Surface Area Porous Carbon Research Articles

Spider silk-derived nanoporous activated carbon fiber for CO2 capture and CH4 and H2 storage

High surface area porous carbon with fibrous microstructure offers a broader application potential than powder form. However, controlling the microstructure with high porosity is difficult, and if possible then through a complex and time-consuming synthesis method. Herein, the development of high surface area nanoporous activated carbon fiber by activating spider silk (natural biomaterials) using potassium hydroxide is being reported. The specific surface area (SSA) and total pore volume for the developed material were 2730 m2/g and 1.56 cc/g, respectively, and its surface contain high oxygen content. Its high SSA and oxygen-rich surface provide an enhanced CO2 capture and energy carrier gases (H2 and CH4) storage capacity. The CO2 capture capacity at 0 °C and 25 °C, 25 bar, were estimated to be 23.6 and 15.4 mmol/g, respectively, among the highest reported values for porous carbon fiber. Moreover, the developed sample has shown the CH4 storage capacity of 8.6 mmol/g at 0 °C, 25 bar, and for H2, it was 4.1 wt% at − 196 °C, 25 bar. In addition, the developed carbon material demonstrated an easy regeneration and almost negligible loss in uptake capacity, confirmed by adsorption-desorption cycles. The observation of high porosity and promising gas storage and recyclability in spider silk-derived activated carbon fiber indicates that the employed method can effectively convert biomaterials into high surface area activated carbon fibers for advanced energy and environmental applications.

Polysaccharide of agar based ultra-high specific surface area porous carbon for superior supercapacitor

Although extensive research has been focused on porous carbon in supercapacitor, the simple and non-template preparation of high specific surface area (SSA) carbon material with hierarchical porous structure is still a lingering issue. Herein, the cross-linked hierarchical porous carbon with ultra-high SSA of 3184 m2 g−1 is prepared via the sol-gel follows the freeze drying and followed activation process. Agar is used as carbon precursor, L-arginine is nitrogen sources, and the formed gel is activated by KHCO3. The obtained N-doped porous carbon shows a superior specific capacitance of 443.0 F g−1 at 0.5 A g−1 in 6 M KOH, and exhibits an excellent rate capability (255 F g−1 at 50 A g−1). Furthermore, due to the combined synergistic effect of high SSA, hierarchical porous structure and N doping, the symmetric supercapacitor that assembled with the prepared gel electrolyte of Agar-Na2SO4 achieves a superior energy density of 35.5 Wh kg−1 and a long cycle life with the capacitance retention of 99.7% after 20,000 cycles. This work provides an efficient and simple method to prepare ultra-high surface area, hierarchical porous structure carbon materials for high performance supercapacitor.

Rice husk derived porous carbon embedded with Co3Fe7 nanoparticles towards microwave absorption

For eliminating electromagnetic pollution caused by harmful electromagnetic waves, it is urgent to develop electromagnetic absorption materials with strong refection loss and wide bands. In this study, the rice husk was employed as raw material to prepare lightweight and high specific surface area porous carbon (RHC). Subsequently, using RHC as the carrier, the RHC@Co3Fe7 nanocomposites were obtained by embedding Co3Fe7 nanoparticles into the pore of the RHC. Under the synergistic influence of the multiple reflection/scattering of porous structure, magnetic resonance of Co3Fe7 nanoparticles, as well as electron polarization aroused by the heterogeneous interface between RHC and Co3Fe7, the minimal reflection loss (RLmin) of the optimal product reaches to −68.106 dB at 16.24 GHz with the matching thickness of 1.44 mm. Meanwhile, for the optimal sample, the widest effective absorption bandwidth (EAB) is nearly 5 GHz covering the frequency range of 10.96–15.92 GHz at a matching thickness of 1.79 mm. The excellent absorption performance of RHC@Co3Fe7 nanocomposites may provide a new strategy for the preparation of lightweight, thin thickness, strong absorption and wide bandwidth material.

Redgum-derived high surface area porous carbon for electric double layer capacitors

• Red gum tree bark (RTB) derived activated carbon was prepared by the impregnation of KOH at 850 °C. • Enhanced supercapacitor performance in aqueous, organic, and ionic electrolytes for symmetric carbon/carbon electrode cells. • C-RTB offers a specific capacitance of >200 F g −1 with a large potential window of 3.5 V. • The fabricated device in ionic liquid was used to power an LED for more than 4 min after 10 s charging.

