Mesoporous Carbon CMK-3 Research Articles

Testing PtCu Nanoparticles Supported on Highly Ordered Mesoporous Carbons CMK3 and CMK8 as Catalysts for Low-Temperature Fuel Cells

Pt(Cu) nanoparticles supported on CMK3 and CMK8 ordered mesoporous carbons (OMCs) have been synthesized by electroless deposition of Cu followed by galvanic exchange with Pt. The structural characterization by high-resolution transmission electron microscopy and X-ray diffraction showed the formation of Pt(Cu) nanoparticles of 4–5 nm, in which PtCu alloys with contracted fcc Pt lattice and 70–80 at.% Pt was identified. The X-ray photoelectron spectroscopy analyses indicated that the Pt(Cu) nanoparticles were mainly composed of a PtCu alloy core covered by a Pt-rich shell, in agreement with the steady cyclic voltammograms, which did not show any Cu oxidation peaks. Electroactive surface areas up to about 70 m2 gPt−1 were obtained. The onset potentials for CO oxidation and the oxygen reduction reaction were more negative and positive, respectively, as compared to Pt/C, thus indicating higher activity of these Pt(Cu) catalysts with respect to the latter. Based on the corresponding binding energies, these better activities were attributed to the favorable geometric and ligand effects of Cu on Pt, which were able to reduce the adsorption energy of the intermediates on Pt. Pt(Cu)/CMK3 showed competitive mass and specific activities, as well as better stability than Pt/C.

Effect of micropores on CO2 capture in ordered mesoporous CMK-3 carbon at atmospheric pressure

Effect of micropores on CO2 capture in ordered mesoporous CMK-3 carbon at atmospheric pressure

Preparation and electrochemical hydrogen storage application of mesoporous carbon CMK-3 coated Co2B alloy composite

Mesoporous carbon CMK-3 is synthesized using mesoporous molecular sieve SBA-15 as the template. Co2B alloy is prepared by the high temperature solid phase method. Composites of Co2B mixed with 2%, 5%, 7% and 10% of CMK-3 are fabricated via ball-milling to improve the electrochemical performance of Co2B alloy. Ultimately, the discharge capacity reaches a maximum (662.8 mAh/g) for 5% doping amount of CMK-3. The CMK-3/Co2B composite materials exhibit preferable HRD and improved corrosion and oxidation resistance. CMK-3/Co2B displays excellent electrochemical and kinetics properties owing to the unique electrocatalytic activity and structural feature of CMK-3, which can accelerate the hydrogen transmission.

Synthesis and surface-functionalizing of ordered mesoporous carbon CMK-3 for removal of nitrate from aqueous solution as an effective adsorbent

In this study, the adsorption of nitrate onto ordered mesoporous carbon CMK-3 was investigated. First, CMK-3 was synthesized and then directly amino-functionalized by 3-aminopropyl trimethoxysilane (APTMS). The physicochemical properties of as-prepared adsorbent were characterized by XRD, EDS-SEM, FT-IR and N2 adsorption-desorption. Ultraviolet/visible spectroscopy was used to evaluate the adsorbent ability for nitrate reduction. In batch experiments, the influence of effective parameters such as contact time, adsorbent dosage, solution pH, initial concentration and temperature was investigated on the nitrate adsorption capacity. The obtained results indicated 100% removal efficiency for initial nitrate concentration of 50 mg l−1 and 78% for the concentration of 100 mg l−1, at low adsorbent dosage (3 g l−1) and very fast equilibrium attainment (5 min) without pH dependency (in the range of 2.0–8.0). The maximum nitrate adsorption capacity of Amino-CMK-3 was 48.78 mg g−1 in the concentration range of 50–250 mg g−1. Kinetic studies confirmed that the process followed a pseudo-second-order and that the Langmuir isotherm best fitted the equilibrium adsorption of nitrate. Nitrate desorption occurred after a reasonable time (3 h) and confirmed the adsorbent reusability without further treatment. The higher adsorption capacity of CMK-3 stemmed from its incredible mesoporous structure, including nano-channels that were completely functionalized by amino groups. Grafting aminopropyl groups potentially turned the CMK-3 to a promising adsorbent for nitrate removal.

