Porous Carbonaceous Materials Research Articles

Recyclable magnetic carbonaceous porous composites derived from MIL-100(Fe) for superior adsorption and removal of malachite green from aqueous solution.

Development of novel porous materials for efficient adsorption and removal of environmental pollutants from aqueous solution is of great importance and interest in environmental science and chemistry. Herein, we reported a facile synthesis of recyclable magnetic carbonaceous porous composite derived from iron-based metal–organic framework MIL-100(Fe) for superior adsorption and removal of malachite green (MG) from aqueous solution. Because of large surface area and high porosity, the synthesized magnetic carbonaceous porous material presented a superior adsorption capacity of 2090 mg g−1 for MG. The adsorption of MG on magnetic carbonaceous porous composite is endothermic and spontaneous. The prepared magnetic carbonaceous porous composite could be separated easily and rapidly from the solution matrix by an external magnet. The rapid adsorption, large adsorption capacity and good reusability make it attractive for practical use in the adsorption and removal of dyes from aqueous solutions.

Nitrogen-rich hierarchically porous carbon as a high-rate anode material with ultra-stable cyclability and high capacity for capacitive sodium-ion batteries

Carbon-based anode materials hold a promising future for sodium-ion batteries (SIBs) due to their natural abundance and low cost of development. In spite of carbon's important role in the commercialization of lithium-ion batteries (LIBs), further exploration is necessary in order to find high-performance, high-rate carbon anode materials for SIBs. A honeycomb-like, nitrogen-rich (17.72 at%), hierarchically porous, and highly disordered carbonaceous material (N-HC) with an expanded interlayer distance (0.44 nm in average) is synthesized by spray drying and subsequent pyrolysis under flowing NH3. The hierarchically porous structure and rich nitrogen doping result in a large specific surface area (722 m2 g−1), more defects and active sites, and greater functional interface accessibility for the active porous carbonaceous material and electrolyte. When N-HC is used as the anode material for SIBs, the batteries display favorable discharge capacities (255.9 mA h g−1 in the 3000th cycle at 500 mA g−1) and good capacitive-energy-storage behavior (67% at a scan rate of 0.5 mV s−1) with excellent high-rate performance and ultra-stable cyclability over 10,000 cycles at 5000 mA g−1. Our results show that the combination of the hierarchically porous structure and nitrogen doping leads to improved energy storage by increasing the capacitive energy storage, which enhances the high-rate performance of N-HC. To further enhance the performance of the material, an electrical pretreatment is employed to increase the initial Coulombic efficiency of N-HC to 79.5%, a record high for an SIB cell. A full cell with an N-HC anode and a Na3V2(PO4)3/C cathode shows a high capacity with a favorable cyclability (238.7 mA h g−1 after 100 cycles at 100 mA g−1 and a capacity retention of 95.3% compared to the second cycle).

Porous carbon materials derived from in situ construction of metal-organic frameworks for high-performance sodium ions batteries

Abstract In this study, a novel 3D porous carbon (3DPC) materials have been designed and synthesized from metal-organic frameworks as precursors. The resultant 3DPC exhibits high specific surface area and large pore volume, which can largely increase contact area, shorten ion diffusion pathways and improve ion kinetics upon cycling. When used as anode materials for sodium ions batteries (SIBs), 3DPC shows satisfied electrochemical performance with a high maximum reversible capacity of 284 mAh g−1 after 100 cycles at a current density of 50 mA g−1, excellent rate capability with a high reversible capacity of 125 mAh g−1 can be obtained even at a high current density of 2.5 A g−1 and robust long-term cycling stability for 3000 cycles with a remarkable capacity of 175 mAh g−1 at 1 A g−1, showing great potential for high-performance SIBs. This work provides a new approach for constructing porous carbonaceous materials from metal-organic frameworks.

3D-printed conductive static mixers enable all-vanadium redox flow battery using slurry electrodes

State-of-the-art all-vanadium redox flow batteries employ porous carbonaceous materials as electrodes. The battery cells possess non-scalable fixed electrodes inserted into a cell stack. In contrast, a conductive particle network dispersed in the electrolyte, known as slurry electrode, may be beneficial for a scalable redox flow battery. In this work, slurry electrodes are successfully introduced to an all-vanadium redox flow battery. Activated carbon and graphite powder particles are dispersed up to 20 wt% in the vanadium electrolyte and charge-discharge behavior is inspected via polarization studies. Graphite powder slurry is superior over activated carbon with a polarization behavior closer to the standard graphite felt electrodes. 3D-printed conductive static mixers introduced to the slurry channel improve the charge transfer via intensified slurry mixing and increased surface area. Consequently, a significant increase in the coulombic efficiency up to 95% and energy efficiency up to 65% is obtained. Our results show that slurry electrodes supported by conductive static mixers can be competitive to state-of-the-art electrodes yielding an additional degree of freedom in battery design. Research into carbon properties (particle size, internal surface area, pore size distribution) tailored to the electrolyte system and optimization of the mixer geometry may yield even better battery properties.

