Self-Organized Nanoporous Thin-Film Titania Templates Prepared by Anodic Oxidation

2006 ◽  
Vol 326-328 ◽  
pp. 437-440 ◽  
Author(s):  
Dae Jin Yang ◽  
Ho Gi Kim ◽  
Won Youl Choi
Keyword(s):  
Thin Film ◽  
Pore Diameter ◽  
Gas Sensing ◽  
Formation Rate ◽  
Sem Images ◽  
Average Pore ◽  
Surface Areas ◽  
Self Organized ◽  
Voltage Potential ◽  
20 Nm

Thin-film titania templates were fabricated under different processing conditions. The dependencies of pore morphology and pore formation rate on process parameters were evaluated. It was found that under optimized electrolyte condition and anodizing voltage, a self-organized nanostructure consisting of porous TiO2 was obtained. 1 M Na2SO4 solution with the addition of 0.35 wt.% NaF and voltage potential of 30V were used. SEM images of templates showed very thin layer of ~70 nm thickness with worm-like pores. Pore diameter and average pore spacing of center to center on the surface were ~10 nm and 20 nm, respectively. The nanoporous TiO2 thin film will be very useful gas sensing and photocatalytic materials due to their large surface areas and high reactivities.

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.

Self-Healing and Self-Organized Gold Nanoparticle Films at a Water/Organic Solvent Interface

2006 ◽  
Vol 6 (1) ◽  
pp. 130-134 ◽  
Author(s):  
Olivier Balmes ◽  
Jan-Olov Bovin ◽  
Jan-Olle Malm
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Organic Solvent ◽  
Continuous Production ◽  
Self Healing ◽  
Self Organized ◽  
Transmission Electron ◽  
20 Nm

Gold nanoparticles (5 nm and 20 nm) have been synthesized and stabilized with mercaptoundecanol. These particles, although insoluble in water or common organic solvents, spread as a thin film at the liquid–liquid interface between a water phase and an organic phase. Films of these gold nanoparticles have been observed both by conventional transmission electron microscopy of deposited samples and by cryo-transmission electron microscopy of plunge-frozen samples. The film can be monolayered and extend over centimeter-sized areas. The particle films spontaneously re-assemble and self-organize at the interface when disrupted. This self-healing capacity of the film should make it possible to build a device for continuous production and deposition of the film.

APPARENT DENSITIES AND INTERNAL SURFACE AREAS OF SELECTED CARBON BLACKS

1962 ◽  
Vol 40 (2) ◽  
pp. 184-188 ◽  
Author(s):  
P. L. Walker Jr. ◽  
W. V. Kotlensky
Keyword(s):  
Surface Area ◽  
Pore Diameter ◽  
Internal Surface ◽  
Nitrogen Adsorption ◽  
Roughness Factor ◽  
Internal Surface Area ◽  
Average Pore ◽  
Carbon Blacks ◽  
Surface Areas ◽  
Nitrogen Adsorption Isotherms

It is shown that the open pore volume within carbon blacks can be calculated from nitrogen adsorption isotherms (77°K) on the blacks. From this volume and a helium density, the apparent density of a black can be calculated. Other properties of the blacks which then can be calculated are free surface area, internal surface area, surface roughness factor, and the average pore diameter of the internal surface. These data are presented for five selected carbon blacks.

Preparation and Formation Mechanisms of Monodispersed Mesoporous SiO2 Microspheres by the PICA Method

2007 ◽  
Vol 280-283 ◽  
pp. 1153-1156 ◽  
Author(s):  
Li Zhao ◽  
Jia Guo Yu ◽  
Rui Guo ◽  
Bei Cheng
Keyword(s):  
Silicon Dioxide ◽  
Pore Diameter ◽  
Average Diameter ◽  
Spherical Particles ◽  
Formation Mechanisms ◽  
Average Pore ◽  
Mesoporous Silicon ◽  
Surface Areas ◽  
Sio2 Microspheres ◽  
Scanning Electron

Monodispersed mesoporous silicon dioxide microspheres were prepared by polymerization-induced colloid aggregation (PICA) method and calcined at 850oC. The prepared samples were characterized with scanning electron microscopy (SEM), thermogravimetry (TG) and BET surface areas. The results showed that the obtained SiO2 microspheres had an average diameter of about 2.0 µm, a surface area of 253.3 m2g-1, an average pore volume of 0.62 mLg-1, and an average pore diameter of 7.9 nm. The formation mechanism of SiO2 spherical particles was discussed.

