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Hydrothermal preparation and persistence characteristics of nanosized phosphor SrS:Eu^(2+),Dy^(3+) 被引量:8
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作者 段晓霞 黄世华 +1 位作者 由芳田 康凯 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第1期43-46,共4页
Nanosized long-persistent phosphors SrS:Eu^2+, Dy^3+ were prepared by the hydrothermal method.The samples were characterized by X-ray powder diffraction, transmission electron microscopy, and charge-coupled device ... Nanosized long-persistent phosphors SrS:Eu^2+, Dy^3+ were prepared by the hydrothermal method.The samples were characterized by X-ray powder diffraction, transmission electron microscopy, and charge-coupled device spectrometry.The persistence characteristic was studied using the decay curves.The results showed that the emission intensity decreased sharply with temperature increasing, although the particle size increased.The S2-vacancies caused by oxidization served as shallow traps, and Dy3+ served as deep traps in SrS:Eu^2+, Dy^3+.The afterglow intensity of SrS:Eu^2+, Dy^3+ was higher than that of SrS:Eu2+ prepared at the same temperature.However, the minimization span of initial afterglow with temperature for the former sample was larger than that for the latter.Binary-doped phosphor decayed more slowly than the singly doped one.The afterglow of SrS:Eu^2+, Dy^3+ decayed more quickly with the increase of sintering temperature. 展开更多
关键词 hydrothermal preparation nanosized phosphor luminescence quenching afterglow spectra rare earths
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Surfactant-aided hydrothermal preparation of La(2-x)Sr_xCuO_4 single crystallites and their catalytic performance on methane combustion 被引量:4
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作者 Lei Zhang Yue Zhang +1 位作者 Jiguang Deng Hongxing Dai 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第1期69-75,共7页
Perovskite-like oxide La2-xSrxCuO4 (x = 0, 1) single crystallites with microrod-like morphologies and tetragonal crystal structures were prepared hydrothermally at 240 ℃ with poly(ethylene glycol) (PEG) or hexa... Perovskite-like oxide La2-xSrxCuO4 (x = 0, 1) single crystallites with microrod-like morphologies and tetragonal crystal structures were prepared hydrothermally at 240 ℃ with poly(ethylene glycol) (PEG) or hexadecyltrimethyl ammonium bromide (CTAB) as a surfactant and after calcination at 850 ℃. The physicochemical properties of the materials were characterized by means of XRD, BET, SEM, TEM/SAED (selected-area electron diffraction), XPS and H2-TPR techniques. It is found that doping Sr2+ to La2CuO4 lattice enhanced the catalytic activity for methane combustion and the LaSrCuO4 catalyst derived from PEG is the best among the tested ones. It is concluded that factors, such as adsorbed oxygen species concentration, reducibility and surface area, determined the catalytic performance of such single-crystalline materials. 展开更多
关键词 perovskite-like oxide La2-xSrzCuO4 single crystallite surfactant-aided hydrothermal preparation methane combustion
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Hydrothermal preparation and crystal habit of X-zeolite powder 被引量:2
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作者 申少华 张术根 +1 位作者 王大伟 方克明 《Journal of Central South University of Technology》 2005年第3期315-319,共5页
The preparation of X-zeolite powder was investigated in hydrothermal system, the crystal growth process of X-zeolite in hydrothermal condition was characterized by means of X-ray diffraction, scanning electron microsc... The preparation of X-zeolite powder was investigated in hydrothermal system, the crystal growth process of X-zeolite in hydrothermal condition was characterized by means of X-ray diffraction, scanning electron microscope and infrared ray. The results show that X-zeolite powder with uniform granularity and intact crystal shape can be obtained in hydrothermal system of acid-treated stellerite KG-*5CD*2KG-*9NaOHKG-*5CD*2KG-*9NaAl(OH)4KG-*5CD*2KG-*9H2O; the crystallite size is in the range of 2CD*23μm. The best reaction time of hydrothermal preparation is 6h. The formation phases of X-zeolite crystal are as follows: dissolution of feedstocks → formation of [SiO4] 4- and [AlO4] 5- tetrahedron, many-membered ring, β cage → formation of crystal nucleus and nano-particle → aggregation growth of nano-particle → coalescence growth of crystallite. The crystal habits of X-zeolite are intimately related with crystallization orientation of β cage in crystal and with its coupling stability on every crystal face family. 展开更多
