Preparation and Characterization of Phloroglucinol-Resorcinol-Formaldehyde Carbon Aerogels

2013 ◽  
Vol 423-426 ◽  
pp. 523-527
Author(s):  
Xuan Liu ◽  
Zhen Fa Liu ◽  
Hao Lin Fu ◽  
Rui He ◽  
Li Hui Zhang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
High Specific Surface Area ◽  
Carbon Aerogels ◽  
Resorcinol Formaldehyde ◽  
Sol Gel Process ◽  
Solvent Replacement ◽  
Organic Aerogels

Phloroglucinol-resorcinol-formaldehyde organic aerogels (PRF) were prepared using phloroglucinol, resorcinol and formaldehyde in a sol-gel process, solvent replacement and drying at room temperature. The phloroglucinol-resorcinol-formaldehyde carbon aerogels (CPRF) were prepared by charring the PRF at high temperature under the aegis of helium flow. The microstructure of CPRF was characterized by infrared spectroscopy, specific surface area analyzer and scanning electron microscopy. The results showed that the CPRF had continuous network structure and high specific surface area.

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

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.

Preparation of CuO-CoO-MnO/SiO2 Nanocomposite Aerogels and the Effect of Synthesis Conditions on Gelation

2010 ◽  
Vol 148-149 ◽  
pp. 920-923
Author(s):  
Yue Qing Zhao ◽  
Ying Hua Liang ◽  
Feng Feng Li ◽  
Hong Ping Chen ◽  
Xin Hua Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Synthesis Conditions ◽  
Sol Gel Process ◽  
Bet Method

CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate (TEOS) as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercritical drying (SCD) technique. The effect of synthesis conditions on gelation was investigated. The composition of the nanocomposite aerogels was characterized by electron dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The specific surface area of the nanocomposite aerogels was determined by the Brunauer-Emmett-Teller (BET) method. The results show that the range of optimal temperature for gelation is 30-45 °C, and the pH is 3.0-4.5. CuO-CoO-MnO/SiO2 nanocomposite aerogels are porous with a specific surface area of 384.9-700.6 m2/g. Compared to CO2 SCD, ethanol SCD is even favorable to the formation of aerogel with high specific surface area. The transition metals content in the nanocomposite aerogels can be controlled to be 0.71-13.77 at.%.

Frontiers of carbon materials as capacitive deionization electrodes

2020 ◽  
Vol 49 (16) ◽  
pp. 5006-5014 ◽  
Author(s):  
Yuanyuan Li ◽  
Nan Chen ◽  
Zengling Li ◽  
Huibo Shao ◽  
Liangti Qu
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Materials ◽  
High Specific Surface Area ◽  
Carbon Aerogels ◽  
Capacitive Deionization

Carbon materials are widely used as capacitive deionization (CDI) electrodes due to their high specific surface area (SSA), superior conductivity, and better stability, including activated carbon, carbon aerogels, carbon nanotubes and graphene.

Novel Al2O3–SiO2composite aerogels with high specific surface area at elevated temperatures with different alumina/silica molar ratios prepared by a non-alkoxide sol–gel method

RSC Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 5611-5620 ◽  
Author(s):  
Xiaodong Wu ◽  
Gaofeng Shao ◽  
Xiaodong Shen ◽  
Sheng Cui ◽  
Ling Wang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Elevated Temperatures ◽  
Inorganic Salt ◽  
Sol Gel ◽  
High Specific Surface Area ◽  
Gel Method ◽  
Molar Ratios ◽  
Composite Aerogels

We have developed a new sol–gel route to synthesise Al2O3–SiO2composite aerogels with different alumina/silica (Al/Si) molar ratios using an inexpensive inorganic salt.

Synthesis and Structural Characterization of SiO2-Al2O3 Xerogels

2007 ◽  
Vol 336-338 ◽  
pp. 2286-2289
Author(s):  
Fei He ◽  
Xiao Dong He ◽  
Yao Li
Keyword(s):  
Structural Change ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Molar Ratio

Low-density xSiO2-(1-x)Al2O3 xerogels with x=0.9, 0.8, 0.7, 0.6 (mole fractions) were prepared by sol-gel and non-supercritical drying. Silica alkogels, which were the framework of binary composite materials, formed from tetraethyl orthosilicate (TEOS) by hydrolytic condensation with a molar ratio of TEOS: H2O: alcohol: hydrochloric acid: ammonia =1: 4: 10: 7.5×10-4: 0.0375. Aluminum hydroxide derived from Al(NO3)3·9H2O and NH4OH acting in the alcohol solution under the condition of catalyst. After filtrating and washing, the precipitation was mixed into silica sols to form SiO2-Al2O3 mixed oxide gels with different silicon and aluminum molar ratio. The structural change and crystallization of the binary xerogels were investigated after heat treatment at 600 for 2 h by the means of X-ray diffraction. Nitrogen adsorption experiment was performed to estimate specific surface area, porous volume and pore size distribution. The structural change of xerogels was observed by FT-IR spectroscopy. The resulting mixed xerogels possess of mesoporous structure which is characteristic of cylindrical pores, high specific surface area of 596-863 m2/g and a relatively narrow pore distribution of 2.8-30 nm. Al2O3 is introduced into the SiO2 phase and some of Al-O-Si bonds form.

Synthesis and sintering of Ca0.5Sr0.5Zr4P6O24 powders by the decomposition/combustion of Ca-, Sr-, nitrate-ammonium dihydrogen phosphate-urea mixtures

1994 ◽  
Vol 9 (9) ◽  
pp. 2398-2403 ◽  
Author(s):  
Chang S. Hong ◽  
P. Ravindranathan ◽  
Dinesh K. Agrawal ◽  
Rustum Roy
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sintered Density ◽  
Sol Gel ◽  
Combustion Method ◽  
High Specific Surface Area ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Batch Weight

Ca0.5Sr0.5Zr4P6O24 (CSZP) powders were prepared by the decomposition/combustion method using Ca(NO3)2 · 4H2O, Sr(NO3)2, ZrO(NO3)2 · xH2O, NH4H2PO4, urea, and NH4NO3 as starting materials. The homogenized slurries of the mixture were heated at 500 °C for 5 min to obtain CSZP powders. The as-synthesized powders were amorphous and crystallized after heating 800 °C for 2 h. The specific surface area of the powder was varied with the batch weight of starting materials or the amount of urea and ammonium nitrate. Powders with high specific surface area (150 m2/g) could be produced by this method. The sinterability of the powders was comparable to that of sol-gel derived powders. The sintered density of the compacts was 99% of theoretical after firing in air at 1350 °C for 6 h.

Rapid preparation process, structure and thermal stability of lanthanum doped alumina aerogels with a high specific surface area

RSC Advances ◽  
2016 ◽  
Vol 6 (31) ◽  
pp. 26271-26279 ◽  
Author(s):  
Jingfeng Yang ◽  
Qihua Wang ◽  
Tingmei Wang ◽  
Yongmin Liang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Rapid Preparation ◽  
Alumina Aerogels ◽  
Process Structure ◽  
Thermal Stability Of

In this study, we developed a new and rapid preparation method of alumina aerogels based on the sol–gel method and supercritical drying technique and prepared alumina aerogels with high specific surface area.

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