Sulfur encapsulated in porous hollow CNTs@CNFs for high-performance lithium–sulfur batteries

2014 ◽  
Vol 2 (26) ◽  
pp. 10126-10130 ◽  
Author(s):  
Yuming Chen ◽  
Xiaoyan Li ◽  
Kyu-Sung Park ◽  
Jianhe Hong ◽  
Jie Song ◽  
...  

A novel carbon-sulfur nanoarchitecture with a high Brunauer–Emmett–Teller (BET) specific surface area of ~80 m2 g−1 and a total pore volume of ~0.2cm3 g−1 shows a high capacity of ~ 700 mAh g−1 at 1 C and 520 mAh g−1 at 5 C after 100 cycles, which makes it a superior cathode material for a rechargeable Li–S battery.

2010 ◽  
Vol 4 (2) ◽  
pp. 110-116 ◽  
Author(s):  
Silvester Tursiloadi ◽  
Hiroshi Hirashima

Stable anatase is attractive to its notable functions for photo catalysis and photon-electron transfer.   Stable anatase TiO­2 containing amorphous SiO2 aerogel was prepared by hydrolysis of Ti (OC3H7)4 and Si (OC3H7)4 in a 2-propanol solution with acid catalyst. The solvent in wet gels was supercritically extracted in CO2 at 60 oC and 22 Mpa. Thermal evolutions of the microstructure of the gels were evaluated by TGA-DTA, N2 adsorption and XRD. A stable anatase TiO2 containing amorphous SiO2 aerogel with a BET specific surface area of 365 m2/g and a total pore volume of 0.20 cm3/g was obtained as prepared condition. The anatase phase was stable after calcination up to 1000 oC, and BET specific surface area, total pore volume and average pore diameter did not change significantly after calcination up to 900 oC.   Keywords: Supercritical extraction, sol-gel, aerogel, stable anatase structure


2019 ◽  
Author(s):  
Dandan Fang ◽  
Xiaodong Li ◽  
Meishuai Zou ◽  
Xiaoyan Guo ◽  
Aijuan Zhang

To systematically explore the effects of the synthesis conditions on the porosity of hyper-cross-linked polymers (HCPs), a series of 9-phenylcarbazole HCPs (P1-P11) have been made by changing the dosage of cross-linker, the reaction temperature, catalyst usage and solvent dosage. Fourier transform infrared spectroscopy is utilized to characterize the structure of the obtained polymers. The TG analysis shows a high thermal stability of the HCPs. More importantly, comparative studies on the porous properties reveals that: molar ration of cross-linker and building block is the main factor of BET specific surface area; Improving reaction temperature or the usage of catalyst could increase the total pore volume greatly but sacrifice part of BET specific surface area; Fortunately changing solvent dosage could remedy this situation, that is slightly changing solvent dosage could simultaneously obtain high surface area and high total pore volume. The BET specific surface areas of P3 is up to 769 m2g-1 with narrow pore size distribution and the CO2 adsorption capacity of P11 is up to 52.4 cm3g-1 (273 K/1.00 bar).


2019 ◽  
Vol 15 ◽  
pp. 2856-2863 ◽  
Author(s):  
Dandan Fang ◽  
Xiaodong Li ◽  
Meishuai Zou ◽  
Xiaoyan Guo ◽  
Aijuan Zhang

To systematically explore the effects of the synthesis conditions on the porosity of hyper-cross-linked polymers (HCPs), a series of 9-phenylcarbazole (9-PCz) HCPs (P1–P11) has been made by changing the molar ratio of cross-linker to monomer, the reaction temperature T 1, the used amount of catalyst and the concentration of reactants. Fourier transform infrared spectroscopy was utilized to characterize the structure of the obtained polymers. The TG analysis of the HCPs showed good thermal stability. More importantly, a comparative study on the porosity revealed that: the molar ratio of cross-linker to monomer was the main influence factor of the BET specific surface area. Increasing the reaction temperature T 1 or changing the used amount of catalyst could improve the total pore volume greatly but sacrificed a part of the BET specific surface area. Fortunately changing the concentration of reactants could remedy this situation. Slightly changing the concentration of reactants could simultaneously obtain a high surface area and a high total pore volume. The BET specific surface areas of P3 was up to 769 m2 g−1 with narrow pore size distribution and the CO2 adsorption capacity of P11 was up to 52.4 cm3 g−1 (273 K/1.00 bar).


2018 ◽  
Vol 37 (1) ◽  
pp. 194-218 ◽  
Author(s):  
Hongjie Xu ◽  
Shuxun Sang ◽  
Jingfen Yang ◽  
Jun Jin ◽  
Huihu Liu ◽  
...  

Indentifying reservoir characteristics of coals and their associated shales is very important in understanding the co-exploration and co-production potential of unconventional gases in Guizhou, China. Accordingly, comprehensive experimental results of 12 core samples from well LC-1# in the northern Guizhou were used and analyzed in this paper to better understand their vertical reservoir study. Coal and coal measured shale, in Longtan Formation, are rich in organic matter, with postmature stage of approximately 3.5% and shales of type III kerogen with dry gas generation. All-scale pore size analysis indicates that the pore size distribution of coal and shale pores is mainly less than 20 nm and 100 nm, respectively. Pore volume and area of coal samples influenced total gas content as well as desorbed gas and lost gas content. Obvious relationships were observed between residual gas and BET specific surface area and BJH total pore volume (determined by nitrogen adsorption). For shale, it is especially clear that the desorbed gas content is negatively correlated with BET specific surface area, BJH total pore volume and clay minerals. However, the relationships between desorbed gas and TOC (total organic carbon) as well as siderite are all well positive. The coals and shales were shown to have similar anoxic conditions with terrestrial organic input, which is beneficial to development of potential source rocks for gas. However, it may be better to use a low gas potential assessment for shales in coal-bearing formation because of their low S1+S2 values and high thermal evolution. Nevertheless, the coalbed methane content is at least 10 times greater than the shale gas content with low desorbed gases, indicating that the main development unconventional natural gas should be coalbed methane, or mainly coalbed methane with supplemented shale gas.


Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 298
Author(s):  
Chenlong Ding ◽  
Jinxian He ◽  
Hongchen Wu ◽  
Xiaoli Zhang

Ordos Basin is an important continental shale gas exploration site in China. The micropore structure of the shale reservoir is of great importance for shale gas evaluation. The Taiyuan Formation of the lower Permian is the main exploration interval for this area. To examine the nanometer pore structures in the Taiyuan Formation shale reservoirs in the Lin-Xing area, Northern Shaanxi, the microscopic pore structure characteristics were analyzed via nitrogen adsorption experiments. The pore structure parameters, such as specific surface area, pore volume, and aperture distribution, of shale were calculated; the significance of the pore structure for shale gas storage was analyzed; and the main controlling factors of pore development were assessed. The results indicated the surface area and hole volume of the shale sample to be 0.141–2.188 m2/g and 0.001398–0.008718 cm3/g, respectively. According to the IUPAC (International Union of Pure and Applied Chemistry) classification, mesopores and macropores were dominant in the pore structure, with the presence of a certain number of micropores. The adsorption curves were similar to the standard IV (a)-type isotherm line, and the hysteresis loop type was mainly similar to H3 and H4 types, indicating that most pores are dominated by open type pores, such as parallel plate-shaped pores and wedge-shaped slit pores. The micropores and mesopores provide the vast majority of the specific surface area, functioning as the main area for the adsorption of gas in the shale. The mesopores and macropores provide the vast majority of the pore volume, functioning as the main storage areas for the gas in the shale. Total organic carbon had no notable linear correlation with the total pore volume and the specific surface area. Vitrinite reflectance (Ro) had no notable correlation with the specific surface area, but did have a low “U” curve correlation with the total pore volume. There was no relationship between the quartz content and specific surface area and total pore volume. In addition, there was no notable correlation between the clay mineral content and total specific surface area and total pore volume.


2017 ◽  
Vol 5 (42) ◽  
pp. 22120-22124 ◽  
Author(s):  
Yonggang Liu ◽  
Weikun Wang ◽  
Anbang Wang ◽  
Zhaoqing Jin ◽  
Hailei Zhao ◽  
...  

A NiS2-modified sulfurized polyacrylonitrile composite is prepared by simply co-heating a mixture of sulfur, NiCO3, and polyacrylonitrile.


2018 ◽  
Vol 37 (1) ◽  
pp. 251-272 ◽  
Author(s):  
Junjian Zhang ◽  
Chongtao Wei ◽  
Gaoyuan Yan ◽  
Guanwen Lu

To better understand the structural characteristic of adsorption pores (pore diameter < 100 nm) of coal reservoirs around the coalbed methane production areas of western Yunnan and eastern Guizhou, we analyzed the structural and fractal characteristics of pore size range of 0.40–2.0 nm and 2–100 nm in middle–high rank coals ( Ro,max = 0.93–3.20%) by combining low-temperature N2/CO2 adsorption tests and surface/volume fractal theory. The results show that the coal reservoirs can be divided into three categories: type A ( Ro,max < 2.15%), type B (2.15% <  Ro,max <2.50%), and type C ( Ro,max > 2.15%). The structural parameters of pores in the range from 2 to 100 nm are influenced by the degree of coal metamorphism and the compositional parameters (e.g., ash and volatile matter). The dominant diameters of the specific surface areas are 10–50 nm, 2–50 nm, and 2–10 nm, respectively. The pores in the range from <2 nm provide the largest proportion of total specific surface area (97.22%–99.96%) of the coal reservoir, and the CO2-specific surface area and CO2-total pore volume relationships show a positive linear correlation. The metamorphic degree has a much greater control on the pores (pore diameter less than 2 nm) structural parameters than those of the pore diameter ranges from 2 to 100 nm. Dv1 and Dv2 can characterize the structure of 2–100 nm adsorption pores, and Dv1 (volume heterogeneity) has a positive correlation with the pore structural parameters such as N2-specific surface area and N2-total pore volume. This parameter can be used to characterize volume heterogeneity of 2–10 nm pores. Dv2 (surface heterogeneity) showed type A > type B > type C and was mainly affected by the metamorphism degree. Ds2 can be used to characterize the pore surface heterogeneity of micropores in the range of 0.62–1.50 nm. This parameter has a good correlation with the pore parameters (CO2-total pore volume, CO2-specific surface area, and average pore size) and is expressed as type C < type B < type A. In conclusion, the heterogeneity of the micropores is less than that of the meso- and macropores (2–100 nm). Dv1, Dv2, and Ds2 can be used as effective parameters to characterize the pore structure of adsorption pores. This result can provide a theoretical basis for studying the pore structure compatibility of coal reservoirs in the region.


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