Mesoporous Carbon Composites Research Articles

Nanosized CeO2C2 with rich oxygen vacancies embedded in hollow mesoporous carbon as a multifunctional sulfur-loaded matrix for lithium-sulfur batteries

The innovative structural and compositional design of sulfur-loaded matrices is an effective strategy to improve the performance of lithium-sulfur batteries (LSBs). Herein, nanosized CeO2C2 with rich oxygen vacancies embedded in hollow mesoporous carbon composites (HMC/CeO2C2) were synthesized by hydrothermal and annealing reduction processes. This structure has several advantages: the large specific surface area and mesoporous carbon walls facilitate sulfur penetration and electron/ion transport; the abundant mesopores and hollow inner cavities provide the structural basis for sulfur storage and buffer its volume expansion; the oxygen vacancy-rich CeO2C2 nanoparticles grown in situ in HMC and in close contact with carbon form an electrically favorable CeO2C2/C heterointerface as an efficient catalyst, which is conducive to catalyzing the redox reaction of sulfur. Consequently, the retention capacity of the HMC/CeO2C2/S electrode is 728 mAh g−1 after 500 cycles at 0.5 C with a decay rate of 0.056 % per cycle, and it maintains a high reversible area capacity of 3.18 mAh cm−2 and excellent cycling performance even under a high sulfur loading of 4.7 mg cm−2. It provides an idea for the development of multifunctional sulfur-loaded materials with high sulfur loading, high conductivity, and high catalytic activity.

A simple melamine-assisted cellulose pyrolysis synthesis of magnetic and mesoporous N-doped carbon composites with excellent adsorption of Congo red

A magnetic and mesoporous metal/N-doped carbon composite is prepared using a melamine-assisted pyrolysis method of hydroxypropyl methylcellulose with Fe(NO3)3. The magnetic composite has a 3D hierarchical structure composed of 1D nanostructure interlaced with each other and a large pore volume distributed mainly in mesopores. Meanwhile, its N-doped carbon surface with sp2 hybridized structure is positively charged due to the promotion action of its mixed Fe phase, Fe3C and Fe3N, inducing the production of electron deficient conjugated structures as electron acceptors. Its characteristic microstructure determines that the adsorption of anionic Congo red on its surface is achieved mainly through multiple adsorption mechanisms of electrostatic and π-π interaction. Thus, the magnetic composite has an excellent dye adsorption capacity, even improved dramatically at high pH conditions, and simultaneously, the spent composite is quickly separated from wastewater solution by using its magnetic properties. In contrast, these undoped or N-doped carbon composites prepared in the absence of melamine and Fe salts have very poor or partially improved adsorption efficiencies to the Congo red dyes due to their inactive characteristic microstructures, such as lower pore volume, more microporous structures and negatively charged mesoporous surface.

Efficient and low-cost mesoporous magnetic carbon composites derived from date palm stones for environmental remediation of hexavalent chromium

This study was performed to achieve two important scientifically challenging goals, environmental remediation of toxic heavy metals and utilization of agricultural lignocellulosic wastes. In this work, a series of mesoporous magnetic carbon (MMC) adsorbents were synthesized by carbothermic reduction at different temperatures employing date palm (Phoenix dactylifera L.) stones as the carbon source. The synthesized adsorbents were characterized by different technquies and the results confirmed the presence of zero-valent iron (ZVI) nanoparticles and other iron oxides as products of the carbothermal reduction. The nature of phases present, crystallite size and the surface properties were found to be dependent on the calcination temperature. The adsorbent MMC700 exhibited the smallest (ZVI) crystallite size 36 nm and the largest SBET 341 m2/g. All adsorbents showed mesoporous structure with mesopore average diameter lower than 6 nm. The performance was evaluated in the removal process of toxic Cr(VI) in an aqueous medium, and the optimum conditions of the process were reported. The removal process was dependant of solution pH where best results was achieved at pH = 2. Complete removal of chromium was achieved in less than 5 min by MMC700. The results were better fitted with pseudo-second-order kinetics and followed the Freundlich model isotherm. The maximum adsorption capacity was found to be 265.25 mg/g for MMC700, suggesting its application as an efficient, low-cost, and easily separable adsorbent for the toxic Cr(VI) removal process. The prepared adsorbents exhibited superior performance in the removal process compared to other agricultural wastes or biomass - derived adsorbents reported in literature.