Ordered nano-structured mesoporous CMK-8 and other carbonaceous positive electrodes for rechargeable aluminum batteries

The chloroaluminate ion storage properties of various carbonaceous electrodes, namely soft carbon (SC), hard carbon (HC), activated carbon (AC), and ordered mesoporous carbon CMK-8, are investigated. The effects of carbon crystallinity, surface area, and pore size are systematically examined. Due to their non-ideal graphitic structures, the charge–discharge capacities of SC and HC electrodes are unfavorable for practical applications, although SC, with its relatively high crystallinity, outperforms HC. The high-surface-area AC and CMK-8 exhibit reversible capacities of 59.0 and 100.5 mAh g−1, respectively, at 300 mA g−1. Pore size and geometry play important roles in determining the electrochemical properties. The CMK-8 framework not only serves as an electronic conduction pathway but also provides interpenetrating three-dimensional open channels for electrolyte accessibility and complex AlCl4− anion transport. The charge storage mechanism of the CMK-8 electrode, confirmed by electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry, has a capacitive contribution and a diffusion-controlled intercalation/deintercalation contribution. Based on this unique mechanism, great rate capability, and excellent cyclability of the CMK-8 electrode are demonstrated.

Simultaneous determination of 114 pesticides in complex Chinese herbal medicine Fritillaria using ordered mesoporous carbon CMK-3 as a reversed-dispersive solid phase extraction sorbent.

Fritillaria, a traditional Chinese herbal medicine, is classified into many medicinal species and contains numerous complex components. It is thus difficult to simultaneously detect multiple pesticide residues in different Fritillaria species. An easy, reliable, and widely applicable analytical method based on a modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method coupled with LC-MS/MS was developed to solve these problems encountered during pesticide residue analysis in complex Fritillaria matrices. Ordered mesoporous carbon CMK-3 and a primary secondary amine (PSA) were used as efficient purification sorbents by optimization of the QuEChERS process. Systematic method validation was performed for four species of Fritillaria. The matrix effect of pesticides varied among different Fritillaria species, and matrix-matched standard solutions were thus employed for quantitative analysis. The mean recoveries of all pesticides ranged from 88.6% to 95.5%, with mean relative standard deviations (RSD) lower than 6% at spiked concentrations of 30, 120, and 240 μg kg−1. The limits of quantification (LOQ) for the developed method were in the range of 30–120 μg kg−1. This method was further used to analyze 47 Fritillaria samples from Zhejiang province, China, and seven pesticides were detected in 22 Fritillaria samples. These results demonstrate that the developed method is suitable for an accurate analysis of multiple pesticide residues in various Fritillaria.

High Dynamics of Vapor Adsorption in Ordered Mesoporous Carbon CMK-5: A Small Angle X-ray Scattering Study

Adsorption of dichloromethane in CMK-5 is a highly dynamic process going along with substantial rearrangement of both the adsorbent phase and the adsorbate phase. The carbon nanotubes of CMK-5 expa...

Selective adsorption of benzene, toluene, and m-xylene on sulfonated carbons

In recent years, several new materials were developed to improve the adsorption of benzene, toluene, and m-xylene (BTX) in the vapor phase, typically concerning its application of BTX removal from the Claus furnace feed gas. In this connection, the present work attempts to synthesis carbon-based adsorbents, as well as understand its physico-chemical characteristics typically referred to as sulfonated carbon (SC) using the H2SO4, sucrose, and TEOS as the precursors. The synthesized adsorbent was characterized utilizing the BET surface area analyzer, XRD, FTIR, XPS, CHNSO, SEM, and HR-TEM. The adsorbents were subjected to BTX adsorption through a gravimetric technique covering different temperatures. The sulfonated carbon possesses higher adsorption capacity for BTX as compared to a highly porous ordered mesoporous carbon CMK-3. The overall adsorption characteristics of the SC prepared at 300 °C (SC-300) seems to be better than the samples heat-treated at 600 and 900 °C, promising to be suitable adsorbent for commercial adoption.

