Preparation of High Surface Area Anatase TiO2 by a Low Temperature Hydrothermal Process

2011 ◽  
Vol 299-300 ◽  
pp. 106-109
Author(s):  
Mei Zhen Gao ◽  
Zhi Rong Zhang ◽  
Wen Li ◽  
Wen Bao Liu ◽  
Bing Jun Yang
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Surface Area ◽  
Pore Diameter ◽  
High Surface ◽  
Hydrothermal Process ◽  
Mesoporous Structure ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Adsorption Desorption

Pure anatase TiO2spheres with mesoporous structure were prepared by a simple urea assisted hydrothermal process at low temperature. The characterization of TiO2was examined by X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), N2adsorption-desorption and ultraviolet visible spectrophotometer (UV-VIS). The TEM and N2adsorption-desorption results confirmed that TiO2spheres has a mesoporous structure. The surface area of TiO2annealed at 400 °C is up to 302.3 m2/g with average pore diameter about 4.1 nm. While after annealed at 500 °C, the average pore diameter of TiO2is about 6.8 nm, but the surface area reduces to 142.6 m2/g

Effects of mesoporous structure on grain growth of nanostructured tungsten oxide

2004 ◽  
Vol 19 (9) ◽  
pp. 2687-2693 ◽  
Author(s):  
Lay Gaik Teoh ◽  
Jiann Shieh ◽  
Wei Hao Lai ◽  
Min Hsiung Hon
Keyword(s):  
Activation Energy ◽  
Surface Area ◽  
Grain Growth ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
Average Pore ◽  
Transmission Electron ◽  
Show Evidence ◽  
Different Temperatures ◽  
Adsorption Desorption

The effects of mesoporous structure on grain growth were investigated in this study. The synthesis was accomplished using block copolymer as the organic template and tungsten chloride as the inorganic precursor. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy, x-ray diffractometry (XRD), transmission electron microscopy, and N2 adsorption/desorption isotherms were used to characterize the microstructures obtained for different temperatures. TGA and XRD analyses demonstrate that copolymers were expelled at 150–250 °C, and mesoporous structure was stable up to 350 °C. The pore diameter and the surface area evaluated from the Barrett-Joyner-Halenda model and Brunauer–Emmett–Teller method indicated that the average pore diameter is 4.11 nm and specific surface area is 191.5 m2/g for 250 °C calcination. Arrhenius equation used to calculate the activation energy for grain growth demonstrates that the activation energy for grain growth was about 38.1 kJ/mol before mesostructure collapse and 11.3 kJ/mol after collapse. These results show evidence of two different mechanisms governing the process of grain growth. The presence of the pore can be related to the obstacle for grain growth.

scholarly journals Structural Characterization and Adsorption Capability of Carbonaceous Matters Extracted from Carbonaceous Gold Concentrate

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Huiqun Niu ◽  
Hongying Yang ◽  
Linlin Tong
Keyword(s):  
Particle Size ◽  
Humic Acid ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Complex Organic Compound

In this paper, the structures of element carbon and humic acid extracted from carbonaceous gold concentrate were characterized employing a variety of analytical methods. The extracted amounts of ECE (elemental carbon extract) and HAE (humic acid extract) were 14.84–38.50 and 11.55–28.05 mg g−1, respectively. SEM and porosity analysis indicated that ECE occurred mostly as irregular blocky particles with a mesoporous surface with the average pore diameter being 31.42 nm. The particle size of ECE was mainly ranged from 5.5 to 42 μm and the specific surface area was 20.35 m2 g−1. The physicochemical features and structure of ECE were close to activated carbon, and the crystallinity was slightly lower than graphite. The particle size distribution of HAE varied from 40 to 400 nm with the specific surface area of 42.84 m2 g−1, whereas the average pore diameter of HAE was 2.97 nm. FTIR and UV–VIS analyses indicated that HAE was a complex organic compound containing the enrichment of oxygen-containing structure. The results showed that the adsorption amounts of ECE and HAE under the acidic conditions were 470.46 and 357.60 mg g−1, respectively. In an alkaline environment, the amount of ECE was 449.02 mg g−1 and the value of HAE was 294.72 mg g−1. ECE mainly utilized the outer surface and mesoporous structure to adsorb gold, while the functional groups’ complexation or surface site adsorption was the leading approach for HAE to adsorb gold.

