Properties Of Porous Carbon Research Articles

Porous carbon derived from center part of the corn cob for high-performance symmetrical supercapacitors

The central part of agricultural waste biomass corn cob was used as carbon precursor and KHCO3 as activating agent, and porous carbon materials were prepared by one-step carbonization method. The effect of KHCO3 on the structure and properties of porous carbon was studied. The results show that KHCO3 has an etching effect on porous carbon, and the greater the amount of KHCO3, the stronger the etching effect. The obtained biomass porous carbon material has abundant pores, reasonable pore size distribution and high specific surface area, which is conducive to ion transfer and charge storage. In addition, the heteroatom self-doping of porous carbon can improve surface hydrophilicity and generate additional pseudocapacitance, thereby improving its electrochemical properties. Electrochemical characterization shows that the porous carbon has a specific capacitor of up to 323 F g−1. The assembled symmetric supercapacitor (SSC) has an energy density of 20 Wh kg−1 at a power density of 350 W kg−1. This low-cost, high-performance electrode material has potential applications in high-power supercapacitors.

Optical Limiting Response of Porous Carbon Dispersions.

With the wide application of intense lasers, the protection of human eyes and detectors from laser damage is becoming more and more strict. In this paper, we study the nonlinear optical limiting (OL) properties of porous carbon with a super large specific surface area (2.9 × 103 m2/g) using the nanosecond Z-scan technique. Compared to the traditional OL material C60, the porous carbon material shows an excellent broadband limiting effect, and the limiting thresholds correspond to 0.11 J/cm2 for 532 nm and 0.25 J/cm2 for 1064 nm pulses, respectively. The nonlinear scattering experiments showed that the OL behavior was mainly attributed to the nonlinear scattering effect, which is caused by the rapid growth and expansion of bubbles in the dispersion induced by laser irradiation, and the scattered light distribution is consistent with the results of Mie's scattering. These results suggest that porous carbon materials are expected to be applied to the field of laser protection in the future to further protect the human eye and precision optical instruments.

Removal of metronidazole from simulated wastewater using Fe/C catalyst with a combination of heterogenous Fenton and ozonation

This study examined roles of iron oxide/porous carbon material (Fe/C) for removing metronidazole in simulated wastewater by adsorption and then followed by a degradation using advanced oxidation process (H2O2, O3 and combination of H2O2/O3). Fe/C was produced by an impregnation of iron oxide precursors during resorcinol-formaldehyde synthesis followed by pyrolysis at 800 °C. For comparison, blank carbon (without iron loading) was also synthesized. The properties of porous carbon were investigated by SEM-EDX and N2-sorption analyzer. Blank carbon and Fe/C featured the specific surface area of 755 m2g-1 and 394 m2g-1, respectively. The loading of iron oxide altered the pore structures of material. The adsorption isotherm data were followed by the Langmuir isotherm model with metronidazole uptake up to 46.07 mg g-1 and 39.97 mg g-1 at 30oC by Fe/C and blank carbon. The degradation study was then carried out with catalyst dosage of 0.1 g/100 mL solution and 120 min reaction time at 30 oC. It is noticeably that, the degradation of metronidazole was better when a combination of H2O2/O3 was employed, compared with an individual of H2O2 or O3. Regarding the stability, Fe/C maintained its high activity upon four consecutive runs.

Preparation of renewable porous carbons for CO2 capture – A review

A diversity of renewable wastes such as biomass and plastic can be employed for the synthesis of porous carbons, which have emerged as promising materials for CO2 capture under a wide range of conditions owing to their unique properties. Because of limited review articles in this field, this paper provided the recent progress and significant challenges in the synthesis of renewable porous carbons for CO2 capture with the objective of guiding future works on the CO2 abatement technologies towards a sustainable direction. Among the post-consumer plastics, PET has been widely used for the synthesis of porous carbons for effective CO2 capture because of its high carbon and oxygen content. In general, porous carbons derived from waste biomass and plastic are quite attractive for CO2 capture due to their tunable textural properties, simple synthesis methods and high CO2 adsorption capacities, which are closely associated with the structures and properties of porous carbons (e.g., microporous structure, heteroatoms doping). Particularly, the doped N species (e.g., pyridinic-N, pyrrolic-N) can transform the electronic state of the H atoms in the –CH and –NH groups on porous carbons to form hydrogen bonds between H and the O atom of CO2 molecule, thus for enhancing the CO2 adsorption.