Space-Confined Synthesis of Ultrasmall SnO2 Nanodots within Ordered Mesoporous Carbon CMK-3 for High-Performance Lithium Ion Batteries

SnO2 suffers from the severe pulverization problem when used as an anode material for lithium ion batteries (LIBs). To overcome its drawbacks, hybridizing nanosized SnO2 with carbon-based materials is very impactful, and we herein successfully synthesize ultrasmall SnO2 nanodots (average size of around 5 nm) within the channels of the commercial ordered mesoporous carbon (CMK-3), in which the tin precursor is prefilled under a vacuum and then is easily converted into SnO2 by annealing at 350 °C in air. The as-prepared SnO2@CMK-3 composite demonstrates good lithium storage properties, displaying a discharge capacity of 898.8 mA h/g at the 150th cycle at 500 mA/g, apparently higher than that for the bare SnO2 and CMK-3 electrodes. The superior electrochemical performance of SnO2@CMK-3 can be due to the high conductivity and vast pore volume of the CMK-3 carbon matrices, which efficiently alleviate the volume change induced pulverization and enhance the electrode conductivity. Besides, the uniform distribution of the ultrasmall SnO2 nanodots within CMK-3 maximally enlarges the lithium storage sites and minimizes the effect of the volume variation.

Ultrafast microwave synthesis of rambutan-like CMK-3/carbon nanotubes nanocomposites for high-performance supercapacitor electrode materials

Ordered mesoporous carbon materials show great potential for electric double-layer supercapacitors because of their high specific surface area, designable pore structure, and tunable morphology. However, low graphitic crystallinity nature and poor contact between particles lead to their high inherent resistance, which limits the supercapacitance performance. Herein, we report on a hierarchically rambutan-morphological design of carbon composites with ordered mesoporous carbon as the core and carbon nanotubes as the shell, which significantly improve the electric contact between mesoporous carbon particles and promote the electrochemical performance. By an ultrafast microwave process in a household microwave heater under ambient condition, carbon nanotubes grow out from the pores of ordered mesoporous carbon and are dispersed on its surface like the whiskers of rambutan. As-synthesized ordered mesoporous carbon CMK-3/carbon nanotubes nanocomposites show significantly enhanced specific capacitance (315.6 F·g−1 at 1 A·g−1, as compared with 172.1 F·g−1 of CMK-3), high rate capability (214.6 F·g−1 at 50 A·g−1), and cycling durability (10,000 cycles, 99.32%). The structural design and microwave synthesis enable a facile preparation of the hybrid ordered mesoporous carbon CMK-3/carbon nanotubes nanocomposites, and show potential for easy and low-cost production of high performance electric double-layer supercapacitors materials.

Amine‐ and Amide‐Functionalized Mesoporous Carbons: A Strategy for Improving Sulfur/Host Interactions in Li–S Batteries

AbstractLithium–sulfur (Li–S) batteries are of great interest due to their potentially high energy density, but the low electronic conductivity of both the sulfur (S8) cathode active material and the final discharge product lithium sulfide (Li2S) require the use of a conductive host. Usually made of relatively hydrophobic carbon, such hosts are typically ill‐suited to retain polar discharge products such as the intermediate lithium polysulfides (LiPs) and the final Li2S. Herein, we propose a route to increase the sulfur utilization by functionalizing the surface of ordered mesoporous carbon CMK3 with polar groups. These derivatized CMK3 materials are made using a simple two‐step procedure of bromomethylation and subsequent nucleophilic substitution with amine or amide nucleophiles. We demonstrate that, compared to the unfunctionalized control, these modified CMK3 surfaces have considerably larger binding energies with LiPs and Li2S, which are proposed to aid the electrochemical conversion between S8 and Li2S by keeping the LiPs species in close proximity to the carbon surface during Li–S battery cycling. As a result, the functionalized cathodes exhibit significantly improved specific capacities relative to their unmodified precursor.

Hierarchical NiO/CMK-3 Photocathode for a p-Type Dye-Sensitized Solar Cell with Improved Photoelectrochemical Performance and Fast Hole Transfer.