Use of High Surface Area TiO2 Nanosheet in Dye-sensitized Solar Cell

2006 ◽  
Vol 951 ◽  
Author(s):  
Sorapong Pavasupree ◽  
Supachai Ngamsinlapasathian ◽  
Yoshikazu Suzuki ◽  
Susumu Yoshikawa
Keyword(s):  
Surface Area ◽  
Pore Diameter ◽  
High Surface ◽  
High Surface Area ◽  
Mesoporous Structure ◽  
Energy Conversion Efficiency ◽  
Bet Surface Area ◽  
Average Pore ◽  
Dye Sensitized ◽  
Solar Energy Conversion Efficiency

ABSTRACTHigh surface area nanosheet TiO2 with mesoporous structure were synthesized by hydrothermal method at 130 °C for 12 h. The samples characterized by XRD, SEM, TEM, SAED, and BET surface area. The nanosheet structure was slightly curved and approximately 50-100 nm in width and several nanometers in thickness. The as-synthesized nanosheet TiO2 had average pore diameter about 3-4 nm. The BET surface area and pore volume of the sample were about 642 m2/g and 0.774 cm3/g, respectively. The solar energy conversion efficiency (η) of the cell using nanorods/nanoparticles TiO2 (from the nanosheet calcined at 450 °C for 2 h) with mesoporous structure was about 7.08 % with Jsc of 16.35 mA/cm2, Voc of 0.703 V and ff of 0.627; while η of the cell using P-25 reached 5.82 % with Jsc of 12.74 mA/cm2, Voc of 0.704V and ff of 0.649.

Hydrothermal Synthesis of Nanorods/Nanoparticles TiO2 for Photocatalytic Activity and Dye-sensitized Solar Cell Applications

2006 ◽  
Vol 951 ◽  
Author(s):  
Sorapong Pavasupree ◽  
Supachai Ngamsinlapasathian ◽  
Yoshikazu Suzuki ◽  
Susumu Yoshikawa
Keyword(s):  
Photocatalytic Activity ◽  
Surface Area ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
Energy Conversion Efficiency ◽  
Bet Surface Area ◽  
Average Pore ◽  
Dye Sensitized ◽  
Prepared Material ◽  
20 Nm

ABSTRACTNanorods/nanoparticles TiO2 with mesoporous structure were synthesized by hydrothermal method at 150 °C for 20 h. The samples characterized by XRD, SEM, TEM, SAED, HRTEM, and BET surface area. The nanorods had diameter about 10-20 nm and the lengths of 100-200 nm, the nanoparticles had diameter about 5-10 nm. The prepared material had average pore diameter about 7-12 nm. The BET surface area and pore volume of the sample are about 203 m2/g and 0.655 cm3/g, respectively. The nanorods/nanoparticles TiO2 with mesoporous structure showed higher photocatalytic activity (I3− concentration) than the nanorods TiO2, nanofibers TiO2, mesoporous TiO2, and commercial TiO2 (ST-01, P-25, JRC-01, and JRC-03). The solar energy conversion efficiency (η) of the cell using nanorods/nanoparticles TiO2 with mesoporous structure was about 7.12 % with Jsc of 13.97 mA/cm2, Voc of 0.73 V and ff of 0.70; while η of the cell using P-25 reached 5.82 % with Jsc of 12.74 mA/cm2, Voc of 0.704 V and ff of 0.649.

A Facile Template Approach for Preparing Microstructures of Bimodal Crystalline Mesoporous Titania Powders

2012 ◽  
Vol 616-618 ◽  
pp. 1797-1800
Author(s):  
Yu Mei Gong ◽  
Qing Liang ◽  
Jing Chuan Song ◽  
Ling Ming Xia
Keyword(s):  
Electron Microscope ◽  
Surface Area ◽  
Nitrogen Adsorption ◽  
Mesoporous Titania ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption

This paper presents the preparation of bimodal crystalline macro-/mesoporous titania powders by using a pluronic polymer (EO20PO70EO20, P123) as a template through a hydrothermal treatment. The as-prepared powders were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results reveal that the amount of P123 has a significant effect on the surface area of the mesoporous titania. When the mass ratio of P123:TBOT is 1:14, the crystalline macro-/mesoporous titania has the largest surface area (120.96 m2/g), the average pore diameter of this sample reaches a minimum of 6.67 nm.

scholarly journals COMPARISON OF PORE FRACTAL CHARACTERISTICS BETWEEN MARINE AND CONTINENTAL SHALES

Fractals ◽  
2018 ◽  
Vol 26 (02) ◽  
pp. 1840016 ◽  
Author(s):  
JUN LIU ◽  
YANBIN YAO ◽  
DAMENG LIU ◽  
YIDONG CAI ◽  
JIANCHAO CAI
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Clay Minerals ◽  
Specific Surface Area ◽  
Pore Diameter ◽  
Fractal Dimensions ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Dimension Formula ◽  
Marine Shale

Fractal characterization offers a quantitative evaluation on the heterogeneity of pore structure which greatly affects gas adsorption and transportation in shales. To compare the fractal characteristics between marine and continental shales, nine samples from the Lower Silurian Longmaxi formation in the Sichuan basin and nine from the Middle Jurassic Dameigou formation in the Qaidam basin were collected. Reservoir properties and fractal dimensions were characterized for all the collected samples. In this study, fractal dimensions were originated from the Frenkel–Halsey–Hill (FHH) model with N[Formula: see text] adsorption data. Compared to continental shale, marine shale has greater values of quartz content, porosity, specific surface area and total pore volume but lower level of clay minerals content, permeability, average pore diameter and methane adsorption capacity. The quartz in marine shale is mostly associated with biogenic origin, while that in continental shale is mainly due to terrigenous debris. The N[Formula: see text] adsorption–desorption isotherms exhibit that marine shale has fewer inkbottle-shaped pores but more plate-like and slit-shaped pores than continental shale. Two fractal dimensions ([Formula: see text] and [Formula: see text] were obtained at [Formula: see text] of 0–0.5 and 0.5–1. The dimension [Formula: see text] is commonly greater than [Formula: see text], suggesting that larger pores (diameter [Formula: see text][Formula: see text]nm) have more complex structures than small pores (diameter [Formula: see text][Formula: see text]nm). The fractal dimensions (both [Formula: see text] and [Formula: see text]) positively correlate to clay minerals content, specific surface area and methane adsorption capacity, but have negative relationships with porosity, permeability and average pore diameter. The fractal dimensions increase proportionally with the increasing quartz content in marine shale but have no obvious correlation with that in continental shale. The dimension [Formula: see text] is correlative to the TOC content and permeability of marine shale at a similar degree with dimension [Formula: see text], while the dimension [Formula: see text] is more sensitive to those of continental shale than dimension [Formula: see text]. Compared with dimension [Formula: see text], for two shales, dimension [Formula: see text] is better associated with the content of clay minerals but has worse correlations with the specific surface area and average pore diameter.

GRANULAR-ACTIVATED CARBON FROM MUKAH COAL USING CARBON DIOXIDE ACTIVATION

2015 ◽  
Vol 75 (11) ◽  
Author(s):  
Farid Nasir Ani ◽  
Muhammad Mat Junoh ◽  
Zarina Ab Muis
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Pore Diameter ◽  
Continuous Process ◽  
Average Pore Diameter ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
Activation Process ◽  
Average Pore ◽  
One Step

A study was conducted on Mukah coal using fixed bed reactor and one step activation with varying resident time and temperatures. CO2 gas was used for the activation process. The one-step continuous process comprised of carbonization and activation processes. The burn off analysis for 80 grams of Mukah coal was done to obtain volatiles removal at various carbonization temperatures. The results obtained showed that at 900oC, the percentages of burn off and the remaining weight were 42.2% and 57.8% respectively. Micrometrics ASAP2010 was used to analyze Mukah coal activated carbon in obtaining the BET surface area, the micropore area, and the average pore diameter. The results obtained indicated that activation at 900oC gave the highest BET surface area with 675m2/g, while the highest micropore area with 427 m2/g was obtained at 800oC. In addition, the average pore diameter range was within 18.5 to 26.4 A. 