Biomass derived hierarchical porous carbon for supercapacitor application and dilute stream CO2 capture

High surface area porous carbons derived from sustainable biomass wastes are excellent functional materials for energy storage and gas sorption applications. Tasmanian Blue Gum (TBG) tree bark is selected as the raw material for preparing activated porous carbon (AC), using a simple KOH activation and carbonization method. The as-prepared AC-TBG sample possesses a hierarchically connected mesoporous structure having a surface area of 971 m2 g−1 with an average pore size of 2.2 nm. AC-TBG exhibits high electrochemical storage capacity as fabricated symmetric supercapacitor, with excellent specific capacitances of 212 F g−1 at 1 A g−1 current density retaining 90% of its capacitance after 5000 cycles. An outstanding maximum power density of 4.9 kW kg−1 was obtained for the EDLC in 1 M KOH at a maximum energy density of 18.84 Wh kg−1, which is among the highest values reported in this class of materials. Furthermore, exploiting the multiscale porosity and oxygen/hydroxyl functionalities on the surface, AC-TBG was deployed for CO2 capture from concentrated source as well as dilute 4% CO2 simulated flue stream. AC-TBG showed an excellent uptake of 4.5 mmol/g of CO2 at 1 bar and 0 °C for pure CO2 and a working capacity of 1.6 mmol/g at 40 °C in 4% CO2. This work provides a simple, and feasible strategy for converting sustainable waste biomass to value-added activated carbon with potential applications in high-performance energy storage and greenhouse gas capture.

Nitrogen-Doped High Surface Area Porous Carbon Material Derived from Biomass and Ionic Liquid for High-Performance Supercapacitors

In this work, bioderived high surface area, porous activated carbons (ACs) are synthesized from dried Sterculia foetida (SF) fruit shells via KOH activation. Further, for high-performance supercapacitor (SC) application, the nitrogen-doped AC (NAC) has been derived by pyrolysis of a nitrogen-enriched ionic liquid (IL) and AC mixture. Herein, aprotic 1-ethyl-3-methyl-imidazolium dicyanamide ([EMIM][DCN]) IL is used as a nitrogen precursor. A series of NACs has been successfully developed by tuning the weight ratio of IL and AC. The optimized NAC (2:1) exhibits suitable graphitization degree, hierarchical micromesopores to ensure effective electrolyte diffusion, high surface area, and enhanced wettability. Further, in a three-electrode configuration, the NAC (2:1) electrode shows a high specific capacitance of 567 F g–1 at 0.5 A g–1. Moreover, a symmetric two-electrode SC device was constructed, providing excellent specific energy of 13 Wh kg–1 at 300 W kg–1. Overall, this study presents the positive aspects of an IL as a nitrogen precursor to synthesize high surface area NACs as a promising electrode material for SC applications.

Effects of Preparation and Activation Manner on Surface Area of Hierarchical Porous Carbons Derived from Nut (Euryale ferox) Shell

AbstractHierarchical nano‐micro carbon spheres porous carbon composites are successfully synthesized derived from Euryale ferox shells by the in‐situ decoration of the porous carbon with carbon spheres from carboxymethyl cellulose under the activation of KOH. Effects of fabrication and activation manner on surface area of porous carbons were investigated. The influence of activation temperature, impregnation ratio and modifier were analyzed. The specific surface area, pore volume and average pore diameter of porous carbon was characterized by N2 adsorption isotherms. Porous carbon produced at 800 °C with an impregnation ratio of 3, 2 hours of carbonization time, 20 hours immersion time has been found 2506 m2 g−1, 1.515 cm3 g−1 and 2.4 nm of the optimum specific surface area, pore volume and average pore diameter, respectively. The result of Fourier‐infrared spectroscopy analysis of the prepared porous carbon confirmed that it has abundant functional groups on the surface. The scanning electron micrographs of the prepared porous carbon indicated that a well‐developed pore structure was formed during the experiment.