Porous carbonaceous materials from hydrothermal carbonization and KOH activation of corn stover for highly efficient CO2 capture

ABSTRACTSustainable biomass-derived carbon materials were produced by hydrothermal carbonization of corn stover that was followed by chemical activation with KOH. The prepared carbon materials were used for CO2 adsorption and had a CO2 uptake of 7.14 mmol/g at a pressure of 1 bar and at 0°C that was much higher than CO2 uptake by activated carbon that was prepared from direct activation of corn stover (2.78 mmol/g). The porous corn stover-derived carbonaceous material had high surface area (2442 m2/g) and large pore volume (1.55 cm3/g). Product yields obtained by the activation of hydrothermally carbonized corn stover were significantly higher than those obtained by the direct activation of corn stover (36–75 vs. 8%). The prepared corn stover-derived porous carbon had a high CO2/N2 selectivity of 15.5 and exhibited constant CO2 uptake for five successive reuse cycles. The hydrothermal carbonization step plays an important role for producing porous carbons from biomass that have high and specific adsorption properties.

Natural cotton as precursor for the refractory boron carbide—a hydrothermal synthesis and characterization

Boron carbide (B4C) is an excellent covalent carbide that finds applications in industries and nuclear power plants. The present synthesis methods of boron carbide are expensive and involve the use of toxic chemicals that adversely affect environment. In the present work, we report for the first time the use of the hydrothermal method for converting the cellulose from cotton as the carbon precursor for B4C. The carbon precursor is converted into functionalized porous carbonaceous material by hydrothermal treatment followed by sodium borohydride. It is further treated with boric acid to make it a B4C precursor. The precursor is characterized by UV–visible diffuse reflectance, Raman, Fourier transform infrared, photoluminescent and energy dispersive spectroscopy. The morphology and structure analysis is carried out using field emission scanning electron microscopy and x-ray diffraction techniques. The results of structural and optical characterization of the sample synthesized are compared with the commercial B4C. The thermal stability of the sample is studied by thermogravimetric analysis. The sample annealed at 700 °C is found to be B4C devoid of amorphous carbon with a yield of 44.7%. The analysis reveals the formation of boron carbide from the sample.

Facile synthesis of hierarchically porous carbonaceous materials derived from olefin/aldehyde precursors using silica as templates.

Porous carbon is exceptionally useful, but it remains a great challenge to develop a facile route to prepare porous carbon materials with hierarchical structure and enhanced porosity. This work demonstrates a novel synthetic pathway for hierarchical carbonaceous materials (HCM) using isobutene and formaldehyde as carbon precursors via silica templates impregnated with phosphorus. Different from the traditional nanocasting method, the formation of the carbon structure is caused by heavy coke deposits on the solid catalyst in the course of the olefin/aldehyde vapor reaction. The coke-derived carbonaceous materials indicated by transmission electron microscopy (TEM) and nitrogen adsorption–desorption measurement are hierarchically mesoporous structures with a large surface area (971 m2 g−1) and pore volume (1.91 cm3 g−1). We have demonstrated for the first time that the olefin/aldehyde reaction may provide a convenient route to develop a porous carbon texture. The newly developed method may lead to porous carbon having scientific and technological importance in adsorption and catalysis applications.

Synthesis of carbon molecular sieve microspheres via amino phenolic resin as precursor formed from in-situ reaction composite micelles

The carbon molecular sieve microspheres (CMSm) is one kind of porous carbonaceous materials. Owing to its high surface area and stability, CMSm have been attracted immense attention in various fields. In this study, the CMSm with tunable pore structure has been synthesized via self-assembling, in-situ reaction and soft-templating method in aqueous system. Meanwhile, the influence of carbonization temperature, heating rate, surfactant content and the amount of pore-forming agent (1, 3, 5-trimethylbenzene) on the morphology and pore properties of CMSm were studied. The result of nitrogen adsorption/desorption analysis indicates that the volume of the micropores increases as carbonization temperature increases, and generally decreases as the heating rate increases. The amount of surfactant and pore-forming agent have little influence on the volume of the micropores. It is also found that the CMSm have good hydrogen storage performance.

