Sol-gel preparation of AlPO4–SiO2 glasses with high surface mesoporous structure

2006 ◽  
Vol 16 (14) ◽  
pp. 1323 ◽  
Author(s):  
Carla C. de Araujo ◽  
Long Zhang ◽  
Hellmut Eckert
2016 ◽  
Vol 45 (13) ◽  
pp. 5765-5774 ◽  
Author(s):  
Kripasindhu Sardar ◽  
Richard Bounds ◽  
Marina Carravetta ◽  
Geoffrey Cutts ◽  
Justin S. J. Hargreaves ◽  
...  

Low oxygen silicon imidonitride samples are produced from Si(NHMe)4 and NH3 with NH4OTf catalyst and structurally characterised.


2020 ◽  
Vol 12 (11) ◽  
pp. 1255-1264
Author(s):  
Nada D. Al-Khthami ◽  
Mohammed Alsawat ◽  
Reda M. Mohamed ◽  
Yousef G. Alghamdi ◽  
Zaki I. Zaki

In order to create a new design for an efficient photocatalyst, you need to decrease the obtained band gap and isolate the charge carriers photogenerated while setting up a new visible light methodology. The latter option could be accomplished via combination of catalyst in the metal oxide form over the surface of semiconductor. Hence, the current work aimed at synthesizing a new nanocomposite material from LaFeO3/g-C3N4 through the use of mesoporous silica as a template processing g-C3N4 higher surface area, which was subsequently decorated with LaFeO3. The LaFeO3 of variable content of 1∼4% was used to decorate our targeted basic material. The structure was confirmed by ordinary techniques, in addition to photocatalytic ability via splitting water reaction. g-C3N4 and LaFeO3 photocatalytic efficiencies were compared to the newly developed LaFeO3/g-C3N4 nanocomposites showing their outstanding activity. The optimum LaFeO3 content was confirmed as 3%, which gave higher photocatalytic efficiency against both g-C3N4 and LaFeO3 (34 and 21 times respectively). To enhance the catalytic system efficiency, a scavenger with a positive hole was added as glycerol. A maximum of five runs of higher efficient reuse was examined as required, as well as stable nanocomposite photocatalyst. The mesoporous structure, high surface area, and capacity of charge separation over the photocatalysis process were all investigated as main conditions which affect photocatalytic activity of LaFeO3/g-C3N4 nanocomposites.


NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550001 ◽  
Author(s):  
Kui Zhang ◽  
Xiangdong Wang ◽  
Xiaoling Guo ◽  
Jie Dai ◽  
Jingyu Xiang

Mesoporous TiO 2 nanoparticles were synthesized via a fast and classical sol–gel method, respectively. Polyacrylamide was used as the template in the fast sol–gel route; the polymerization crosslink by hydrogen bonds between the template and hydrolysates of Ti alkoxides shortens the reaction time from several days to several hours. The X-ray diffraction results testified that only anatase was obtained in the samples, and the crystallite sizes of the samples prepared by fast and classical sol–gel method were 13.6 nm and 20 nm, respectively. Transmission electron microscopy and N 2 adsorption–desorption reveal that the nanocrystals have typical mesoporous structure and high surface areas. The pore sizes and surface areas of the samples prepared by fast and classical sol–gel method are 17.3 nm and 28.2 nm, 154.7 m2/g and 102.6 m2/g, respectively. The photocatalytic degradation of methyl orange solution under UV light irradiation suggests that the mesoporous TiO 2 photocatalyst prepared by the fast sol–gel method exhibits higher photocatalytic activity than the mesoporous TiO 2 prepared via classical sol–gel method.


Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 668 ◽  
Author(s):  
Serena Esposito

The sol-gel method is an attractive synthetic approach in the design of advanced catalytic formulations that are based on metal and metal oxide with high degree of structural and compositional homogeneity. Nowadays, though it originated with the hydrolysis and condensation of metal alkoxides, sol-gel chemistry gathers plenty of fascinating strategies to prepare materials from solution state precursors. Low temperature chemistry, reproducibility, and high surface to volume ratios of obtained products are features that add merit to this technology. The development of different and fascinating procedure was fostered by the availability of new molecular precursors, chelating agents and templates, with the great advantage of tailoring the physico-chemical properties of the materials through the manipulation of the synthesis conditions. The aim of this review is to present an overview of the “traditional” sol-gel synthesis of tailored and multifunctional inorganic materials and their application in the main domain of heterogeneous catalysis. One of the main achievements is to stress the versatility of sol-gel preparation by highlighting its advantage over other preparation methods through some specific examples of the synthesis of catalysts.


