Luminescence Properties of ZnS:Cu,Tm Semiconductor Nanocrystals Synthesize by a Hydrothermal Process

2011 ◽  
Vol 415-417 ◽  
pp. 499-503
Author(s):  
Mei Xin ◽  
Dong Ping Liu ◽  
Nai Sen Yu ◽  
Xiao Hui Qi ◽  
Hui Li
Keyword(s):  
Hydrothermal Treatment ◽  
Emission Intensity ◽  
Treatment Time ◽  
Semiconductor Nanocrystals ◽  
Hydrothermal Process ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
Pl Emission ◽  
Hydrothermal Approach ◽  
Hydrothermal Treatment Time

ZnS:Cu,Tm nanocrystal with 15nm cubic structures have been synthesized by hydrothermal approach at 200°C. The photoluminescence (PL) properties and the effect of hydrothermal treatment time on the structure, morphology and PL spectra of ZnS:Cu,Tm samples have been studied. The as-obtained samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectra.The result indicated that the PL emission spectrum of codoped with Cu and Tm sample compares with undoped ZnS and doped with Cu alone samples has a significant changes, while the PL emission peak has red shift and PL emission intensity increased. The samples size and crystallization are increase with extending of the treatment time. However, when the hydrothermal treatment time is too long(>12h), the PL emission intensity of sample instead of decreased. Demonstrated changes in surface state of nanomaterials have a greater impact on its luminescence properties.

Crystalline microstructure of boehmites studied by multi-peak analysis of powder X-ray diffraction patterns

2017 ◽  
Vol 32 (S1) ◽  
pp. S87-S98 ◽  
Author(s):  
Pablo Pardo ◽  
Marek Andrzej Kojdecki ◽  
José Miguel Calatayud ◽  
José María Amigó ◽  
Javier Alarcón
Keyword(s):  
Hydrothermal Treatment ◽  
Treatment Time ◽  
Crystalline Lattice ◽  
X Ray Diffraction ◽  
Hydrothermal Aging ◽  
X Ray ◽  
Boehmite Nanoparticles ◽  
Diffraction Patterns ◽  
Crystalline Microstructure ◽  
Hydrothermal Treatment Time

Nanocrystalline boehmite (gamma-aluminium-oxyhydroxide) is a material of industrial importance, the functionality of which follows from its crystalline microstructure. A procedure for preparing boehmite nanoparticles, comprising the formation of a precipitate by the alkalization of an aqueous solution of aluminium nitrate and subsequent hydrothermal aging, was previously elaborated. The application of an additive (maltitol or tartaric acid) to control the sizes and shapes of crystallites in the produced polycrystalline powder of boehmite was developed. The aim of this work is a study of the effect of the hydrothermal treatment time on nanocrystalline characteristics of boehmite, both in absence and in presence of the additive. The obtained materials were investigated by using X-ray diffraction (XRD) as principal technique and additionally by scanning and transmission electron microscopy. The multi-peak analysis of powder XRD patterns was applied to determine the prevalent crystallite shape, volume-weighted crystallite size distribution, and second-order crystalline lattice strain distribution being principal quantitative characteristics of the crystalline microstructure. Based on these characteristics, three types of the microstructure correlated with the production procedures were observed and discussed in detail. The nanoparticles of boehmites were found to be monocrystalline grains with characteristic habits and sizes of order of ten nanometers weakly dependent on the hydrothermal treatment time.

Synthesis of Nanocrystalline InVO4 by Hydrothermal Process and its Visible-Light Photocatalytic Activity

2011 ◽  
Vol 284-286 ◽  
pp. 734-737 ◽  
Author(s):  
Pei Song Tang ◽  
Hai Feng Chen ◽  
Feng Cao ◽  
Guo Xiang Pan ◽  
Kun Yan Wang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Diffuse Reflectance Spectroscopy ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
Visible Light Absorption ◽  
Visible Light Photocatalytic Activity ◽  
Hydrothermal Approach ◽  
Visible Light Photocatalytic

Monophasic orthorhombic InVO4 was synthesized using InCl3 and NH4VO3 as starting materials by a hydrothermal approach. The as-prepared InVO4 product was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). It was found that the as-prepared InVO4 shows strong visible-light absorption with absorption onset of 515 nm, indicating a narrow optical band gap of 2.4 eV. Furthermore, the as-prepared InVO4 shows high visible-light photocatalytic activity for decomposition of methyl orange, which is ascribed to the strong visible-light absorption.

scholarly journals Coating Characteristic of Hydroxyapatite on Titanium Substrates via Hydrothermal Treatment

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1226
Author(s):  
Pham Trung Kien ◽  
Tran Ngo Quan ◽  
Le Huynh Tuyet Anh
Keyword(s):  
Hydrothermal Treatment ◽  
Treatment Time ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Optical Microscope ◽  
Initial Fixation ◽  
Phosphate Solutions ◽  
Titanium Substrates ◽  
Hydrothermal Treatment Time ◽  
Hydrothermal Methods

