Effect of Heat Treatment on Specific Surface Area of Si-C-O Fibers

2008 ◽  
pp. 1639-1641
Author(s):  
Zeng Yong Chu ◽  
Rong An He ◽  
H.F. Cheng ◽  
Xiao Dong Li ◽  
Jun Wang
Keyword(s):  
Heat Treatment ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area

Effect of Heat Treatment on Specific Surface Area of Si-C-O Fibers

2008 ◽  
Vol 368-372 ◽  
pp. 1639-1641
Author(s):  
Zeng Yong Chu ◽  
Rong An He ◽  
Hai Feng Cheng ◽  
Xiao Dong Li ◽  
Jun Wang
Keyword(s):  
Heat Treatment ◽  
Weight Loss ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Treatment Time ◽  
Porous Ceramic ◽  
Ceramic Fiber

In this paper, effect of heat treatment on the SSA of Si-C-O fibers was investigated and morphologies of the treated fibers were studied using SEM. The results revealed that weight loss was proportional to the treatment time at 1573K and the specific surface area (SSA) increased sharply when the weight loss reached above 6wt%. A rough and porous ceramic fiber with SSA of 23.76m2/g could be obtained at the weight loss of 9.1wt%, as a result of the treatment at 1573K for 32h.

Hydrothermal Synthesis of Phthalocyanine Sensitization TiO2 Nanowires

2012 ◽  
Vol 531 ◽  
pp. 387-390 ◽  
Author(s):  
Ling Ling Zhan ◽  
Hai Feng Chen ◽  
Jian Qiang Ye
Keyword(s):  
Heat Treatment ◽  
Hydrothermal Synthesis ◽  
Methyl Orange ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Raw Materials ◽  
Nano Tio2 ◽  
Prepared Sample ◽  
Photocatalytic Activities

Phthalocyanine sensitization nano-TiO2 have been successfully synthesized by controlling TiO2's nuclear growth and CoPcTs adsorption simultaneously via a hydrothermal way by using TiO2, NaOH and CoPcTs as raw materials. XRD, BET, TG-DTA and FI-IR were used to characterize the features of the as-synthesized phthalocyanine sensitization TiO2 nanowires. The results showed that anatase nano- TiO2 with phthalocyanine sensitization have been prepared after heat treatment and cyanine materials are easily decomposed when the temperature above 450 °C; the specific surface area TiO2 and phthalocyanine sensitization nano-TiO2 is 42.2 m2/g and 110.5 m2/g, respectively. Methyl orange dyes were chosen to test the photocatalytic activities of the as-prepared sample in this experiment, and it found that the loading of 1% wt CoPcTs was the best.

Excellent fluoride removal performance by electrospun La-Mn bimetal oxide nanofibers

2021 ◽  
Author(s):  
Shaoju Jian ◽  
Yiting Cheng ◽  
xiaofan ma ◽  
Hongtao Guo ◽  
Jiapeng Hu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Fluoride Removal ◽  
Treatment Technology ◽  
Heat Treatment Technology ◽  
Defluoridation Of Water

La-Mn bimetal oxide nanofibers used as adsorbent for the defluoridation of water was synthesized by electrospinning - heat treatment technology. The La-Mn bimetal oxide nanofiber adsorbent with specific surface area...

scholarly journals Fabrication of carbon nanospheres by the pyrolysis of polyacrylonitrile–poly(methyl methacrylate) core–shell composite nanoparticles

2017 ◽  
Vol 8 ◽  
pp. 1897-1908 ◽  
Author(s):  
Dafu Wei ◽  
Youwei Zhang ◽  
Jinping Fu
Keyword(s):  
Heat Treatment ◽  
Methyl Methacrylate ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Core Shell ◽  
Carbon Nanospheres ◽  
High Concentration ◽  
Poly Methyl Methacrylate ◽  
Bet Specific Surface Area

Carbon nanospheres with a high Brunauer–Emmett–Teller (BET) specific surface area were fabricated via the pyrolysis of polyacrylonitrile–poly(methyl methacrylate) (PAN–PMMA) core–shell nanoparticles. Firstly, PAN–PMMA nanoparticles at high concentration and low surfactant content were controllably synthesized by a two-stage azobisisobutyronitrile (AIBN)-initiated semicontinuous emulsion polymerization. The carbon nanospheres were obtained after the PAN core domain was converted into carbon and the PMMA shell was sacrificed via the subsequent heat treatment steps. The thickness of the PMMA shell can be easily adjusted by changing the feeding volume ratio (FVR) of methyl methacrylate (MMA) to acrylonitrile (AN). At an FVR of 1.6, the coarse PAN cores were completely buried in the PMMA shells, and the surface of the obtained PAN–PMMA nanoparticles became smooth. The thick PMMA shell can inhibit the adhesion between carbon nanospheres caused by cyclization reactions during heat treatment. The carbon nanospheres with a diameter of 35–65 nm and a high BET specific surface area of 612.8 m2/g were obtained from the PAN–PMMA nanoparticles synthesized at an FVR of 1.6. The carbon nanospheres exhibited a large adsorption capacity of 190.0 mg/g for methylene blue, thus making them excellent adsorbents for the removal of organic pollutants from water.

