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1. 暨南大学化学系,广东 广州,510632
2. 暨南大学 纳米化学研究所,广东 广州,510632
收稿日期:2008-09-04,
修回日期:1900-01-02,
网络出版日期:2009-06-30,
纸质出版日期:2009-06-30
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李锦清, 杨创涛, 孟建新. 水热法制备MgWO4 及其发光性质[J]. 发光学报, 2009,30(3):327-331.
LI Jin-qing, YANG Chuang-tao, MENG Jian-xin. Hydrothermal Synthesis of MgWO4 and Its Luminescence[J]. Chinese journal of luminescence, 2009, 30(3): 327-331.
以硝酸镁、钨酸钠为原料
氢氧化钠和硝酸作为pH调节剂
在180~230 ℃水热条件制备纯相的MgWO
4
。探讨了水热反应温度对MgWO
4
纯相形成以及煅烧温度对其晶型、发光性质的影响。分别用粉末X射线衍射、荧光光谱、扫描电子显微镜和综合热分析等手段对样品进行表征。结果表明
水热法可以直接制得不含结晶水MgWO
4
晶体
属于四方晶系
形貌呈片状
厚度约为几个纳米。样品热重分析和高温煅烧的结果表明
水热法所得MgWO
4
晶体在850 ℃附近出现晶型转化
由四方晶系转变为单斜晶系
并导致发光性质的明显变化。SEM显示煅烧前的样品形貌为片状
不同温度煅烧后由片状逐渐向棒状转变。
MgWO
4
is a self-activated luminescent material
chemical and luminous properties are stable. It has high quantum efficiency and has been used as lamp phosphor for a long-term. MgWO
4
is usually prepared by solid-phase method using high purity MgO or MgCO
3
mixture with WO
3
then sintered at about 1 200 ℃ for several hours. Solid-phase approach leads to unhomogeneous distribution of sample size
the particles easily reunion
and the particle size is difficult to control
but hydrothermal method can overcome these shortco-mings. In recent years
hydrothermal method has been used to synthesis some kinds of tungstate samples
such as BaWO
4
NaLa(WO
4
)
2
PbWO
4
and so on
but to synthesis MgWO
4
it has not been reported.Amberg and John.R synthesized pure MgWO
4
·H
2
O and MgWO
4
·2H
2
O by mild hydrothermal method
but without studying on their luminescent properties. This article reports about using hydrothermal method to synthesis MgWO
4
crystal without crystalline H
2
O. A pure phase MgWO
4
was synthesized by hydrothermal method from Mg(NO
3
)
2
and Na
2
WO
4
solutions. The effects of hydrothermal temperatures on lattice phase
sintering temperatures on the morphology
structure and fluorescence intensity of MgWO
4
powder were investigated. Samples were characterized by X-ray diffraction (XRD)
fluorescence spectrometer
scanning electron microscope(SEM) and TG-DSC. The results showed that MgWO
4
without crystalline H
2
O molecule can be synthesized at 180~230 ℃ hydrothermal temperatures. The as-prepared sample has a tetragonal structure and transfer to monocline structure when sintered at 850 ℃ or higher temperature. Fluorescence spectra showed that MgWO
4
has a broad emission band peaked at 480 nm. The emission intensity becomes stronger as the sintering temperature increases from 750 ℃ to 1 050 ℃. SEM images showed that the size of MgWO
4
particles increases with the sintering temperature.
. Zhang Zhongtai, Zhang Junying. Photoluminescence Inorganic Materials and Applications [M]. Beijing: Chemical Industry Press, 2005,128.
. Guo Qiti, Ole Jakob Kleppa. Enthalpies of formation from the component oxides of MgWO4, CaWO4(scheelite), SrWO4 and BaWO4,determined by high-temperature direct synthesis calorimetry [J].Thermochimica Acta, 1996, 288 (1-2):53-61.
. Liu Zhengwei, Liu Yingliang, Yuan Dingsheng, et al. Long-lasting phosphorescence in Eu3+doped CaWO4[J]. J. Inorganic Chem.(无机化学学报), 2004, 20 (12):1433-1436 (in Chinese).
. Wei Ang, Huang Wei, Xu Chunxing, et al. CO gas sensor based on ZnO nanorod array grown by hydrothermal decomposition [J]. Chin. J. Lumin. (发光学报), 2007, 28 (6):880-884 (in Chinese).
. Liu Bao, Wu Youshi, Wu Lili, et al. Hydrothermal preparation and optical properties of Sn-doped ZnO nanocrystals [J]. Chin. J. Lumin. (发光学报), 2008, 29 (3):532-536 (in Chinese).
. Liang Lifang, Zhuang Jianle, Wu Hao, et al. White up-conversion emission of hydrothermally synthesized hexagonal NaYF4 : Er3+/Tm3+ [J]. Chin. J. Lumin. (发光学报), 2008, 29 (6):996-102 (in Chinese).
. Zhang Fan, Yang Shiping, Chen Hongmei, et al. The effect of an anionic starburst dendrimer on the crystallization of BaWO4 under hydrothermal reaction conditions [J]. J. Crystal Growth, 2004, 267 (3-4):569-573.
. Wang Feng, Fan Xianping, Pi Daibo, et al. Hydrothermal synthesis and luminescence behavior of rare-earth-doped NaLa(WO4)2 powders [J]. J. Solid State Chem., 2005, 178 (3):825-830.
. An Changhua, Tang Kaibin, Shen Guozhen, et al. Hydrothermal preparation of luminescent PbWO4 nanocrystallites [J]. Materials Lett., 2002, 57 (3):565-568.
. Fu Hongbo, Lin Jie, Zhang Liwu, et al. Photocatalytic activities of a novel ZnWO4 catalyst prepared by a hydrothermal process [J]. Appl. Catalysis A: General, 2006, 306 (7):58-67.
. John R, Günter, Marcel Amberg. Crystal structure and topotactic dehydration of magnesium tungstate dihydrate, MgWO4·2H2O [J]. Solid State Ionics, 1989, 32-33 (Part 1):141-146.
. Amberg M, Günter J R, Schmalle H, et al. Preparation, crystal structure, and luminescence of magnesium molybdate and tungstate monohydrates, MgMoO4·H2O and MgWO4·H2O [J]. J. Solid State Chem., 1988, 77 (1):162-169.
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