Medical pure titanium (Ti) shows excellent chemical stability and mechanical properties in clinical uses, but its initial fixation with host bone, when implanted, is usually delayed owing to the bioinert Ti surface. In this study, we fabricate the hydroxyapatite (HA)-coated titanium by three steps reactions: (1) to form an activated O2− layer by immersing Ti substrate into an alkaline solution such as NaOH; (2) the O2− bonds with Ca2+ to form Ca–O–Ti bonding, in which O plays the part of bridge materials between Ca and Ti substrate and (3) the conversion of Ca–O–Ti samples to HA-coated Ti samples by immersion into Na2HPO4 2 M at 180 °C for 48 h using hydrothermal methods. The effect of different phosphate solutions (NaH2PO4 2 M and Na2HPO4 2 M solution) and hydrothermal treatment time (24 and 48 h) on the characteristic of hydroxyapatite coating titanium substrate is also investigated using the optical microscope, thin film XRD and SEM/EDX. The HA-coated Ti samples fabricated by immersion into Na2HPO4 2 M at 180 °C for 48 h show fiber HA covering Titan substrate with a diameter varying from 0.1 to 0.3 µm. These HA-coated Ti samples can be regarded as promising multifunctional biomaterials.

scholarly journals Hydrothermal Synthesis of Cellulose Nanocrystal-Grafted-Acrylic Acid Aerogels with Superabsorbent Properties

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1168 ◽  
Author(s):  
Xuehua Liu ◽  
Rue Yang ◽  
Mincong Xu ◽  
Chunhui Ma ◽  
Wei Li ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Adsorption Capacity ◽  
Environmental Remediation ◽  
Freeze Drying ◽  
Treatment Time ◽  
Hydrothermal Process ◽  
Cellulose Nanocrystal ◽  
Maximum Adsorption Capacity ◽  
Simple Method ◽  
Hydrothermal Treatment Time

In this work, we applied a fast and simple method to synthesize cellulose nanocrystal (CNC) aerogels, via a hydrothermal strategy followed by freeze drying. The characteristics and morphology of the obtained CNC-g-AA aerogels were affected by the hydrothermal treatment time, volume of added AA (acrylic acid), and the mass fraction of the CNCs. The formation mechanism of the aerogels involved free radical graft copolymerization of AA and CNCs with the cross-linker N,N′-methylene bis(acrylamide) (MBA) during the hydrothermal process. The swelling ratio of the CNC-g-AA aerogels was as high as 495:1, which is considerably greater than that of other polysaccharide-g-AA aerogels systems. Moreover, the CNC-g-AA aerogels exhibited an excellent methyl blue (MB) adsorption capacity and the ability to undergo rapid desorption/regeneration. The maximum adsorption capacity of the CNC-g-AA aerogels for MB was greater than 400 mg/g. Excellent regeneration performance further indicates the promise of our CNC-g-AA aerogels as an adsorbent for applications in environmental remediation.

Improved HA Coating on Titanium Substrate Using Induction Heating and Hydrothermal Treatment Methods

2009 ◽  
Vol 610-613 ◽  
pp. 1227-1230
Author(s):  
Chun Li Zou ◽  
Xin Bo Xiong ◽  
Xie Rong Zeng
Keyword(s):  
Hydrothermal Treatment ◽  
Induction Heating ◽  
Hydrothermal Process ◽  
Titanium Substrate ◽  
Scratch Test ◽  
X Ray Diffraction ◽  
Ha Coating ◽  
Apatite Coating ◽  
Naoh Solution ◽  
Coating Methods

An adherent apatite coating was deposited on titanium substrate through the three steps. First, titanium substrate was modified in 10M NaOH solution at 60°C, and then immersed in acidic solution of calcium phosphate resulting in the deposition of monetite (CaHPO4) coating using induction heating technique. Finally the monetite crystals were transformed to HA by a hydrothermal process at 160°C for 2 hours. Composition、morphology and structure of the initial and final coatings were identified using X-ray diffraction (XRD), Scanning Electron Microscopy, and Energy Dispersive Spectroscopy (EDS). The final coating consisted of compact HA crystals and these HA apatite crystals stacked tightly and kept the initial morphology of the monetite crystals. The coating adhesion measured using scratch test was 25.25N. In conclusion, hydrothermal treatment and induction heating techniques are effective surface coating methods that improve bonding to titanium substrate.

