scholarly journals Influence of Graphene Oxide Incorporation on Resorcinol-Formaldehyde Polymer and Carbon Aerogels

2018 ◽  
Vol 62 (4) ◽  
Author(s):  
Balázs Nagy ◽  
Andrea Domán ◽  
Alfréd Menyhárd ◽  
Krisztina László
Keyword(s):  
Graphene Oxide ◽  
Nitrogen Adsorption ◽  
Supercritical Drying ◽  
Carbon Aerogel ◽  
Nitrogen Atmosphere ◽  
Carbon Aerogels ◽  
Polymer Gel ◽  
X Ray Diffraction ◽  
Resorcinol Formaldehyde ◽  
Polymer Hydrogels

Resorcinol-formaldehyde based polymer hydrogels with various graphene oxide (GO) content were synthesized using Na2CO3 as catalyst at pH=6 conditions. After supercritical drying they were converted to carbon aerogels in nitrogen atmosphere. The heat treatment not only pyrolysed the polymer gel, but also reduced GO. The GO added varied within 0-14% related to the mass of resorcinol which resulted in the reinforcement of the polymer matrix. The texture of the polymer and the carbon aerogels were characterized and compared in the nanoscale using SEM and TEM imaging, X-ray diffraction (XRD) and low temperature nitrogen adsorption measurements. The transition from polymer to carbon state was studied by thermogravimetry. In agreement with reference works in the GO range studied the morphology was not affected by the GO content either in the polymer or in the carbon form. The direct current (DC) conductivity however linearly increased with the added GO and already 10 % doubled the conductivity of the plain carbon aerogel.

Fabrication of Carbon Aerogels

2006 ◽  
Vol 11-12 ◽  
pp. 19-22 ◽  
Author(s):  
Y.N. Feng ◽  
Lei Miao ◽  
Yong Ge Cao ◽  
T. Nishi ◽  
Sakae Tanemura ◽  
...  
Keyword(s):  
Pore Size ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Limited Range ◽  
Molar Ratio ◽  
Carbon Aerogels ◽  
Resorcinol Formaldehyde ◽  
Catalyst Content ◽  
Fabrication Parameters ◽  
Pyrolysis Processes

RF (Resorcinol-Formaldehyde) aerogels and carbon aerogels were prepared through the sol-gel method following the routes of polymerization, gelation, supercritical drying and pyrolysis processes. The influence of fabrication parameters on the textural structure of the samples, e.g., specific surface area, pore size, and pore size distribution, etc., were systematically investigated. With a decrease in the R/F molar ratio, or an increase in the catalyst content within a limited range, the porosity of the nanostructure materials increases. The optimal temperature of pyrolysis for RF aerogel was investigated by TGA (Thermogravimetric Analysis).

Hierarchically Nanostructured Zeolites of Tunable Porosities with Aerogel Templating

2011 ◽  
Vol 1306 ◽  
Author(s):  
Yousheng Tao ◽  
Morinobu Endo ◽  
Katsumi Kaneko
Keyword(s):  
Carbon Dioxide ◽  
Template Synthesis ◽  
Colloidal Silica ◽  
Lower Cost ◽  
Supercritical Drying ◽  
Nanoporous Carbon ◽  
Carbon Aerogels ◽  
Resorcinol Formaldehyde ◽  
Carbon Xerogels ◽  
Recent Developments

ABSTRACTWe present the synthesis of resorcinol-formaldehyde aerogels and carbon aerogels of different nanoporosities, emphasizing on the recent developments in fabrication pathways of lower cost. Recent results showed a simple way to the production of highly nanoporous carbon xerogels. While using an approach combined colloidal silica nanocasting and carbon dioxide supercritical drying, hydrophilicity-controlled carbon aerogels with high mesoporosity were synthesized. Then, we demonstrate the functions of these aerogels for template synthesis of hierarchically nanostructured zeolites having micropores and mesopores.

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 Shape-Memory and Anisotropic Carbon Aerogel from Biomass and Graphene Oxide

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5715
Author(s):  
Zilu Lin ◽  
Wenzhao Jiang ◽  
Zehong Chen ◽  
Linxin Zhong ◽  
Chuanfu Liu
Keyword(s):  
Graphene Oxide ◽  
Shape Memory ◽  
Electronic Devices ◽  
High Stress ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Drying Process ◽  
Cyclic Compression ◽  
Wearable Electronic ◽  
Wearable Electronic Devices

Biomass, as the most abundant and sustainable resource on the earth, has been regarded as an ideal carbon source to prepare various carbon materials. However, manufacturing shape-memory carbon aerogels with excellent compressibility and elasticity from biomass remains an open challenge. Herein, a cellulose-derived carbon aerogel with an anisotropic architecture is fabricated with the assistance of graphene oxide (GO) through a directional freeze-drying process and carbonization. The carbon aerogel displays excellent shape-memory performances, with high stress and height retentions of 93.6% and 95.5% after 1000 compression cycles, respectively. Moreover, the carbon aerogel can identify large ranges of compression strain (10%–80%), and demonstrates excellent current stability during cyclic compression. The carbon aerogel can precisely capture a variety of biological signals in the human body, and thus can be used in wearable electronic devices.