Valorisation of waste rice straw for the production of highly effective carbon based adsorbents for dyes removal

Highly porous carbons have been produced through an activated pyrolysis process from waste rice straw. The methodology avoids the use of extensive pre-treatments and utilises lower temperatures than those previously reported (700 °C), to generate materials suitable for water purification. Activation of rice straw was achieved with carbon dioxide, potassium hydroxide and phosphoric acid to yield porous carbonaceous materials and those prepared with phosphoric acid exhibited an extremely high proportion of mesoporosity (94–95%). The characterisation of the activated carbon demonstrated that rice straw pre-carbonisation at 400 °C prior to activation using potassium hydroxide at 700 °C, resulted in a material with surface area of 1973 m2/g. The pre-carbonised potassium hydroxide activated carbon was demonstrated to be highly effective at the adsorption of methylene blue (cationic dye) and congo red (anionic dye) with the adsorption capacity of 527.6 and 531.4 mg/g respectively. In many cases these adsorption capacities exceeded those of other absorbents previously reported within the literature but importantly require less pre-treatment. An economic assessment of the process demonstrated that these highly porous carbons from waste rice straw are cost competitive with other commercially available activated carbons. These activated carbons may find use as an inexpensive yet effective adsorbents for dye removal and also the mesoporous carbons can be utilised in other applications including catalysis and chromatography.

Porous nitrogen-enriched carbonaceous material from marine waste: chitosan-derived carbon nitride catalyst for aerial oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid

Chitosan-derived, porous nitrogen-enriched carbonaceous carbon nitride catalyst (PCNx) has been synthesized from marine waste and its use demonstrated in a metal-free heterogeneous selective oxidation of 5-hydroxymethyl-furfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using aerial oxygen under mild reaction conditions.

Turning Waste Chemicals into Wealth-A New Approach To Synthesize Efficient Cathode Material for an Li-O2 Battery.

An Li-O2 battery requires the oxygen-breathing cathode to be highly electronically conductive, rapidly oxygen diffusive, structurally stable, and often times electrocatalytically active. Catalyst-decorated porous carbonaceous materials are the chosen air cathode in this regard. Alternatively, biomass-derived carbonaceous materials possess great ability to remove heavy and toxic metal ions from waste, forming a metal-adsorbed porous carbonaceous material. The similar structure between the air cathode and the metal-adsorbed biomass-derived carbon nicely bridges these two irrelevant areas. In this study, we investigated the electrochemical activity of a biochar material Ag-ESB directly synthesized from ethanol sludge residue in a rechargeable aprotic Li-O2 battery. Ag ions were adsorbed from sewage and became Ag nanoparticles with uniform coverage on the biochar surface. The as-prepared material exhibits good electrochemical behavior in battery testing, especially toward the battery efficiency and cyclability. This study provides the possibility of synthetically efficient cathode material by reusing "waste" such as biofuel sludge residue. It is an economically and environmentally friendly approach both for an energy-storage system and for waste recycling.

Three-dimensional hierarchical and interconnected honeycomb-like porous carbon derived from pomelo peel for high performance supercapacitors

The urgent need for sustainable development of human society has forced material scientists to explore novel materials starting from cheap natural precursors for next-generation energy storage devices by using environmentally friendly strategies. In this work, heteroatom-functionalized porous carbonaceous materials with 3D hierarchical and interconnected honeycomb-like structure have been successfully synthesized by using waste biomass pomelo peel as raw material through the combination of hydrothermal carbonization and followed KOH activation procedure. Benefiting from the unique honeycomb-like structure and high specific surface area, the as-obtained carbon material exhibits satisfactory capacitive behavior: 374F/g at 0.1A/g; excellent cycling stability of 92.5% capacitance retention over continuous 5000 cycles. More importantly, the as-assembled symmetric supercapacitors based on as-prepared electrode material can deliver high gravimetric and volumetric energy density of 20Wh/kg and 18.7Wh/L in 6M KOH, respectively, as well as outstanding cycling stability. The obtained results demonstrate the possibility for taking full advantage of sustainable and large scale advanced carbon materials by choosing waste biomass, particularly the pomelo peel as a raw material.

Biochar – Ecological Product and Its Application in Environmental Protection

Biochar is a product of the pyrolysis of waste from the process of biomass fermentation. It is the case of a porous carbonaceous material with a compact hydrophobic core of predominantly aromatic structure, sheathed with a shell exhibiting hydrophilic and chemically active properties (surface groups: -OH, C=O, -COOH). One of properties usable in environmental protection is its adsorption ability toward heavy metals and organic pollutants (pesticides, PAHs, pharmaceutical products, industrial wastes). The contribution contains the description of preparation, surface analysis (SEM), identification of functional groups (FTIR) and proposal for possible surface modifications (sonification, oxidation, reduction, hydrothermal pyrolysis with graphene oxide, etc.) with a view to increase the sorption ability of biochar.

