Carbon Aerogel Materials Research Articles

Chitosan derived N-doped carbon aerogel nanostructures for high-performance supercapacitors

This study presented a chitosan-derived activated carbon aerogel material (ACAM), which was prepared via a sol–gel method, freeze-drying, and carbonization. The prepared nitrogen-doped carbon materials had nanopore structures with a highly specific surface area of 2341 m2 g−1 that was expected to be suitable as active electrode materials for supercapacitors). The prepared electrode exhibited a high capacitance of 215 F g−1 at 1.0 A g−1. Moreover, the electrode could retain almost 93% of the original capacitance, and the Coulombic efficiency remains over 97% after 5,000 cycles. The findings suggest a low-price and high-performance material for supercapacitors.

Green Synthesis of Carbon Aerogel from Rose Apple (Syzygium jambos) for Ciprofloxacin, Diesel Oil, Organic Solvents Adsorption, and Electrochemical Properties

AbstractThe ascribed work suggests a fabrication pathway of carbon aerogel material from the rose apple (Syzygium jambos) fruit (RACA), in which a hydrothermal step, followed by a calcination process under various temperatures from 600 to 900 °C was carried out. RACA were characterized via multiple methods to briefly determine the optimal calcination temperature for the application, revealing that the temperature of 700 °C provided an intermediate deconstruction effect to form the amorphous structure and amplified the surface area. Whence, the materials were assessed for the adsorption capacities towards diesel oil which provided a capacity of approximately 35 g/g, although the adsorption capacity decreased slightly after 5 cycles of recovery and reuse. Furthermore, RACA‐700 exhibits high adsorption capacity of organic solvents (toluene, cyclohexane, butanol, hexane, and chloroform) and the ciprofloxacin antibiotic. Besides, the utilization of the fabricated carbon aerogel in the supercapacitor was also investigated. The obtained results elucidate the highest specific capacitance of 61.20 F/g, corresponding with the lowest resistance of 195.6 Ω, which indicates the ability to maintain capacitance after 5000 cycles and still retain 60 % efficiency, thereby signifying the potential application of carbon aerogel in sustainable material construction.

Carbon aerogel materials synthesized from recycle paper and their VOC adsorbtion capacity

This study presented the process of synthesizing carbon aerogel materials from waste paper for the purpose of absorbing volatile organic compounds (VOCs). The fabricated materials showed suitable properties as adsorbent materials: low density, high porosity and large surface area. The carbonization temperature and density of carbon aerogel were studied and showed a clear influence on the adsorption capacity of the materials. The adsorption capacity of the material has been tested and it is shown that it can reach 400 mg/g for toluene and acetone.

Lightweight HfC nanowire-carbon fiber/graphene aerogel composites for high-efficiency electromagnetic interference shielding

Electromagnetic interference (EMI) and pollution triggered by electromagnetic waves are becoming a severe issue with the rapid development of various e-devices. Developing low-density and high-efficiency electromagnetic shielding materials is of great importance. Carbon aerogel materials have received worldwide attention due to their significant electromagnetic interference shielding properties and physicochemical stability. Herein, lightweight hafnium carbide nanowire (HfCnw)-carbon fiber (CF)/graphene aerogel (GA) composites with excellent electromagnetic shielding performance were fabricated by successively introducing CF via hydrothermal process, pyrolytic carbon (PyC) coating via chemical vapor infiltration (CVI), and HfCnw via catalytic chemical vapor deposition (CCVD) into GA. It was found that the electrical conductivity of the HfCnw-CF/GA composites with the HfCnw growth time of 4 h reached 94.0 S/cm, which was far higher than 1.1 S/cm of pristine GA and 2.7 S/cm of the CF/GA composites. The EMI shielding effectiveness (SE) of the HfCnw-CF/GA composites was as high as 66.4 dB in the X-band, which was 3 times that (25.4 dB) for GA and 1.5 times that (45.8 dB) for the CF/GA composites. The EMI shielding performance of the HfCnw-CF/GA composites was improved mainly due to the enhanced multiple reflection loss, conductance loss, and interfacial polarization loss. Moreover, the HfCnw-CF/GA composites had a specific SE (SSE) value of 364.1 dB cm3/g, which exhibits good application prospects in the EMI field to meet the needs for light weight and high SE.

