Brunauer–Emmett–Teller (BET) specific surface area analysis of different graphene materials: A comparison to their structural regularity and electrical properties

2020 ◽  
Vol 320 ◽  
pp. 114004 ◽  
Author(s):  
Velram Balaji Mohan ◽  
Krishnan Jayaraman ◽  
Debes Bhattacharyya
Clay Minerals ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 665-674 ◽  
Author(s):  
Emmanuel Ajenifuja ◽  
Abimbola P.I. Popoola ◽  
Kabir O. Oyedotun ◽  
Olawale Popoola

ABSTRACTKaolin and diatomite are abundant and widely available geological materials that may immobilize or stabilize functional chemical species on their surfaces for various applications. Acid-treated kaolin and diatomite were intercalated with photocatalyst Ag-TiO2nanoparticles using the sol–gel technique to prepare nanocomposite ceramic materials. The nanocomposites were sintered between 900°C and 1000°C to induce thermal reactions and to enhance nanoparticle–substrate attachment. Chemical and thermal characterizations of the acid-treated materials and intercalated nanocomposites were performed with energy-dispersive X-ray (EDX) analysis and differential scanning calorimetry (DSC), respectively. The Brunauer–Emmett–Teller (BET)-specific surface area and scanning electron microscopy (SEM) were employed for physical and microstructural characterization of the nanocomposites, respectively. Morphological studies revealed a uniform distribution of Ag-TiO2nanocrystallites in pores and on mineral particle surfaces. The BET analysis showed remarkable surface and grain modification by sintering. Decreases in the BET-specific surface area were observed for the sintered ceramic nanocomposite, Ag-TiO2-kaolin (20.244 to 5.446 m2/g) and Ag-TiO2-diatomite (19.582 to 10.148 m2/g).


2010 ◽  
Vol 349 (1) ◽  
pp. 275-282 ◽  
Author(s):  
S. Kaufhold ◽  
R. Dohrmann ◽  
M. Klinkenberg ◽  
S. Siegesmund ◽  
K. Ufer

2011 ◽  
Vol 287-290 ◽  
pp. 2094-2101
Author(s):  
Zi Yu Liu ◽  
Yue Qi ◽  
Ying Xu Wei ◽  
Zong Bin Wu ◽  
Zhong Min Liu

A mesostructured zirconium oxide was synthesized hydrothermally using cetyltrimethylammonium bromide (CTAB) as the structure-directing agent and ZrSO4. 4H2O as the reactant. Subsequent post-synthetic treatment with H3PO4followed by the treatment with AlCl3solutions resulted in mesoporous Zr-P-Al materials, which exhibited high BET specific surface area before calcination. The phosphoric acid concentrationaffected the textual data of the resulting Zr-P and Zr-P-Al materials greatly. 0.1-0.5 M H3PO4increased obviously the long-range order of the as-synthesized Zr-P materials while 0.76 M H3PO4decreased it. After calcination at 773 K, the Zr-P materials turned to nonporous materials except the one synthesized by 0.5 M H3PO4, which showed micropores with a BET specific surface area of 147 m2/g. Further treating the Zr-P materials (synthesized from different concentration of phosphoric acid) with the same amount of AlCl3solution resulted in mesoporous Zr-P-Al materials, but the long-range order of which decreased when the H3PO4concentration increased. Similarly, the BET specific surface area of the above-mentioned Zr-P-Al materials decreased from 462 m2/g for 0.25 M H3PO4to 394 m2/g for 0.5 M H3PO4and finally to 332 m2/g for 0.76 M H3PO4after calcination at 773 K, while the pore size increased gradually from 3.0 to 3.5 nm. It was found that about 90% of the CTAB had been removed during the AlCl3treatment and that the as-synthesized Zr-P-Al materials exhibited high BET specific surface area as well as mesopores. The AlCl3amount is another factor affecting the textual data of the uncalcined Zr-P-Al materials besides the H3PO4concentration. With the phosphoric acid concentration of 0.25 M, the BET specific surface area of the as-synthesized Zr-P-Al materials increased from 477 m2/g to as high as 734 m2/g with the increasing AlCl3amount before it decreased from then on.


Author(s):  
Nahid Haghnazari ◽  
Mozaffar Abdollahifar ◽  
Farahnaz Jahani

Mesoporous AlOOH was synthesized by hydrothermal treatment from aluminium nitrate and NaOH or KOH. The effect of NaOH and KOH as precipitating agents on the characterization of samples were investigated. xrd, ftir, fesem and N<sub>2</sub> adsorption-desorption analytical techniques were used to characterize the products. Our results showed that using KOH as precipitating agent was favourable for the formation of mesoporous and crystalline AlOOH with high bet-specific surface area of 98 m<sup>2</sup>/g.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4569
Author(s):  
Barbara Kozub ◽  
Jan Kazior ◽  
Aneta Szewczyk-Nykiel

The subject of this work was the study of processes occurring during sintering of water atomized AISI 316L austenitic stainless steel powder modified by the addition of graphite nanoparticles. The main purpose of the work was to determine the effect of modification of the AISI 316L stainless steel austenitic powder by the addition of graphite nanopowder on the sintering kinetics and oxide reduction mechanism. The phenomena occurring during the sintering process and oxide reduction mechanisms were subjected to detailed characterizations. Mixtures with two types of nanopowder with a high BET (measurement technique of the specific surface area of materials based on Brunauer–Emmett–Teller theory) specific surface area of 350 and 400 m2/g and for comparison with graphite micropowder with a poorly developed BET specific surface area of 15 m2/g were tested. The conducted thermal analysis showed that the samples made of austenitic stainless steel doped with 0.2% and 0.3% by weight graphite nanopowder with a BET specific surface area of 400 m2/g, sintered best the oxide reduction reactions, with a more intensive participation of carbon, for these samples.


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