As2O3 capture from incineration flue gas by Fe2O3-modified porous carbon: Experimental and DFT insights

A series of Fe2O3-modified porous carbon sorbents (Fe/PC) were synthesized and used for As2O3 capture from incineration flue gas. The molecular interaction mechanism was investigated by theoretical calculations based on density functional theory (DFT). The results indicate that the flourishing pore structure and high specific surface area of porous carbon are beneficial for Fe2O3 dispersing, which provides affluent active sites for arsenic capture. Fe/PC sorbent with a Fe content of 14.93 wt% exhibited high arsenic removal capacity of 16.09–29.32 mg/g in a wide temperature window (150–400 °C). The pseudo-first-order model best fitted the experimental data of As2O3 removal. The influences of flue gas compositions depend on the adsorption temperature. H2O promoted arsenic removal at lower temperature. HCl and SO2 played facilitation roles in arsenic removal at higher temperature. The states of arsenic in sorbents were As3+ and As5+, both adsorption and oxidation processes are responsible for As2O3 removal by Fe/PC sorbents. DFT calculation results indicate that the O-hollow site on the Fe2O3 surface has the strongest adsorption affinity for As2O3. The deep orbital hybridization and electron sharing between As2O3 and Fe2O3 are responsible for the high adsorption performance of Fe/PC sorbent.

The effects of local graphitization on the charging mechanisms of microporous carbon supercapacitor electrodes

The electrochemical quartz crystal microbalance (EQCM) technique has been used to study the charge mechanisms in two TiC-derived nanoporous carbons (CDC), synthesized at 800 ℃ and 1100 ℃. These two carbons have a similar pore size and porous volume, but the CDC prepared at 1100 °C shows a more graphitic microstructure. The EQCM study revealed that the charge storage mechanism in the CDC-800 is mainly controlled by a counter-ion adsorption process, while an expanded ion-exchange process was observed for the CDC-1100. Combined with the potential of zero charge (PZC), these measurements suggest a strong interaction between the anions and graphitic carbon. For the first time, we provide experimental evidence that the local carbon structure affects the charge storage mechanism of the electrical double-layer capacitance in high surface area porous carbons.

Ultra-high surface area porous carbon from catechol rectification residue with excellent adsorption capacity for various organic pollutants

• Catechol rectification residue-based porous carbons were prepared via different methods. • Porous carbon prepared by novel NaNH 2 self-synergy strategy possessed ultrahigh surface area, up to 3954 m 2 /g. • NaNH 2 self-synergy effect brought the most comprehensive activation abilities. • CC-N exhibited excellent adsorption capacity for seven typical pollutants in various industries. • Hydrophobic, π–π bond interactions played important roles in tetracycline adsorption. It is challenging to turn fine chemical industrial residue into porous carbons with ultrahigh surface area and excellent adsorption property for various organic pollutants. Herein, to address this issue, a novel NaNH 2 self-synergy strategy and other four traditional activation methods (KOH, H 3 PO 4 , CO 2 and air) were developed to synthesize different catechol rectification residue-based porous carbons. Then, structure characteristics, surface morphologyies and chemical properties of these carbons were analyzed to systematically investigate the effect of these methods on the structure-performance of carbons. Results showed that porous carbon (CC-N) prepared by NaNH 2 self-synergy strategy possessed ultrahigh specific surface area, up to 3954 m 2 /g, which was 1.5 ∼ 66 times higher than that of other carbons prepared by traditional activation methods and NaNH 2 activation without self-synergy strategy. Additionally, in-depth study revealed that part of NaNH 2 reacted with the water from residue carbon to form self-synergy effect during activation process. This effect brought the most comprehensive activation abilities. In terms of application, the adsorption capacity of CC-N for various popular organic pollutants was considerable. CC-N had the highest adsorption capacity (1205 mg/g) for tetracycline (TC) among most of the reported adsorbents. Adsorption mechanisms of TC onto CC-N were proved by hydrophobic interactions, π–π interaction, H-bond. In general, this article can be served as one new reference to improve the porosity and adsorption performance of porous carbon by novel adjustable NaNH 2 self-synergy strategy.