Microwave-mediated ultrafast solid-state construction of O vacancies enriched cobalt oxide/nitrogen carbon aerogel toward efficient tetracycline degradation with peroxymonosulfate

A rapid microwave assisted carbonization of dicyandiamide and cobalt nitrate was developed for the first time to prepare cobalt oxide/nitrogen carbon aerogel materials, in which cobalt oxide species were uniformly loaded with the characteristics of multivalent Co species. Moreover, the rapid heating process introduced abundant oxygen vacancies and N containing heterocycles in Co@NC3A materials. The optimal Co@NC3A exhibited complete TC degradation within 10 min with a rate constant up to 0.8609 min−1 at 25 °C. Meanwhile, the Co@NC3A also had general applicability in various antibiotics and dyes degradation. Radical quenching experiment and EPR test revealed the coexistence of radical and non-radical activation process in Co@NC3A/PMS system. Multivalent Co species could activate PMS to facilitate the SO4•- and •OH production. In addition, 1O2 and direct electron transfer mediated non-radical pathways were accelerated with O vacancies and N containing heterocycle.

Synthesis of carbon aerogels with controlled morphology and pore structure to modulate their bulk density and thermal conductivity via a quick one-pot preparation strategy

How to improve the preparation efficiency and reduced production costs in synthesizing high-performance polymer-derived carbon aerogel materials with ultra-low density and excellent thermal protection properties is currently a crucial research topic that has been plaguing scientists for decades. In this study, we innovatively propose a “one-pot” preparation strategy to synthetize carbon aerogel, which can simplify the complex processes of conventional fabrication methods, greatly shorten the preparation time of phenolic resin-based organic aerogel, and obtain the corresponding carbon aerogels after carbonization. Here, a series of carbon aerogel samples are obtained by regulating the solvent species, and their physicochemical properties such as morphology, pore structure shrinkage, density, and thermal conductivity of these samples are discussed in detail. CA@isoamylol is screened out exhibiting the lowest bulk density (0.15 g/cm3) and thermal conductivity (0.0499 ± 0.0029 W/m·K at 25 °C and 0.1069 ± 0.0090 W/m·K at 1200 °C), which is comparable to the reported values of best-in-class carbon aerogel values, and much lower than the conventional carbon foams. The synthesized CA@isoamylol is promising as a condidate for thermal insulation material. It is expected that the “one-pot” method could alleviate the above-mentioned bottlenecks of the carbon aerogel discipline to produce high-performance carbon aerogel materials with a low-cost and efficient routes.

NiO quantum dot-modified high specific surface carbon aerogel materials as an advanced host for lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) have great potential for development in next-generation storage devices, which are severely hampered by the shuttle effect of polysulfides and poor sulfur conductivity. To surmount these problems, a high specific carbon aerogel material (NiOQDs/HCA) modified by NiO quantum dots is constructed in this paper as a sulfur host, NiO quantum dots (NiOQDs) attached to porous carbon substrates provide active sites for the chemisorption and transformation of polysulfides. Meanwhile, HCA makes the entire substrate form a complete conductive network, increasing the speed of electron transport. Based on the above advantages, the LSBs with NiOQDs/HCA as the cathode still has a reversible capacity of 440 mA h g−1 after 900 cycles at 0.5 C and a capacity decay rate of 0.052% after 1000 cycles at 1.0 C. The discharge-specific capacity at 0.1 C also reaches up to 818 mA h g−1 at a high sulfur load of 3.3 mg cm−2, with a capacity retention rate of 66% after 100 cycles.

