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.

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

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.

Synthesis and Characterization of Co/SBA-15 Catalysts

2016 ◽  
Vol 881 ◽  
pp. 35-40
Author(s):  
Franciele Oliveira Costa ◽  
Carla Gabriela Azevedo Misael ◽  
André Miranda da Silva ◽  
Bianca Viana de Sousa
Keyword(s):  
Molecular Sieve ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Wet Impregnation ◽  
X Ray ◽  
Different Temperatures ◽  
Temperature Programmed

The mesoporous silica SBA-15 molecular sieve has been widely studied due to its unidirectional mesoporous structure, its high average pore diameter, its high thermal and hydrothermal stability and its ability to absorb metal ions, allowing its use as support material for catalysts. This study aimed to synthesize the Co/SBA-15 catalyst, and characterize it through the techniques of X-ray diffraction, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The SBA-15 support was synthesized from the following molar composition of reaction mixture: 1TEOS: 0.017 P123: 5.7 HCl: 173 H2O: 40 EtOH, and after calcined at 550 °C for 6 hours. The Co/SBA-15 catalyst was prepared by incorporating 10% cobalt by wet impregnation. Through the X-ray diffractograms, it was found that the impregnation has not changed the structure of the material. RTP profiles showed the presence of peaks at different temperatures that may be caused by dispersion of the cobalt.

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.

Adsorption characteristics of benzene on biosolid adsorbent

2003 ◽  
Vol 47 (1) ◽  
pp. 83-87
Author(s):  
C. Hung-Lung ◽  
T.-C. Chen ◽  
M.-C. Tsai ◽  
Y.-L. Chen
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Pore Diameter ◽  
Treatment Plant ◽  
Raw Material ◽  
Bet Surface Area ◽  
Size Analysis ◽  
Average Pore ◽  
Pore Size Analysis ◽  
Different Temperatures

This study selected biosolids from a petrochemical wastewater treatment plant as the raw material. The sludge was immersed in 0 to 5 mol l-1 of ZnCl2 solutions and pyrolyzed at different temperatures. When the sludge was pyrolyzed for 30 min at temperatures of 400, 500, 600, and 700°C, the corresponding surface area of the biosolid adsorbent was 46, 401, 921, and 727 m2/g, respectively. Pore size analysis indicated that the mesopore (20 to 500 Å) contributed more than the macropore and micropore in the sludge pyrolytic residue. When the benzene influent concentration was 800 ppmv, the adsorption capacity ranged from 59 to 164 mg/g for different biosolid adsorbents. A larger BET surface area and smaller average pore diameter yielded a larger benzene adsorption capacity.

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.

Behaviors of Carbon in Different Concentration of Sulfuric Acid

2010 ◽  
Vol 146-147 ◽  
pp. 18-21 ◽  
Author(s):  
Rui Rui Zhao ◽  
Dong Shu ◽  
Hong Yu Chen
Keyword(s):  
Sulfuric Acid ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Acid Concentration ◽  
Activated Carbons ◽  
Sulfuric Acid Concentration ◽  
Average Pore ◽  
Transmission Electron ◽  
Adsorption Desorption

N2 adsorption-desorption method, scanning electron microscope and transmission electron microscopy were employed to test changes of the specific surface area, average pore diameter and appearances of activated carbons treated with different concentration of sulfuric acid. It can be concluded that these performances altered with sulfuric acid concentration. Activated carbon can be oxidized when the acid concentration increase to a certain value and this process takes time that sulfuric acid molecules first insert in the pore of the carbon which represented by reduction of the specific surface area of carbon and then oxidization occurred. This study is very significant in the development of carbon which is suitable for lead acid battery.

Comparision of the Preparation Methods of Mesoporous Phosphate Compounds Belonging to NZP Family

2013 ◽  
Vol 631-632 ◽  
pp. 116-120
Author(s):  
Peng Zheng ◽  
Lin Hua Zhu ◽  
Tian Si ◽  
Yan Lin Sun
Keyword(s):  
Pore Diameter ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Powder Materials ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Preparation Methods ◽  
X Ray ◽  
Low Thermal Expansion ◽  
Adsorption Desorption

Using polyethylene oxide (PEO) as template, the new types of mesoporous phosphate compound which belongs to NaZr2(PO4)3(NZP) family were synthesized by copreciptate, sol-gel and mechanochemical activation(MA) route respectively. The physical phase and pore structure of the synthesized powder materials were characterized by X-ray diffraction (XRD) and N2 adsorption–desorption. The results showed that the crystalline NZP family compound with mesoporous structure is formed by sol-gel route followed with calcination as well as MA method followed with hydrothermal treatment when the mole ratio of PEO to Zr is 1:10, and the specific surface area, average pore diameter and pore volume of the synthesized powder is 20-50m2/g, 3-6.nm and 0.05-0.12cm3/g respectively. The above research results indicate that it is promising to expand the application field of the powder of NZP family from low thermal expansion ceramics to catalytic materials.

Fuels Desulphurisation by Adsorbtion on Fe / Bentonite

2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Adsorption Process ◽  
Continuous System ◽  
Gas Oil ◽  
Average Pore ◽  
Atmospheric Distillation

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.

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