An innovative strategy on co-production of porous carbon and high purity hydrogen by alkaline thermal treatment of rice husk

An innovative biomass conversion method was proposed to co-produce porous carbon and high purity hydrogen by alkaline thermal treatment (ATT). Hydrogen with purity over 80 vol % and porous carbon with a specific surface area of 2298.5 m2/g were co-produced at 500 °C for the first time. In this study, the effects of various reaction parameters on hydrogen production and the properties of porous carbon were investigated. The composition of gas products was tested, and the pore structure, morphology, graphitization degree and crystal structure of porous carbon were analyzed. The results showed that the optimum experimental conditions were alkali/rice husk mass ratio of 3:1, reaction temperature of 500 °C and reaction time of 60 min. A variety of characterization results showed that alkali etched the surface of rice husk at appropriate temperature, forming a large number of pore structures, and releasing volatile substances and hydrogen. The addition of alkali reduced the microcrystalline structure between graphite layers and increased the proportion of amorphous structure in porous carbon. Electrochemical test results showed that the specific capacitance of porous carbon prepared under the best reaction conditions reached 228.94 F/g at the current density of 0.2 A/g.

In-situ design of porous vanadium nitride@carbon nanobelts: A promising material for high-performance asymmetric supercapacitors

Vanadium nitride and porous carbon are emerging as new class of electrodes and are extensively being explored as high-performance supercapacitor (SC) materials for their interesting properties. In this study, vanadium nitride@porous carbon (VN@C) nanostructured hybrid material for SCs is synthesized utilizing in-situ, one-pot chemical synthesis technique. The VN@C hybrid nanostructure has achieved very high capacitance by utilizing the combinations of electric double layer capacitive (EDLC) properties of porous carbon and pseudocapacitive characteristics of VN nanoparticles (VN NPs) and delivered maximum specific capacitance of 1850 C g−1 @10 A g−1 current density, with an excellent rate capability of 98% over 2000 cycles. Exploring the excellent electrochemical characteristics of VN@C, an asymmetric supercapacitor (ASC) cell is constructed with activated carbon (AC) as negative and VN@C as positive electrode. Remarkably, the as-constructed VN@C//AC ASC device achieves an excellent capacitance of 102 F g−1 at 1 A g−1 with the energy and power densities of 17–30 Wh kg−1 and 701–5608 W kg−1, respectively, over the current density range of 1–8 A g−1. Our facile preparation of highly porous carbon nanobelt-vanadium nitride composite along with high-energy storage properties pave the way for the development of various carbon–metal nitride hybrid nanostructures for promising energy storage applications.

Virtual voids method to generate low-density microporous carbon structures using quenched molecular dynamics simulation

The creation and properties of porous carbons are of extreme importance for optimizing the performance of battery and supercapacitor electrodes, as well as vehicular hydrogen storage. Atomistic simulation methods with reactive potentials have shown promise to create realistic porous carbon structures. However, such models have been unable to reproduce low-density microporous carbon structures due to clustering of atoms in high density regions, resulting in a small number of mesopores. Here we present a new method using virtual voids, generating excluded volume by a soft repulsive potential which is progressively decoupled from the carbon atoms. This allows us to prevent densification and to create disordered carbon models with porosities up to 90%. We vary the size and density of the virtual voids and show that the mean of the pore size distribution and the accessible surface area can be controlled. By choosing the desired porosity and virtual void size, we create amorphous carbon models with mean pore sizes ranging from 10 to 32 Å, which agree favorably with experimental pore sizes for low-density microporous carbons.

