Synthesis and Structural Characterization of Ti2C Nanosheets

2015 ◽  
Vol 833 ◽  
pp. 44-47 ◽  
Author(s):  
Jing Xiao Li ◽  
Yu Lei Du ◽  
Chong Cui
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Structural Characterization ◽  
Room Temperature ◽  
Atomic Composition ◽  
Two Dimensional

In this paper, two-dimensional (2D) Ti2C nanosheets were synthesized by exfoliation of Ti2AlC powders in HF solution at room temperature. The surface atomic composition and chemistry of as-prepared Ti2C nanosheets were studied by XPS. The specific surface area of Ti2C nanosheets were determined by BET. The as-prepared Ti2C nanosheets are stacked and held together, which leads to the lower specific surface area of the as-prepared Ti2C nanosheets.

Preparation and Characterization of the Typical Pt-NSR Catalyst

2011 ◽  
Vol 412 ◽  
pp. 365-369
Author(s):  
Yuan Feng Huang ◽  
Wei Jun Zhang ◽  
Li Shen ◽  
Jin Hu ◽  
Zhuo Heng Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Performance Testing ◽  
High Specific Surface Area ◽  
Impregnation Method ◽  
Temperature Programmed Reduction ◽  
Temperature Programmed ◽  
Co Precipitation

A series of Ba-Al-O NSR supports and Pt/Ba-Al-O NSR catalysts are prepared by co-precipitation and impregnation method in this work. The catalyst and the support are characterized by XRD, SEM, SBET performance testing. The structure and texture of the supports is observed and discussed. The results of SBET indicate that the supports possess relative high specific surface area (94~110 m2/g). Temperature programmed reduction is characterized by means of H2-TPR.

Mineralogical study of clays from Dobrodo, Serbia, for use in ceramics

Clay Minerals ◽  
2019 ◽  
Vol 54 (4) ◽  
pp. 369-377 ◽  
Author(s):  
Maja Milošević ◽  
Predrag Dabić ◽  
Sabina Kovač ◽  
Lazar Kaluđerović ◽  
Mihovil Logar
Keyword(s):  
Specific Surface ◽  
Cation Exchange ◽  
Surface Area ◽  
Specific Surface Area ◽  
Cation Exchange Capacity ◽  
Mineralogical Composition ◽  
Exchange Capacity ◽  
Mineralogical Characterization ◽  
Mineralogical Study

AbstractThis study focuses on the mineralogical characterization of four raw clay samples from Dobrodo deposit, Serbia. Several analytical methods were applied to determine the chemical and mineralogical composition, morphology and physical properties (colour, plasticity, specific surface area, particle size and cation-exchange capacity) of the clay samples. Kaolinite, smectite and illite are the predominant phases in all of the samples studied that contain between 60.2 and 87.1 wt.% of clay. Quartz, feldspars, paragonite and Ti- and Fe-bearing phases were also identified. The relatively high SiO2/Al2O3 mass ratio indicates abundant quartz. The cation-exchange capacity of the samples varied between low and moderately charged clay minerals (12–52 mmol 100 g–1) with specific surface area values ranging from 94 to 410 m2 g–1. The plasticity index values (11–23%) suggest low to moderate plasticity. Preliminary results show that most of the raw clay from Dobrodo deposit might be suitable for use in ceramic applications.

Fabrication and Characterization of Cu Doped CeO2 by Hydrothermal Process for Antimicrobial Activity

2019 ◽  
Vol 391 ◽  
pp. 114-119 ◽  
Author(s):  
Yeon Bin Choi ◽  
Jeong Hun Son ◽  
Dong Sik Bae
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Hydrothermal Process ◽  
Antibacterial Properties ◽  
Reaction Times ◽  
X Ray Diffraction ◽  
Spherical Type ◽  
Average Size

Cu doped CeO2 nanopowder was synthesized by hydrothermal process at 180°C for 2~10h. The average size and distribution of the synthesized Cu doped CeO2 nanopowder was controlled by reaction times. The crystallinity of the synthesized Cu doped CeO2 nanoparticles was investigated by X-ray diffraction (XRD). The morphology of the synthesized Cu doped CeO2 nanoparticles was observed by FE-SEM. The specific surface area of the synthesized Cu doped CeO2 nanoparticles was measured by BET. The crystal size of the synthesized Cu doped CeO2 nanoparticles decreased with decreasing reaction times. The average size of the synthesized Cu doped CeO2 nanoparticles was below 10nm and narrow, respectively. The shape of the synthesized Cu doped CeO2 nanoparticles was spherical type. The specific surface area of the synthesized Cu doped CeO2 nanoparticles increased with decreasing reaction times. Antibacterial properties of Cu doped CeO2 were analyzed by MIC method. The synthesized Cu doped CeO2 nanopowders showed antibacterial properties against E.coli and B.sub bacteria.

scholarly journals Measuring specific surface area of snow by near-infrared photography

2006 ◽  
Vol 52 (179) ◽  
pp. 558-564 ◽  
Author(s):  
Margret Matzl ◽  
Martin Schneebeli
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Near Infrared ◽  
Two Dimensions ◽  
Chemical Models ◽  
Snow Stratigraphy ◽  
Physical And Chemical

AbstractThe specific surface area (SSA) is considered an essential microstructural parameter for the characterization of snow. Photography in the near-infrared (NIR) spectrum is sensitive to the SSA. We calculated the snow reflectance from calibrated NIR images of snow-pit walls and measured the SSA of samples obtained at the same locations. This new method is used to map the snow stratigraphy. The correlation between reflectance and SSA was found to be 90%. Calibrated NIR photography allows quantitative determination of SSA and its spatial variation in a snow profile in two dimensions within an uncertainty of 15%. In an image covering 0.5–1.0 m2, even layers of 1mm thickness can be documented and measured. Spatial maps of SSA are an important tool in initializing and validating physical and chemical models of the snowpack.

