scholarly journals Synthesis and Characterization of Nanoporous Carbon Materials; The Effect of Surfactant Concentrations and Salts

2011 ◽  
Vol 8 (1) ◽  
pp. 196-200 ◽  
Author(s):  
Shokoofeh Geranmayeh ◽  
Alireza Abbasi ◽  
Alireza Badiei
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Nanoporous Carbon ◽  
Pluronic F127 ◽  
Molar Ratio ◽  
Soft Template ◽  
Carbon Framework ◽  
Evaporation Induced Self Assembly

Nanoporous carbon framework was synthesized using phenol and formaldehyde as carbon precursors and triblock copolymer (pluronic F127) as soft templateviaevaporation induced self-assembly. Hexagonal mesoporous carbon with specific surface area of 350 m2/g through optimizing the situation was obtained. The effects of different surfactant/phenol molar ratio and presence of salts on specific surface area, pore size and pore volume for all the prepared samples were studied by means of the Brunauer-Emmett-Teller (BET) formalism, powder X-ray diffraction technique and FT-IR spectroscopy.

Aerosol-Assisted Sol-Gel Synthesis of Mesoporous TiO2 Materials, and Their Use as Support for Ru-Based Methanation Catalysts

2019 ◽  
Author(s):  
Ara Kim ◽  
Clément Sanchez ◽  
Bernard Haye ◽  
Cédric Boissière ◽  
Capucine Sassoye ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Sol Gel ◽  
Textural Properties ◽  
High Specific Surface Area ◽  
Spherical Particles ◽  
Aerosol Process ◽  
Evaporation Induced Self Assembly

<div>Mesoporous TiO<sub>2</sub> materials have been prepared by an aerosol process, which leverages on the acetic acid-mediated sol-gel chemistry and on the evaporation-induced self-assembly phenomenon to obtain materials with high specific surface area and large mesoporous volume. The obtained spherical particles are calcined to release the porosity. It is shown that the mesoscopic order can be preserved when the calcination is carried out at relatively low temperature (375 °C and below). Harsher calcination conditions lead to the progressive destruction of the mesostructured, concomitant with a progressive drop of textural properties and with the crystallization of larger anatase domains. The mesoporous TiO<sub>2</sub> material calcined at 350°C (specific surface area = 260 m².g<sup>-1</sup>; pore volume = 0.36 cm³.<sup>-1</sup>; mean pore diameter = 5.4 nm) was selected as a promising support for preformed RuO<sub>2</sub> nanoparticles, and subsequently annealed in air. It is shown that the presence of RuO<sub>2</sub> nanoparticles and subsequent annealing provoke further intense modification of the texture and crystallinity of the TiO<sub>2</sub> materials. In addition to a drop in the textural parameters, a RuO<sub>2</sub>-mediated crystallization of rutile TiO<sub>2</sub> is highlighted at temperature as low as 250°C. After an in situ reduction in H<sub>2</sub>, the catalysts containing TiO<sub>2</sub> rutile and relatively small RuO<sub>2</sub> crystals showed the highest activity in the methanation of CO<sub>2</sub>. </div>

Aerosol-Assisted Sol-Gel Synthesis of Mesoporous TiO2 Materials, and Their Use as Support for Ru-Based Methanation Catalysts

2019 ◽  
Author(s):  
Ara Kim ◽  
Clément Sanchez ◽  
Bernard Haye ◽  
Cédric Boissière ◽  
Capucine Sassoye ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Sol Gel ◽  
Textural Properties ◽  
High Specific Surface Area ◽  
Spherical Particles ◽  
Aerosol Process ◽  
Evaporation Induced Self Assembly

<div>Mesoporous TiO<sub>2</sub> materials have been prepared by an aerosol process, which leverages on the acetic acid-mediated sol-gel chemistry and on the evaporation-induced self-assembly phenomenon to obtain materials with high specific surface area and large mesoporous volume. The obtained spherical particles are calcined to release the porosity. It is shown that the mesoscopic order can be preserved when the calcination is carried out at relatively low temperature (375 °C and below). Harsher calcination conditions lead to the progressive destruction of the mesostructured, concomitant with a progressive drop of textural properties and with the crystallization of larger anatase domains. The mesoporous TiO<sub>2</sub> material calcined at 350°C (specific surface area = 260 m².g<sup>-1</sup>; pore volume = 0.36 cm³.<sup>-1</sup>; mean pore diameter = 5.4 nm) was selected as a promising support for preformed RuO<sub>2</sub> nanoparticles, and subsequently annealed in air. It is shown that the presence of RuO<sub>2</sub> nanoparticles and subsequent annealing provoke further intense modification of the texture and crystallinity of the TiO<sub>2</sub> materials. In addition to a drop in the textural parameters, a RuO<sub>2</sub>-mediated crystallization of rutile TiO<sub>2</sub> is highlighted at temperature as low as 250°C. After an in situ reduction in H<sub>2</sub>, the catalysts containing TiO<sub>2</sub> rutile and relatively small RuO<sub>2</sub> crystals showed the highest activity in the methanation of CO<sub>2</sub>. </div>