Magnetically recyclable mesoporous carbon/zirconia composites for highly efficient removal of Cr(III) organic complexes from high salinity water: adsorption behavior and mechanism

ABSTRACT In this study, zirconia-functionalized magnetic core-shell mesoporous carbon composites (Fe3O4@C-ZrO2) were synthesized for the effective removal of Cr(III)-EDTA in high-salinity wastewater. Fe3O4@C-ZrO2 with Fe3O4 as a magnetic core and ZrO2 embedded in a mesoporous carbon skeleton were prepared by the sol-gel method in the nano-casting stage, which can be magnetically separated. The presence of ZrO2 on the adsorbents enhanced the adsorption of Cr(III)-EDTA and the maximum adsorption capacity of Fe3O4@C-ZrO2 was 16.21 mg·g−1 at pH = 3.0, which is remarkably higher than that of Fe3O4@C (3.65 mg·g−1). Fe3O4@C-ZrO2 has a strong anti-interference capability for cations in water, which can exhibit effective adsorption properties in presence of high concentration cations and anions (80 mmol·L−1) and high salt/complexant agent environments. Cr(III)-EDTA removal by adsorption of Fe3O4@C-ZrO2 was mainly through the formation of ternary complexes between ZrO2 in Fe3O4@C-ZrO2 and carboxylic acid groups in Cr(III)-EDTA. The Cr(III)-EDTA saturated Fe3O4@C-ZrO2 can be easily regenerated in 0.1 mol·L−1 NaOH than in 0.1 mol·L−1 HCl and still demonstrated an effective adsorption capacity for Cr(III)-EDTA after three repeated cycles. The results reflect the effective removal of Cr(III)-EDTA by Fe3O4@C-ZrO2 in high-salinity water, providing a new method for removing heavy metals in complex water.

Evaluation of the adsorption and degradation performance of lanthanum-modified mesoporous carbon nitride composite materials for tetracycline wastewater treatment

Lanthanum-modified mesoporous graphite nitride carbon composites (La-g-C3N4) were synthesized using a thermal shrinkage polymerization method. The La30-g-C3N4 sample exhibited rapid and efficient degradation, along with excellent adsorption capacity for both TC and AF.

Ag-Containing Carbon Nanocomposites: Physico-Chemical Properties and Antimicrobial Activity

The subject of the present work is the synthesis and analysis of the structural and morphological properties of Ag-containing carbon composites and the investigation of their practical application in water purification and disinfection. A series of composites were synthesized by carbonization of resorcinol–formaldehyde polymers filled with Ag-containing fumed silica under an inert atmosphere at 800 °C. The as-synthesized micro- and mesoporous carbon composites were characterized by their specific surface area of 466–529 m2/g. The suitability of the composites for flow-through filters was evaluated by kinetic studies on the adsorption of 4-chlorophenol. The composite with the highest amount of metallic nanophase showed the most effective kinetics with a rate constant (log k) and half-life (t0.5) of −2.07 and 81 min, respectively. The antimicrobial susceptibility was determined against Gram-positive (Staphylococcus aureus ATCC 25923) and Gram-negative strains (Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, and Acinetobacter baumannii ATCC 19606). The zones of bacterial growth inhibition correlated with the silver nanoparticle content and were the lowest for RFC-02 (10–12 mm) and the highest for the RFC-1 composite (15–16 mm), resulting from the increase in number of evenly distributed small Ag nanoparticles (3–5 nm) in the samples.