scholarly journals The effect of gamma-irradiation on graphene oxide in a monoglyceride/ethanol solution

2016 ◽  
Vol 6 (3) ◽  
pp. 48-56
Author(s):  
Anh Tuyen Luu ◽  
Thuc Huy Ha ◽  
Thanh Duoc Nguyen ◽  
Binh Doan ◽  
Thu Hong Pham Thi
Keyword(s):  
Graphene Oxide ◽  
Gamma Irradiation ◽  
Absorbed Dose ◽  
Nitrogen Atmosphere ◽  
Ethanol Solution ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Etoh Solution ◽  
Irradiation Sample

Gamma-irradiation effects on graphene oxide (GO) in a monoglyceride/ethanol (MG/EtOH) solution was investigated.  GO was dispersed in MG/EtOH solution (GOM) with the GO: MG ratio of 1:10 (w/w). The prepared GOM was irradiated by g-ray under nitrogen atmosphere in a range of absorbed dose from 0 to 50 kGy. The characteristics and morphology of reduced GOM were analyzed by Ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The results confirmed that the structure of reduced graphene oxide in monoglyceride solution was changed and exfoliated completely after g-ray irradiation at absorbed dose 50 kGy compared with non-irradiation sample.

scholarly journals Convenient Preparation of Graphene Oxide from Expandable Graphite and Its Characterization by Positron Annihilation Lifetime Spectroscopy

2019 ◽  
Vol 5 (1) ◽  
pp. 6 ◽  
Author(s):  
Guido Panzarasa ◽  
Giovanni Consolati ◽  
Marco Scavini ◽  
Mariangela Longhi ◽  
Fiorenza Quasso
Keyword(s):  
Graphene Oxide ◽  
Positron Annihilation ◽  
Nitrogen Adsorption ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Expandable Graphite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Convenient Preparation ◽  
Extract Information

Graphene oxide (GO) is conveniently prepared from expandable graphite using a simplified Hummers’ method. The product is thoroughly characterized by usual techniques (UV-vis, Fourier-transform infrared (FTIR) and Raman spectroscopies, zeta potential, electron microscopy, X-ray diffraction, nitrogen adsorption) to confirm the success of synthesis. Positron annihilation lifetime spectroscopy (PALS) is then used to extract information on the microenvironment in between the layers of graphene oxide.

scholarly journals Lithium perrhenate catalyst for carbon aerogel-based supercapacitor

2020 ◽  
Vol 2 (5) ◽  
Author(s):  
Mateusz Ciszewski ◽  
Andrzej Koszorek ◽  
Małgorzata Osadnik ◽  
Katarzyna Szleper ◽  
Michał Drzazga ◽  
...  
Keyword(s):  
Energy Storage ◽  
Lithium Ion ◽  
Supercritical Drying ◽  
Carbon Aerogel ◽  
High Specific Surface Area ◽  
Carbon Aerogels ◽  
Energy Storage Materials ◽  
Unique Type ◽  
Energy Storage Properties ◽  
Structure Collapse

Abstract Carbon aerogels are unique type of amorphous carbon-based materials with an extraordinary properties including light weight, well-developed and tailored pore structure, high specific surface area, low electrical resistivity and high purity. Therefore carbon aerogels can be used in numerous applications, including energy storage materials such as supercapacitors or lithium-ion batteries. Synthesis of hydrogel requires accurate concentration of monomers and catalysts, exact temperature and time. Low-density carbon aerogel can be produced using a complicated supercritical drying method, which allows to expel solvent without carbon porous structure collapse. Here we report a possibility to use novel type of resorcinol/formaldehyde gelation catalyst based on rhenium salt. The organic gel obtained using lithium perrhenate was traditionally carbonized and examined with respect to energy storage properties. It was found that interaction of lithium and rhenium atoms with monomers resulted in completely different structure than using typical sodium carbonate catalyst. Graphic abstract

Fabrication of Activated Carbon Fibers/Carbon Aerogels Composites by Gelation and Supercritical Drying in Isopropanol

2003 ◽  
Vol 18 (12) ◽  
pp. 2765-2773 ◽  
Author(s):  
Ruowen Fu ◽  
Bo Zheng ◽  
Jie Liu ◽  
Steve Weiss ◽  
Jackie Y. Ying ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Surface Area ◽  
Mass Density ◽  
Carbon Matrix ◽  
Supercritical Drying ◽  
Carbon Aerogel ◽  
Micropore Volume ◽  
Activated Carbon Fiber ◽  
Carbon Aerogels