Surfactant-Templated Synthesis of Modified Porous Clay Heterostructure (PCH)

2008 ◽  
Vol 55-57 ◽  
pp. 317-320 ◽  
Author(s):  
K. Srithammaraj ◽  
Rathanawan Magaraphan ◽  
H. Manuspiya
Keyword(s):  
Pore Volume ◽  
Pore Diameter ◽  
Condensation Reaction ◽  
High Surface ◽  
High Surface Area ◽  
Bentonite Clay ◽  
Directed Assembly ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Surface Areas

Porous Clay Heterostructures (PCHs) have been prepared by the surfactant-directed assembly of mesostructured silica within the two-dimensional interlayer galleries of clays. The PCH is an interesting material to use as entrapping system such as ethylene scavenger, owing to its high surface area with uniform and specific pore size. In the present work, the PCH was synthesized within the galleries of Na-bentonite clay by the polymerization of tetraethoxysilane (TEOS) in the presence of surfactant micelles. In addition, a mesoporous clay with organic-inorganic hybrid (HPCH) is modified via co-condensation reaction of TEOS with methyltriethoxysilane (MTS) to enhance hydrophobicity of PCH material for entrapping system. According to pore characterization, PCHs have surface areas of 421-551 m2/g, an average pore diameter in the supermicropore to small mesopore range of 4.79-5.02 nm, and a pore volume of 0.57-0.66 cc/g while HPCHs have surface areas of 533-966 m2/g, an average pore diameter of 4.28-6.38 nm, and a pore volume of 0.42-0.77cc/g.

scholarly journals Synthesis of mesoporous alumina using polyvinyl alcohol template as porosity control additive

2007 ◽  
Vol 1 (1-2) ◽  
pp. 5-9 ◽  
Author(s):  
Zoltán Ecsedi ◽  
Ioan Lazău ◽  
Cornelia Păcurariu
Keyword(s):  
Polyvinyl Alcohol ◽  
Pore Diameter ◽  
Mercury Porosimetry ◽  
Sol Gel ◽  
Particle Morphology ◽  
Nitrogen Adsorption ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Alumina Films ◽  
Adsorption Desorption

The effects of polyvinyl alcohol (PVA) template and calcinations temperatures on the characteristics of the alumina films were investigated. The samples were prepared by sol-gel method using aluminium triisopropylate precursor. The variation of microstructure, pore size and pore volume, were determined by nitrogen adsorption/ desorption analysis and the macropore size distribution was determined using mercury porosimetry. TEM and SEM were used to observe the texture of these samples and the particle morphology. Experimental observation after drying and annealing shows that it is possible to produce crack free nanoporous alumina films using polyvinyl alcohol template. The obtained alumina samples have macroporous microstructure (with the average pore diameter dav = 34.9 ?m, for sample prepared with 42.5 wt% of PVA addition and annealed at 1000?C) with high portion of mesopores (with the average pore diameter Dav = 14.0 nm for the same sample).

Pillaring of a Layered Titanate With Alumina: Effect of Hydrolysis Solution

1998 ◽  
Vol 549 ◽  
Author(s):  
F. Kooli ◽  
T. Sasaki ◽  
V. Rives ◽  
M. Watanabe
Keyword(s):  
Surface Area ◽  
Pore Diameter ◽  
High Surface ◽  
High Surface Area ◽  
Average Diameter ◽  
Average Pore ◽  
Keggin Ions ◽  
Layered Titanate ◽  
Pillaring Solution ◽  
Thermal Stability Of

AbstractA layered titanate with a lepidocrocite-type structure has been pillared with Al13 Keggin ions to prepare a porous and high-surface-area material. Pillaring was achieved by ion exchange of hexylammonium (HA-Ti) or tetrabuthylammonium (TBA-Ti) intercalated titanates with Keggin Al13 complex. The thermal stability of the Al13 intercalates depended on the amount of aluminum incorporated. The surface area and porosity can be tailored by controlling the amount of aluminum uptake and by the nature of base used to prepare the aluminium pillaring solution. In addition, the material derived from HA-Ti exhibited a sharp pore size distribution with an average diameter of 2 nm, while the pillared product obtained from TBA-Ti showed mostly a broad mesoporous distribution with an average pore diameter of 4 nm.

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