Study on Hydrothermal Process Variables Correlation to WO3 Nanostructure through Design of Experiments (DOE) Approach

2014 ◽  
Vol 607 ◽  
pp. 47-50
Author(s):  
Amirul Abd Rashid ◽  
Nor Hayati Saad ◽  
Daniel Bien Chia Sheng ◽  
Kah Yaw Lee ◽  
Wai Yee Lee ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Design Of Experiments ◽  
Tungsten Trioxide ◽  
Ph Value ◽  
Hydrothermal Process ◽  
Synthesis Temperature ◽  
Synthesis Process ◽  
Process Variables ◽  
Material Source ◽  
Experimental Procedure

There are few known parameters which govern tungsten trioxide (WO3) hydrothermal synthesis process which includes material source concentration, synthesis temperature, duration, pH value and additive level. Using design of experiments (DOE) approach, a systematic experimental procedure was conducted to investigate the effect of each parameter to the final morphology of the synthesized nanostructure. Despite the response obtained from this study is in qulitative form, the analysis still can be done to identify the combination of variables that most likely can produce either 1-D, 2-D or 3-D nanostructure. This insight is essential before further optimization of the process can be done in order to predict the behavior of the WO3 hydrothermal synthesis process.

scholarly journals A Novel Process for the Synthesis of NaV2O5 Mesocrystals from Alkaline-Stripped Vanadium Solution via the Hydrothermal Hydrogen Reduction Method

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 271
Author(s):  
Guobin Zhang ◽  
Yimin Zhang ◽  
Shenxu Bao ◽  
Liuhong Zhang
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Reduction ◽  
Ph Value ◽  
Hydrothermal Process ◽  
Reduction Process ◽  
Oriented Attachment ◽  
Synthesis Process ◽  
Synthesis Mechanism ◽  
Time Saving ◽  
Synthesis Time

NaV2O5 mesocrystals were successfully synthesized from an alkaline-stripped pentavalent vanadium solution through a novel hydrothermal hydrogen reduction process. The optimal conditions for the hydrogen partial pressure, reaction temperature, initial solution pH value, and reaction time for the pure-phase NaV2O5 synthesis were ascertained to be 4 MPa, 200 °C, 4.0, and 2 h, respectively. The synthesis time (only 2 h) was greatly shortened, by nine times, compared with the most time-saving (18 h) hydrothermal process at present. X-ray diffraction (XRD) analysis revealed that the as-prepared powders demonstrated a typical layered orthorhombic structure of NaV2O5. The purity of the as-prepared NaV2O5 reached up to 99.98%. An electrochemical test showed that the as-prepared NaV2O5 has a potential application in sodium ion batteries. According to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses, the as-prepared NaV2O5 powders were identified to have rod-like mesocrystals consisting of small rods which preferentially grow along the (010) direction. Furthermore, the phase transformation mechanism and crystal growth mechanism in NaV2O5 preparation were discussed systematically, based on which the synthesis mechanism of NaV2O5 was proposed as pentavalent vanadates pre-sedimentation, hydrogen reduction with dehydration, sodium ions insertion, and finally self-assembly oriented attachment. The synthesis process is characterized as time-saving and low-cost, and thus it may have great application prospects.

YVO4: RE3+(RE = Eu, Sm, Dy, Er) nanophosphors: Facile hydrothermal synthesis, microstructure, and photoluminescence

2009 ◽  
Vol 24 (10) ◽  
pp. 3050-3056 ◽  
Author(s):  
Bing Yan ◽  
Jianhua Wu
Keyword(s):  
Particle Size ◽  
Rare Earth ◽  
Electron Microscope ◽  
Hydrothermal Synthesis ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Synthesis Process ◽  
Average Particle ◽  
Sodium Vanadate ◽  
Rare Earth Nitrates