Preparation and Characterization of Pr-CeO2 Nano-Powders by Co-Precipitation-Hydrothermal Method

2008 ◽  
Vol 368-372 ◽  
pp. 781-783
Author(s):  
Zhen Feng Zhu ◽  
Jing Ping Li ◽  
Jun Yang
Keyword(s):  
Hydrothermal Method ◽  
Hydrothermal Treatment ◽  
Treatment Time ◽  
Raw Materials ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Nano Size

Pr-CeO2 nano-size powders with the average crystallites size of 12 nm and particle size of 18 nm were prepared by a co-precipitation-hydrothermal method using Ce(NO3)3·6H2O, Pr6O11 as raw materials and ammonia as the precipitation agent. The influence of hydrothermal treatment time, hydrothermal treatment temperature on the average crystallites size, color of powders and the solubility of praseodymium were investigated. The synthesized powders were characterized by X-ray diffraction, transmission electron microscopy and color measurements. Results showed that after calcining at 800°C for 4 hours, the color of the as-prepared powder changes from light red to red brown, the solubility of praseodymium and the crystallites size of the Pr-CeO2 powder both increase.

scholarly journals Effect of Reaction Time and Hydrothermal Treatment Time on the Textural Properties of SBA-15 Synthesized Using Sodium Silicate as a Silica Source and Its Efficiency for Reducing Tobacco Smoke Toxicity

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 808
Author(s):  
Nerea Juárez-Serrano ◽  
Desiré Berenguer ◽  
Isabel Martínez-Castellanos ◽  
Inmaculada Blasco ◽  
Maribel Beltrán ◽  
...  
Keyword(s):  
Reaction Time ◽  
Hydrothermal Treatment ◽  
Sodium Silicate ◽  
Tobacco Smoking ◽  
Treatment Time ◽  
Textural Properties ◽  
Smoke Toxicity ◽  
Silica Source ◽  
Plant Experiment ◽  
Hydrothermal Treatment Time

The synthesis of SBA-15 has been optimized using sodium silicate, an inexpensive precursor of SBA-15. In this work, the influence of synthesis times of the precipitation and the hydrothermal treatment steps, on the textural properties developed as well as for reducing the toxic compounds generated in tobacco smoking, has been studied. The hydrothermal treatment has been proved to be necessary to obtain materials with adequate performance in this particular application. Twenty-four hours of hydrothermal treatment provide materials with the best properties. Although the reaction stage usually involves the mixing of reagents during 24 h, 40 min is enough to obtain a material with stick-like morphology and typical textural properties. Moreover, between 1 and 2 h of reaction time, the material proved to have the best performance for the purpose of reducing the toxicity of the products generated during the tobacco smoking process. These results are of great significance for an eventual scaling up to industrial scale of the SBA-15 manufacturing process. Results of a pilot plant experiment in a batch of 4 kg of SBA-15 are reported.

scholarly journals Development of a novel sequential pretreatment strategy for the production of bioethanol from coconut pulp residue

2019 ◽  
Vol 1 (3) ◽  
pp. 1-8
Author(s):  
Alissandra Pauline B. Mariano ◽  
Yuwalee Unpaprom ◽  
Rameshprabu Ramaraj
Keyword(s):  
Sulphuric Acid ◽  
Hydrothermal Treatment ◽  
Waste Disposal ◽  
Treatment Time ◽  
Sugar Concentration ◽  
Bioethanol Production ◽  
Cooking Fuel ◽  
Handling Cost ◽  
Sequential Pretreatment ◽  
Hydrothermal Treatment Time

Coconut pulp residues waste generated after extraction of milk or oil. These wastes end up as feed to animals, fertilizers and firewood/cooking fuel whilst large quantities often left to rot in the field, which causes cause pollution, waste disposal problems and increase handling cost for farmers. In order to alleviate this problem, coconut pulp residue was used as feedstock for bioethanol production. However, improvements on pretreatment are necessary to produce higher sugar concentration prior to fermentation. Bioethanol production from coconut pure pulp residue (PPR) and combined pulp residue (CPRS) was investigated. The results showing 40 minutes’ pre-hydrothermal treatment time and 2% mild sulphuric acid for PPR and 20 minutes’ hydrothermal treatment time and 2% mild sulphuric acid for CPRS.

Synthesis of flower-like Al doped ZnO microstructures by hydrothermal process and analysis of their gas sensing properties

2014 ◽  
Vol 07 (04) ◽  
pp. 1450037 ◽  
Author(s):  
Zan Li ◽  
Wei Qin ◽  
Wenjie Zhao ◽  
Xiaohong Wu
Keyword(s):  
Gas Sensing ◽  
Hydrothermal Process ◽  
Hexagonal Wurtzite Structure ◽  
Underlying Mechanism ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Doped Zno ◽  
Hydrothermal Approach

Al -doped ZnO (AZO) powders with flower-like microstructures were successfully synthesized through a simple and efficient hydrothermal approach, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy diffraction spectrum (EDS). All the samples presented high crystallinity with a hexagonal wurtzite structure. The heater gas sensors based on AZO were fabricated and investigation of gas sensing properties was conducted. The sensors showed high response values and reproducible response-recovery for 50–1800 ppm ethanol at 332°C, comparing with NH 3, SO 2, CO , and HCHO . The underlying mechanism was discussed.

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