The sluggish photoelectrochemical performance of p-type dye-sensitized solar cells (p-DSSCs) has hindered its commercial use. In this work, we introduce a novel hierarchical nanocomposite of NiO nanoparticles anchored on highly ordered mesoporous carbons CMK-3 (NiO/CMK-3). Using CMK-3 as a backbone effectively prevented the self-aggregation of NiO nanoparticles and subsequently increased the total specific surface area of the composite for more dye adsorption. The interconnected conductive networks of CMK-3 also served as a split-flow high-speed channel, which was beneficial for hole spin-flow to accelerate hole transfer. The hierarchical NiO/CMK-3 photocathode improved the photovoltaic conversion efficiency to 1.48% in a cell with a Cobalt(II)/(III) electrolyte and a PMI-6T-TPA dye.

Highly Dispersed Pt Nanoparticles on N-Doped Ordered Mesoporous Carbon as Effective Catalysts for Selective Hydrogenation of Nitroarenes

Highly-dispersed Pt nanoparticles supported on nitrogen-modified CMK-3 mesoporous carbon (Pt/N-CMK-3) were first fabricated by a two-step impregnation route. The influences of N content on the catalyst porous structure, Pt nanoparticle size, surface properties, and interaction between Pt species and the support were investigated in detail using N2 sorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS). The N species acted as anchoring sites for the stabilization of Pt particles. Benefiting from the formation of ultrafine metal nanoparticles, the Pt/N-CMK-3 exhibited excellent catalytic activity and selectivity for the selective hydrogenation of nitro aromatics to the corresponding anilines with hydrogen. The Pt/N-CMK-3 catalyst could be reused eight times and keep its catalytic performance.

Preparation and characterization of proton exchange polyvinylidene fluoride membranes incorporated with sulfonated mesoporous carbon/SPEEK nanocomposite

Sulfonation of mesoporous carbon CMK-3 (sCMK-3) prepared by nano-casting technique was carried out post synthesis using one-step process. The incorporation of the acid groups was confirmed using XRD, Raman spectroscopy, FTIR, SEM, TEM and BET isotherm. The sCMK-3 was incorporated into sulfonated poly(ether ether ketone) to form a nanocomposite which was introduced into polyvinylidene fluoride matrix to form a proton exchange membrane. The physicochemical characteristics of the nanocomposite incorporated membranes were characterized using FTIR, ionic exchange capacity, water uptake, swelling ratio, mechanical stability and TGA. The nanocomposite incorporated membranes showed greater surface wettability and higher ion-exchange capacity. The presence of the –SO3H acid groups plays a major role in improving the proton conductivity through the Grotthuss-type mechanism. M4 membrane was identified to be a suitable replacement in the DMFC as it had sufficiently high tensile strength (862.2 MPa), high proton conductivity (0.081 S cm−1) at 45 °C and ultra-low methanol permeability (2.17 × 10−8 cm2 s−1). No evident hydrolytic damage could be identified and had sufficiently high thermal stability and hence can be proposed as a suitable alternative for Nafion membranes in high temperature, low humidity DMFC applications.

Photocatalytic degradation of ibuprofen using modified titanium oxide supported on CMK-3: effect of Ti content on the TiO2 and carbon interaction

TiO2 nanoparticles dispersed in ordered mesoporous CMK-3 carbon with different Ti contents were successfully synthesized and their activity in the photocatalytic degradation of ibuprofen was presented.

Synthesis and characterization of Cu–N, N′-Dicyclohexylcarbodiimide supported on CMK-3 as a novel, efficient and recoverable nanocatalyst for synthesis of tetrazole, polyhydroquinoline, and sulfoxide derivatives

Mesoporous carbon CMK-3 was prepared using SBA-15 silica mesoporous as a hard template. Then, Cu–N, N′-Dicyclohexylcarbodiimide was supported on CMK-3 as a reusable and highly efficient nanocatalyst for the synthesis of tetrazole, polyhydroquinoline, and sulfoxide derivatives. This new catalyst was characterized by FT-IR spectroscopy, XRD, SEM, BET, TGA, EDX, and ICP-OES techniques. After completing reactions, the catalyst was easily separated from the reaction mixture using centrifuge and reusable five times without significant loss of their catalytic efficiency.

