scholarly journals Two-Step Hydrothermal Synthesis of Well-Dispersed (Na0.5Bi0.5)TiO3 Spherical Powders

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Zhuo Shi ◽  
Lianlai Sun ◽  
Kun Liu ◽  
Yingying Zhang ◽  
Weiyuan Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Synthesis Method ◽  
Spherical Shape ◽  
Raw Material ◽  
Second Step ◽  
In Situ Crystallization ◽  
Uniform Particle Size

(Na0.5Bi0.5)TiO3 (NBT) powders that have well-dispersed, uniform particle size and well-developed spherical shape were successfully prepared by a two-step hydrothermal synthesis method. Nanosized TiO2 powders were firstly synthesized by a hydrothermal method, and then the TiO2 particles are used as a raw material to synthesize NBT powders. It was found that by using the TiO2 nanoparticles as Ti source, the well-dispersed spherical NBT powders with about 200 nm in size could be obtained at 200°C for 4 h with a low mineralizer concentration of 6 mol/L NaOH in the second step. The formation of spherical NBT powders can be explained by first generating nuclei on the surface of TiO2 nanoparticles via in situ crystallization mechanism and then crystal growing and agglomerating by dissolution-recrystallization mechanism.

scholarly journals Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Synthesis Method ◽  
Double Perovskite ◽  
Synthesis Methods ◽  
X Ray ◽  
Sol Gel Synthesis

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.

scholarly journals Microwave-Assisted vs. Conventional Hydrothermal Synthesis of MoS2 Nanosheets: Application towards Hydrogen Evolution Reaction

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1040 ◽  
Author(s):  
Getachew Solomon ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Isabella Concina ◽  
Alberto Vomiero
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Crystal Morphology ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Mos2 Nanosheets ◽  
Microwave Assisted

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.

scholarly journals Significantly enhanced thermoelectric performance of Cu-doped p-type Bi0.5Sb1.5Te3 by a hydrothermal synthesis method

RSC Advances ◽  
2017 ◽  
Vol 7 (65) ◽  
pp. 41111-41116 ◽  
Author(s):  
Zichen Wei ◽  
Chenyang Wang ◽  
Li You ◽  
Shijie Zhao ◽  
Kang Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Synthesis Method ◽  
Thermoelectric Performance ◽  
P Type

Increased electrical conductivity and decreased thermal conductivity were achieved simultaneously in the Cu-doped Bi0.5Sb1.5Te3 synthesized by a hydrothermal method.

In situ solution plasma synthesis of mesoporous nanocarbon-supported bimetallic nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (37) ◽  
pp. 29131-29134 ◽  
Author(s):  
Jun Kang ◽  
Nagahiro Saito
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Small Particle ◽  
Electrocatalytic Activity ◽  
Bimetallic Nanoparticles ◽  
Synthesis Method ◽  
Simple Synthesis ◽  
Plasma Synthesis ◽  
Small Particle Size

We report a novel in situ simple synthesis method of bimetallic nanoparticles (NPs) supported on carbon black, which can markedly prevent the aggregation of NPs, resulting in a small particle size, good dispersion, and high-electrocatalytic-activity.

Preparation of Zirconia Nanoparticles in Ionic Liquid –Water and Characterization

2011 ◽  
Vol 52-54 ◽  
pp. 630-632
Author(s):  
Xiang Dong Ma ◽  
Fei Lei Liu ◽  
Hui Zhang ◽  
Liu Jie Xu ◽  
Shi Zhong Wei ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Hydrothermal Synthesis ◽  
Liquid Water ◽  
Synthesis Method ◽  
Experimental Results ◽  
Raw Material ◽  
Structure And Morphology ◽  
Xrd And Tem ◽  
Zirconia Nanoparticles

Zirconia nanoparticles were prepared in ionic liquid BMIMBF4-water using zirconium salt (ZrOCl2•8H2O), urea as raw material by hydrothermal synthesis method. The structure and morphology of zirconia were characterized by XRD and TEM. The experimental results showed zirconia nanoparticles could be prepared at 170°C for 24 hours in a hydrothermal kettle. Its size was about 10-30nm and the particles dispersed uniformly, and had no agglomeration phenomenon.

Hydrothermal Synthesis of Na(Nb1-xTax)O3 Powder for Fabrication of Lead-Free Piezoelectric Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1899-1901 ◽  
Author(s):  
Kong Jun Zhu ◽  
Jin Hao Qiu ◽  
Koji Kajiyoshi ◽  
Kazumichi Yanagisawa
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Fine Particles ◽  
Lead Free ◽  
Surface Areas ◽  
Ft Ir ◽  
Specific Surface Areas ◽  
Bet Technique ◽  
Ft Ir Spectroscopy

Hydrothermal method was used to synthesize the Na(TaxNb1-x)O3 (x = 0.1-0.5) powders with the addition of isopropanol. The phases of the obtained powders were confirmed by XRD. The morphology and particle size were observed by FE-SEM. The specific surface areas were measured by multipoint BET technique. The presence of water and organic group were determined by (FT-IR) spectroscopy. The results indicate that the pure Na(TaxNb1-x)O3 (x = 0.1-0.5) powders with perovskite structure and fine particles were successfully synthesized by hydrothermal method at 240 °C for 8 hours with the addition of isopropanol.