关键词 X-zeolite powder acid-treated stellerite hydrothermal preparation crystal habit
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Hydrothermal Preparation and White-Light-Controlled Resistive Switching Behavior of BaWO_4 Nanospheres 被引量:1
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作者 Bai Sun Yonghong Liu +2 位作者 Wenxi Zhao Jinggao Wu Peng Chen 《Nano-Micro Letters》 SCIE EI CAS 2015年第1期80-85,共6页
In this work, BaWO4 nanospheres were successfully prepared by hydrothermal process. The bipolar resistive switching behavior of Ag/BaWO4/FTO device is observed. Moreover, this resistive switching behavior can be modul... In this work, BaWO4 nanospheres were successfully prepared by hydrothermal process. The bipolar resistive switching behavior of Ag/BaWO4/FTO device is observed. Moreover, this resistive switching behavior can be modulated by white light. The device can maintain superior stability in the dark and under white-light illumination. This study is useful for developing the light-controlled nonvolatile memory devices. 展开更多
关键词 BaWO4 nanospheres Resistive switching hydrothermal preparation White light
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Hydrothermal Preparation and Photocatalytic Water Splitting Properties of ZrW_2O_8
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作者 蒋丽 上官文峰 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第6期919-923,共5页
ZrW2O8 was prepared by adjusting Zr:W mole ratio and HCl concentration in hydrothermal reaction processes.The obtained sample was crystallized in α-ZrW2O8 phase (cubic,P213),with band gap energy of 4.0 eV.The prop... ZrW2O8 was prepared by adjusting Zr:W mole ratio and HCl concentration in hydrothermal reaction processes.The obtained sample was crystallized in α-ZrW2O8 phase (cubic,P213),with band gap energy of 4.0 eV.The properties of photocatalytic water splitting were examined under UV light irradiation.The average rate of H2 evolution over 0.3wt% Pt/ZrW2O8 in the presence of CH3 OH as electron donor (ED) was 23.4 μmol/h,while the average rate of O2 evolution over ZrW2O8 in the presence of AgNO3 as electron scavenger (ES) was 9.8 μmol/h.Moreover,H2 was evolved over 0.3wt% Pt/ZrW2O8 from pure water splitting at a rate of 5.2 μmol/h.The study indicated that the band structure of ZrW2O8 was suitable for reducing H + to H2 and oxidizing H2O to O2.The band structure and photocatalytic water splitting properties of ZrW2O8,different from either ZrO2 (5.0 eV) or WO3 (2.7 eV),were attributed to the hybridization of W5d and Zr4d in conduction band (CB) as well as the change in crystal structure. 展开更多
关键词 PHOTOCATALYST HYDROGEN zirconium tungsten oxide hydrothermal preparation
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Hydrothermal preparation and photoluminescent property of LiY(MoO_4)_2:Pr^(3+) red phosphors for white light-emitting diodes 被引量:9
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作者 李兆 赵西成 江元汝 《Journal of Rare Earths》 SCIE EI CAS CSCD 2015年第1期33-36,共4页
Praseodymium doped lithium yttrium molybdate Li Y1-8x Pr x(Mo O4)2(x=0.005-0.025) phosphors were successfully prepared by the hydrothermal method. The phase, morphology, and luminescent property of the prepared ph... Praseodymium doped lithium yttrium molybdate Li Y1-8x Pr x(Mo O4)2(x=0.005-0.025) phosphors were successfully prepared by the hydrothermal method. The phase, morphology, and luminescent property of the prepared phosphors were investigated by X-ray diffraction and scanning electron microscopy. The results indicated that doping of Pr^3+ ions did not change the main phase of the phosphors. The samples emitted red luminescence upon excitation at 453 nm and the strongest emission peak corresponding to the characteristic transition of the Pr3+ ion: 3P0→3F2 was observed at 657 nm. Li Y(Mo O4)2:Pr^3+ red phosphors could be effectively excited by blue light emitting-diodes to emit red light; thus, acting as potential candidates for compensating the red light deficiency of cerium doped yttrium aluminum garnet yellow phosphor. 展开更多
关键词 white light emitting diode LiY(MoO4)2:pr^3+ hydrothermal preparation PHOTOLUMINESCENT rare earths
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Hydrothermal preparation and formation mechanism of titanium dioxide microcrystallites 被引量:5
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作者 郑燕青 施尔畏 +4 位作者 元如林 李汶军 王步国 仲维卓 胡行方 《Science China(Technological Sciences)》 SCIE EI CAS 1999年第3期302-311,共10页
