Batch Supercritical Hydrothermal Synthesis of CeO2 Nanoparticles

2011 ◽  
Vol 284-286 ◽  
pp. 773-780
Author(s):  
Dan Zhao ◽  
Da Liang Li ◽  
Xin Qiang Wu ◽  
En Hou Han
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Reaction Temperature ◽  
Ph Value ◽  
Synthesis Method ◽  
Additional Treatment ◽  
Reactant Concentration ◽  
Size And Morphology ◽  
Supercritical Hydrothermal Synthesis

CeO2 nanoparticles with diameter of about 5 nm were prepared by batch supercritical hydrothermal synthesis method at 390 °C without additional treatment. It was found that the characteristics of products depended on the pH value, reactant concentration (C0), and reaction temperature. The reaction time and coexisting cations (Li+, Na+ and K+) had little effect on the size and morphology of CeO2 particles. Uniform CeO2 nanoparticles were synthesized at 390 °C, pH = 9 and C0 = 0.06 M. The mechanism for batch supercritical hydrothermal synthesis of CeO2 nanoparticles is discussed.

scholarly journals Facile Synthesis of Silver Nanoparticles and Preparation of Conductive Ink

Nanomaterials ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 171
Author(s):  
Gui Bing Hong ◽  
Yi Hua Luo ◽  
Kai Jen Chuang ◽  
Hsiu Yueh Cheng ◽  
Kai Chau Chang ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Electrical Resistivity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Ph Value ◽  
Chemical Reduction ◽  
Flexible Substrate ◽  
Synthesis Method ◽  
Future Research ◽  
Conductive Ink

In the scientific industry, sustainable nanotechnology has attracted great attention and has been successful in facilitating solutions to challenges presented in various fields. For the present work, silver nanoparticles (AgNPs) were prepared using a chemical reduction synthesis method. Then, a low-temperature sintering process was deployed to obtain an Ag-conductive ink preparation which could be applied to a flexible substrate. The size and shape of the AgNPs were characterized by ultraviolet–visible spectrophotometry (UV-Vis) and transmission electron microscopy (TEM). The experiments indicated that the size and agglomeration of the AgNPs could be well controlled by varying the reaction time, reaction temperature, and pH value. The rate of nanoparticle generation was the highest when the reaction temperature was 100 °C within the 40 min reaction time, achieving the most satisfactorily dispersed nanoparticles and nanoballs with an average size of 60.25 nm at a pH value of 8. Moreover, the electrical resistivity of the obtained Ag-conductive ink is controllable, under the optimal sintering temperature and time (85 °C for 5 min), leading to an optimal electrical resistivity of 9.9 × 10−6 Ω cm. The results obtained in this study, considering AgNPs and Ag-conductive ink, may also be extended to other metals in future research.

The Preparation Technique of Nanometer Molybdenum Trioxide by Hydrothermal Synthesis

2011 ◽  
Vol 117-119 ◽  
pp. 807-810
Author(s):  
Ji Wen Li ◽  
Yan Hua Ma ◽  
Fang Fang Gong ◽  
Guo Shang Zhang ◽  
Liu Jie Xu ◽  
...  
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Reaction Temperature ◽  
Molybdenum Trioxide ◽  
Ph Value ◽  
Ultrafine Particle ◽  
Preparation Technique ◽  
Optimum Ph ◽  
Optimum Reaction ◽  
Optimal Reaction

The technique of hydrothermal synthesis is used to prepare nanometer molybdenum trioxide through controlling the parameters such as the acidification condition, the reaction temperature, the reaction time and so on. The technique is under high temperature and high pressure by water as the solvent. Synthesized molybdenum trioxide powder is characterized by XRD, SEM, and HRTEM. The optimal reaction time is 40h, the optimum reaction temperature is 170°C, and the optimum pH value is 1.0. The results indicate that powder has an ultrafine particle size, high purity, and narrow size distribution, good fluidity, light agglomerate and is perfect in crystal.

Research on Affecting Factor of Preparation of Calcium Sulfate Whisker with FGD Gypsum

2014 ◽  
Vol 624 ◽  
pp. 82-85
Author(s):  
Ying Wang ◽  
Dan Jun Tan ◽  
Xiao Li ◽  
Fan Li ◽  
Peng Qi Wang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Calcium Sulfate ◽  
Ph Value ◽  
Synthesis Method ◽  
Raw Material ◽  
Optimum Conditions ◽  
Fgd Gypsum ◽  
Slurry Concentration ◽  
Calcium Sulfate Whisker

Using FGD gypsum as raw material, calcium sulfate whisker was prepared by hydrothermal synthesis method. Through testing the aspect ratio of calcium sulfate whisker, the effect of reaction temperature, reaction time, desulfurization gypsum slurry concentration and pH value on the growth of calcium sulfate whisker were deeply researched. The optimum conditions for the preparation were that the reaction temperature was 150 °C, reaction time was 270min, the slurry concentration was 10% and the slurry pH value was 6.

Synthesis Method and its Influence Factors of Hydrotalcite-Like Compounds

2013 ◽  
Vol 690-693 ◽  
pp. 351-354 ◽  
Author(s):  
Hong Dan Xue ◽  
Fu Li Wang ◽  
Guo Li Li ◽  
Pu Liu ◽  
Yong Qing Bai ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Reduction Method ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Synthesis Method ◽  
Influence Factors ◽  
Synthetic Methods ◽  
Molar Ratio ◽  
Temperature Reaction

Hydrotalcite-like compounds are a class of anionic lays or layed double hydroxiods (LDHs) which consists of alkalescence, anion-exchanges and memory effect. The synthetic methods of LDHs include coprecipitation, hydrothermal synthesis, mirowave radiation, ion exchange, sol-gel method, roasting reduction method, instant synthesis, etc.The molar ratio of raw materials, pH value,reaction temperature,reaction time and so on have a greater impact on the purity and crystallinity of the LDHs.