Cobalt-loaded three-dimensional mesoporous carbon as sulfur host for lithium‑sulfur batteries

The practical application of lithium‑sulfur batteries has been limited due to the poor electrical conductivity of sulfur, the shuttling effect of polysulfide, and the slow redox kinetics of sulfur species. Designing a multifunctional sulfur host with good conductivity, strong adsorption, and high catalytic activity could effectively address these issues. In this work, the cobalt nanoparticles-loaded three-dimensional mesoporous carbon (Co-TDMC) composite was developed as the multifunctional host for lithium‑sulfur batteries. Due to its large specific surface area (2404.7 m2 g−1), abundant mesopores, and good-catalytic performance, the composite could effectively contain sulfur, adsorb polysulfide, and accelerates the conversion reaction of sulfur species. Therefore, when Co-TDMC was used as the sulfur carrier, the sulfur cathode had an excellent initial discharge capacity (1403 mAh g−1 at 0.1C) and a good rate performance (780.2 mAh g−1 at 1C)·In addition, it has excellent long-term cycling stability (a low decay rate of 0.06 % per cycle during 500 cycles at 1C). This work provides a feasible strategy for improving the cycle stability of lithium‑sulfur batteries.

Eco-friendly and magnetic sucrose-derived Fe-containing mesoporous carbon composites for high-efficiency Congo red adsorption and supercapacitor applications

In this study, eco-friendly and magnetic sucrose-derived Fe-containing mesoporous carbon (Fe-MC) composites have been prepared by carbothermal reduction. The Fe-MC3-1000 prepared from sucrose and FeSO4 with a mass ratio of 1:1 at 1000 °C has a uniform mesoporous structure with a BET surface area of 184 m2/g. The carbothermal reduction of Fe2O3 had dual effects of the pore-forming and the loading. Batch adsorption experiments and electrochemical measurements show that the Fe-MC3-1000 has the optimum performance in both adsorption and supercapacitor applications. For adsorption, the maximum adsorption capacity for Congo red (CR) arrived at 972.1 mg g−1 with a removal percentage of 97.2 %. The adsorption process has good agreement with Langmuir isotherm and Elovich kinetic models. Besides, the Fe-MC3-1000 exhibits good recyclability after five adsorption-desorption cycles. For supercapacitor, the Fe-MC3-1000 electrode has a capacitance value of 179.23 F g−1 and a capacitance retention of 92.8 % at 10 A g−1 after 2000 cycles. The outstanding adsorption and electrochemical performances suggest that the Fe-MC3-1000 is a competitive bi-functional material for adsorption and supercapacitor.

Preparation of Magnetic Iron/Graphitic Mesoporous Carbon Composites as Efficient Returnable Adsorbents for Methyl Orange Removal

Preparation of Magnetic Iron/Graphitic Mesoporous Carbon Composites as Efficient Returnable Adsorbents for Methyl Orange Removal

Synthesis of LiTiO2 Nanocrystals/Ordered Mesoporous Carbon Composite Hosts for High‐Performance Lithium–Sulfur Batteries

Metal oxide nanocrystals/mesoporous carbon composite materials are promising in the energy storage field. However, the construction of stoichiometric ternary nanocrystals‐functionalized mesoporous carbon materials remains a great challenge. Herein, the synthesis of ultradispersed and ultrasmall LiTiO2 nanocrystals/ordered mesoporous carbon composites via a chelation‐mediated multicomponent coassembly strategy is reported. In this case, the self‐assembly into ordered mesostructures and the crystallization of nanoparticle processes can be decoupled by the molecular chelate strategy where citrate ligands can effectively inhibit the hydrolysis and phase separation of metal oxide precursors and confine the crystallization into nanocrystals without aggregation. The obtained 33%‐LiTiO2–OMC composites present a high specific surface area (≈912 m2 g−1), a large pore volume (≈0.62 cm3 g−1), a uniform pore size (≈4.1 nm), and ultradispersed LiTiO2 nanocrystals (≈3 nm). When loading 60% sulfur, the composites exhibit a high reversible capacity (966 mAh g−1 after 100 cycles at 0.5C), an excellent rate capacity (700 mAh g−1 at 5C), and a long‐term cycling performance (63% retention after 1000 cycles at 5C). This method is very simple and reproducible, which paves a new way for the design and synthesis of functional mesoporous materials.