高分子材料衍生多孔碳的制备及其电化学性能研究

高分子材料衍生多孔碳的制备及其电化学性能研究

Nanoporous Carbon Prepared from Palm Kernel Shell for CO2/CH4 Separation

The presence of impurity in biogas like CO2, H2S and H2O reduce the efficiency and heating value of this renewable energy. While removal of H2S and H2O is relatively simple, effective purification is needed to remove CO2 which presence in biogas up to 45%. The separation of CO2 from CO2/CH4 mixture can be performed by carbon-based molecular sieves. Separation by molecular sieves is based on differences in the diffusivity of CO2 and CH4 passing through the pore of the carbon. This paper discusses a preparation of porous carbon from palm kernel shell as molecular sieves and its adsorption properties (equilibrium and kinetics) and separation performance for biogas purification. Porous carbon was synthesized by carbonization under steam activation at various temperature. The properties of porous carbon were characterized by N2-sorption analysis, scanning electron microscopy and proper adsorption study (equilibrium and kinetics). The results showed that the surface area of porous carbon increased with the increasing temperature of carbonization then decreased when the temperature raised to 1000 °C. The highest surface area of 803 m2 g−1 was obtained at a temperature of 800 °C and mesoporous structures increase with increasing temperatures but dropped at temperatures above 1000 °C. In the adsorption study at 1 atm and 30 °C, the results showed that the uptake capacities of CO2 (2.0 mmol g−1) was higher than that of CH4 (1.1 mmol g−1). based on ideal adsorption solution theory, adsorption of mixed CO2–CH4 showed an adsorption capacity of 1.3 mmol g−1. The adsorption kinetics test as well as breakthrough experiment showed that CO2 can be separated from mixture of CO2/CH4 using the carbon-based molecular sieve producing high purity of CH4 (> 95%).

Modifying Nanoporous Carbon through Hydrogen Peroxide Oxidation for Removal of Metronidazole Antibiotics from Simulated Wastewater

This study examined change in pore structure and microstructure of nanoporous carbon after surface oxidation and how it affects the adsorption performance of metronidazole antibiotics. The surface oxidation was performed by hydrogen peroxide at 60 °C. The properties of porous carbon were investigated by N2-sorption analysis (pore structure), scanning electron microscopy (surface morphology), the Boehm titration method (quantification of surface functional group), and Fourier transform infrared spectroscopy (type of surface functional group). The results showed that the oxidation of porous carbon by hydrogen peroxide has a minor defect in the carbon pore structure. Only a slight decrease in specific surface area (8%) from its original value (973 m2g−1) was seen but more mesoporosity was introduced. The oxidation of porous carbon with hydrogen peroxide modified the amount of oxide groups i.e., phenol, carboxylic acid and lactone. Moreover, in the application the oxidized carbon exhibited a higher the metronidazole uptake capacity of up to three-times manifold with respect to the pristine carbon.

Facile preparation and properties of porous carbon from chlorinated polymer with high chlorine content

Chlorinated polypropylene(CPP), chlorinated polyethylene(CPE) and chlorinated polyvinyl chloride(CPVC) with high chlorine content were used to prepare porous carbons under inert gas and air atmosphere, respectively. Due to their flame retardance, carbon materials were both prepared from two atmosphere through thermal dehydrochlorination. The microstructure and porous textures of the obtained carbons were characterized by BET, XPS, SEM, TEM, XRD and Raman, respectively. The results show that the dehydrochlorination of all precursors is more efficient in air than nitrogen, because the oxygen molecular in air atmosphere accelerates the elimination of hydrogen chloride(HCl). Moreover, CPP-derived carbons display apparent higher surface area than that derived from CPE and CPVC. Furthermore, the carbonization condition is optimized and porous carbon with a surface area of 1035 m2/g is prepared in mild carbonization condition and without any activation.