Enhanced Photocatalytic Performance and Mechanism of Ag3PO4 Particles Synthesized via a Sonochemical Process

2018 ◽  
Vol 10 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Chengxiang Zheng ◽  
Hua Yang ◽  
Yang Yang ◽  
Haimin Zhang
Keyword(s):  
Particle Size ◽  
Photocatalytic Activity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Ph Value ◽  
Dye Degradation ◽  
Sonochemical Method ◽  
Simulated Sunlight ◽  
Spherical Nanoparticles ◽  
Direct Oxidation

A facile sonochemical method was used to synthesize Ag3PO4 particles and the effect of pH value, reaction temperature and reaction time on the products was investigated. It is found that the samples prepared at neutral (pH = 7) and alkaline (pH = 11) environments exhibit a similar particle morphology and size. The particles are shaped like spheres with a size distribution majorly focusing on a range of 200–450 nm, and the average particle size is about 300 nm. The sample prepared at acidic environment (pH = 3) is composed of polyhedral microparticles with size of 5–8 μm. At relatively low temperatures of 20–50 °C, the spherical nanoparticles do not undergo obvious morphology/size changes; however, when the temperature is increased up to 80 °C, the nanoparticles are aggregated to form large-sized polyhedral microparticles in the size range of 4–7 μm. Compared to the pH value and reaction temperature, the reaction time has a minor effect on the morphology of Ag3PO4 particles. RhB was chosen as the target pollutant to evaluate the photocatalytic activity of the as-prepared Ag3PO4 samples under simulated-sunlight irradiation. It is shown that the samples consisting of spherical nanoparticles exhibit an extremely high photocatalytic activity, and the degradation percentage of RhB after reaction for 50 min reaches over 90%. The samples of polyhedral microparticles have a relatively low photocatalytic activity, which is possibly due to their large particle size. Hydroxyl (.OH) radical was detected by spectrofluorimetry using terephthalic acid as a .OH scavenger and was not found to be produced over the simulated-sunlight-irradiated Ag3PO4 catalyst. The effect of ethanol, benzoquinone and ammonium oxalate on dye degradation was also investigated. Based on experimental results, the direct oxidation by h+ is suggested to the dominant mechanism toward the dye degradation.

Adsorption of Lead Ions in Aqueous Solution Using Yttrium Oxide Nanoparticles

2012 ◽  
Vol 16 ◽  
pp. 83-87
Author(s):  
Sodeh Sadjadi ◽  
Seyed Javad Ahmadi ◽  
Morteza Hosseinpour
Keyword(s):  
Yttrium Oxide ◽  
Heavy Metal Ions ◽  
Synthesis Method ◽  
Additional Treatment ◽  
Single Step ◽  
Lead Ions ◽  
Oxide Nanoparticles ◽  
Nano Structure ◽  
Supercritical Hydrothermal Synthesis ◽  
Yttrium Oxide Nanoparticles

By a single-step supercritical hydrothermal synthesis method, yttrium oxide nanoparticles were successfully prepared without additional treatment. Yttrium oxide nanoparticles were employed as an adsorbent to study the adsorption of some heavy metal ions. This study revealed that nano structure yttrium oxide was an effective adsorbent for removal of lead ions from aqueous solutions.

Preparation of FePO4•2H2O with Flower-like Microstructure by a Facile Hydrothermal Synthesis Method

2013 ◽  
Vol 423-426 ◽  
pp. 550-553 ◽  
Author(s):  
Bing Jiang ◽  
Wen Qin Wang ◽  
Yu Song Liu ◽  
Zhi Meng Guo
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Formation Mechanism ◽  
Low Cost ◽  
Hydrothermal Process ◽  
Synthesis Method ◽  
Large Area ◽  
Facile Hydrothermal Process

FePO4·2H2O with orthorhombic flower-like microstructure was synthesized by a facile hydrothermal process which was of low-cost and easy processing in large area. The formation mechanism of the flower-like FePO4·2H2O was discussed in details by investigating the different concentration of reactants and reaction time. The results show that the morphology of FePO4·2H2O changed from microsphere to flower-like structure, which possess an unique morphology with six petals and the angle of each petal being 60o. The formation mechanism of FePO4·2H2O flowers can be explained by the dissolution-recrystallization and crystal splitting.

Study on Catalytic Degradation of Diesel Pollution in Seawater by Laccase

2013 ◽  
Vol 781-784 ◽  
pp. 2324-2327
Author(s):  
Xu Zheng ◽  
Xiao Cai Yu ◽  
Yun Qing Liu ◽  
Xiao Xv ◽  
Jin Fang Chen
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Sea Water ◽  
Oil Pollution ◽  
Ph Value ◽  
Degradation Process ◽  
Catalytic Degradation ◽  
Initial Concentration ◽  
Optimization Study ◽  
Optimum Reaction

Sea water joining diesel was selected to prepare simulated marine oil pollution. With the target of removing diesel from seawater, the influence of various factors on the laccase-catalyzed degradation process was discussed. The experimental results show that the laccase-catalyzed degradation process was significantly affected by laccase dosage, reaction temperature, reaction time, pH of the solution and initial concentration of diesel in the oily wastewater. A systematic optimization study was carried out through a orthogonal test on the basis of the results of the single-factor experiments,and the optimum reaction conditions of laccase catalytic degradation diesel pollutants in seawater was determined. The results indicate that under the conditions of diesel initial concentration of 0.1g/L, laccase dosage of 8mg/L, pH value of 6, the reaction temperature of 25°C and the reaction time of 4h, laccase catalytic degradation rate of diesel pollution can be up to 63.85%.

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