scholarly journals N-Doped Carbon Aerogels Obtained from APMP Fiber Aerogels Saturated with Rhodamine Dye and Their Application as Supercapacitor Electrodes

2019 ◽  
Vol 9 (4) ◽  
pp. 618 ◽  
Author(s):  
Lei E ◽  
Wei Li ◽  
Jiaming Sun ◽  
Zhenwei Wu ◽  
Shouxin Liu
Keyword(s):  
Freeze Drying ◽  
Sol Gel ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Alkaline Peroxide ◽  
3D Network ◽  
Rhodamine Dye ◽  
Carbon Network ◽  
Pyridinic N ◽  
A Current

We developed an efficient and environmentally friendly strategy for synthesizing an N-doped carbon aerogel by the carbonization of an alkaline peroxide mechanical pulp (APMP) fiber aerogel saturated with rhodamine B (RB) dyes. The APMP aerogel was prepared via cellulose extraction, sol-gel, and freeze drying. The resulting aerogel had a high adsorption capacity (250 mg g−1) and a fast adsorption rate (within 30 s) towards RB dyes. The saturated aerogel was used as a starting material for further carbonization to prepare N-doped carbon aerogels. SEM studies showed that the 3D network structure of the APMP aerogels was well preserved after RB adsorption and carbonization. The prepared carbon aerogel exhibited a graphitized structure, and N (2.15%) was doped at pyridinic N and pyrrolic N sites in the 3D carbon network. The specific capacitance of the N-doped carbon aerogel reached 185 F g−1 at a current density of 1 A g−1, which is higher than carbon aerogels (155 F g−1).

scholarly journals Environmentally Friendly and Multifunctional Shaddock Peel-Based Carbon Aerogel for Thermal-Insulation and Microwave Absorption

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Weihua Gu ◽  
Jiaqi Sheng ◽  
Qianqian Huang ◽  
Gehuan Wang ◽  
Jiabin Chen ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Thermal Insulation ◽  
Freeze Drying ◽  
Thermal Infrared ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
List Type ◽  
Drying Method ◽  
Cross Sectional ◽  
Compression Resistance

Highlights The eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method. Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel. Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition. . Abstract Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

Konjac Glucomannan Derived Carbon Aerogels for Multifunctional Applications

NANO ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. 1850113 ◽  
Author(s):  
Jie Lian ◽  
Jiwei Li ◽  
Liang Wang ◽  
Ru Cheng ◽  
Xiuquan Tian ◽  
...  
Keyword(s):  
Oil Spills ◽  
Chemical Characterization ◽  
Carbon Aerogel ◽  
High Water ◽  
Economic Benefits ◽  
Carbon Aerogels ◽  
Step Method ◽  
Water Contact ◽  
Cycle Times ◽  
3D Network

Environmental and energy issues have always been a hot topic of global research. Oil leakage has caused great damage to the environment, affecting a wide area and it is difficult to clean up. In most cases, carbon-based adsorbents are typically utilized to remove oil spills because of their economic benefits and high adsorbent efficiency. At the same time, its excellent material properties can also be used for the preparation of supercapacitors. In this paper, the carbon aerogels were prepared by the one-step method. The prepared materials endowed a 3D network structure with a huge number of micropores and mesoporous, and the material is light-weight, stable, hydrophobic and has affinity for oil (17.02[Formula: see text]g/g) to the KGM carbon aerogel. Through the physic-chemical characterization, the KGM carbon aerogel shows specific surface area is 689[Formula: see text]m2/g, high water contact angle (136.64[Formula: see text]) and excellent reusability (more than 15 cycle times). In addition, we also discussed the electrochemical properties of the material and obtained the specific electrical capacity of 139[Formula: see text]F/g under the condition of 1[Formula: see text]A/g.

Preparation of High Weight Loading Lithium Borohydride in Carbon Aerogels

2013 ◽  
Vol 631-632 ◽  
pp. 287-290
Author(s):  
Xia Yan Yan ◽  
You Li ◽  
Jie Du ◽  
Xiao Na Luo ◽  
Cheng Qin
Keyword(s):  
Pore Volume ◽  
High Weight ◽  
Sol Gel ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Nitrogen Absorption ◽  
Lithium Borohydride ◽  
Pmma Microsphere ◽  
Large Pore Volume ◽  
Weight Loading

We describe approaches using modified carbon aerogels for increasing the weight loading of LiBH4. Large pore volume carbon aerogels were prepared with a sol-gel method and a polymethyl methacrylate (PMMA) microsphere template. Compared to those without using templates, the pore volume has been up to 3.8 times with a PMMA template. After incorporation into carbon aerogels, the weight loading of LiBH4 has reached 80%. Nitrogen absorption/desorption measurements show that more than 95% free space of carbon aerogels has been incorporated with LiBH4. Rama spectra suggest that there is no PMMA or chemical reaction during the synthesis of LiBH4/carbon aerogel composites.

