Comparison of sol-gel and hydrothermal synthesis methods on the structural, optical and photocatalytic properties of Nb/Ag codoped TiO2 mesoporous nanoparticles

Author(s):  
Behzad Koozegar Kaleji ◽  
Mahtab Gorgani
Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.


2020 ◽  
Vol 96 (3) ◽  
pp. 511-520
Author(s):  
Joanna Mastalska-Popławska ◽  
Marek Sikora ◽  
Piotr Izak ◽  
Zuzanna Góral

Abstract The main goal of this work was to demonstrate a broad range of starch applications in ceramic powder synthesis, and to point out that starch and its derivatives can successfully replace polyvinyl derivatives commonly used in ceramic formulations, as they are water-soluble saccharides, burn out more easily, reduce the exothermicity of the combustion reaction, and allow to receive fine and uniform ceramic powders. Starch is an eco-friendly and easily transformable natural carbohydrate polymer that is found in a variety of applications in ceramics and materials science. In this paper, we review the influence of starch on the physicochemical properties of the ceramic powders obtained by means of various synthesis methods (sol–gel method, combustion process, combined methods, and hydrothermal synthesis). Starch plays a differentiated role in each of these methods, i.e., it is a polymerizing agent in sol–gel method, a fuel in combustion process, and a substrate for carbon spheres in hydrothermal synthesis.


Materials ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 939 ◽  
Author(s):  
Hsu-Hui Cheng ◽  
Shiao-Shing Chen ◽  
Sih-Yin Yang ◽  
Hui-Ming Liu ◽  
Kuang-Shan Lin

2013 ◽  
Vol 28 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Guo-Cong LIU ◽  
Zhen JING ◽  
Xi-Bing ZHANG ◽  
Xian-Feng LI ◽  
Hong LIU

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060018
Author(s):  
E. M. Bayan ◽  
T. G. Lupeiko ◽  
L. E. Pustovaya ◽  
M. G. Volkova

Sn-doped TiO2 nanomaterials were synthesized by sol–gel method. It was shown the phase compositions and phase transitions change with the introduction of different tin amounts (0.5–20[Formula: see text]mol.%). X-ray powder diffraction was used to study the effect of different tin amounts on the anatase–rutile phase transition. It was found that the introduction of ions increases the thermal stability of anatase modifications. The material’s photocatalytic activity was studied in reaction with a model pollutant (methylene blue) photodegradation under UV and visible light activation. The best photocatalytic properties were shown for material, which contains 5[Formula: see text]mol.% of Sn.


2021 ◽  
Vol 46 (24) ◽  
pp. 12961-12980
Author(s):  
Amanda Chen ◽  
Wen-Fan Chen ◽  
Tina Majidi ◽  
Bernadette Pudadera ◽  
Armand Atanacio ◽  
...  

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1040 ◽  
Author(s):  
Getachew Solomon ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Isabella Concina ◽  
Alberto Vomiero

Molybdenum sulfide (MoS2) has emerged as a promising catalyst for hydrogen evolution applications. The synthesis method mainly employed is a conventional hydrothermal method. This method requires a longer time compared to other methods such as microwave synthesis methods. There is a lack of comparison of the two synthesis methods in terms of crystal morphology and its electrochemical activities. In this work, MoS2 nanosheets are synthesized using both hydrothermal (HT-MoS2) and advanced microwave methods (MW-MoS2), their crystal morphology, and catalytical efficiency towards hydrogen evolution reaction (HER) were compared. MoS2 nanosheet is obtained using microwave-assisted synthesis in a very short time (30 min) compared to the 24 h hydrothermal synthesis method. Both methods produce thin and aggregated nanosheets. However, the nanosheets synthesized by the microwave method have a less crumpled structure and smoother edges compared to the hydrothermal method. The as-prepared nanosheets are tested and used as a catalyst for hydrogen evolution results in nearly similar electrocatalytic performance. Experimental results showed that: HT-MoS2 displays a current density of 10 mA/cm2 at overpotential (−280 mV) compared to MW-MoS2 which requires −320 mV to produce a similar current density, suggesting that the HT-MoS2 more active towards hydrogen evolutions reaction.


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