [Bmim]Cl after eight recycle runs. Furthermore, the recovered ionic liquid showed results similar to the fresh one.

Polyaniline-Coated Mesoporous Carbon/Sulfur Composites for Advanced Lithium Sulfur Batteries

Lithium sulfur (Li–S) batteries have been considered as a promising candidate for high energy density applications with a high theoretical capacity of 1675 mAh g–1 and a high energy density of 2600 Wh kg–1. In this work, a polyaniline (PANi)-coated mesoporous carbon composite is synthesized by direct polymerization of aniline monomer in mesoporous Ketjenblack (KB) carbon and is used as cathode material for Li–S batteries. Different mass percentages of PANi can be infiltrated into the pores of KB carbon by simply varying the amount of monomer. Sulfur is encapsulated into the composite by the melt diffusion method, and the electrochemical performance of lithium sulfur batteries is investigated. The results indicate that the mass percentage of PANi plays a crucial role in the cycle stability of lithium sulfur batteries. The infiltrated PANi is capable of enhancing the intimate contact of sulfur with carbon and trapping polysulfides, which improves the utilization of active material. However, excess PANi dimi...

A V₂O₃-ordered mesoporous carbon composite with novel peroxidase-like activity towards the glucose colorimetric assay.

It is of great scientific and practical significance to explore inorganic mimetic enzymes to replace natural enzymes due to their instability and high cost. Herein we present an interesting discovery that a V2O3-ordered mesoporous carbon composite (V2O3-OMC) has a novel peroxidase-like activity towards fast redox reaction of typical peroxidase substrates H2O2 and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS). Due to the small size effect and large surface area of V2O3 nanoparticles supported by OMC, V2O3-OMC exhibited excellent catalytic performance with a k(cat) of 1.28 × 10(4) s(-1), K(M) (ABTS) of 0.067 mM and K(M) (H2O2) of 0.16 mM, and a significantly higher catalytic efficiency (k(cat)/K(M)) towards the oxidation of ABTS in comparison with the natural peroxidases. Furthermore, the Ping-pong BiBi mechanism was proposed to explain the catalytic reaction by V2O3-OMC. Based on this highly active biomimetic peroxidase and the colorimetric detection of H2O2, a facile analytical method was developed to detect glucose by using V2O3-OMC and glucose oxidase, which had a wide linear range (0.01-4 mM glucose), good selectivity and reliability for successful detection of various real samples. Thus, the novel V2O3-OMC peroxidase mimetic holds great promise for broad potential applications.

PNiPAM-FUNCTIONALIZED MESOPOROUS CARBON FOR THE ADSORPTION OF VITAMIN B2

The present research reports the synthesis of poly-N-isopropylacrylamide / mesoporous carbon composites, prepared by radical polymerization of N-isopropylacrylamide inside mesoporous carbon pores functionalized with carboxylic groups. The deposition of poly-N-isopropylacrylamide on mesoporous carbon was confirmed by FT-IR spectroscopy, TEM, N2-sorption measurements. The mesoporous carbon material was found to adsorb vitamin B2 from aqueous solution at room temperature. The obtained composite, poly-N-isopropylacrylamide / mesoporous carbon, exhibited a higher adsorption capacity for vitamin B2 as compared to un-functionalized mesoporous carbon sample, due to hydrogen bonding between carbonyl groups of poly-Nisopropylacrylamide immobilized on the mesoporous carbon surface and amino groups of vitamin B2 molecules.

Synergistic effects of mixing sulfone and ionic liquid as safe electrolytes for lithium sulfur batteries.

A strategy of mixing both an ionic liquid and sulfone is reported to give synergistic effects of reducing viscosity, increasing ionic conductivity, reducing polysulfide dissolution, and improving safety. The mixtures of ionic liquids and sulfones also show distinctly different physicochemical properties, including thermal properties and crystallization behavior. By using these electrolytes, lithium sulfur batteries assembled with lithium and mesoporous carbon composites show a reversible specific capacity of 1265 mAh g(-1) (second cycle) by using 40 % 1.0 M lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) in N-methyl-N-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide with 60 % 1.0 M LiTFSI in methylisopropylsulfone in the first cycle. This capacity is slightly lower than that obtained in pure 1.0 M LiTFSI as the sulfone electrolyte; however, it exhibits excellent cycling stability and remains as high as 655 mAh g(-1) even after 50 cycles. This strategy provides a method to alleviate polysulfide dissolution and redox shuttle phenomena, at the same time, with improved ionic conductivity.

A magnetic carbon sorbent for radioactive material from the Fukushima nuclear accident.

Here we present the first report of a carbon-γ-Fe2O3 nanoparticle composite of mesoporous carbon, bearing COOH- and phenolic OH- functional groups on its surface, a remarkable and magnetically separable adsorbent, for the radioactive material emitted by the Fukushima Daiichi nuclear power plant accident. Contaminated water and soil at a level of 1,739 Bq kg−1 (134Cs and 137Cs at 509 Bq kg−1 and 1,230 Bq kg−1, respectively) and 114,000 Bq kg−1 (134Cs and 137Cs at 38,700 Bq kg−1 and 75,300 Bq kg−1, respectively) were decontaminated by 99% and 90% respectively with just one treatment carried out in Nihonmatsu city in Fukushima. Since this material is remarkably high performance, magnetically separable, and a readily applicable technology, it would reduce the environmental impact of the Fukushima accident if it were used.