Preparation of ultrafine microporous nitrogen self-doped chitosan (CS) carbon aerogel based on a Zn-Zn system for high-performance supercapacitors

In light of the depletion of fossil resources, global warming, and other energy and environmental challenges, the utilization of biomass as an energy storage solution holds tremendous promise. In this research, Chitosan (CS)/CH3COOH/(CH3COO)2Zn hydrogels were produced through a cross-linking process that involves both ionic bonding and hydrogen bonding. Subsequently, CS carbon aerogels with extremely fine microporous structures were manufactured via freeze-drying, carbonization, and activation processes utilizing the Zn-Zn system. The dehydrating agent and activator used was ZnCl2, whereas in situ doping of Zn2+ in the carbon precursor functioned as an activation assistant. The activated CS carbon aerogel ACS-Zn20-700 prepared at 700 °C had a specific surface area of 857.47 m2/g, a microporous ratio of 89.44%, a pyridine-N content of 35.58%. The distribution of micropores and ultrafine pores facilitates effective connection and ion transport at the electrode–electrolyte interface, leading to an increase in the number of active sites in carbon materials and ultimately improving their specific capacitance. Nitrogen-containing groups also provided additional pseudocapacitance. In a three-electrode system, ACS-Zn20-700 obtained a specific capacitance of 380.8F/g at the current density of 0.5 A/g. The ACS-Zn20-700 supercapacitor in the two-electrode system had an energy density of 12.8 kW h−1 (at 125 W kg−1) and a capacitance retention rate of 85.27% (at 10,000 cycles). The findings of this work serve as a useful reference for the development of environmentally friendly biomass-derived carbon aerogel materials as potential candidates for supercapacitor electrode applications.

An improved preparation method of carbon aerogels derived from alginate / chitosan with a superiority of promoting nZVI for chromium(VI) ions removal from aqueous solution

CAs (carbon aerogels) are potential novel adsorbents for Cr(VI). However, their tradition preparation method presents a series of problems such as the tedious processes and the limited scaling up production caused by extreme conditions. Improved preparation methods are tried to explore so that supercritical process could be avoided. While the explanation of the adsorption behavior and mechanism remain incomplete in the presence of polyanions. In this paper, a series of sodium alginate/chitosan composite (SA/CTS) carbon aerogels with or without nZVI (nano zero-valent iron) doped are intentionally designed, which were prepared without supercritical process and expected to a significant improvement in Cr(VI) removal in wastewater while facilitating preparation and separation. The adsorption performance of carbon aerogels for Cr(VI) were investigated as functions of pH, adsorbent dosage and adsorption temperature. Following the study of adsorption behavior of Cr(VI) in the coexistence of polyanions, this work presented a detailed rationale for the different competing anions having different effects on Cr(VI) sorption. Four isotherms and three kinetic models were used to explain the adsorption behaviors. The maximum adsorption capacities of CTS900 and nZVI@CTS900 were estimated to be 183.85 mg/g and 204.35 mg/g at 35 °C using the Sips model, respectively, which showed favorable performance over carbon aerogel materials that have been reported so far. Besides the study of factors influencing adsorption, the mechanism of Cr(VI) sorption mainly involved electrostatic interactions, hydrogen bonding attraction, and redox reactions were demonstrated through the multi characteristic analysis. As a result, prepared CTSs and nZVI@CTSs perform acceptable application prospects in Cr(VI)-containing water and wastewater.

Ultralight carbon aerogel composites derived from MOFs and cross-linked chitosan: Synthesis, characterization, and U(VI) adsorption

An environmentally friendly and cost-effective adsorbent for removing U(VI) from radioactive wastewater is of significant importance for protecting the environment. In this work, we successfully prepared an ultralight carbon aerogel material (CUCA/MPCs) derived from chitosan and MOFs, and synthesized an adsorbent (CUCA/MPCs-PO4) with a high chelation ability to U(VI) through phosphorylation modification. Various characterization techniques were used to characterize the microscopic morphology and crystallographic structure of the adsorbents. During the batch experiments, it was determined that the optimum pH for the adsorbents for U(VI) was 6.5. According to the linear Langmuir isotherm model and pseudo-second-order kinetic model, U(VI) adsorption on the adsorbent is a monolayer chemisorption reaction. The fitted maximum adsorption capacities of CUCA-PO4, CUCA/1MPCs-PO4, and CUCA/2MPCs-PO4 for U(VI) were 357.1 mg/g, 526.3 mg/g, and 592.0 mg/g, respectively. Furthermore, the three adsorbents showed good recyclability, maintaining 79.0 %, 77.4 %, and 82.2 % of the initial adsorption capacity after eight cycles, respectively. The results of actual U(VI) waste adsorption experiments showed that CUCA/2MPCs-PO4 achieved 92.2 % removal of U(VI), showing good potential for practical applications. Finally, the possible adsorption mechanism between U(VI) and adsorbent was discussed in the context of experimental and characterization results. Overall, this study provides a valuable research idea for the treatment of radioactive wastewater containing U(VI).