Ultra-High Specific Surface Area Porous Carbons Derived from Chinese Herbal Residues with Potential Applications in Supercapacitors and Co2 Capture

Ultra-High Specific Surface Area Porous Carbons Derived from Chinese Herbal Residues with Potential Applications in Supercapacitors and Co2 Capture

A single step solid NH4F-assisted method for the removal of hard silica template to obtain microporous carbon for electrochemical applications

A new method for removing silica templates to prepare high surface area porous carbons is reported. In this method solid NH4F is used as a sacrificial agent to remove silica as SiF4 in a single step process, thus eliminating the corrosive methods by using HF/NaOH in multi-step processes. This method is versatile to enhance the surface area and porous-network of carbons at higher calcination temperatures. The carbon sample prepared at 900 °C exhibits high surface area (861 m2 g−1) among others and shows specific capacitance of 240 F g−1 at current density 0.5 A g−1.

2-amino-6-methylpyridine based salt converted to carbon electrode material for supercapacitive application

• Molecular structure of 6-methyl-2-aminopyridine based co-crystal. • Efficient and catalyst free method for synthesis of porous carbon. • The specific capacitance of 44.69 f/g at sweep rate 2mv/s. • 83.88% specific capacitance retention after 1900 cycles. Supercapacitors or ultra-capacitors are well thought-out best approach to fulfil the indispensable requirements of energy storage. Supercapacitive electrode materials have become interest of scientists. In the present study, we have reported an efficient and catalyst free method for synthesis of porous carbon by the pyrolysis of salt, prepared by reaction of organic acid with organic base for supercapacitive application. The prepared salt was characterized by single crystal analysis, 1 H NMR, single crystal XRD and FT-IR. The salt derived porous carbon material was then characterized by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). The specific surface area of porous carbon was calculated by BET analysis found to be 347 m 2 /g. Electrode material showed good capacitive response. The specific capacitance of sample was Ca. 44.69 F/g at sweep rate 2 mV/s and retains 83.88% of its initial capacitance after 1900 cycles.

Unraveling porogenesis in nitrogen rich K+-activated carbons

Though potassium activation is one of the most common methods for producing high surface area porous carbons, a detailed understanding of the influence of precursor properties on the resulting physicochemical properties is lacking. To this end, polycondensation products of sucrose and melamine served as a useful platform to understand the role of precursor N content on the surface chemistry and porosity after potassium activation. By manipulating the nitrogen:carbon:potassium ratios in the precursors, a suite of porous carbons with variable surface areas (528–2740 m2/g) and nitrogen contents (0–22 at%) were synthesized. Analysis of both the byproducts and the carbons’ resulting physicochemical properties revealed a complex interplay of various known reaction schemes (viz., gas evolution, carbothermal reduction, chemical etching, and molten salt templating), which are not mutually exclusive and can each contribute to the resulting porosity and surface chemistry. With this comprehensive study and careful control of the precursor composition, we define specific nitrogen:potassium regimes where certain porogenesis pathways dominate. Our work emphasizes that straightforward mechanisms focused on carbothermal reduction and exfoliation cannot always explain porogenesis in nitrogen-rich carbons. This work endeavors to serve as a roadmap for greater understanding and control of the structure and chemistry of nitrogen-rich, potassium-activated porous carbons.

Low Temperature Performance of Solid Electrochemical Capacitors: Effects of Electrolytes Additives and Electrode Design