Hydrothermal preparation experiments of TiO2 microcrystallites were carried out. The formation of TiO2 microcrystallites of polymorphic forms was related to the precursor types and the basicity or acidity of reaction ... Hydrothermal preparation experiments of TiO2 microcrystallites were carried out. The formation of TiO2 microcrystallites of polymorphic forms was related to the precursor types and the basicity or acidity of reaction mediums under hydrothermal conditions. Based on the “growth unit” model, the space lattice graphs of growth units responding to different polymorphs were established. The stable energy of growth unit was calculated for different basicity or acidity of reaction mediums. The formation of polymorphic TiO2 microcrystallites under hydrothermal conditions was discussed based on the experimental results. 展开更多
关键词 growth unit model TiO2 microcrystallites POLYMORPHISM hydrothermal preparation
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Hydrothermal Preparation and Photophysical Properties of a Ni(Ⅱ) Complex Containing Quinoline Derivative and Phen Ligands 被引量:2
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作者 CHEN Hai-Hui YI Xiu-Guang +2 位作者 PAN Chang-Wang WEN Ji-Wu ZHANG Cong 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2021年第4期501-506,408,共7页
A novel nickel complex[Ni_(2)L_(2)Phen_(3)]·3H_(2)O (HL=3-hydroxy-2-methylquioline-4-carboxylic acid)has been synthesized by a hydrothermal approach and is structurally determined by single-crystal X-ray diffract... A novel nickel complex[Ni_(2)L_(2)Phen_(3)]·3H_(2)O (HL=3-hydroxy-2-methylquioline-4-carboxylic acid)has been synthesized by a hydrothermal approach and is structurally determined by single-crystal X-ray diffraction.The title complex crystallizes in triclinic space group P1.Crystal data for the title complex:C58H44N8Ni2O9,Mr=1108.35,a=11.8648(4),b=12.7369(4),c=17.0728(5)A,α=97.694(3),β=96.702(2),γ=99.566(3)°,V=2495.66(14)A^(3),Z=2,T=293(2) K,Dc=1.475 g/cm^(3),μ(Mo Kα)=0.824 mm^(–1),F(000)=1140,R=0.0757,w R=0.2129 and GOF=1.017.The nickel ions are surrounded by five oxygen and six nitrogen atoms to yield two slightly distorted octahedral geometries.Solid-state photoluminescence spectrum reveals that it shows blue purple emission.Solid-state UV/Vis diffuse reflectance spectroscopy exhibits that it has an optical band gap of 1.702 e V. 展开更多
关键词 hydrothermal preparation crystal structure photophysical properties
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Preparation and properties of HA coating hydrothermally synthesized from plasma sprayed Ca HPO_4 coating
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《Chinese Journal of Biomedical Engineering(English Edition)》 2001年第3期138-140,共3页
关键词 HA preparation and properties of HA coating hydrothermally synthesized from plasma sprayed Ca HPO4 coating SBF CA HPO
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Sintering of Doped, Nanocrystalline CeO_2 Powders Prepared under Hydrothermal Conditions 被引量:1
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作者 Yanchun ZHOU(Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110015, China)M.N.Rahaman (Ceramic Engineering Department, University of Missouri-Rolla, Rolla, MO 65401, USA) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1995年第6期429-434,共6页
Nanocrystalline CeO2 powders (particle size ≈10-15 nm), doped with up to 20 at.-% of Mg,Ca or Y were prepared by chemical precipitation under hydrothermal conditions. The particle size and shape of the powders change... Nanocrystalline CeO2 powders (particle size ≈10-15 nm), doped with up to 20 at.-% of Mg,Ca or Y were prepared by chemical precipitation under hydrothermal conditions. The particle size and shape of the powders change slightly with the dopant concentrations. The the of the dopants on the sintering of the compacted powders was investigated during heating at a constant rate of 10℃/min. The elemental composition and the concentration of the dopant has significant efFect on the densification and grain growth. Compared to undoped CeO2, the dopants produce a shift in the densification curve to higher temperatures. For the same dopant concentration and under identical sintering conditions, the Ca doped samples reach nearly full density with the smallest grain size (≈50 nm), however, the Mg doped sample has the lowest density (≈95% of the theoretical) with the largest grain size (≈1 μm) 展开更多
关键词 Brook TGA Nanocrystalline CeO2 Powders Prepared under hydrothermal Conditions Sintering of Doped