The Influence of Fe/Al Molar Ratio on Microreactor-Based Catalyst Preparation and Carbon Nanotube Preparation

2021 ◽  
Vol 1036 ◽  
pp. 130-136
Author(s):  
Ting Qun Tan ◽  
Lei Geng ◽  
Yan Lin ◽  
Yan He
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Small Diameter ◽  
High Specific Surface Area ◽  
Detection Methods ◽  
Molar Ratio ◽  
High Catalytic Activity

In order to prepare carbon nanotubes with high specific surface area, small diameter, low resistivity, high purity and high catalytic activity, the Fe-Mo/Al2O3 catalyst was prepared based on the microreactor. The influence of different Fe/Al molar ratios on the catalyst and the carbon nanotubes prepared was studied through BET, SEM, TEM and other detection methods. Studies have shown that the pore structure of the catalyst is dominated by slit pores at a lower Fe/Al molar ratio. The catalytic activity is the highest when the Fe/Al molar ratio is 1:1, reaching 74.1%. When the Fe/Al molar ratio is 1:2, the catalyst has a higher specific surface area, the maximum pore size is 8.63 nm, and the four-probe resistivity and ash content of the corresponding carbon nanotubes are the lowest. The higher the proportion of aluminum, the higher the specific surface area of the catalyst and the carbon nanotubes, and the finer the diameter of the carbon nanotubes, which gradually tends to relax. The results show that when the Fe/Al molar ratio is 1:2, although the catalytic activity of the catalyst is not the highest, the carbon nanotubes prepared have the best performance.

Facile synthesis of novel Roe-like TiO2 hollow nanospheres with mesoporous cavity for improved photocatalytic activity

2017 ◽  
Vol 10 (03) ◽  
pp. 1750028 ◽  
Author(s):  
Yan Zhu ◽  
Xiaoxia Yan ◽  
Yuanxin Ge ◽  
Shumin Wang ◽  
Dongmei Deng ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Charge Separation ◽  
Synergistic Effects ◽  
Assembly Process ◽  
Hollow Nanospheres ◽  
Facile Synthesis

A facile approach was developed to synthesize novel Roe-like TiO2 hollow nanospheres via a template-assisted self-assembly process. These TiO2 nanospheres possessing mesoporous cavity manifest significantly improved photocatalytic activity owing to the synergistic effects of increased charge separation, more efficient use of the light and specific surface area.

Polyhedral oligomeric silsesquioxane as a recyclable soft template to synthesize mesoporous polymeric carbon nitride with enhanced photocatalytic hydrogen evolution

2021 ◽  
Vol 5 (1) ◽  
pp. 112-116
Author(s):  
Zhiwei Liang ◽  
Lei Liu ◽  
Xiaojia Zhuang ◽  
Zicheng Tang ◽  
Haiping Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Specific Surface Area ◽  
Carbon Nitride ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Soft Template ◽  
Photocatalytic Hydrogen Evolution ◽  
Oligomeric Silsesquioxane ◽  
Polymeric Carbon

A novel recyclable template was used to prepare mesoporous polymeric carbon nitride with prominently increased specific surface area and photoactivity.