Toward a molecular design of porous carbon materials

The molecular design of porous solids from predefined building blocks, in particular metal-organic and covalent frameworks, has been a tremendous success in the past two decades approaching record porosities and more importantly was an enabler for integrating predefined molecular functionality (enantioselectivity, optical and catalytic properties) into pore walls. Recent efforts indicate that this concept could also be applicable to rationally design porous and nanostructured carbonaceous materials, a class of materials hitherto and especially in the past often considered as “black magic” in terms of pore-wall structure definition and surface functionality. Carbon precursors with structural and compositional information in their molecular backbone, pre-formed covalent bonds, or integrated functional groups enable the design of carbon materials that can be tailored for certain applications. We review this exciting field of synthetic approaches based on molecular building blocks such as ionic liquids, bio molecules, or organic precursor monomers enabling the design of advanced carbonaceous architectures such as porous carbons, porous carbon-rich polymers or graphene nanoribbons. Moreover, our review includes approaches using the reactive and thermal transformation of periodic crystalline structures such as metal-organic frameworks, or carbides into equally defined carbon material. Such molecularly designed carbons are not only ideal model materials for fundamental science but also emerge in applications with until now unattained functionality.

Ultramicroporous carbon with extremely narrow pore distribution and very high nitrogen doping for efficient methane mixture gases upgrading

It is notably challenging to fabricate heavily heteroatom-doped porous carbonaceous materials with narrow ultramicropore size distributions for highly effective mixed-gas separation. In this study, new carbon-based materials with narrow ultramicropore size (<7 Å) distributions (>95%) and high N doping contents (>10 at%) are fabricated through the pyrolysis of a perchloro-substituted porous covalent triazine-based framework (ClCTF). In particular, the sample prepared at 650 °C (ClCTF-1-650) possesses the highest ultramicropores content (98%) and large N content (12 at%) and demonstrates a very high CH4 and CO2 capacity, as well as a low N2 uptake under ambient conditions. The extraordinarily high CH4/N2 and CO2/N2 selectivities correlate with both the ideal adsorption solution theory (IAST) method and performed dynamic separation experiments (breakthrough experiments). The results reported in this study far exceed the CH4/N2 and CO2/N2 selectivities of previously reported carbon-based adsorbents including various nitrogen-doped ones. These results are believed to be associated with the unusually high N content, as well as the suitably narrow ultramicropore size distribution. This report introduces a new pathway to design porous absorbents with precisely controlled ultramicropores for gas separation.

Direct synthesis of interconnected N, S-codoped porous exfoliated carbon nanosheets as advanced electrocatalysts for oxygen reduction reaction

The pursuit of porous carbonaceous materials with large specific surface area, well-defined pore structure and desirable dopants remain challenges for both energy storage and conversion. Here, we fabricate a novel interconnected N, S-codoped porous exfoliated carbon nanosheets (ECNs) with large specific area and pore volume through a one-step carbonization process by using glucose/melamine-sulphate-salt (GMSS) as precursor. By carefully examining the carbonization process of the precursor, we propose a phase separation mechanism for the formation of ECNs. The optimized sample, composed of interconnected thin graphite layers with N and S co-doping in the carbon lattice, exhibits outstanding ORR activity in terms of half-wave potential (0.83 V vs. RHE) and onset potential (0.97 V vs. RHE), together with 4-electron selectivity (H2O2 yield less than 8%), one of the best among all reported metal-free ORR catalysts.

Tomography-based radiative characterisation of decomposing carbonaceous heat shield materials

This work evaluates the changes in radiative properties of two decomposing carbonaceous porous materials, each composed of two semi-transparent, homogeneous and isotropic phases. The understanding of the complex dependence of macroscopic optical behaviour on material microstructure, bulk phase properties and the wavelength of incoming radiation is paramount for modelling, design and optimisation of systems incorporating such media. Experimental and numerical techniques were combined to solve the homogenised radiative transfer equations using Monte Carlo ray tracing in the limit of geometrical optics. Effective radiative properties required by these equations were determined by Monte Carlo techniques using the exact 3D microstructures of the samples, obtained through high-resolution synchrotron computed tomography. This methodology is applied to a medium density carbon phenolic and a high density graphite reinforced polymer composite, each composed of semi-transparent solid and fluid phases. The extent of material decomposition is seen to affect the absorption behaviour of both samples. This effect is more obvious in the lower density carbon phenolic, where an 18% increase in absorptance is observed due to decomposition, compared to an increase of just 2% for the graphite. A library of absorption data is presented for use in continuum heat transfer modelling of similar chemically reacting macroporous carbon composites.