Evaluation of ultimate engineering properties of polytetrafluoroethylene/carbon-aerogel/glass fiber porous composite

A novel polytetrafluoroethylene (PTFE)/ carbon-aerogel (CA) coating was applied on the glass fiber mat (GFM) via a dip-coating procedure followed by a pad-dry-cure method. Dispersions and distribution of CA, fiber diameter, and surface roughness were assessed through scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The effect of different coating baths — 50 and 100 g/L PTFE with various CA concentrations (0–6 W/V.%) — on thermal, electrical, mechanical, acoustical, permeability, and surface properties of the CA/PTFE/GFM composites was studied. Thermal and electrical properties revealed that porous carbonic fillers could improve thermal insulation and enhance electrical conductivity illustrating carbon-aerogel materials' notable property. After coating procedure, tensile strength increased from 1.06 MPa for neat GFM to 1.62 and 1.63 MPa for CA6/PTFE50/GFM and CA6/PTFE100/GFM, respectively, due to reducing fibers' surface defects and well-diffused PTFE polymer chains within the CA networks that generates strong interfacial interaction. In addition, air permeability and noise absorption coefficient decreased via raising the CA content due to enhancing the thickness and attenuating the received sounds through porous CA. Eventually, contact angle and sliding angle illustrated that the hydrophobicity increased by adding CA and PTFE due to reducing surface tension of the composites.

Environmental life cycle assessment of supercapacitor electrode production using algae derived biochar aerogel

Porous carbon aerogel material has gained an increasing attraction for developing supercapacitor electrodes due to its cost-effective synthesis process and relatively high electrochemical performance. However, the environmental performances of supercapacitor electrodes produced from different carbon aerogel materials are never comparatively studied, hindering our knowledge of supercapacitor electrode production in a sustainable pattern. In this study, nitrogen-doped biochar aerogel-based electrode (BA-electrode) produced from Entermorpha prolifera was simulated to investigate the environmental performance by using life cycle assessment method. For comparison, the assessment of graphene oxide aerogel-based electrode (GOA-electrode) was also carried out. It can be observed that the life cycle global warming potential for the BA-electrode was lower than that of GOA-electrode with a reduction of 53.1‒68.1%. In comparison with GOA-electrode, the BA-electrodes endowed smaller impacts on environment in majority of impact categories. Moreover, in comparison with GOA-electrode, the environmental damages of BA-electrode were greatly decreased by 35.8‒56.4% (human health), 44.9‒62.6% (ecosystems), and 87.0‒91.2% (resources), respectively. The production stages of GOA and graphene oxide and stages of nitrogen-doped biochar aerogel production and Entermorpha prolifera drying were identified as the hotspots of environmental impact/damage for the GOA-electrode and BA-electrode, respectively. Overall, this finding highlights the efficient utilization of algae feedstock to construct a green and sustainable technical route of supercapacitor electrode production.

A Strategy to Optimize the Performance of Bio-Derived Carbon Aerogels by a Structuring Additive

In this work, we investigated the influence of gum arabic (GA) as a structuring additive, on the electrochemical behavior of bio-derived carbon aerogels (CAGs). Modified carbonaceous materials were prepared by the gelatinization process of potato starch (PS) with the addition of GA in various quantities, followed by the thermal treatment of the obtained gels in an inert gas atmosphere. The obtained anode materials were examined by X-ray diffraction (XRD), elemental analysis (EA), galvanostatic charge/discharge tests (GCDT), extensive cycling (LT-GCDT) and cyclic voltammetry (CV) methods. The highest electrochemical performance was achieved for carbon aerogel material, in which 1% w/w GA was added. The results showed that the proper composition of carbon precursor with a structuring promoter improves the rheological properties of starch gel and stabilizes the final aerogel structure affecting CAG functional properties.

