La_2O_3/La_2O_2CO_3纳米复合材料的凝胶燃烧法合成  

Gel Combustion Synthesis of La_2O_3/La_2O_2CO_3 Nanocomposites

作　　者：闫玉芳[1] 霍慧琴 李晓芳[1] 田苗苗[1] 储刚[1] 姜恒[1] 

机构地区：[1]辽宁石油化工大学化学与材料科学学院,辽宁抚顺113001

出　　处：《稀有金属》2015年第8期710-714,共5页Chinese Journal of Rare Metals

基　　金：辽宁省自然科学基金项目(201202122);辽宁省教育厅科学研究一般项目(L2012125)资助

摘　　要：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。La2O3/ La2O2CO3 nanocomposites were synthesized by gel combustion synthesis with citric acid monohydrate as the complexing agent and La（ NO3）3·6H2O（ A. R） as the lanthanum source（ mole ratio of citric acid to La（ NO3）3= 1. 0 - 1. 2 ∶ 1. 0）,and ammonia solution was added to adjust the p H value to 2 - 4. Then the wet gel or precipitate could be obtained and was subsequently heated in muffle furnace at 600 - 700 ℃ for 1 - 2 h to cause the self-propagating combustion. La2O3/ La2O2CO3 nanocomposites with different sizes（ 30 - 100 nm） and phase ratios could be synthesized by calcining at different temperatures and time. Structure and morphology of the final products were characterized by X-ray powder diffraction（ XRD）,thermo-gravimetric / differential thermal analyzer（ TG-DTA） and transmission electron microscopy（ TEM）. La2O3 in La2O3/ La2O2CO3 nanocomposites was unstable in the air and finally deliquesced with the moisture and formed La（ OH）3. However,it was observed that the deliquescence was reversible,the product could transform to La2O3/ La2O2CO3 nanocomposites completely after calcining at 650 ℃ for 2 h.

关 键 词：凝胶燃烧法 La2O3/La2O2CO3纳米复合产物 组分分析 

分 类 号：O614[理学—无机化学]