Development of Mesoporous Carbon Composites with Waste Plastics Derived Graphene and MnO2 for Supercapacitor Applications

This study demonstrates the influence of incorporating the composites such as waste plastics derived graphene (WPDG) and manganese dioxide (MnO2) in the mesoporous carbon (CR) and their consequent characteristics. The CR having WPDG as composite is named as CRG and MnO2 containing CR composite is termed as CRM. CRG possess the surface area as high as 790 m2g−1 along with pore volume of 0.565 cc g−1 and radius of 3.82 nm. Cyclic voltammetry (CV) study suggested that CR and CRG showed non-Faradic capacitive behavior with almost rectangular shaped CV profiles at low scan rates and this shows the existence of electric double layer structure. On the other hand, pseudo-capacitance is observed for CRM. Galvanostatic charge/discharge investigation revealed that the specific capacitance can be enhanced by 6 times upon subsequent immobilization of WPDG in CR whereas 4-fold upgrading in the specific capacitance after treating CR with MnO2. Interestingly, CRM showed higher capacitance retention as compared to CRG and is attributed to its smaller value of equivalent series resistance as compared to CRG. Ragone plots shown that the higher energy and power densities are found for the case of CRG.

Heterogeneous catalytic oxidation of tetracycline hydrochloride based on persulfate activated by Fe3O4/MC composite

In this study, a novel magnetic mesoporous carbon composite (Fe3O4/MC) was prepared by manganese carbonate (MnCO3) as the template to activate persulfate (PS) for tetracycline hydrochloride (TC) degradation. The characterization results showed that Fe3O4 nanoparticles were evenly distributed on the surface of MC, and Fe3O4/MC had the large surface area of 433.88 m2∙g−1. When the initial TC concentration was 50 mg·L−1, Fe3O4/MC dosage was 0.0336 g, PS dosage was 0.0476 g and the reaction temperature was 30 °C, Fe3O4/MC + PS system could degrade 92.9% of TC within 90 min. TC degradation efficiency increased with the increase of Fe3O4/MC dosage and temperature, but decreased with the increase of TC initial concentration and pH value. The increase of PS concentration first improved TC degradation efficiency, and then was not conducive to its degradation. The quenching experiments indicated that the sulfate radical (SO4•−), superoxide radical (•O2–) and singlet oxygen (1O2) in Fe3O4/MC + PS system contributed to TC degradation. Meanwhile, the toxicity evaluation of the degradation products confirmed that the toxicity of TC in Fe3O4/MC + PS system was greatly reduced. Totally, this study systematically investigated the performance of the Fe3O4/MC + PS system for TC removal, laying a theoretical and practical foundation for treatment of potential antibiotic wastewater (ppm range) in the future.

Mesoporous SnSe2-grafted N-doped carbon composites with integrated flaky structure for electrochemical sensing of carbendazim

Innovative and efficient electrocatalysts using selenide based composites are essential for electrochemical analyses and could significantly impact various modern technologies. This paper prepared a flake-like architecture comprising SnSe2 grafted N-doped carbon (NC) (SnSe2-NC) through a simple hydrothermal method and successfully applied the material for electrochemical sensing of carbendazim (CBZ). We investigated impacts from calcination temperature on prepared SnSe2 materials using various characterization methods, including XRD, XPS, BET, TGA, HR FE-SEM and FE-TEM. Nanocomposite electrochemical activity toward CBZ detection was ascribed to synergy between NC providing a conductive matrix and SnSe2 agglomeration providing large active surface area, superior conductivity, and abundant active surface sites. The fabricated sensor detected CBZ across a wide linear concentration range 0.002–139.38 μM under ideal conditions, with limit of detection = 0.67 nM. The propound sensor was effectively applied to detect CBZ in pure water and vegetable extracts, with reasonable recovery rates.

Tailoring co-doping of cobalt and nitrogen in a fullerene-based carbon composite and its effect on the supercapacitive performance

Controllable cobalt and nitrogen are in situ formed in mesoporous carbon composites via fullerene self-assembly and pyrolysis, which lead to an enhanced electrochemical performance.