Effect of Synthesis Conditions on Carbon Aerogels Material to Remove Pesticide in Cuu Long Delta Rivers

Carbon aerogel is taken into account for a new material with many unique properties that can be applied in many different application fields. The properties of carbon aerogels are distributed across a wide range and are controlled by many conditions in the synthesis process. For each different application area, carbon aerogel is synthesized under different conditions to meet the required properties for materials such as: surface area, specific gravity, conductivity, pore size, etc. Therefore, the assessment of the quality of synthetic carbon aerogels will create a premise to guide them in appropriate fields. Besides, it is also possible to optimize the synthesis process to achieve materials of good quality, properties suitable for each specific requirement. The specific weight less than 0.5 g/cm3. Specific surface area from 633 to 800 m2/g. Pore size from 7 to 22 A With the properties of carbon aerogel materials synthesized, assess the adsorption capacity of carbon aerogel to treat heavy metals Fe, As and pesticides (Cypermethrin / DDT) in laboratory water samples and surface water samples taken from the rivers in the Cuu Long Delta. The results show that the ability to adsorb and process metals and pesticides is very good. Processing efficiency of iron and arsenic reaches 92-99%. Meanwhile, the ability to absorb plant protection drugs Cypermethrin / DDT also reached 95 - 99 %.

Activity and Durability of Platinum-Based Electrocatalysts with Tin Oxide–Coated Carbon Aerogel Materials as Catalyst Supports

Platinum nanoparticles were deposited onto carbon aerogel with three different tin coatings. The coatings were synthesized at pH = 0.7 or 11.5 and with various masses of SnCl2.H2O precursor: 1, 2, and 10 g. The nanoparticles dispersion was found dependent on the morphological properties of the support, i.e., its specific surface, porosity, and coverage by tin oxide. The material electrochemical activity for the oxygen reduction reaction (ORR) and stability was investigated: two accelerated stress tests (ASTs), mimicking either a base-load cycle procedure (P1) or a start-stop procedure (P2), were performed at T = 80 °C. The sample coated at pH = 0.7 and the sample with the lowest loading, deposited at pH = 11.5, exhibited interesting performances, both in term of stability (under P1) and activity. On the contrary, samples with highly covering tin oxide coating displayed unsatisfactory initial performances, owing to the low electrical conductivity of their catalytic support. In any case, the aging under P2 leads in a dramatic decrease of the electrocatalyst activity. This either resulted from (i) the low degree of organization of the carbon aerogel, the latter being prone to harsh corrosion when non-covered by the tin oxide, or (ii) by the chemical changes undergone by the tin oxide during the AST, leading to the formation of an amorphous, low electrical conductivity support.

Carbon aerogel materials promoted catalytic ozonation of residual dyes in waste effluents from cotton dyeing

Carbon aerogel materials promoted catalytic ozonation of residual dyes in waste effluents from cotton dyeing

Regeneration and reuse of highly polluting textile dyeing effluents through catalytic ozonation with carbon aerogel catalysts