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 Oxidation of 4-Chlorophenol by Mesoporous Titania: Effect of Surface Morphological Characteristics

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Osmín Avilés-García ◽  
Jaime Espino-Valencia ◽  
Rubí Romero ◽  
José Luis Rico-Cerda ◽  
Reyna Natividad
Keyword(s):  
Pore Diameter ◽  
Uv Light ◽  
Morphological Characteristics ◽  
Oxygen Demand ◽  
Average Crystallite Size ◽  
Mesoporous Titania ◽  
Structure Directing Agent ◽  
Average Pore ◽  
Surface Areas ◽  
Effect Of Surface

Mesoporous nanocrystalline anatase was prepared via EISA employing CTAB as structure directing agent. The drying rate was used as a key synthesis parameter to increase the average pore diameter. The resultant mesoporous crystalline phases exhibited specific surface areas between 55 and 150 m2 g−1, average unimodal pore sizes of about 3.4 to 5.6 nm, and average crystallite size of around 7 to 13 nm. These mesophases were used as photocatalysts for the degradation of 4-chlorophenol (4CP) with UV light. Under the studied conditions, the mesoporous anatase degraded 100% 4CP. This was twice faster than Degussa P-25. 57% reduction of chemical oxygen demand (COD) value was achieved.

Effect of Heat-Treatment on the Microstructure and Properties of SiO2-TiO2 Aerogels Synthesized via Supercritical Drying

2016 ◽  
Vol 848 ◽  
pp. 770-776 ◽  
Author(s):  
Yong Gang Jiang ◽  
Yan Qing Qin ◽  
Jun Zong Feng ◽  
Jian Feng ◽  
Lin Xu
Keyword(s):  
Heat Treatment ◽  
Specific Surface ◽  
Three Dimensional ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Sem Images ◽  
Average Pore ◽  
Microstructure And Properties ◽  
Surface Areas ◽  
Heat Treated

Monolithic SiO2-TiO2 aerogels were prepared via supercritical drying using tetraethoxysilane and tetrabutyltitanate as precursors and ethanol as solvent. Influence of the heat-treatment on the microstructure and properties of SiO2-TiO2 aerogels were investigated in detail. The results showed that the as-prepared SiO2-TiO2 aerogels had low densities, high specific surface areas, small average pore diameters, and three-dimensional nanoporous structures. The anatase TiO2 phase of SiO2-TiO2 aerogels could form during supercritical drying process, and the transition to rutile TiO2 phase occurred after experiencing 1200°C for 2 h. SiO2-TiO2 aerogels containing 30 wt% TiO2 (ST3) still presented relatively high specific surface area of 451 m2/g even they undergo the treatment of 1000°C for 2 h. And the SEM images indicated that the agglomerated particles derived from ST3 appeared gradually to some extent. The glassy luster of ST3 heat-treated at 1200°C for 2 h illuminates SiO2 started to vitrify. Besides, the thermal conductivity of ST3 at room temperature is up to 0.03257 W·m-1·K-1.

scholarly journals Fast and Reliable Identification of Ammonia Phylotypes T1, T2 and T6 Using a Stereomicroscope: Implication for Large-Scale Ecological Surveys and Monitoring Programs

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3563
Author(s):  
Jean-Charles Pavard ◽  
Julien Richirt ◽  
Lucie Courcot ◽  
Pascal Bouchet ◽  
Laurent Seuront ◽  
...  
Keyword(s):  
Large Scale ◽  
Pore Diameter ◽  
Staining Method ◽  
Morphological Variability ◽  
Molecular Tools ◽  
Ne Atlantic ◽  
Sem Images ◽  
Average Pore ◽  
Research Perspectives ◽  
The Rose