scholarly journals LOW-TEMPERATURE SYNTHESIS OF BARIUM TITANITE IN AQUEOUS SOLUTION

2018 ◽  
Vol 61 (12) ◽  
pp. 56-62 ◽  
Author(s):  
Alexandr V. Agafonov ◽  
Konstantin V. Ivanov ◽  
Olga V. Alekseeva
Keyword(s):  
Heat Treatment ◽  
Barium Titanate ◽  
Thermal Treatment ◽  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Temperature Phase ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis

Barium titanate powder with average particle size near 300 nm was produced using the low-temperature synthesis. It was established using scanning electron microscopy that at the thermal treatment, the particles gradually decrease with the formation of polydisperse aggregates. Based on the thermogravimetric analysis of the synthesized powder held in air for 4 months, it was shown that along with the low-temperature phase, the sample contains a high-temperature phase of carbonates, which removes at ~ 900 °C. Sorption characteristics of barium titanate thermally treated at various temperatures were obtained from the results of adsorption-desorption of nitrogen vapors. The specific surface area of the BaTiO3 powder was 76 m2/g. It was found that further heat treatment leads to a decrease in the specific surface area. The X-ray diffraction analysis of barium hydroxotitanil annealed at temperatures from 120 °C to 800 °C showed that the thermal treatment of the sample leads to the formation of a completely formed phase of barium titanate. The DSC temperature was used to determine the Curie temperatures for a HTB powder thermally treated in the temperature range from 120 to 800 °C. Dielectric spectra of suspensions of the synthesized powder were obtained during the heat treatment. <span style="opacity: 0;"> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . </span>

scholarly journals Conversion of Black Carbon Emitted from Diesel-Powered Merchant Ships to Novel Conductive Carbon Black as Anodic Material for Lithium Ion Batteries

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1280 ◽  
Author(s):  
Jae-Hyuk Choi ◽  
Dae-Yeong Kim ◽  
Won-Ju Lee ◽  
Jun Kang
Keyword(s):  
Heat Treatment ◽  
Carbon Black ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Coulombic Efficiency ◽  
Lithium Ion ◽  
Industrial Applications ◽  
Spherical Particles ◽  
Conductive Material

Waste soot generated from diesel engine of merchant ships has ≥ 2 µm agglomerates consisting of 30–50 nm spherical particles, whose morphology is identical to that of carbon black (CB) used in many industrial applications. In this study, we crystallized waste soot by heat treatment to transform it into a unique completely graphitic nano-onion structure, which is considerably different from that of commercial conductive CB. While commercial CB has a large specific surface area because of many surface micropores generated due to quenching by water-spraying in the production process, the heat-treated waste soot has a smooth micropore-free surface. Thus, the treated waste soot acquires the shape of CB but has a much smaller specific surface area. When the treated soot is used as a conductive material in lithium ion battery (LIB) half cells, the Coulombic efficiency of the entire anode is improved significantly owing to its low specific surface area; the electrochemical performance of the LIB is considerably enhanced compared to that of conventional conductive materials. Thus, polluting soot generated in marine propulsion can be transformed into a new class of CB with a unique structure by simple heat treatment; this soot can also be used as an inexpensive conductive material to enhance the LIB performance.

Preparation of Nanoscale High-Purity α-Alumina Powders

2007 ◽  
Vol 336-338 ◽  
pp. 2051-2053 ◽  
Author(s):  
Xiu Lan Wu ◽  
Qiang Ren ◽  
Xuan Meng He
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Purity ◽  
High Specific Surface Area ◽  
Aluminium Isopropoxide ◽  
Reaction Progress ◽  
Α Al2o3

High-purity nanoscale α-alumina powders with high specific surface area were prepared from boehmite powders synthesized by the method of aluminium isopropoxide hydrolysis. The physiochemical transformation of boehmite powders under heat-treatment was investigated. The results showed that the reaction progress of boehmite under heat-treatment is as follows: AlO(OH) → Al2O3 (amorphous) → γ-Al2O3 → δ-Al2O3 → α-Al2O3. The phase transformation from δ-Al2O3 to α-Al2O3 begins at 1050oC, and the α-Al2O3 grains growth accelerates as temperature increases. High-purity α-Al2O3 nanometer powders with higher specific surface area can be obtained after incineration at 1100oC for 4 h.