Solid-state, thin, and flexible electrochemical capacitors (ECs) can provide energy storage for next-generation wearable electronics such as smart textiles and medical sensors. One of the enablers for high performance and safe electrical double layer capacitors ECs is neutral pH polymer electrolytes due to their wide operating potentials, good ionic conductivity and benign chemical nature [1-3]. Nonetheless, the operation temperature is often limited to above the freezing point of water. For example, a polymer electrolyte based on Na2SO4 ion conductor and polyacrylamide (PAM) host has shown a promising performance at ambient (good shelf-life >30 days and wide 1.8 V window with activated carbon [4]), but its performance degraded drastically at sub-zero conditions [5]. Furthermore, it is of practical importance to understand the effect of high surface area porous carbon materials (e.g. carbon nanotube (CNT) [6-7] or activated carbon (AC) [7-9]) on solid EC at low temperatures, which has not been extensively characterized. To ensure robustness of EC devices operating under winter/sub-arctic and outer space conditions, it is necessary to develop proper polymer electrolytes and the right match of electrode/electrolyte for low temperature ECs.In this study, the performances of solid EC cells constructed with carbon electrodes and Na2SO4-PAM-based electrolytes were assessed at ambient and low temperatures. The objectives were to (i) improve the performance of Na2SO4-PAM electrolytes using anti-icing additives and (ii) elucidate the key characteristics of electrodes (i.e. pore structure and electrode loading/thickness) affecting cell performance at low temperatures.To improve the low temperature performance of the Na2SO4-PAM electrolyte, several anti-icing additives (e.g. dimethyl sulfoxide/DMSO or ethylene glycol/EGly) have been investigated and shown promising improvement to the ionic conductivity of the electrolyte at low temperatures. Leveraging the polymer electrolyte with these additives, capacitive CV profiles were attained at -10 ˚C (Fig. 1a), much more pronounced than their binary baseline. The cell performance with the DMSO-containing ternary electrolyte was then evaluated using either CNT or AC electrodes at various carbon loadings (Fig. 1b). Although solid cells with AC electrodes demonstrated higher capacitance at ambient, those with CNT electrodes retained more capacitance at low temperature. This is likely due to better ion accessibility into CNT electrodes with relatively more open pores. Meanwhile, AC electrodes with lower carbon loading have higher capacitance retention at low temperature due to better electrode utilization in a thinner electrode. These observations will provide the guideline for designing the next generation of ECs that are suitable for low temperature applications.

(Invited) Pt Alloy Octahedral Nanoparticle Catalysts from Screening Studies to Fuel Cell Measurements

In proton exchange membrane fuel cells (PEMFCs) hydrogen is oxidized at the anode and oxygen is reduced at the cathode, where Pt-based catalysts represent the state of the art. Due to the sluggish oxygen reduction reaction (ORR) kinetics, Pt loadings per vehicles are still rather high when compared to platinum-group metal (PGM) loadings in combustion engine cars ( ~ 5 gPGM/vehicle in light-duty internal combustion engine vehicles),1 impacting the cost of fuel cell electric vehicles.Octahedral PtNi nanoparticles have been reported to achieve extremely high ORR mass activity in rotating disk electrode (RDE) experiments,2 which would allow for a significant decrease of Pt loadings in fuel cells. In addition, the introduction of a third metal (X) as a surface dopant has been recently shown to have beneficial effects on the RDE performance, enhancing both activity and stability.3 However, despite these promising steps toward shape-stable PtNiX octahedral nanoparticles, the morphological stability and the performance in membrane electrode assembly (MEA)-based fuel cell measurements still needs to be improved to match and surpass the state of the art Pt and de-alloyed Pt alloy catalysts.4 In this contribution, we will show the results of our recent investigations that were aimed at improving the performance of PtNi based octahedral nanoparticle catalysts towards integration in low Pt loading cathodes for PEMFCs. These include exploration of different dopants, Pt loadings and carbon supports. Preliminary screening by RDE identified promising dopants (i.e. Mo4 and other transition metals) and Pt:Ni atomic ratios. The activity and stability of the PtNiX octahedral nanoparticles were then investigated in a comparative study by using different carbon supports, including high surface area porous carbon. Finally, selected catalysts were investigated in MEA-based fuel cells and their activity compared with state-of-the art reference Pt and PtNi alloy materials, measured under the same conditions. References A. Kongkanand and M. F. Mathias, J Phys Chem Lett, 2016, 7, 1127-1137.P. Strasser, Science, 2015, 349, 379-380.X. Q. Huang, Z. P. Zhao, L. Cao, Y. Chen, E. B. Zhu, Z. Y. Lin, M. F. Li, A. M. Yan, A. Zettl, Y. M. Wang, X. F. Duan, T. Mueller and Y. Huang, Science, 2015, 348, 1230-1234.F. Dionigi, C. C. Weber, M. Primbs, M. Gocyla, A. M. Bonastre, C. Spöri, H. Schmies, E. Hornberger, S. Kühl, J. Drnec, M. Heggen, J. Sharman, R. E. Dunin-Borkowski and P. Strasser, Nano Lett, 2019, 19, 6876-6885. Acknowledgements The GAIA project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 826097. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe Research.

