Moderate Specific Surface Areas Help Three-Dimensional Frameworks Achieve Dendrite-Free Potassium-Metal Anodes

Ultrafine porous boron nitride nanofibers with high aspect ratios, high specific surface areas and large pore volumes has been synthesized in large quantity via a freeze-drying and post pyrolysis process.

Download Full-text

Experimental Investigation of Coal Dust Wettability Based on Surface Contact Angle

Journal of Chemistry ◽

10.1155/2016/9452303 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8 ◽

Cited By ~ 15

Author(s):

Gang Zhou ◽

Han Qiu ◽

Qi Zhang ◽

Mao Xu ◽

Jiayuan Wang ◽

...

Keyword(s):

Surface Tension ◽

Contact Angle ◽

Specific Surface ◽

Coal Dust ◽

Single Point ◽

Contact Angles ◽

Critical Surface ◽

Volume Percentage ◽

Surface Areas ◽

Specific Surface Areas

Wettability is one of the key chemical properties of coal dust, which is very important to dedusting. In this paper, the theory of liquid wetting solid was presented firstly; then, taking the gas coal of Xinglongzhuang coal mine in China as an example, by determination of critical surface tension of coal piece, it can be concluded that only when the surface tension of surfactant solution is less than 45 mN/m can the coal sample be fully wetted. Due to the effect of particle dispersity, compared with the contact angle of milled coal particle, not all the contact angles of screened coal powder with different sizes have a tendency to increase. Furthermore, by the experiments of coal samples’ specific surface areas and porosities, it can be achieved that the volume of single-point total pore decreases with the gradual decreasing of coal’s porosity, while the ultramicropores’ dispersities and multipoint BET specific surface areas increase. Besides, by a series of contact angle experiments with different surfactants, it can be found that with the increasing of porosity and the decreasing of volume percentage of ultramicropore, the contact angle tends to reduce gradually and the coal dust is much easier to get wetted.

Download Full-text

Facile Method To Synthesize Mesoporous Multimetal Oxides (ATiO3, A = Sr, Ba) with Large Specific Surface Areas and Crystalline Pore walls

Chemistry of Materials ◽

10.1021/cm903303v ◽

2010 ◽

Vol 22 (4) ◽

pp. 1276-1278 ◽

Cited By ~ 39

Author(s):

Xiaoxing Fan ◽

Ying Wang ◽

Xinyi Chen ◽

Ling Gao ◽

Wenjun Luo ◽

...

Keyword(s):

Specific Surface ◽

Surface Areas ◽

Specific Surface Areas

Download Full-text

Synthesis, Characterization and Photocatalytic Activity of Nanocrystalline First Transition-Metal (Ti, Mn, Co, Ni and Zn) Oxisde Nanofibers by Electrospinning

Applied Sciences ◽

10.3390/app9010008 ◽

2018 ◽

Vol 9 (1) ◽

pp. 8 ◽

Cited By ~ 5

Author(s):

Yu Chen ◽

Weipeng Lu ◽

Yanchuan Guo ◽

Yi Zhu ◽

Haojun Lu ◽

...

Keyword(s):

Electron Microscope ◽

Transition Metal ◽

Metal Oxide ◽

Specific Surface ◽

Three Dimensional ◽

Photogenerated Electron ◽

Practical Applications ◽

Surface Areas ◽

Tio2 Nanofiber ◽

Transmission Electron

In this work, five nanocrystalline first transition-metal (Ti, Mn, Co, Ni and Zn) oxide nanofibers were prepared by electrospinning and controlled calcination. The morphology, crystal structure, pore size distribution and specific surface area were systematically studied by scanning electron microscope (SEM), transmission electron microscope (TEM), surface and pore analysis, and thermo gravimetric analyzer (TGA). The results reveal that the obtained nanofibers have a continuously twisted three-dimensional scaffold structure and are composed of neat nanocrystals with a necklace-like arrangement. All the samples possess high specific surface areas, which follow the order of NiO nanofiber (393.645 m2/g) > TiO2 nanofiber (121.445 m2/g) > ZnO nanofiber (57.219 m2/g) > Co3O4 nanofiber (52.717 m2/g) > Mn2O3 nanofiber (18.600 m2/g). Moreover, the photocatalytic degradation of methylene blue (MB) in aqueous solution was investigated in detail by employing the five kinds of metal oxide nanofibers as photocatalysts under ultraviolet (UV) irradiation separately. The results show that ZnO, TiO2 and NiO nanofibers exhibit excellent photocatalytic efficiency and high cycling ability to MB, which may be ascribed to unique porous structures and the highly efficient separation of photogenerated electron-hole pairs. In brief, this paper aims to provide a feasible approach to achieve five first transition-metal oxide nanofibers with excellent performance, which is important for practical applications.

