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《稀有金属》2015,(8)
采用燃烧法合成了纳米La2O3/La2O2CO3复合材料,以六水合硝酸镧和一水合柠檬酸分别为镧源和络合剂,以氨水调节p H值,p H=2~4、柠檬酸与硝酸镧的摩尔比在1.0~1.2∶1.0之间,将得到的凝胶加热到一定温度发生自蔓延燃烧反应,燃烧反应产物在600~700℃煅烧1~2 h,得到膨松粉末状纳米La2O3/La2O2CO3复合产物。煅烧温度和恒温煅烧时间不同,得到不同粒径和组分比例的纳米La2O3/La2O2CO3复合材料。利用X射线衍射(XRD)、差热-热重分析(TG-DTA)和透射扫描电镜(TEM)等测试方法对凝胶热分解过程产物及最终形成的纳米La2O3/La2O2CO3复合产物粉体进行了分析和表征,产物的平均粒径在30~100 nm之间可控。纳米La2O3/La2O2CO3复合产物中的纳米La2O3在空气中具有不稳定性,极易与空气中的H2O发生反应生成La(OH)3,生成了La(OH)3/La2O2CO3复合产物,而产物在650℃煅烧2 h后即可完全转化为La2O3/La2O2CO3复合产物,说明这个过程是可逆的。 相似文献
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以Zn(CH3COO)2.2H2O,AgNO3为原料,丙烯酰胺为单体,N,N’-亚甲基双丙烯酰胺为网络剂,采用高分子凝胶法在550℃下制得纳米ZnO/La2O3。通过XRD物相分析,得知沉积稀土氧化物La2O3的ZnO纳米粒子样品的物相均是六方晶系纤锌矿结构;TEM形貌观察,粒子基本为球形,纳米ZnO/La2O3的平均粒径约为26 nm,红外光谱分析高分子的分解程度,在550℃时分解完全。水溶液中次甲基蓝染料在ZnO/La2O3半导体光催化条件下,pH值为9时,能迅速分解,在降解90 min时,次甲基蓝的降解率达到81%。 相似文献
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以Zn(CH3COO)2·2H2O,AgNO3为原料,丙烯酰胺为单体,N,N'-亚甲基双丙烯酰胺为网络剂,采用高分子凝胶法在550℃下制得纳米ZnO/La2O3.通过XRD物相分析,得知沉积稀土氧化物La2O3的ZnO纳米粒子样品的物相均是六方晶系纤锌矿结构;TEM形貌观察,粒子基本为球形,纳米ZnO/La2O3的平均粒径约为26
nm,红外光谱分析高分子的分解程度,在550℃时分解完全.水溶液中次甲基蓝染料在ZnO/La2O3半导体光催化条件下,pH值为9时,能迅速分解,在降解90
min时,次甲基蓝的降解率达到81%. 相似文献
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针对传统Mn3O4生产过程中存在工艺控制复杂和污染物排放量大的问题,结合传统液相法和焙烧法的优点,提出了先用NaOH滴加含有分散剂十二烷基硫酸钠(SDS)的硫酸锰溶液制备四氧化三锰前驱体,再焙烧前驱体制备Mn3O4,用SEM、XRD对产物进行表征。试验结果表明:在SDS投加量1.5g/L、反应温度60℃、反应时间30min和搅拌转速300r/min条件下,可得到粒径约100nm、大小分布均匀的纳米级前驱体颗粒,其主要由Mn(OH)2、MnOOH和Mn3O4组成;前驱体焙烧制备Mn3O4最佳温度为1 000℃,此时可得到呈四方尖晶石结构、粒径约500nm、颗粒大小均匀的Mn3O4产品。 相似文献
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以LaCl_3·6H_2O和H_2C_2O_4·2H_2O为原料,用室温固相化学反应首先合成出前驱物草酸镧,经750℃分解3h,得到产物纳米氧化镧。用X-射线粉末衍射和透射电镜对产物的组成、大小、形貌进行表征。结果表明:纳米氧化镧为粒度分布均匀的长方体形结构,平均粒径12nm。并考察了表面活性剂对粒径大小和分散性的影响。 相似文献
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采用电弧熔炼法合成LaNi5合金,LaNi5合金破碎研磨制备粉末,然后对LaNi5合金粉末采用H2/H2O进行选择性氧化处理,制备Ni/La2O3粉末。分别对LaNi5合金粉末和Ni/La2O3粉末进行了XRD结构分析、扫描电镜形貌观察。XRD结构分析结果表明,电弧熔炼法合成了单一物相的LaNi5粉末;Ni/La2O3粉末除La2O3和Ni两相外,未见其它杂相。扫描电镜形貌观察发现LaNi5粉末与Ni/La2O3粉末形貌相同。对Ni/La2O3粉末测量XRD图谱中衍射峰的半高宽,采用Scherrer公式,计算了La2O3和Ni物相的晶粒度在10 nm~40 nm范围内。扫描电镜多点能谱分析表明,Ni/La2O3粉末元素含量分布均匀有望在催化剂材料中得到应用。 相似文献
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以Sr(NO3)2,La(NO3)3·6H2O,Mn(NO3)2为原料,丙烯酰胺为单体,N,N'-亚甲基双丙烯酰胺为网络剂,采用高分子网络凝胶法在600 ℃下制得纳米La0.65Sr0.35MnO3.通过XRD物相分析,得知La0.65Sr0.35MnO3粒子样品的物相是立方晶系钙钛矿结构;La0.65Sr0.35MnO3粒子平均粒径为17 nm.水溶液中亚甲基蓝染料在La0.65Sr0.35MnO3太阳光催化条件下,能迅速分解,在降解120 min时,亚甲基蓝的降解率达到92%. 相似文献
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In this paper,various techniques including BET,XRD,SEM and XPS were used to study the sintering ofpure and La_2O_3-doped titania.The experimental results show that sintering of titania proceeds via volume diffu-sion.Adding of lanthanum oxide decreases the rate of sintering and hinders the phase transition from anatase torutile crystal by strong surface interaction between the mixed crystals(La_4Ti_9O_(24),La_(0.66)TiO_(2.99))and TiO_2. 相似文献
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《中国稀土学报(英文版)》2020,38(3):281-291