EFFECT OF CARBONIZATION TEMPERATURE ON DIELECTRIC AND MICROWAVE ABSORBING PROPERTIES OF COBALT DOPED MESOPOROUS CARBON COMPOSITES

Co doped mesoporous carbon composites (MC– Co ) have been synthesized at different carbonization temperatures via evaporation-induced multicomponent co-assembly strategy. The nanostructures and chemical compositions of MC– Co composites were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction analysis (XRD), etc. Their electromagnetic and microwave absorption properties were investigated in the frequency ranging from 2 GHz to 18 GHz. By the measurement of electromagnetic parameters and theoretical simulation of reflection loss (RL), the results showed that the minimum RL value of the optimum composite MC– Co -800 reached up to -41.9 dB at 13.5 GHz with a thickness of only 1.80 mm, and the effective absorption bandwidth (&lt; -10 dB) is 4.4 GHz (from 11.4 GHz to 15.8 GHz). This work demonstrated that the optimum carbonization temperature of the obtained composites is 800°C, which is critical to its electromagnetic properties. The excellent microwave absorption properties can be attributed to dielectric loss, Ohmic loss, and characteristic impedance matching. Therefore, the as-synthesized composites could be acted as a candidate of microwave absorber, especially for the light weight demand.

Additive-Driven Self-Assembly of Well-Ordered Mesoporous Carbon/Iron Oxide Nanoparticle Composites for Supercapacitors

Ordered mesoporous carbon/iron oxide composites were prepared by cooperative self-assembly of poly(t-butyl acrylate)-block-polyacrylonitrile (PtBA-b-PAN), which contains both a carbon precursor block and a porogen block, and phenol-functionalized iron oxide nanoparticles (NPs). Because of the selective hydrogen bonding between the phenol-functionalized iron oxide NPs and PAN, the NPs were preferentially dispersed in the PAN domain and subsequently within the mesoporous carbon framework. Ordered mesoporous carbon nanocomposites with Fe2O3 NPs mass loadings as high as 30 wt % were obtained upon carbonization at the block copolymer composites at 700 °C. The morphology of the mesoporous composites was studied using small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and N2 adsorption. The results confirmed high-fidelity preservation of morphology of the NP-doped block copolymer composites in the mesoporous carbon composites. The electrochemical performance of the mesoporous composite ...

In Situ Electrochemical Generation of Mesostructured Cu2S/C Composite for Enhanced Lithium Storage: Mechanism and Material Properties

AbstractAn effective strategy is explored for the in situ generation of a Cu2S/tubular mesoporous carbon composite by exploiting the charge–discharge processes of a S/C composite on a copper‐foil current collector. By studying the reaction mechanism, we discover that the dissolved polysulfide ions (from the reaction of pristine sulfur) and inserted Li+ are firmly anchored by the copper ions released from the copper foil, which forms insoluble CuxS intermediates in the mesopore channels of the carbon matrix. Moreover, the new electrochemically active CuxS intermediates are gradually converted to the final product, Cu2S, during subsequent cycles. The as‐prepared Cu2S nanoparticles are highly dispersed throughout the tubular mesoporous carbon, and the Cu2S/C composite exhibits a high reversible capacity of 270 mAh g−1 at 0.2 C over 300 cycles, with the negligible capacity loss, when used as a cathode material for a lithium‐ion battery. Furthermore, the composite shows an outstanding rate capability with a reversible capacity of 225 mAh g−1 under a high rate of 10 C. This work provides a convenient platform for the controlled synthesis of metal sulfides for lithium‐storage applications.

Tin oxide - mesoporous carbon composites as platinum catalyst supports for ethanol oxidation and oxygen reduction

Unique tin oxide-mesoporous carbon (SnO2-CMK-3) composites have been synthesized as platinum nanoparticle electrocatalyst supports for low temperature fuel cell applications. In comparison with state-of-the-art commercial carbon-supported platinum (Pt/C) and pure CMK-3-supported platinum (Pt/CMK-3), Pt/SnO2-CMK3 demonstrated improved Pt-mass and surface area based ethanol oxidation reaction (EOR) activity through half-cell electrochemical investigations, providing a 64.7 and 97.6mV reduction in overpotential at 100mAmg−1Pt upon comparison to Pt/CMK-3 and commercial Pt/C. Furthermore, improvements to the oxygen reduction reaction (ORR) kinetics were observed, with Pt/SnO2-CMK3 providing a kinetic current density of 3.40mAcm−2 at an electrode potential of 0.9V vs RHE. The improved performance of Pt/SnO2-CMK-3 for EOR and ORR was attributed to the beneficial impact of the support properties, along with potential interactions occurring between the support and catalyst particles. Complemented by extensive physicochemical characterization, these unique materials show high promise for application in low temperature fuel cells.

Preparation of Mesoporous Carbon/Sulfur Composite Loaded with ZnS and Its Property for Lithium-sulfur Batteries

With the aim to obtain high performance cathode materials for lithium-sulfur batteries, composite of mesoporous carbon (MC) loaded with ZnS (ZnS/MC) was prepared through ultrasonic dispersion and heat treatment. The as-prepared composite was blended with elemental sulfur by heating, then cathode materials (ZnS/MC/S) was obtained. The ZnS/MC composite was characterized by XRD, SEM, EDS and N2 adsorption-desorption isotherms. The results showed that ZnS particle was uniformly loaded to the surface of MC through ultrasonic dispersion when content of ZnS was less than 17wt%. ZnS nanoparticles aggregated to form sphalerite ZnS by heat treatment or increasing content of ZnS. Cyclic voltammetry test showed that ZnS accelerated the oxidation process of polysulfides. Charge/ discharge tests indicated that the initial discharge specific capacity was 1354.6 mAh/g, while the coulombic efficiency of the first charge and discharge was 98.7%. The capacity still remained 650 mAh/g after 50 cycles.