Porous carbons from inverse vulcanised polymers

Elemental sulfur is an underutilised industrial by-product. It has been recently shown that it can be simply and scalably co-polymerised, by “inverse vulcanisation” with organic crosslinkers. The properties of porous carbons, which have extensive uses in science and industry, are influenced by the materials from which they are generated. Reported here are the first examples of porous carbons produced from high-sulfur inverse vulcanised polymers. The materials produced show micro-porosity, gas selectivity, and are doped with sulfur. The simplicity of the technique, and wide range of other potential inverse vulcanised feedstocks, gives scope for transferability and control of properties.

Microwave irradiated palm shell-polyetheretherketone porous carbons as CO2 sorbents: Optimization using response surface methodology (RSM)

Palm shell being one of the abundant biomass in Malaysia, was used together with polyetheretherketone (PEEK) as precursors for the preparation of porous carbons via microwave induced potassium carbonate chemical activation. Design expert software version 7.1.6 using central composite design coupled with surface response methodology was used in predicting and optimization of the CO2 adsorption of the porous carbons. Effect of three independent variables (i.e. microwave power, irradiation time and amount of PEEK) on the sorbent performance for CO2 adsorption was investigated. A quadratic model was developed to calculate the optimum preparation conditions of activated carbon, which relate the factors to the response (CO2 adsorption). The influence of process parameters on the properties of porous carbon was investigated using analysis of variance (ANOVA) to identify the significant parameters. Microwave power was found to be the most significant factor influencing the porous carbon for CO2 adsorption. The porous carbons (PCs) preparation conditions were optimized by maximizing the CO2 adsorption capacity. The predicted CO2 adsorption capacities from the models agreed satisfactorily with the experimental values. The optimum carbon was obtained at microwave power of 500 W; irradiation time 6.55 min; and amount of PEEK 26.03 %. Therefore, the Microwave-irradiated palm-PEEK was found to be a suitable adsorbent for uptake of CO2. Research paper: Microwave irradiated Palm shell-polyetheretherketone porous carbons as CO2 sorbents: Optimization using response surface methodology (RSM).

Effect of furfural alcohol/phenol-formaldehyde resin mass ratio on the properties of porous carbon

Porous carbons were prepared from resin mixtures containing furfuryl alcohol (FA) and phenolic-formaldehyde resin (PF) as the carbon precursors. The effect of FA/PF mass ratio on the pore structure of the porous carbons was systematically investigated. Crosslinked carbon network could be obtained with the mass ratio of FA and PF changing from 0:10 to 3:7. With increasing FA content in the mixtures, the pore size distribution of carbon monoliths broadened, and the average pore size and apparent porosity of the carbonized products increased from 11.8 to 127.7nm and from 40.9% to 51.6%, respectively. The morphological and pore structure change of the porous carbons was a result of polymerization kinetics change induced by varying the FA/PF mass ratio in the polymer system on curing of initial resin compositions. Increasing FA/PF mass ratio led increased atomic order to occur in the amorphous structure.

Activated Carbon from Date Palm Seed: Process Optimization Using Response Surface Methodology

Date palm being one of the major biomass sources, largely being cultivated in UAE, is assessed for its potential to be an appropriate precursor for preparation of porous carbon. Porous carbon is prepared using the date palm pits in a tubular furnace with CO2 as the activating agent assessing the effect of process variables activation temperature, activation time and CO2 flow rate. Process optimization is performed to identify the process conditions that maximize the yield and BET surface area of the porous carbon using surface response methodology (RSM) based on central composite design (CCD). The influence of process parameters on the properties of porous carbon is investigated using analysis of variance (ANOVA) to identify the significant parameters. The optimum conditions for the preparation of porous carbon has been identified to be an activation temperature of 971°C, activation time of 56 min and CO2 flow rate of 5.1 cc/min based on the maximizing the yield and BET surface area. The optimum yield and BET surface area has been predicted to be 14.8% and 666 m2/g using the process optimization software. The textural characteristic of the optimized sample using nitrogen adsorption isotherm show the carbon to be predominantly microporous with the mean pore diameter estimated to be 1.76 nm using NLDFT method.