Facile route for synthesis of Fe0/Fe3C/γ-Fe2O3 carbon composite using hydrothermal carbonization of sugarcane bagasse and its use as effective adsorbent for sulfamethoxazole removal

Non-toxic mesoporous magnetic carbon composite was synthesised from hydrothermal carbonization of sugarcane bagasse with Iron (III) nitrate nonahydrate in two steps along with thermo-chemical oxidation process using sodium hydroxide. IR spectrum exposed the presence of oxygenated functional groups and FeO whereas XRD analysis revealed the availability of Fe0/Fe3C/γ-Fe2O3 at varying intensities. SEM analysis showed the spherical shaped carbon is well encapsulated with iron particles. Textural studies showed that after thermo-chemical activation intensified the surface area on composites to about 491.474 m2 g−1 thereby, promoting improved porosity on the carbon matrix. The fabricated composite showed magnetization of 32.84 emu g−1 and SMX adsorption capacity as 169.49 mg g−1. Kinetics and isotherm studies revealed that removal of SMX fitted well in Pseudo-second order and Langmuir models. The mode of interaction of SMX on magnetic carbon composites with respect to different pH was studied showing that π-π electron donor interaction (EDA), hydrophobic interaction, charge assisted hydrogen bond formation were responsible for SMX removal. The selectivity nature of magnetic composite with respect to SMX was studied in the presence of multiple pollutant. Use of magnetic carbon helps in industrialising the material to high level due to their unique property in separation and recycling. Application of hydrothermal carbonization is found to be applicable for wet solid substance thereby evolving structural carbon compound.

High-performance asymmetric supercapacitor achieved by CoS2 nanoparticles decorated polyaniline functionalized SBA-15-derived mesoporous nitrogen-doped carbon with rod-like architectures

The promising candidates for high-performance electrode materials, transition metal species@N-doped mesoporous carbon composites (M/MO/M(OH)2@NDMCs), were synthesized by carbonization of metal ion-doped polyaniline (PANI) functionalized mesoporous silica SBA-15, followed by etching the mesoporous silica template. The yielded M/MO/M(OH)2@NDMC can be further converted into sulfide via a simple hydrothermal sulfidization treatment. The mesoporous structure, large amount of the accessible electrochemically active nitrogen species, partially graphitic structure, and transition metal compounds of transition metal species@NDMC composites will increase the electronic and ionic conductivity by reducing the internal and ion diffusion resistances resulting in fast diffusion of ions in the electrolyte to the electrode surface. These endowed them good electrochemical performance characteristics for use in supercapacitor electrodes. Correspondingly, NiO/Ni(OH)2@NDMC, Co/Co(OH)2@NDMC, and CoS2@NDMC as the electrodes in 2 M KOH showed specific capacitance of 337, 589, and 1178 F g–1 at 2.0 A g–1, respectively. Furthermore, the assembled asymmetric supercapacitor device utilizing CoS2@NDMC as a cathode exhibited a satisfactory energy storage capability (50 Wh kg–1 at 750 W kg–1) with an admirable cyclic life (retaining ~99% initial capacitance over 6000 repeated cycles). This finding gives these transition metal species@NDMC composites, especially CoS2@NDMC, prospective applications as high-performance supercapacitor electrode materials, where a fast charge/discharge is required.

Glucose electrocatalysts derived from mono‐ or dicarbene coordinated nickel(II) complexes and their mesoporous carbon composites

AbstractMolecular electrocatalysts that contain a metal atom under precise ligand field in a definite geometry feasible for redox reactions has boundless significance in numerous electrocatalytic reactions. Herein, we report nickel‐based molecular electrocatalysts anchored on the sterically varied 1,2,4‐triazol‐5‐ylidene ligands. The two metal complexes bearing different ligand system wherein one is mono‐NHC nickel(II) complex and the other is a bis‐NHC nickel(II) complex were compared and studied in terms of morphology and electrochemical glucose sensing. The kinetics and sensitivity of the nickel(II) complexes were significantly enhanced by the mesoporous carbon and demonstrated high electrode sensitivity (2.57–124.92 μA mM−1 cm−2) at a fixed potential towards glucose detection. The chronoamperometric studies evidenced the detection of glucose up to 27.5 mM with a linear range of detection up to 9.5 mM (LOD of 44.59 μM). The selectivity towards glucose in the presence of other blood constituents was investigated. Finally, the stability was studied after 18 days of electrode preparation, and negligible variation in the glucose sensing performance was found. The electrocatalysts prepared are found to be the viable candidates for potential engineering high‐performance molecular non‐enzymatic glucose sensor.