A lanthanide ion-doped Ba3Sc2F12 phosphor: hydrothermal synthesis, morphological control, energy transfer, and temperature-sensing performance

2020 ◽  
Vol 49 (18) ◽  
pp. 5881-5889
Author(s):  
Yini Mao ◽  
Li Jiang ◽  
Shanshan Hu ◽  
Jianfeng Tang ◽  
Yu Luo ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Temperature Sensing ◽  
Raw Material ◽  
Lanthanide Ion ◽  
Morphological Control ◽  
One Step ◽  
Sensing Performance

Ba3Sc2F12 crystals were synthesized by a facile one-step hydrothermal method with Ba/Sc raw material in a ratio of 3 : 2.

In Situ Synthesis and Characterization of Nanosize Hydroxyapatite/Polyacrylonitrile Composite Bead

2013 ◽  
Vol 743-744 ◽  
pp. 486-490
Author(s):  
Ming Mei Xu ◽  
Wang Xiao ◽  
Yong Zhu Cui ◽  
Wei Shao ◽  
Yan Ling Sui ◽  
...  
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Sem Analysis ◽  
Physical Interaction ◽  
X Ray Diffraction ◽  
Composite Bead ◽  
Composite Beads ◽  
High Conversion Ratio

nanosize hydroxyapatite/polyacrylonitrile composite bead was prepared via in-situ synthesis method. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), particle size measurement and X-ray diffraction (XRD) were used to characterize the HAp/PAN composite bead. XRD curve indicates low crystallinity of HAp. Particle size and SEM analysis demonstrates that decreased partical size of synthesized HAp as well as good distribution with the addition of PAN is found. The HAp is well-distributed and the combination between HAp and PAN is well. FTIR showed that there was no shift of characteristic peaks of synthesized HAp in PAN, which proves the physical interaction between PAN and HAp. The approximate HAp content of 28.6% calculated from thermal analysis curves means high conversion ratio of HAp. The adsorption amount of cadmium ions onto composite beads is lower than HAp particles.

The effect of temperature on morphology and electrochemical properties of NiCo2S4 by hydrothermal synthesis

2018 ◽  
Vol 11 (03) ◽  
pp. 1850063
Author(s):  
Yanwei Sui ◽  
Haihua Hu ◽  
Yuanming Zhang ◽  
Bin Tang ◽  
Jiqiu Qi ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Electrochemical Properties ◽  
Specific Capacitance ◽  
Hydrothermal Method ◽  
Current Density ◽  
Level Structure ◽  
Hydrothermal Process ◽  
Effect Of Temperature ◽  
Second Step ◽  
Carbon Sphere

The hydrothermal method, using the template is a conspicuous way to change the morphology of the product, so it is used widely in many reports. The effect of temperature on morphology of NiCo2S4 by hydrothermal synthesis and its electrochemical properties is distinct as high-performance electrode materials for supercapacitors. With the help of the template (carbon sphere), different morphologies of NiCo2S4 under 90[Formula: see text]C, 120[Formula: see text]C and 180[Formula: see text]C were obtained. They have different properties after electrochemical analysis. In order to build a hierarchical multi-level structure, two-step vulcanization was carried out at each temperature, resulting in the difference in the morphology and performance of the six sample of electrodes. The obtained NiCo2S4 electrodes exhibit 1000[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text] in the second-step of the hydrothermal process under 120[Formula: see text]C, which is superior to the microblocks NiCo2S4 electrode (90[Formula: see text]C, 888[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text]) and microparticles NiCo2S4 electrode (180[Formula: see text]C, 574[Formula: see text]F[Formula: see text]g[Formula: see text] at the same current density) in the second-step hydrothermal, which shows a high-rate capability (640[Formula: see text]F[Formula: see text]g[Formula: see text] at 20[Formula: see text]A[Formula: see text]g[Formula: see text]). The obtained nanoparticles NiCo2S4 under 180[Formula: see text]C in the first-step hydrothermal electrode had an excellent cycle retention rate (89.7%), although its specific capacitance was lower. At the same time, the specific capacitance of these sample electrodes obtained in the second-step hydrothermal process is superior to those from the first-step. It was mainly attributed to the fact that temperature can influence the morphology by controlling ion exchange. And our experiment aims to use the hydrothermal method and the template method to find a more suitable temperature range to provide more ideas.

Sign in / Sign up

Export Citation Format

Share Document