Greener synthesis of ionic liquid(IL) assisted lanthanum oxide(La_2O_3) nanoparticles(NPs) was followed using Andrographis paniculata leaves extract by hydrothermal method at low temperature,The IL assisted La_2O_3(La_2O_3-IL) NPs were characterized by various properties such as structural,spectral,optical,morphological,and biological studies.Powder X-ray diffraction studies confirm that La_2O_3-IL NPs crystallize in the form of body-centered cubic structure and average crystalline size is shown-43 nm.FTIR and Laser Raman spectroscopy confirm the La-O,O-H and various functional groups.The La-O stretching vibration band attributes at 639 cm~(-1).The optical property of La_2O_3-IL NPs was characterized by UV-Vis and photo luminesce nce spectroscopy.The sharp and intense absorbance peak observed in the UV region at 288 nm can be assigned.In the PL spectrum,we observe two different emission bands like blue and green emission.The morphological and particle size determination were investigated by SEM with EDX spectra and TEM analyses.The agglomerated particles of hexagonal,spherical,and parallelogram shape are observed in the TEM images.The chemical elements,binding energies as well as La metal states on the surface of these synthesized NPs were determined using XPS.La_2O_3 NPs for good biological activities regarding antibacterial and anti-inflammatory potentials could be utilized in different biological applications to the food and biomedical industries.La_2O_3-IL has a high percentage of inhibitions than La_2O_3 and standard diclofenac. 相似文献
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StudyofBi_2O_3-basedRareEarthSolidElectrolyteUsedinFuelCell¥HeLanying;ChenGuangyu;LiuJiang;SuWenhui(DepartmentofPhysics,JilinU... 相似文献
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采用熔盐电解法研究了La2O3电脱氧反应过程。由电位阶越实验及取样电流电位分析和对电解产物进行X衍射分析表明La2O3的电脱氧反应是可以进行的,La2O3得电子还原为低价脱氧产物LaO,接着LaO作为中间产物与阳极气体Cl结合生成氯氧镧。 相似文献
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Nanomaterialshavebacteriostaticandbacterici dalactivityonplant[1,2 ] .Rareearthmaterialsnoton lypossessbacteriostaticandbactericidalactivity ,butalsohavetheactionofnutrientbearerandactasnu trientregulator[3] .Becausetheparticlesizeandho mogeneityofmaterialshavenotbeenrequiredexactly ,nanorareearthmaterialwhichisfrom 1nmto 10 0nmforbiologyapplicationisalsopreparedbyamethodhomogeneousprecipitant[4 ,5] .Currently ,generalpre cipitatorsaremostlyammonia ,urea ,oxalicacidandammoniumbicarbonateaswell… 相似文献
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FeAl intermetallic compound with different contents of rare earth oxide La2O3 addition was prepared by hot pressing the mechanically alloyed powders.Effect of La2O3 on microstructure and high-temperature wear property of the sintered FeAl samples was investigated in this paper.The results showed that 1 wt.% La2O3 addition could refine the microstructure and increase the density of the FeAl intermetallic compound,and correspondingly improved the high-temperature wear resistance.SEM and EDS analyses of the wo... 相似文献