Activation of Asphalt to Prepare High Surface Area Carbon Material

High surface area porous carbon material was prepared via a method of activating asphalt with pretreatment. The crystalline, textural structure, morphology, and surface functionalities of the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), diffuse reflectance FTIR spectroscopy (DRIFTS), and Brunauer-Emmett-Teller (BET) techniques. When the asphalt was pretreated at 400 °C for 3 h under Ar flow, and then activated using KOH as activating agent at 800 °C for 3 h under Ar flow, the prepared porous carbon material has an amorphous nature and possesses a high surface area of 2460 m2/g, a narrow pore size distribution of 3 ∼ 5 nm, and a mean pore diameter of 3.8 nm.

A high specific surface area porous carbon skeleton derived from MOF for high-performance Lithium-ion capacitors

Lithium-ion capacitor (LICs) is expected to replace the traditional double-layer capacitor and lithium-ion battery as a new energy storage device. However, the slow de/intercalation of Li+ in battery-type electrodes (anode) limits the power density of lithium-ion capacitors (LICs). In this work, a high specific surface area porous carbon skeleton (Z-T-PC) is synthesized derived from MOF (Zn-TFBDC). Benefit from the large specific surface area and 3D conductive skeleton, the Z-T-PC shows that the sample has a high specific capacity and stable cycling performance as the LIC anode. The assembled asymmetric LICs exhibit high power density and energy density with Z-T-PC anode. The work provides new thinking for the application of the novel anode material of LICs.

Ultra-high specific surface area porous carbon derived from chestnut for high-performance supercapacitor

The preparation of biomass-derived porous carbon having a high specific surface area for high-performance supercapacitors has been recognised as an important research topic in the past decade. In this study, chestnut-pulp-derived porous carbon is prepared by employing a two-step process involving carbonisation and KOH chemical activation for the first time. The synthesized hierarchical porous carbon samples have an ultra-high specific surface area of 2646 m2 g−1 and good conductivity, and their O-doping can be controlled. They exhibit excellent electrochemical performance as carbon electrodes owing to the synergistic effects of their advantageous features. In a three-electrode system, the as-obtained electrode yields a high specific capacitance of 373 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte. Furthermore, it exhibits excellent rate performance with ~70.8% capacity retention when the discharge current increases from 1 to 10 A g−1 and prominent cycling stability with ~99.7% capacity retention after 10000 cycles. These values indicate that chestnut-pulp-based carbon materials have excellent electrochemical properties when used as supercapacitor electrodes and may promote the large-scale application of 3D porous carbons in energy storage.

CoFe2O4- mesoporous carbons derived from Eucommia ulmoides wood for supercapacitors: Comparison of two activation method and composite carbons material synthesis method

The mesoporous activated carbon (AC) was synthesized by low temperature phosphoric acid activation based on Eucommia ulmoides Oliver (EUO) wood (one-step) and EUO-charcoal (two-step). The pore structure, surface composition and graphitization degree of carbons synthesized by one-step and two-step activation were systematically investigated. The results exhibited that the specific surface area of porous carbon varies from 1264.8 m2/g (two-step activation, AC2) to 1506.7 m2/g (one-step activation, AC1), which indicated AC1 gained more well-developed mesoporous structure (the mesoporous ratio reached 75.27 %) than that of AC2. Besides, as CoFe2O4 spinel-type metal oxides nanoparticles (NPs) were anchored on ACs by hydrothermal method and chemical co-precipitation, the electrochemistry characteristics were presented in a three-electrode system. As compared with the products (ACs/CF2) prepared by chemical co-precipitation to prepared, AC1 combined with CoFe2O4 by hydrothermal method (AC1/CF1) showed higher specific capacitance of 596.26 F/g (0.005 V/s), which was profited from the synergistic effect of double-layer capacitance and pseudo-capacitance, and the capacitance retention maintained 93.7 % after 10,000 cycles of charging-discharging at 2 A/g. Therefore, EUO wood is a promising feedstock for the preparation of porous carbon, its metal compound (ACs/CFs) provided excellent performance in potential supercapacitors applications, and by the means of the comparisons for the activation method and the scheme for combination of CoFe2O4, this study generated significative guidance for the preparation of activated carbon and its composite.