Effect of pH, Molar Ratio of Fuel to Nitrates and Calcination Temperature on the Glycine-Nitrate Synthesis of Nano CoAl2O4

2010 ◽  
Vol 68 ◽  
pp. 176-181 ◽  
Author(s):  
Seyyed Hamid Jazayeri ◽  
Federica Bondioli ◽  
Shiva Salem ◽  
Ali Allahverdi ◽  
Mansoor Shirvani ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Precursor Solution ◽  
Molar Ratio ◽  
Effect Of Ph ◽  
Molar Ratios ◽  
Metal Nitrates ◽  
Powder Characteristics

In this research, solution-based combustion synthesis is applied to prepare the spinel CoAl2O4 pigment from precursor solution of Al(NO3)3 .9H2O, Co(NO3)2 .6H2O and glycine. Effect of pH values (2.5, 7, 10.5), molar ratio of fuel to metal nitrates in the precursor solutions (1.5, 2) and subsequent calcination temperature (800, 1000, 1200 °C) on the powder characteristics are described. Gel formation, morphologies, specific surface area and colour of the powder are characterized using DTA/TG, XRD, TEM, BET and UV-Vis. The results indicate that the crystalline spinel CoAl2O4 is formed at all different Gl/(metal nitrates) molar ratios, pH and temperatures and higher temperature promote the increase of the crystallite size. According to TEM figures most of the particles calcined at 800 and 1000 °C has sizes less than 50 and 100 nm, respectively. Corresponding to results of BET experiment, specific surface area has its maximum values at pH 7 and decreases with increasing of temperature. Finally, colorability test indicates the complete stability of the synthesized powder in the glass matrix.

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

Synthesis and Structural Characterization of SiO2-Al2O3 Xerogels

2007 ◽  
Vol 336-338 ◽  
pp. 2286-2289
Author(s):  
Fei He ◽  
Xiao Dong He ◽  
Yao Li
Keyword(s):  
Structural Change ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Molar Ratio

Low-density xSiO2-(1-x)Al2O3 xerogels with x=0.9, 0.8, 0.7, 0.6 (mole fractions) were prepared by sol-gel and non-supercritical drying. Silica alkogels, which were the framework of binary composite materials, formed from tetraethyl orthosilicate (TEOS) by hydrolytic condensation with a molar ratio of TEOS: H2O: alcohol: hydrochloric acid: ammonia =1: 4: 10: 7.5×10-4: 0.0375. Aluminum hydroxide derived from Al(NO3)3·9H2O and NH4OH acting in the alcohol solution under the condition of catalyst. After filtrating and washing, the precipitation was mixed into silica sols to form SiO2-Al2O3 mixed oxide gels with different silicon and aluminum molar ratio. The structural change and crystallization of the binary xerogels were investigated after heat treatment at 600 for 2 h by the means of X-ray diffraction. Nitrogen adsorption experiment was performed to estimate specific surface area, porous volume and pore size distribution. The structural change of xerogels was observed by FT-IR spectroscopy. The resulting mixed xerogels possess of mesoporous structure which is characteristic of cylindrical pores, high specific surface area of 596-863 m2/g and a relatively narrow pore distribution of 2.8-30 nm. Al2O3 is introduced into the SiO2 phase and some of Al-O-Si bonds form.

Synthesis, Characterisation, and Photocatalytic Behaviour of Mesoporous ZnS Nanoparticles Prepared Using By-Product Templating

2017 ◽  
Vol 70 (10) ◽  
pp. 1099 ◽  
Author(s):  
Hosein B. Motejadded Emrooz ◽  
Ali R. Rahmani ◽  
Francisco J. Gotor
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Diffuse Reflectance Spectroscopy ◽  
High Surface ◽  
Ultrasonic Waves ◽  
Soft Template ◽  
Bandgap Energy ◽  
Zns Nanoparticles

High surface area mesoporous ZnS nanoparticles (MZN) were obtained with the aid of the by-product of the synthesising reaction. This by-product, namely NaNO3, can be considered as a soft template responsible for the formation of pores. Ethanol and water were chosen as the synthesis media. Ultrasonic waves were used as an accelerator for the synthesis of MZNs. Photocatalytic activities of the synthesised samples for the degradation of methylene blue (MB) were investigated under ultraviolet irradiation. Synthesised specimens were characterised using field emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, diffuse reflectance spectroscopy, N2-physisorption, and FT-IR spectroscopy. Results indicated that the synthesis media has a pronounced effect on the surface properties of the final porous particles by several mechanisms. The specific surface area of the MZN samples synthesised in water and ethanol were determined to be 53 and 201 m2 g−1, respectively. The difference in the specific surface area was attributed to the weak solvation of S2− ions (Na2S·5H2O in ethanol) and also to the by-product of the synthesis reaction. The photocatalytic behaviour of the mesoporous ZnS nanoparticles synthesised in these two media were investigated and the results have been interpreted with the aid of effective surface area, pore volume, and bandgap energy of the specimens.

Sign in / Sign up

Export Citation Format

Share Document