Novel Carbon Porous Material with Nanostructural for Separation of Arsenic(III) from Water with Highest Adsorption Capacity

Arsenic is a heavy metal and exists in an oxidation state of -3, 0, +3 or +5 which the As (III) is more toxic than other. Due to the extreme toxicity of As(III) in drinking water many research was done to find natural and economical adsorber for removing it from the water. Porous carbonaceous nanostructural materials have been widely used in the adsorption of contaminated water, gas storage, separation, and purification. By special experimental method were produced in Beshel Activated Carbon Industry (BACI) a new carbon adsorber material (BACI-2017) with nano pores, for removal of As (III) in contaminated water. Because of existing an appropriate pores and surface area, the new adsorber has shown a high tendency for adsorption of Arsenic (III) from water. Experiment: Two different particle sizes, mesh 4x8 and mesh 100 and greater than 100 mesh, were used. The separation of As(III) were done with 0.5 gram of BACI-2017 with mesh 4x8 and 0.1 gram of BACI-2017 with 100 mesh and greater than100 mesh and six different concentrations of As(III) solution, 5, 10, 20, 30, 50, 100 and 100, 200, 300, 400, 500, 1000 ppm respectively. In all experiments the pH was about 8.5. The results showed that the maximum adsorption capacity of As(III) calculated from Langmuir isotherm was found 41.48 mg/g for 0.5 gram of GRG-2017 with mesh 4x8 and 0.1 gram of BACI-2017 calculated from Freundlich isotherm was 455 mg/g for 100 mesh and greater than 100 mesh. The contact time in all experiments was 15 minutes. The study showed that the adsorption capacity of arsenic is strongly depending on the particle size of adsorber. The results: The BACI-2017 nanopores adsorber for removal of As (III) from aqueous solution shown that the As (III) can be separated from water with a high capacity of 455 mg/g or 455 g of As (III) per kg of adsorber BACI-2017. This is a world record with highest adsorption capacity in comparison with other studies till now, March 2017.

Magnetic Porous Carbonaceous Material Produced from Tea Waste for Efficient Removal of As(V), Cr(VI), Humic Acid, and Dyes

Magnetic porous carbonaceous (MPC) materials derived from tea waste were synthesized by an integrated biosorption–pyrolysis process and were applied as adsorbents for wastewater cleanup. On the basis of various characterizations, we demonstrated that the formation mechanism of γ-Fe2O3 anchored on the porous carbonaceous material surface consisted of the adsorption of iron ions and then the γ-Fe2O3 nucleation and growth through pyrolysis at alternative peak temperatures (300–500 °C). The sample pyrolyzed at 300 °C (MPC-300) showed good capacities for As(V) (38.03 mg g–1) and Cr(VI) (21.23 mg g–1) adsorption, outperforming that of commercial bulk Fe2O3 and many other materials. Moreover, the large available positive charge density can facilitate the effective adsorption of anionic dye (MO) and humic acid (HA) on the γ-Fe2O3 surface while the adsorption performance is sluggish for cationic dyes (MB and RhB). Relatively, the adsorption isotherms could significantly conform to the Langmuir model, and the pseud...

Metal-organic framework-derived carbons: Preparation from ZIF-8 and application in the adsorptive removal of sulfamethoxazole from water

In this study, we prepared highly porous carbonaceous materials from a metal-organic framework (MOF), ZIF-8, by pyrolysis. Pyrolysis temperature had a significant effect on the porosity of MOF-derived carbons (MDCs); the MDCs obtained at 1000°C (MDC-1000) exhibited the highest surface area and pore volume. The MDC-1000 showed almost twice the porosity of the original ZIF-8 used to prepare it. The obtained MDC was applied to the adsorptive removal of a pharmaceutical product [sulfamethoxazole (SMX)] from water, and the adsorption amount on MDC was 20 times higher than that on the original ZIF-8. Moreover, a very high adsorption for SMX was exhibited by the prepared MDC, in fact, the best ever reported for any adsorbent. Plausible adsorption mechanisms, such as H-bonding, could be suggested based on the effect of the solution pH on the status and adsorbed quantity of SMX and the zeta potential of MDC. Moreover, MDC-1000 and SMX acted as the H-donor and H-acceptor, respectively, in the mechanism (H-bonding) for adsorption. MDC can be a potential adsorbent for the removal of SMX because of its high adsorption capacity and ready recyclability.