YVO4: 10%RE3+(RE = Eu, Sm, Dy, Er) nanophosphors have been synthesized by a facile modified hydrothermal technology to obtain the high purity. The key procedure for this hydrothermal process is the adding order of precursors, in which excess sodium vanadate should be added in the solution of rare earth nitrates. The microstructure (crystal phase, morphology, particle size) of these phosphors are characterized by x-ray powder diffraction, scanning electron microscope, and transmission electron microscope, which indicates that there are some cube-like crystals with tetragonal zircon structure and the average particle size is approximately 40 nm. The luminescent behaviors for the four rare earth ion-activated YVO4nanophosphors have been studied, and, for YVO4: 10%Eu3+nanophosphors in particular, it is found that a different hydrothermal process influences the phase composition, microstructure, and photoluminescence. This result suggests that the hydrothermal synthesis process (by adding sodium vanadate to the solution of rare earth nitrates) is favorable for YVO4nanophosphor to obtain pure phase, small particle size, long luminescent lifetime, and high luminescence quantum efficiency.

scholarly journals SYNTHESIS OF ZEOLITE AND COMPOSITE OF ZEOLITE/TiO2 FROM KAOLIN AND ITS APLICATION TO ADSORPTION-PHOTODEGRADATION OF METHILEN BLUE

2016 ◽  
Vol 11 (2) ◽  
pp. 147
Author(s):  
Linda Trivana ◽  
Sri Sugiarti ◽  
Eti Rohaeti
Keyword(s):  
Methylene Blue ◽  
Hydrothermal Synthesis ◽  
Ultraviolet Light ◽  
Sodium Silicate ◽  
Hydrothermal Process ◽  
Starting Material ◽  
Synthesis Process ◽  
Zeolite X ◽  
Methylene Blue Degradation ◽  
Silica Source

<p>In this study, zeolite was synthesized from kaolin which was founded from Bangka Belitung as the starting material. Meanwhile, sodium silicate was used as silica source. Zeolite is material with many benefits, such as become an adsorbent. Kaolin has been used as starting material due to high content of silica and alumina, i.e 35 - 50 %. Zeolite was prepared by hydrothermal synthesis process, by mixing the metakaolin which was produced by calcination of kaolin at 700 °C for 6 hours, with sodium silicate and NaOH. The NaOH was used to activate the major components of Si and Al in the kaolin.The hydrothermal process was conducted at 100 °C for 24 hours with various concentrations of NaOH, i.e 1.5 N and 2.5 N. The NaOH concentration might determine the type of zeolite obtained. To improve the nature as adsorbent, zeolites modified into zeolit/TiO<sub>2</sub>. The addition of TiO<sub>2</sub>into the prepared zeolit aimed to produce a material with capability as adsorbent-photocatalyst. The result of research found that the addition of NaOH 1.5 N produced zeolite NaP1. Meanwhile, the addition of NaOH 2.5 N produced the NaP1 zeolite, zeolite X, and faujasite. The composite of zeolit/TiO<sub>2</sub>has ability on adsorption-photocatalytic as it was proven by methylene blue degradation under ultraviolet light.</p>

scholarly journals SYNTHESIS OF ZEOLITE AND COMPOSITE OF ZEOLITE/TiO2 FROM KAOLIN AND ITS APLICATION TO ADSORPTION-PHOTODEGRADATION OF METHILEN BLUE

2016 ◽  
Vol 11 (2) ◽  
pp. 147
Author(s):  
Linda Trivana ◽  
Sri Sugiarti ◽  
Eti Rohaeti
Keyword(s):  
Methylene Blue ◽  
Hydrothermal Synthesis ◽  
Ultraviolet Light ◽  
Sodium Silicate ◽  
Hydrothermal Process ◽  
Starting Material ◽  
Synthesis Process ◽  
Zeolite X ◽  
Methylene Blue Degradation ◽  
Silica Source

<p>In this study, zeolite was synthesized from kaolin which was founded from Bangka Belitung as the starting material. Meanwhile, sodium silicate was used as silica source. Zeolite is material with many benefits, such as become an adsorbent. Kaolin has been used as starting material due to high content of silica and alumina, i.e 35 - 50 %. Zeolite was prepared by hydrothermal synthesis process, by mixing the metakaolin which was produced by calcination of kaolin at 700 °C for 6 hours, with sodium silicate and NaOH. The NaOH was used to activate the major components of Si and Al in the kaolin.The hydrothermal process was conducted at 100 °C for 24 hours with various concentrations of NaOH, i.e 1.5 N and 2.5 N. The NaOH concentration might determine the type of zeolite obtained. To improve the nature as adsorbent, zeolites modified into zeolit/TiO<sub>2</sub>. The addition of TiO<sub>2</sub>into the prepared zeolit aimed to produce a material with capability as adsorbent-photocatalyst. The result of research found that the addition of NaOH 1.5 N produced zeolite NaP1. Meanwhile, the addition of NaOH 2.5 N produced the NaP1 zeolite, zeolite X, and faujasite. The composite of zeolit/TiO<sub>2</sub>has ability on adsorption-photocatalytic as it was proven by methylene blue degradation under ultraviolet light.</p>