Calix[6]quinone as high-performance cathode for lithium-ion battery

Organic quinone compounds have attracted wide attention due to their high theoretical capacities. Here, a novel cyclic macromolecular calix[6]quinone (C6Q), which possesses 6 p -quinone units and can provide 12 electrochemical active sites, has been applied as a promising cathode material in lithium ion batteries (LIBs). The as-fabricated LIBs exhibited an initial specific capacity as high as 423 mA h g−1 ( C theo = 447 mA h g−1 ) at 0.1 C . After 100 cycles, the capacity of C6Q maintained at 216 mA h g−1 , and even after 300 cycles, C6Q still achieved a high specific capacity of 195 mA h g−1 with negligible capacity fading (as compared with the 100th cycle). Due to the large capacity and wide electrochemical window, C6Q can deliver a specific energy up to 1201 W h kg−1 . In addition, the method of immobilizing C6Q with ordered mesoporous carbon (OMC) CMK-3 could further enhance the electrochemical performance of C6Q.

Mesostructured CMK-3 carbon supported Ni–ZrO2 as catalysts for the hydrodeoxygenation of guaiacol

Abstract In this work, mesoporous carbon materials were obtained by using the nanocasting method starting from ordered mesoporous SBA-15 and commercial nonporous Cab-O-sil® M − 5 silica hard templates; materials were named CMK-3 and C-Cab, respectively. These carbon materials, displaying different porous structures (mesopore diameter, specific surface area and pore volume) were used to stabilize Ni and ZrO2 particles using different deposition methods for the nickel and zirconium phases. The catalysts were tested in the hydrodeoxygenation of guaiacol. The conversion varied from 40 to 100% depending on the textural properties of the carbon support and reaction time at 300 °C and under 50 bar of hydrogen pressure. The catalysts were selective toward the formation of the hydrogenation product (methoxycyclohexanol) and hydrogenated - partially deoxygenated product (cyclohexanol). The deposition of the Ni and ZrO2 precursors in mesoporous CMK-3 carbon replicas with a unimodal mesopore diameter, with respect to the use of non-ordered carbons, allows to obtain improved selectivity toward cyclohexanol and, more importantly, toward cyclohexane. Preparation using incipient-wetness impregnation favoured the formation of both monoclinic and tetragonal phases, while the deposition-precipitation method led to the formation of ZrO2 with a unique tetragonal structure. The presence of both monoclinic and tetragonal phases modified the density of catalyst acid sites, which allow to improve the selectivity toward cyclohexane and cyclohexanol while decreasing the selectivity toward the undesired methoxycyclohexanol and other oxygenated compounds.

The applicability of as synthesized mesoporous carbon CMK-3 as a heavy metals adsorbent: application to real water samples

ABSTRACT The efficiency of as synthesized mesoporous carbon CMK-3 in removing heavy metals from the water was studied. The carbon was nanocasted from SBA-15 silica as a mold. The carbon obtained was characterized by nitrogen sorption technique, X-ray diffraction (XRD), infrared spectroscopy, and transmission electron microscopy (TEM). CMK-3 material was used as an adsorbent without any further oxidation treatment. The effect of several factors on adsorption were tested (adsorbent mass, time, pH and concentration). The maximum adsorption capacities were found to be 3.45, 3.86 and 4 mmol g−1 for Pb2+, Cd2+ and Cu2+, respectively. Dynamic adsorption experiments were performed using ultrapure and natural groundwater. The presence of different competitors’ ions did not affect the adsorption capacity of CMK-3.

Synthesis and Electrochemical Properties of CMK-3 with Particles of Nickel, Cobalt and Copper

Mesostructured carbon material CMK-3 for electrodes of electrochemical capacitors was obtained by the method of template synthesis. In order to increase the capacitance characteristics, impregnation of metal ions (Co, Ni, and Cu) into the structure of mesoporous carbon CMK-3 was carried out. The structure of the obtained materials was studied by X-ray diffraction and gas adsorption. The study by TEM showed that highly dispersed, nanosized particles are metal oxides Co, Ni and Cu with the size of 30-50 nm. The particles are uniformly distributed inside the carbon material. Electrochemical characteristics were studied in aqueous electrolytes (1M KCl and 1M KOH). It has been established that the impregnation of metal ions increases in the specific capacity of the mesoporous carbon material by about 30 % (from 110 to 156 F/g) in KOH