Characterization of halloysite (North East Rif, Morocco): evaluation of its suitability for the ceramics industry

Clay Minerals ◽  
2018 ◽  
Vol 53 (1) ◽  
pp. 65-78 ◽  
Author(s):  
Abdelilah El Haddar ◽  
Elkhadir Gharibi ◽  
Ali Azdimousa ◽  
Nathalie Fagel ◽  
Iz-Eddine El Amrani El Hassani ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Fine Particles ◽  
High Plasticity ◽  
North East ◽  
Physico Chemical ◽  
Ceramics Industry ◽  
Tubular Crystals

ABSTRACTA halloysite clay from Nador (NE Morocco) was studied to evaluate its suitability in the ceramics industry. A cross-section involving all the Messinian facies was performed in the Melilla Neogene basin, at the foot of the Gourougou volcano, to establish the origin of the halloysite and estimate its reserves. White layers of halloysite and red clays rich in smectite occurring in contact with basal-reef limestone were characterized by mineralogical (XRD, IR), textural (SEM) and physico-chemical analyses (grain-size, Atterberg limits, DTA/TG, XRF and specific surface area). Ceramic properties were evaluated for halloysite fired from 500 to 1100°C to evaluate technical processing for ceramic production.The halloysite clay consists of fine particles with a high plasticity and a large specific surface area. The XRD investigation revealed the presence of 7 Å non-hydrated halloysite along with gibbsite, alunite, K-feldspar and traces of smectite and illite.The presence of halloysite was confirmed from the characteristic IR bands at 3695 and 3618 cm−1and the predominance of tubular crystals observed in the SEM. The chemical analysis revealed high contents linked to the presence of Al-rich phases (gibbsite and alunite). DTA/TG and XRD results of fired clay samples proved the dehydroxylation of halloysite and a rearrangement of metakaolinite to form mullite and spinel at 975°C.The Moroccan halloysite might be suitable for refractory ceramic applications. However, addition of quartz sand might be necessary to avoid crack development during firing and to reduce the plasticity of raw halloysite and minimize shrinkage during sintering.

Preparation and Characterization of Porous Yttrium Oxide Powders with High Specific Surface Area

2006 ◽  
Vol 24 (1) ◽  
pp. 34-38 ◽  
Author(s):  
Yongxiu Li ◽  
Xiaoyun Lin ◽  
Yizheng Wang ◽  
Junming Luo ◽  
Weili Sun
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Yttrium Oxide ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
Oxide Powders

scholarly journals Preparation and Application of 2D MXene-Based Gas Sensors: A Review

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 225
Author(s):  
Qingting Li ◽  
Yanqiong Li ◽  
Wen Zeng
Keyword(s):  
Composite Materials ◽  
Specific Surface ◽  
Surface Area ◽  
Gas Sensor ◽  
Specific Surface Area ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Interlayer Spacing ◽  
Preparation Methods

Since MXene (a two-dimensional material) was discovered in 2011, it has been favored in all aspects due to its rich surface functional groups, large specific surface area, high conductivity, large porosity, rich organic bonds, and high hydrophilicity. In this paper, the preparation of MXene is introduced first. HF etching was the first etching method for MXene; however, HF is corrosive, resulting in the development of the in situ HF method (fluoride + HCl). Due to the harmful effects of fluorine terminal on the performance of MXene, a fluorine-free preparation method was developed. The increase in interlayer spacing brought about by adding an intercalator can affect MXene’s performance. The usual preparation methods render MXene inevitably agglomerate and the resulting yields are insufficient. Many new preparation methods were researched in order to solve the problems of agglomeration and yield. Secondly, the application of MXene-based materials in gas sensors was discussed. MXene is often regarded as a flexible gas sensor, and the detection of ppb-level acetone at room temperature was observed for the first time. After the formation of composite materials, the increasing interlayer spacing and the specific surface area increased the number of active sites of gas adsorption and the gas sensitivity performance improved. Moreover, this paper discusses the gas-sensing mechanism of MXene. The gas-sensing mechanism of metallic MXene is affected by the expansion of the lamellae and will be doped with H2O and oxygen during the etching process in order to become a p-type semiconductor. A p-n heterojunction and a Schottky barrier forms due to combinations with other semiconductors; thus, the gas sensitivities of composite materials are regulated and controlled by them. Although there are only several reports on the application of MXene materials to gas sensors, MXene and its composite materials are expected to become materials that can effectively detect gases at room temperature, especially for the detection of NH3 and VOC gas. Finally, the challenges and opportunities of MXene as a gas sensor are discussed.

scholarly journals The Effect of NaOH and KOH on the Characterization of Mesoporous AlOOH Nanostructures in the Hydrothermal Route

2017 ◽  
Vol 58 (2) ◽  
Author(s):  
Nahid Haghnazari ◽  
Mozaffar Abdollahifar ◽  
Farahnaz Jahani
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Hydrothermal Treatment ◽  
Specific Surface Area ◽  
Analytical Techniques ◽  
Aluminium Nitrate ◽  
Hydrothermal Route ◽  
Bet Specific Surface Area ◽  
Adsorption Desorption

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.

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