Activated carbon fiber/carbon aerogel (ACF/CA) composites were fabricated by gelling a mixture of ACF and resorcinol and furfural, followed by supercritical drying of the mixture in isopropanol. The product then went through carbonization in a nitrogen atmosphere. The fabrication conditions, such as the mass content of R–F, the content of the ACF added, and the gelation temperature, were explored. The textures and pore structures of the ACF/CA composites thus obtained were characterized using transmission electron microscopy, scanning electron microscopy, and a surface area analyzer. The mechanical properties of the samples were assessed primarily through compressive tests. The experimental results indicated that the added ACF disperses uniformly in the resulting ACF/CA composites. The carbon matrix of the ACF/CA composites also consisted of interconnected carbon nanoparticles with sizes in the range of 20 to 30 nm. The ACFs can reinforce the related carbon aerogels when they originally have low mass density and are weak in mechanical strength. When large amounts of ACF were added to the composites, the micropore area and micropore volume of the composites increased, but their external surface area decreased. The mesopore volumes and the related diameters and mesopore size distributions of the ACF/CA composites were mainly affected by the mass density of the composites. The micropore sizes of all the composites were sharply concentrated at about 0.5 nm.

scholarly journals Carbonization of Lignin Extracted from Liquid Waste of Coconut Coir Delignification

2020 ◽  
Vol 20 (4) ◽  
pp. 842
Author(s):  
Widiyastuti Widiyastuti ◽  
Mahardika Fahrudin Rois ◽  
Heru Setyawan ◽  
Siti Machmudah ◽  
Diky Anggoro
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Liquid Waste ◽  
Nitrogen Adsorption ◽  
Nitrogen Atmosphere ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Coconut Coir ◽  
Xrd Patterns ◽  
Adsorption Desorption

Lignin as a by-product of the pulping process is less widely used for worth materials. In this study, the utilization of lignin by-product of the soda delignification process of coconut coir converted to the activated carbon by a simple precipitation method followed by the carbonization at various temperatures is presented. The by-product liquor of the soda delignification process having a pH of 13.4 was neutralized by dropping of hydrochloric acid solution to achieve the pH solution of 4 resulting in the lignin precipitation. The precipitated was washed, filtered, and dried. The dried lignin was then carbonized under a nitrogen atmosphere at various temperatures of 500, 700, and 900 °C. The dried lignin and carbonized samples were characterized using SEM, XRD, FTIR, and nitrogen adsorption-desorption analyzer, to examine their morphology, X-Ray diffraction pattern, chemical bonding interaction, and surface area-pore size distribution, respectively. The characterization results showed that the functional groups of lignin mostly disappeared gradually with the increase of temperature approached the graphite spectrum. The XRD patterns confirmed that the carbonized lignin particles were amorphous and assigned as graphitic. All samples had a pore size of 3–4 nm classified as mesoporous particles. This study has shown that the carbonization lignin at a temperature of 700 °C had the highest surface area (i.e. 642.5 m2/g) in which corresponds to the highest specific capacitance (i.e. 28.84 F/g).

scholarly journals Hydrogen Production from Ethylene Glycol Aqueous Phase Reforming over Ni–Al Layered Hydrotalcite-Derived Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Jianguang Zhang ◽  
Ningge Xu
Keyword(s):  
Ethylene Glycol ◽  
Aqueous Phase ◽  
Nitrogen Adsorption ◽  
Nitrogen Atmosphere ◽  
Hydrogen Yield ◽  
X Ray Diffraction ◽  
Aqueous Phase Reforming ◽  
Metal Composition ◽  
Temperature Programmed ◽  
Adsorption Desorption

By introducing Mg, Cu, Zn, Sn, and Mn into the synthesis processes of Ni and Al based hydrotalcite, Ni–Al layered hydrotalcite-derived catalysts with different metal compositions were prepared. In this paper, the effect of metal composition on the structure of Ni–Al layered hydrotalcite-derived catalysts is investigated, and then catalytic activities of prepared catalysts with different metal compositions on ethylene glycol aqueous-phase reforming are analyzed. The physicochemical properties of the Ni–Al layered hydrotalcite-derived catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), and nitrogen adsorption–desorption technology. The obtained hydrotalcite-derived catalysts were applied to the process of ethylene glycol aqueous-phase reforming (APR). The XRD results confirmed that the precursors of hydrotalcite-derived catalysts with metal compositions of Ni/Mg/Al, Ni/Cu/Al, Ni/Zn/Al, and Ni/Sn/Al had hydrotalcite crystalloid morphology. During the process of ethylene glycol aqueous phase reforming, all the catalysts showed high conversion of ethylene glycol (>90%), and the optimum hydrogen yield (73.5%) was obtained when using the catalyst with metal composition of Ni/Mg/Al at 225 °C under 2.6 MPa in nitrogen atmosphere for 2.5 h.

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