Hierarchical Ba2(B5O9)Cl·(H2O)0.5 microspheres: surfactant-assisted facile hydrothermal synthesis, Tb3+ doping and photoluminescence properties

CrystEngComm ◽  
2015 ◽  
Vol 17 (41) ◽  
pp. 7856-7865 ◽  
Author(s):  
Xiuping Chen ◽  
Linlin Zhang ◽  
Zhaoqiang Zhang ◽  
Lin Zhu ◽  
Wancheng Zhu
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Process ◽  
Photoluminescence Properties ◽  
Host Materials ◽  
Surfactant Assisted

Uniform hierarchical Ba2(B5O9)Cl·(H2O)0.5 microspheres containing nanorod-like sub-units were synthesized via a mild EDTA-2Na assisted hydrothermal process, which were manifested as great potential green-emitting host materials via Tb3+ doping.

scholarly journals Preparation of Ceria-Zirconia Mixed Oxide by Hydrothermal Synthesis

2015 ◽  
Vol 9 (7) ◽  
pp. 134 ◽  
Author(s):  
Siti Machmudah ◽  
M. Akmal Hadian ◽  
Lenno Samodro K. ◽  
Sugeng Winardi ◽  
Wahyudiono Wahyudiono ◽  
...  
Keyword(s):  
Solid Solution ◽  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Mixed Oxides ◽  
Synthesis Process ◽  
Growth Morphology ◽  
Mixed Powder ◽  
Xrd Pattern ◽  
Tube Reactor ◽  
Internal Volume

Ceria-zirconia mixed oxides have been synthesized by hydrothermal synthesis process. Under hydrothermalconditions, water potential to control the direction of crystal growth, morphology, particle size and sizedistribution, because of the controllability of thermodynamics and transport properties by pressure andtemperature. The synthesis was carried out at temperatures of 150 − 200 oC and pressure of 5 MPa in a batchreactor. The reactor made of SUS 304 tube reactor with internal volume of 8.8 ml. The synthesized productswere calcined and characterized using SEM, XRD and FTIR. The results showed that the particles formed weresphere shaped particles with smooth morphology and the size of particle diameters were 35, 61, and 31 nm onaverage for reactions temperatures of 150, 180, and 200oC, respectively. The XRD pattern indicated thatceria-zirconia mixed powder was uniformly distributed in the structure to form a homogeneous solid solution.

Hydrothermal Synthesis of Bi1.5ZnNb1.5O7 Nanopowders

2007 ◽  
Vol 561-565 ◽  
pp. 495-498 ◽  
Author(s):  
Jin Liang Huang ◽  
Xiao Wang ◽  
Liu Shuan Yang ◽  
Chun Wei Cui ◽  
Xing Hua Yang
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Pyrochlore Phase ◽  
Synthesis Temperature ◽  
Minimum Size ◽  
Hydrothermal Reactions ◽  
Prolonged Reaction Time ◽  
Scherrer Equation ◽  
Xrd Patterns

The cubic pyrochlore phase Bi1.5ZnNb1.5O7 nanopowder was successfully synthesized by the hydrothermal method (HTM) from the starting materials: Bi(NO3)3·5H2O, ZnO, Nb2O5 and the mineralizer: KOH. The XRD patterns prove that the cubic pyrochlore phase Bi1.5ZnNb1.5O7 nanopowder can be obtained by HTM, and TEM photographs show that the powders present the regularly granular shape, when the hydrothermal reactions were conducted at synthesis temperatures 140~220°C and reaction time for 6~48h. The crystalline sizes of the powders were calculated by the Scherrer equation to be about 43~49nm. The crystalline sizes decreased both with the increase in synthesis temperature and the prolonged reaction time until they reached to the minimum size about 43nm at 220°C for 24h.However, they tended to increase when the reaction time was above 24h.

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