Performance Study and Structure Control of Carbon Aerogel

2013 ◽  
Vol 706-708 ◽  
pp. 897-900 ◽  
Author(s):  
Rui He ◽  
Xuan Liu ◽  
Zhen Fa Liu ◽  
Li Hui Zhang
Keyword(s):  
High Surface ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Carbon Aerogel ◽  
Preparation Condition ◽  
Carbon Aerogels ◽  
Performance Study ◽  
Structure Control ◽  
Sol Gel Process ◽  
Nanopore Structure

In this research the fabrication of carbon aerogel is reported. nanopore carbon aerogels were prepared via a sol-gel process with resorcinol and formaldehyde (RF) aerogels,which were cost-effectively manufacture form Rf wet gels by an ambient drying technique instead of conventional supercritical drying. The key of the work is to fabricate carbon aerogels with controllable nanopore structure, which means sharp pore size distribution and extremely high surface area.The influence of preparation condition of carbon aerogels was studied by scanning electron microscope and Micropore Physisorption Analyzer. The BET surface of the carbon aerogels are from 749m2/g to 1156m2/g .The size of the carbon nanoparticles are in the range of 20nm~40nm. The micro-pore volume and bore diameter can be controlled by gelation conditions such as RF mass fraction.

scholarly journals Fabrication Of Carbon Aerogels From Coir For Oil Adsorption

2022 ◽  
Vol 964 (1) ◽  
pp. 012033
Author(s):  
Hieu M Nguyen ◽  
Khoi A Tran ◽  
Tram T N Nguyen ◽  
Nga N H Do ◽  
Kien A Le ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Oil Spills ◽  
Sol Gel ◽  
Urea Solution ◽  
Carbon Aerogels ◽  
Low Density ◽  
High Porosity ◽  
Motor Oil ◽  
Sol Gel Process ◽  
Oil Adsorption

Abstract Coir, known as coconut fibers, are an abundant cellulosic source in Vietnam, which are mostly discarded when copra and coconut water are taken, causing environmental pollution and waste of potential biomass. In this research, carbon aerogels from chemically pretreated coir were successfully synthesized via simple sol-gel process with NaOH-urea solution, economical freeze-drying, and carbonization. The samples, including pretreated coir, coir aerogels, and carbon aerogels, are characterized using FTIR spectroscopy, SEM, XRD spectroscopy, and TGA. The carbon aerogels exhibit low density (0.034–0.047 g/cm3), high porosity (97.63–98.32 %), and comparable motor oil sorption capacity (22.71 g/g). The properties of carbon aerogels are compared with those of coir aerogels, indicating such better values than those of coir aerogels. Coir-derived carbon aerogels is a potential replacement for the hydrophobically-coated cellulose aerogels in term of treating oil spills.

The Effect of Different Ratio in Carbon Aerogel on Pore Structure in Ambient Dry

2014 ◽  
Vol 941-944 ◽  
pp. 450-453 ◽  
Author(s):  
Fang Wang ◽  
Lan Fang Yao ◽  
Jun Shen ◽  
Da Yong Guan ◽  
Zhou Fang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Carbon Aerogel ◽  
Surface Characteristic ◽  
Carbon Aerogels ◽  
Water Solvent ◽  
Organic Aerogels

Organic aerogels were prepared by sol-gel polycondensation of resorcinol and formaldehyde using sodium carbonate as a catalyst and dried under ambient pressure. Carbon aerogels were obtained by the dried organic aerogels carbonized under nitrogen atmosphere at high temperature. The pore structures and surface characteristic of the carbon aerogels obtained were investigated by N2 adsorption isotherms, scanning electron microscope (SEM). Through controlling the concentrations of the main ingredients (resorcinol and formaldehyde), catalyst concentration, we can find out the best concentration which the specific surface area can reach the highest. In this experiment the highest specific surface area was 1645m2/g. In addition, the results show that catalyst for the cross link effect between colloidal microspheres is greater than the growth of the colloid itself, and the effect of water solvent plays an important role in the density of carbon aerogel.

The Characterization of Copper-Doped Carbon Aerogels by Transport Properties Measurements

2002 ◽  
Vol 734 ◽  
Author(s):  
R.W. Fu ◽  
N. Yoshizawa ◽  
Y. Hanzawa ◽  
K. Kaneko ◽  
A. P. Santos ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Low Temperature ◽  
Copper Concentration ◽  
Copper Ions ◽  
Sol Gel ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Temperature Dependent ◽  
Spin Concentration ◽  
Magnetic Susceptibilities