Download Full-text

Carbon Microspheres Prepared by High Internal Phase Emulsion Polymerization

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.239-242.3105 ◽

2011 ◽

Vol 239-242 ◽

pp. 3105-3108

Author(s):

Ming Xian Liu ◽

Li Hua Gan ◽

Jun Hu ◽

Hong Lai Liu ◽

Long Wu Chen

Keyword(s):

Electron Microscopy ◽

Specific Surface ◽

Aqueous Phase ◽

Apparent Density ◽

Tween 80 ◽

Carbon Microspheres ◽

High Internal Phase Emulsion ◽

Surface Areas ◽

Internal Phase ◽

Specific Surface Areas

In this paper, we present a novel approach for the synthesis of carbon microspheres via the polymerization of a high internal phase emulsion (HIPE). By using Span 80 and Tween 80 as emulsifiers, 1iquid paraffin as oil phase, and the mixture of resorcinol/formaldehyde (R/F) solution as aqueous phase, an O/W emulsion was obtained. This emulsion phase inverted to a W/O HIPE induced by ammonia which served as the polymerization catalyst. Carbon microspheres (CMs) were prepared by polymerization of the HIPE, followed by drying and carbonization. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analyzer were used to characterize as-prepared CMs. The results indicate that, in case of 0.25 wt% ammonia of the HIPE, the diameters of CMs decreased from about 2 to 1 μm when the mass fraction of aqueous R/F decreased from 0.714 to 0.357; the apparent density and the specific surface areas of the CMs, however, did not change obviously, which are about 0.6 g/cm3and 200 m2/g, respectively. The dosage of ammonia has a significant influence on the morphology and properties of CMs. With increasing of the ammonia mass to 1 wt% of the HIPE, the resultant carbon materials comprise not only CMs, but also some carbon sheets; the apparent density of which increased to 0.9 g/cm3and the specific surface areas of which decreased to below 100 m2/g. In addition, the other parameters for CMs preparation were also investigated. It was found that the proper conditions were controlling the temperature of 303-333 K and the oil/aqueous phase mass ratio of 2.5:7.

Download Full-text

The Experimental Study on Grinding Properties of Gas Quenching Steel Slag

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.612 ◽

2011 ◽

Vol 189-193 ◽

pp. 612-617

Author(s):

Hong Wei Xing ◽

Yue Long ◽

Xiu Li ◽

Gao Liang Li ◽

Yu Zhu Zhang ◽

...

Keyword(s):

Specific Surface ◽

New Technology ◽

Steel Slag ◽

Economic Benefits ◽

Surface Areas ◽

Mineral Phases ◽

Quenching Process ◽

Gas Quenching ◽

Specific Surface Areas ◽

Better Than

A gas quenching process to deal with steel slag and its characteristics of the new technology was briefly introduced. The grinding characteristics, mineral phases of gas quenching steel slag and the potential economic benefits of using it as cement mixing material was studied by compared to heat-stew steel slag. The results indicated that the specific surface areas (S) and grinding times (t) of the gas quenching steel slag showed a first order exponential decay relationship. With the extension of time, the specific surface areas of heat-stew steel slag was tending to balance earlier than that of gas quenching steel slag; The energy consumption of gas quenching steel slag was much lower than that of heat-stew steel slag. Gas quenching steel slag was comprised of C2S, C3S, a certain amount of (Ca2(Al, Fe)2O5）and RO phase, but the content of RO phase was relatively low, which increased the grindability of the quenching steel slag, so that the grindability of gas quenching steel slag was much better than that of heat-stew steel slag. Gas quenching steel slag prepared for cement addictives would bring great economic benefits.

Download Full-text

Photocatalytic activity of CaTaO2N nanocrystals obtained from a hydrothermally synthesized oxide precursor

10.31219/osf.io/qdgam ◽

2019 ◽

Author(s):

Roberto Köferstein

Keyword(s):

Photocatalytic Activity ◽

Methyl Orange ◽

Specific Surface ◽

Morphological Properties ◽

Soft Chemistry ◽

Co Catalyst ◽

Surface Areas ◽

Oxide Precursor ◽

Photocatalytic Activities ◽

Specific Surface Areas

Highly crystalline CaTaO2N nanoparticles possessing large specific surface areas were investigated as photocatalysts for the decomposition of methyl orange. Two different Ca2Ta2O7 precursors were synthesized by classical solid state synthesis and a hydrothermal soft-chemistry approach, respectively. In both cases, nitridation was carried out by thermal ammonolysis. The obtained CaTaO2N samples were compared with respect to their optical, thermal and morphological properties as well as their photocatalytic activities. In particular, the influence of ammonolysis temperature on the photocatalytic properties was studied. Using hydrothermally synthesized Ca2Ta2O7, phase pure CaTaO2N was obtained already at a relatively low ammonolysis temperature of 860 °C. Morphological investigations show that the CaTaO2N samples from the hydrothermally synthesized precursor consist of single-crystalline particles of 45 to 70 nm diameter with high specific surface areas between 12 and 19 m2 g-1, depending on ammonolysis temperature. A considerable photocatalytic activity for methyl orange degredation was found for the nanoscaled CaTaO2N particles prepared at lower ammonolysis temperatures. Using CoOx as co-catalyst, a further strong enhancement of the methyl orange decomposition by a factor 5-10 was achieved.

Download Full-text