scholarly journals Formation of inorganic nanofibers by heat-treatment of poly(vinyl alcohol)-zirconium compound hybrid nanofibers

2013 ◽  
Vol 49 (1) ◽  
pp. 77-82 ◽  
Author(s):  
K. Nakane ◽  
S. Matsuoka ◽  
S. Gao ◽  
S. Yonezawa ◽  
J.H. Kim ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Vinyl Alcohol ◽  
High Specific Surface Area ◽  
Poly Vinyl Alcohol ◽  
Monoclinic Zro2 ◽  
Hybrid Nanofibers ◽  
Zirconium Compound

Poly(vinyl alcohol)-zirconium compound hybrid nanofibers (precursors) were formed by electrospinning employing water as a solvent for the spinning solution. The precursors were converted into oxide (ZrO2), carbide (ZrC) or nitride (ZrN) nanofibers by heating them in air, Ar or N2 atmospheres. Monoclinic ZrO2 nanofibers with high-specific surface area were obtained by heat-treatment of the precursors in air. ZrC and ZrN nanofibers could be obtained below theoretical temperatures calculated from thermodynamics data.

Nitrogen Doping to Metatitanic Acid by NH3 Heat Treatment for Achieving Visible-Light-Responsive Photocatalytic Activity

2013 ◽  
Vol 761 ◽  
pp. 35-39
Author(s):  
Se Keun Park ◽  
Jun Ho Eun ◽  
Hyun Ho Shin
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Nitrogen Doping ◽  
High Specific Surface Area ◽  
Metatitanic Acid ◽  
Heat Treated

Nitrogen doping can be achieved by heating TiO2-based photocatalyst powders under dopant-generating atmospheres such as NH3. In the present work, metatitanic acid (MTA) powder was used as a raw material to obtain nitrogen-doped titania using heat treatment in NH3flow. MTA is an industrially available intermediate product in sulfate process for TiO2production, which is mesoporous material with high specific surface area. The MTA powder was heat-treated in flowing NH3at 400–550°C. For comparison, commercial P25 TiO2powder was heat-treated under the same conditions. The results show that nitrogen dopant can be successfully incorporated into the MTA by heating in NH3 atmosphere. This obviously results in the enhanced visible-light photocatalytic activity, especially in MTA sample heated at 400°C. Due to the fascinating properties of MTA powder such as high specific surface area, the N-doping effect on MTA powder is much higher than the P25 TiO2powder.

scholarly journals Kinetic of sintering of polyethilene glycol and lanthanum dopped aluminum oxide obtained by the sol-gel method

2011 ◽  
Vol 65 (4) ◽  
pp. 355-362
Author(s):  
Tatjana Novakovic ◽  
Ljiljana Rozic ◽  
Zorica Vukovic ◽  
Srdjan Petrovic
Keyword(s):  
Heat Treatment ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Initial Period ◽  
Sol Gel ◽  
Textural Properties ◽  
Sintering Behavior ◽  
Isothermal Heat Treatment ◽  
Surface Areas

Sintering and crystallization of low-density polyethylene glycol (PEG) and lanthanum, La(III)-doped Al2O3 aerogels prepared from aluminum isopropoxide were investigated. The sintering behavior of non-doped and doped aerogels was examined by following the change of specific surface area with isothermal heat-treatment. The specific surface area and crystalline phases of non-doped and PEG+La(III)-doped aerogels were determined, and the effects of dopants on the sintering and crystallization of Al2O3 aerogels are discussed. Isothermal sintering experiments showed that the sintering mechanism of non-doped and PEG+La(III)-doped Al2O3 aerogels is surface diffusion. The specific surface areas of alumina samples decrease rapidly during the initial period of sintering, and more slowly with prolonged sintering time. The change of the porous structure is correlated with the phase transformation of ?-Al2O3 during calcinations of Al2O3 aerogels. The surface area of non-doped Al2O3 aerogels came to about 20 m2g-1 with heat-treatment at 1100?C because of crystallization of ?-Al2O3 after densification. In the case of heattreatment at 1200?C, the largest surface area was observed for PEG+La(III) doped Al2O3 aerogels and the XRD pattern showed only low ordered ?-Al2O3. These indicate that the addition of PEG+La(III) to boehmite sol prevents Al2O3 aerogels from sintering and crystallizing to the ?-Al2O3 phase. Even after 20 h at 1000?C, PEG+La (III)-doped alumina samples maintain a rather good specific surface area (108 m2 g-1) in comparison to the non-doped, containing mainly ?-Al2O3 and minor amounts of ?-Al2O3. Aluminum-oxides with these structural and textural properties are widely used as a coatings and catalyst supports in the field of various catalysis.

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