ABSTRACTCopper-doped carbon aerogels, which were prepared by sol-gel polymerization of a mixture of resorcinol, formaldehyde and copper ions, followed by supercritical drying with liquid CO2 and carbonization at different temperatures under a N2 atmosphere, were characterized by magnetic susceptibility and temperature-dependent conductivity measurements. The experimental results show that the magnetic susceptibilities (χ) of all the copper-doped carbon aerogels are larger than that of the blank carbon aerogel. The temperature-dependent magnetic susceptibilities of the copper-doped carbon aerogels are well fit to a Curie function in the low temperature region (below 45 K). According to the Curie constant obtained, the spin concentration (N) of the copper-doped carbon aerogels was calculated and the results show that the spin concentration of doped samples increases at first with an increase in the copper concentration used in doping, and then drops from the maximum in N and χ when the copper concentration is further increased above 0.1 wt%. Magnetic susceptibility results suggest that copper-doped carbon aerogels carbonized at 800 °C are more disordered than those carbonized at 1000 °C. The conductivity of these copper-doped carbon aerogels is apparently higher than that of the blank carbon aerogel, especially at low temperature (T < 45 K). The temperature-dependent resistivities of both the copper-doped and the blank carbon aerogels follow a linear functional form log ρ(T) ∼ (1/T)1/2 with two distinct regions below and above 45 K, indicating that the conduction of both the copper-doped and the blank carbon aerogels obey a tunneling and/or a hopping mechanism.

Ultramicroporous carbon aerogels encapsulating sulfur as the cathode for lithium–sulfur batteries

2021 ◽  
Author(s):  
Maryam Nojabaee ◽  
Brigitta Sievert ◽  
Marina Schwan ◽  
Jessica Schettler ◽  
Frieder Warth ◽  
...  
Keyword(s):  
Carbon Aerogel ◽  
Composite Cathode ◽  
Microporous Carbon ◽  
Carbon Aerogels ◽  
Lithium Sulfur Batteries ◽  
Lithium Sulfur

In the presented study, a sulfur infiltrated ultra-microporous carbon aerogel as a composite cathode for lithium sulfur batteries is developed and investigated.

scholarly journals Elucidation of the Crystal Growth Characteristics of SnO2 Nanoaggregates Formed by Sequential Low-Temperature Sol-Gel Reaction and Freeze Drying

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1738
Author(s):  
Saeid Vafaei ◽  
Alexander Wolosz ◽  
Catlin Ethridge ◽  
Udo Schnupf ◽  
Nagisa Hattori ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Low Temperature ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Freeze Drying ◽  
Sno2 Nanoparticles ◽  
Sol Gel ◽  
Functional Materials ◽  
Cost Effective ◽  
High Concentration

SnO2 nanoparticles are regarded as attractive, functional materials because of their versatile applications. SnO2 nanoaggregates with single-nanometer-scale lumpy surfaces provide opportunities to enhance hetero-material interfacial areas, leading to the performance improvement of materials and devices. For the first time, we demonstrate that SnO2 nanoaggregates with oxygen vacancies can be produced by a simple, low-temperature sol-gel approach combined with freeze-drying. We characterize the initiation of the low-temperature crystal growth of the obtained SnO2 nanoaggregates using high-resolution transmission electron microscopy (HRTEM). The results indicate that Sn (II) hydroxide precursors are converted into submicrometer-scale nanoaggregates consisting of uniform SnO2 spherical nanocrystals (2~5 nm in size). As the sol-gel reaction time increases, further crystallization is observed through the neighboring particles in a confined part of the aggregates, while the specific surface areas of the SnO2 samples increase concomitantly. In addition, X-ray photoelectron spectroscopy (XPS) measurements suggest that Sn (II) ions exist in the SnO2 samples when the reactions are stopped after a short time or when a relatively high concentration of Sn (II) is involved in the corresponding sol-gel reactions. Understanding this low-temperature growth of 3D SnO2 will provide new avenues for developing and producing high-performance, photofunctional nanomaterials via a cost-effective and scalable method.

scholarly journals Light-induced levitation of ultralight carbon aerogels via temperature control

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reo Yanagi ◽  
Ren Takemoto ◽  
Kenta Ono ◽  
Tomonaga Ueno
Keyword(s):  
Carbon Nanotubes ◽  
Heat Capacity ◽  
Porous Materials ◽  
Temperature Control ◽  
Light Absorption ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Halogen Lamp ◽  
Absorption Properties ◽  
Air Density

AbstractWe demonstrate that ultralight carbon aerogels with skeletal densities lesser than the air density can levitate in air, based on Archimedes' principle, when heated with light. Porous materials, such as aerogels, facilitate the fabrication of materials with density less than that of air. However, their apparent density increases because of the air inside the materials, and therefore, they cannot levitate in air under normal conditions. Ultralight carbon aerogels, fabricated using carbon nanotubes, have excellent light absorption properties and can be quickly heated by a lamp owing to their small heat capacity. In this study, an ultralight carbon aerogel was heated with a halogen lamp and levitated in air by expanding the air inside as well as selectively reducing its density. We also show that the levitation of the ultralight carbon aerogel can be easily controlled by turning the lamp on and off. These findings are expected to be useful for various applications of aerogels, such as in communication and transportation through the sky.

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