Reactive dyeing of cotton generates a great deal of coloring wastewater containing residual dyes, electrolyte, alkali, and other auxiliaries. Especially for the effluent from the first/initial spent dyeing bath, it may be comprised of as high as 60% of the initial dye dosed, 30–90 g/L of sodium chloride or sodium sulfate, and plenty of sodium carbonate, making it to be the most contaminative effluent among the entire reactive dyeing process. This paper presents a new alternative to regenerate the waste effluent from the first spent dyeing bath through catalytic ozonation with novel catalysts for reuse of the effluent in successive dyeing. Two novel ozonation catalysts, mesoporous carbon aerogel and its supported cobalt oxide nanoparticles, were successfully prepared and used in catalytic degradation of residual dyes in waste effluents with ozone. Degradation efficiency was determined by both decolorization and chemical oxygen demand removal. The result showed novel catalysts could improve both of these two targets. For chemical oxygen demand removal, carbon aerogel supported cobalt oxide strikingly enhanced the efficiency by 30% on the whole comparing to ozonation alone (approximately 50%) without the catalyst. Waste effluents after catalytic ozonation were thereafter reused in successive dyeing in the same process. It has been validated that the waste effluent was successfully regenerated and can be additionally reused twice without sacrificing fabric quality, which cannot be realized in ozonation alone. Color difference of the fabric dyed with the regenerated effluent was within the acceptable tolerance, and excellent levelness and equal colorfastness had also been achieved. This is probably the first study to investigate the feasibility of regenerating highly polluting dyeing effluents for reuse by catalytic ozonation with carbon aerogel materials. With novel catalysts, it could be speculated that catalytic ozonation is a promising technology for in-situ regeneration of waste effluents in textile dyeing plant for reuse.

Effect of porosity on electrochemical properties of carbon materials as cathode for lithium-oxygen battery

Porosity effect of carbon materials on the electrochemical performances as cathode materials in non-aqueous Li-oxygen cells has been investigated. A carbon aerogel material is chosen to represent mesoporosity and a couple of activated carbon materials are selected to represent microporosity. Carbon aerogel shows at least ten times higher discharge capacity (4155 mAh g−1) than activated carbons. It is found that as much as 61% of pore volume of carbon aerogel is filled with discharge products (Li2O2) while less than 18% of pore volume is occupied with Li2O2 at the end of discharge in activated carbons, indicating that mesopore is more effective than micropore. In another experiments, the electrolyte impregnated electrode shows a capacitor-like discharge behavior, meaning it is necessary to have some open pore for the oxygen supply even though they are micropores.

N-doped carbon aerogels for carbon dioxide (CO2) capture

The N-doped carbon aerogel materials were investigated to explore their potential use in carbon dioxide (CO2) capture. Carbon aerogels were prepared from a nitrogen-containing polymer precursor using urea as nitrogen source into the polymer matrix through the sol-gel method. CO2 capture performances were evaluated from 273 to 298K at 1 bar. CO2adsorption is influenced by the micropores and amount of a nitrogen-containing the samples. N2 adsorption isotherms have showed different structures of these carbon materials. CO2 adsorption capacities up to 3.6 mmol/g (298K) and 4.5 mmol/g (273K) were achieved. Both texture and surface chemistry affect the CO2 capture performance of the adsorbents. Key word: Adsorption, carbon dioxide (CO2), urea, carbon, aerogel, N-doped.

Formation of Graphitic Structures in Cobalt- and Nickel-Doped Carbon Aerogels

We have prepared carbon aerogels (CAs) doped with cobalt or nickel through sol-gel polymerization of formaldehyde with the potassium salt of 2,4-dihydroxybenzoic acid, followed by ion exchange with M(NO3)2 (where M = Co2+ or Ni2+), supercritical drying with liquid CO2, and carbonization at temperatures between 400 and 1050 degrees C under a N2 atmosphere. The nanostructures of these metal-doped carbon aerogels were characterized by elemental analysis, nitrogen adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Metallic nickel and cobalt nanoparticles are generated during the carbonization process at about 400 and 450 degrees C, respectively, forming nanoparticles that are approximately 4 nm in diameter. The sizes and size dispersion of the metal particles increase with increasing carbonization temperatures for both materials. The carbon frameworks of the Ni- and Co-doped aerogels carbonized below 600 degrees C mainly consist of interconnected carbon particles with a size of 15-30 nm. When the samples are pyrolyzed at 1050 degrees C, the growth of graphitic nanoribbons with different curvatures is observed in the Ni- and Co-doped carbon aerogel materials. The distance of graphite layers in the nanoribbons is approximately 0.38 nm. These metal-doped CAs retain the overall open cell structure of metal-free CAs, exhibiting high surface areas and pore diameters in the micro- and mesoporic region.