Among benthic foraminifera, the genus Ammonia is characterized by high morphological variability which makes it particularly challenging to recognize using traditional morphology-based taxonomy. Despite the joint efforts made by both molecular and morphological taxonomists, it is still hard to identify different phylotypes based on their morphology. A new method was developed recently to discriminate three NE Atlantic phylotypes of Ammonia (T1, T2, and T6). This method is based on two morphometrical parameters using scanning electron microscope (SEM) images (i.e., the average pore diameter and the elevation of sutures on the spiral side), resulting individuals being correctly assigned to their phylotype in more than 90% of cases. In this study, we assess the possibility of implementing these criteria using a stereomicroscope. Phylotype assignations by SEM and stereomicroscopic identifications are in accordance for 62.6% of the scrutinized foraminifera and increase up to 79.5% when only the phylotype T6 is considered. Though the stereomicroscopic identification of Ammonia phylotypes based on these two morphological parameters needs to be cross-validated using molecular tools, this approach noticeably allows the identification of an individual 3 to 7 times faster than using a SEM. The ratio between accuracy and efficiency, an issue that is also attributable to the use of the rose Bengal staining method, suggests prioritizing the use of stereomicroscope identifications in large foraminiferal surveys. Finally, in the context that Ammonia phylotype T6 potentially being an alien species in Europe, this method will help to quickly identify Ammonia phylotypes; hence contributing to monitor the presence of T6 in different regions and then, offering interesting research perspectives to assess the timing and/or the progression of the possible invasion.

scholarly journals Anodic Fabrication of Ti-Ni-Si-O Nanostructures on Ti10Ni5Si Alloy

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1315 ◽  
Author(s):  
Ting Li ◽  
Dongyan Ding ◽  
Nan Li
Keyword(s):  
Pore Diameter ◽  
Ammonium Fluoride ◽  
Anodic Oxide ◽  
Electrolyte Solutions ◽  
Phase Region ◽  
Electrochemical Anodization ◽  
Average Pore ◽  
Self Organized ◽  
Inner Diameter ◽  
Ti2ni Phase

Ti-Ni-Si-O nanostructures were synthesized on Ti10Ni5Si alloy through an electrochemical anodization in electrolyte solutions containing ammonium fluoride (NH4F). The anodic oxide structures were affected by the electrochemical anodization parameters, including the electrolyte viscosity, water content, anodization potential and anodization time. Using an anodization potential of 40 V for 90 min in an ethylene glycol/glycerol electrolyte with 3 vol.% deionized water, highly ordered self-organized nanotube arrays were obtained in the α-Ti phase region of the alloy substrate, with an average inner diameter of 70 nm and a wall thickness of about 12 nm. Self-organized nanopore structures with an average pore diameter of 25 nm grew in the Ti5Si3 phase region. Only etching pits were found in the Ti2Ni phase region. The Ti-Ni-Si-O nanostructures were characterized using scanning electron microscopy and energy dispersive spectroscopy. In addition, a formation mechanism of different nanostructures was presented.

scholarly journals Temperature Optimized Ammonia and Ethanol Sensing Using Ce Doped Tin Oxide Thin Films in a Novel Flow Metric Gas Sensing Chamber

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
K. Govardhan ◽  
Andrews Nirmala Grace
Keyword(s):  
Thin Film ◽  
Tin Oxide ◽  
Gas Sensing ◽  
Vital Role ◽  
Good Sensitivity ◽  
Sem Images ◽  
Film Sensor ◽  
Thin Film Sensor ◽  
Ethanol Sensing ◽  
Gas Chamber

A simple process of gas sensing is represented here using Ce doped tin oxide nanomaterial based thin film sensor. A novel flow metric gas chamber has been designed and utilized for gas sensing. Doping plays a vital role in enhancing the sensing properties of nanomaterials. Ce doped tin oxide was prepared by hydrothermal method and the same has been used to fabricate a thin film for sensing. The microstructure and morphology of the prepared materials were analysed by SEM, XRD, and FTIR analysis. The SEM images clearly show that doping can clamp down the growth of the large crystallites and can lead to large agglomeration spheres. Thin film gas sensors were formed from undoped pure SnO2and Ce doped SnO2. The sensors were exposed to ammonia and ethanol gases. The responses of the sensors to different concentrations (50–500 ppm) of ammonia and ethanol at different operating temperatures (225°C–500°C) were studied. Results show that a good sensitivity towards ammonia was obtained with Ce doped SnO2thin film sensor at an optimal operating temperature of 325°C. The Ce doped sensor also showed good selectivity towards ammonia when compared with ethanol. Pure SnO2showed good sensitivity with ethanol when compared with Ce doped SnO2thin film sensor. Response time of the sensor and its stability were also studied.

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