The ordered mesoporous carbon coated graphene as a high-performance broadband microwave absorbent

There has been a great challenge in developing highly efficient electromagnetic microwave absorbers with strong absorbility, wide effective absorbing bandwidth and lightweight to solve the increasingly severe electromagnetic pollution. Here, we unveil the great potential of highly ordered mesoporous carbon coated graphene composites in the application of microwave absorption. The ordered mesoporous carbon composites possess well-defined spherical mesopores that are uniformly distributed on graphene surfaces and with uniform diameters of ∼20 nm (graphene@mesoporous carbon, abbreviated as G/MC). This renders the nanocomposites with high BET surface areas of up to 316 m2 g−1. Impressively, the G/MC nanosheets carbonized at 900 °C (G/MC-900) exhibit an outstanding microwave absorbility, with a maximum reflection loss (RL) of −66.1 dB and an exceptionally broad effective absorbing bandwidth (EAB) of 8.2 GHz (RL < −10 dB) at ultralow filler loading of only 5 wt%. This microwave absorbility is superior to that of most microwave absorbing materials that have been reported, making the 2D mesoporous carbon nanocomposites a strong candidate for microwave attenuating materials.

Single-step electrochemical sensing toward ppb-level nitrite in cured meat sensitized with functionalized Ia3d mesoporous carbon

A simple and sensitive electrochemical sensor is designed for evaluating nitrite (NO2−) in cured meat by using the functionalized mesoporous carbon composites (CMK-8) as sensing interface. Herein, the synthesized CMK-8 with 3-D bicontinuous cubic (Ia3d) space groups has obvious electrochemical superiority over the usual CMK-3 with 2-D hexagonal (p6mm) space groups, and offers a powerful platform for gold nanoparticles (AuNPs) decoration inside and outside the ordered carbon pores via electrostatic adsorption and size matching. Benefitting from the synergistic effects of AuNPs and CMK-8 under suitable ratio, AuNPs-CMK-8 provides a favorable biocompatible microenvironment for hemoglobin (Hb) attachment, and also accelerates electron transfer between NO2− and active centers of Hb. The electrochemical determination is accomplished through one-step catalytic process without complicated operation or multiple reagents, greatly improving temporal efficiency. The limit of detection (LOD) as low as 2.1 nM (corresponding to 0.097 ppb by weight) is well qualified for the requirement for rapid monitoring nitrite in cured meat. Overall, the sensing strategy possesses the characteristics of excellent sensitivity, anti-interference ability, and single-step fashion, giving a promising solution to evaluate nitrite residual for ensuring cured meat safety.

Synthesis of N-Doped Magnetic Mesoporous Carbon Composites for Adsorption of Ag(I) in Aqueous Solution.

In this work, a novel N-doped magnetic mesoporous carbon (NMC) composite (Fe₃O₄/NMC) was synthesized by a two-step process. First, NMC was prepared by a template method using a melamine formaldehyde resin as nitrogen and carbon sources, and then, Fe₃O₄ nanoparticles were loaded into the as-prepared NMC via in-situ coprecipitation process. The morphology, structure, and magnetic properties of Fe₃O₄/NMC were characterized and its adsorption properties were investigated. It can be found that Fe₃O₄/NMC with saturation magnetization of 20 emu · g-1 features a mesoporous structure, and its specific surface area reaches 513 m² · g-1. These two excellent specificities are propitious to the adsorption and separation of Ag(I) from aqueous solution. The adsorption behavior of Fe₃O₄/NMC nanocomposite has been investigated by adsorption kinetics and isotherms adsorption analyses as well. The adsorption isotherm and the adsorption kinetics of Ag(I) onto Fe₃O₄/NMC agrees well with Langmuir model and pseudo-second-order model, respectively. Moreover, the Fe₃O₄/NMC was easily to recovery by applied magnetic field, the adsorption capacity of Fe₃O₄/NMC was about 90.3% of the initial saturation adsorption capacity after five continuous uses.