2012 ◽  
Vol 1372 ◽  
Author(s):  
R. Carrera ◽  
S. Castillo

ABSTRACTTo establish a promising method for the purification of air containing volatile organic compounds, TiO2 nanoparticles with interesting physicochemical properties were prepared by the sol-gel method to perform the photocatalytic decomposition of acetaldehyde. The obtained samples were characterized by the x-ray diffraction -Rietveld refinement, transmission electron microscopy (TEM) and the Brunauer, Emmet and Teller (BET) model. According to the results, the sample that presented the highest activity (96.4%) in the photocatalytic oxidation of acetaldehyde was the one annealed at 200 °C. This material showed the presence of a mixture of the anatase (higher proportion) and brookite phases, nanometric crystal size (7.03 nm) and high surface area (189 m2g-1). The physicochemical properties present in the TiO2-P-200°C nanoparticles suggest that they may establish a photoassisted reaction process for air purification, in which volatile organic compounds are photocatalitically decomposed.


2018 ◽  
Vol 9 (1) ◽  
pp. 133-139
Author(s):  
Waleed S. Mohammed ◽  
Ahmed H. El-Shazly ◽  
Marwa F. Elkady ◽  
Masahiro Ohshima

Introduction: The utilization of biodiesel as an alternative fuel is turning out to be progressively famous these days because of worldwide energy deficiency. The enthusiasm for utilizing Jatropha as a non-edible oil feedstock is quickly developing. The performance of the base catalyzed methanolysis reaction could be improved by a continuous process through a microreactor in view of the high mass transfer coefficient of this technique. Materials & Methods: Nanozirconium tungstovanadate, which was synthetized using sol-gel preparation method, was utilized in a complementary step for biodiesel production process. The prepared material has an average diameter of 0.066 &µm. Results: First, the NaOH catalyzed methanolysis of Jatropha oil was investigated in a continuous microreactor, and the efficient mixing over different mixers and its impact on the biodiesel yield were studied under varied conditions. Second, the effect of adding the nanocatalyst as a second stage was investigated. Conclusion: The maximum percentage of produced methyl esters from Jatropha oil was 98.1% using a methanol/Jatropha oil molar ratio of 11 within 94 s using 1% NaOH at 60 &°C. The same maximum conversion ratio was recorded with the nanocatalyst via only 0.3% NaOH.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1761
Author(s):  
Izabela Rutkowska ◽  
Jakub Marchewka ◽  
Piotr Jeleń ◽  
Mateusz Odziomek ◽  
Mateusz Korpyś ◽  
...  

Aluminum oxide is one of the most commonly used materials in the industry. It is used in the field of catalysis, refractories, and optics. Despite the fact that there are many techniques available, there is still a great challenge in obtaining a material with desired and designed properties. Nevertheless, there is a great flexibility in making customized alumina materials with desired physicochemical properties synthesized by sol–gel methods. This work consists in characterizing the physicochemical properties of sol–gel synthesized aluminum oxide using different sol–gel preparation routes. Three different sols were obtained by using organic precursors and underwent thermal treatment. The structure (Middle Infrared Spectroscopy, Diffused Reflectance Infrared Spectroscopy, X-ray Diffraction, Magic Angle Spinning Nuclear Magnetic Resonance) and microstructure (Scanning Electron Microscopy with Electron Dispersive Spectroscopy) tests of the materials were carried out. The specific surface area was determined by using the Brunauer–Emmett–Teller (BET) method. Thermal analysis was performed for all the powders, in order to analyze the specific temperature of materials transformation.


2010 ◽  
Vol 93 (12) ◽  
pp. 4047-4052 ◽  
Author(s):  
Padmaja Parameswaran Nampi ◽  
Padmanabhan Moothetty ◽  
Wilfried Wunderlich ◽  
Frank John Berry ◽  
Michael Mortimer ◽  
...  

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