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Ferromagnetism in High-Surface-Area ZnO Nanosheets Prepared by a Template-Assisted Hydrothermal Method
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作者 Hui-Fang Yang Ling-Zhi Tang +3 位作者 Qiang Sun Lei Sun Zhen-Hua Li Shu-Xia Ren 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第6期90-93,共4页
High-surface-area ZnO nanosheets are prepared using a template-assisted hydrothermal method.A saturation moment as high as 0.02 emu/g is obtained for the ZnO nanosheets.Both photoluminescence spectroscopy and x-ray ph... High-surface-area ZnO nanosheets are prepared using a template-assisted hydrothermal method.A saturation moment as high as 0.02 emu/g is obtained for the ZnO nanosheets.Both photoluminescence spectroscopy and x-ray photoelectron spectroscopy demonstrate the existence of abundant oxygen vacancies on the surfaces of the nanosheets.In addition,the oxygen vacancy concentration increases with an increasing nanosheet surface area.The results show that the origin of the room-temperature ferromagnetism is closely related with a large surface area and oxygen vacancies of the nanosheets.This finding suggests that the high-surface-area ZnO nanosheets are promising to be applied to spintronic devices. 展开更多
关键词 ZNO Ferromagnetism in High-Surface-Area ZnO Nanosheets Prepared by a Template-Assisted hydrothermal Method
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The optimization of hydrothermal process of MoS2 nanosheets and their good microwave absorption performances 被引量:3
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作者 Xiaoyu Lin Jing Wang +6 位作者 Zengyong Chu Dongqing Liu Taotao Guo Lingni Yang Zhenyu Huang Sitong Mu Shun Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第5期1124-1128,共5页
In this study,flower-like MoS2 constructed by nanosheets was synthesized by a simple hydrothermal method.The hydrothermal process was optimized and the effects of hydrothermal condition,including reaction temperature,... In this study,flower-like MoS2 constructed by nanosheets was synthesized by a simple hydrothermal method.The hydrothermal process was optimized and the effects of hydrothermal condition,including reaction temperature,reaction time and the ratio of Mo source to S source(Mo:S)in precursor,on microwave absorption performances and dielectric properties were investigated.Our results showed that when the reaction temperature was 180℃,the reaction time was 18 h,and the Mo:S was 1:3.5,the synthesized MoS2 had the best performance:Its minimum reflection loss could reach-55.78 dB,and the corresponding matching thickness was 2.30 mm with a wide effective bandwidth of 5.17 GHz.Further researches on the microwave absorption mechanism revealed that in addition to the destructive interference of electromagnetic waves,various polarization phenomena such as defect dipole polarization were the main reasons for microwave loss.We believe that MoS2 is a candidate for a practical microwave absorbent. 展开更多
关键词 MOS2 hydrothermal preparation Microwave absorption performance Process optimization Microwave absorption mechanism
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Hydrothermal synthesis of Mn-Zn ferrites from spent alkaline Zn-Mn batteries 被引量:8
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作者 Lu Xiao Tao Zhou Jia Meng 《Particuology》 SCIE EI CAS CSCD 2009年第6期491-495,共5页
Nanocrystalline Mn-Zn ferrites (Mno.GZno.4Fe204) with particle size of 12 nm were synthesized hydrotherreally using spent alkaline Zn-Mn batteries, and accompanied by a study of the influencing factors. The nanocrys... Nanocrystalline Mn-Zn ferrites (Mno.GZno.4Fe204) with particle size of 12 nm were synthesized hydrotherreally using spent alkaline Zn-Mn batteries, and accompanied by a study of the influencing factors. The nanocrystals were examined by powder X-ray diffraction (XRD) for crystalline phase identification, and scanning electron microscopy (SEM) for grain morphology. The relationship between concentration of Fe(II), Mn(II), and Zn(II) and pH value was obtained through thermodynamic analysis of the Fe(II)-Mn(II)-Zn(II)-NaOH-H2O system. The results showed that all ions were precipitated completely at a pH value of 10-11. The optimal preparation conditions are: co-precipitation pH of 10.5, temperature of 200 ℃ and time of 9 h. 展开更多
关键词 Spent alkaline batteries Ferrites hydrothermal method preparation
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