A study of properties of porous carbon based on phenol-formaldehyde resin with carbohydrates

Structure and some physical properties of nanoporous carbon powders produced by pyrolysis of mixtures of phenol-formaldehyde resin with saccharose or cellulose were studied.

Preparation of porous carbon derived from mixtures of furfuryl resin and glycol with controlled pore size distribution

This paper describes the preparation and properties of porous carbon by a technique which consists of mixing a carbon precursor (furfuryl resin and furfural alcohol), a pore-forming agent and a solvent (glycol), polymerizing the resin mixture, and pyrolyzing the hybrid of resin and glycol. The properties of porous carbons have been systematically investigated as a function of composition and heat treatment, with emphasis on understanding and controlling their morphology and pore size distribution. The results seem to indicate that by varying the ratios of the constituents in the polymer system, porous carbons with a wide variation in pore size distribution and morphology can be obtained. Three types of morphologies were observed: interconnected carbon with secondary spherical pores, discrete carbon particulates, and a crosslinked carbon network. Porous carbons with a very narrow pore size distribution have been obtained and the average pore size was controlled between 5 and 0.008 μm. The microstructure of porous carbon formed as a result of phase separation of resin-rich phase and glycol-rich phase, rather than a result of the pyrolysis process. Heat treatment had little effect on the properties of the porous carbons.

ブラジル産砂糖きびバカスを原料とした多孔性炭化物質の製造とその性状

ブラジル産の砂糖きびを圧搾した後の廃棄物(バガス)の表面には約8×10-7mの小孔が存在することを明らかにした。このバガスを窒素気流中で加熱炭化することによって,吸着能力を有する多孔性炭化物質が得られることとバガスに含有する水分が賦活作用をもつことを見いだした。炭化の条件を炭化物質の表面形態,比表面積および吸着能で評価し,バガスの含有水分の影響は,収率と比表面積の積であるYSと炭化物質の収率であるYとの賦活曲線でも評価した。その結果,バガスの小孔は炭化温度973Kまで増加した。昇温速度10K/min,炭化温度1273Kで得られた炭化物質は比表面積611×103m2/kg,ヨウ素吸着量960×10-3kg/kg,メチレンブルー吸着量52×10-3m3/kgの吸着能を持つことがわかった。次に,バガスの含有水分量を200%としたとき,昇温速度10K/min,炭化温度1173Kまたは昇温速度5K/min,炭化温度1273Kの条件で,炭化時間は共に所定炭化温度到達時間までとすることによって,比表面積967-1055×103m2/kgの炭化物質が得られた。さらに,この炭化物質のベンゼン蒸気吸着等温線の測定結果は,賦活炭の曲線形状と同じで,Langmuir平衡式で整理できることを見いだした。バガスに所定量の水を含浸させて窒素気流中で炭化することによって賦活炭と同等の吸着機構を持つ炭化物質が得られることを明らかにした。

Electrochemical Behavior of Carbon Aerogels Derived From Different Precursors

ABSTRACTThe ability to tailor the structure and properties of porous carbons has led to their increased use as electrodes in energy storage devices. Our research focuses on the synthesis and characterization of carbon aerogels for use in electrochemical double layer capacitors. Carbon aerogels are formed from the sol-gel polymerization of (1) resorcinol-formaldehyde or (2) phenolic-furfural, followed by supercritical drying from carbon dioxide, and subsequent pyrolysis in an inert atmosphere. These materials can be produced as monoliths, composites, thin films, powders, or microspheres. In all cases, the aerogels have an open-cell structure with an ultrafine pore size (<100 nm), high surface area (400-1100 m2/g), and a solid matrix composed of interconnected particles, fibers, or platelets with characteristic dimensions of 10 nm. This paper examines the effects of the carbon precursor and processing conditions on electrochemical performance in aqueous and organic electrolytes.