Title of article :
Morphology-controlled nonaqueous synthesis of anisotropic lanthanum hydroxide nanoparticles
Author/Authors :
Igor Djerdj، نويسنده , , Georg Garnweitner، نويسنده , , Dang Sheng Su، نويسنده , , Markus Niederberger، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Abstract :
The preparation of lanthanum hydroxide and manganese oxide nanoparticles is presented, based on a nonaqueous sol–gel process involving the reaction of La(OiPr)3 and KMnO4 with organic solvents such as benzyl alcohol, 2-butanone and a 1:1 vol. mixture thereof. The lanthanum manganese oxide system is highly complex and surprising results with respect to product composition and morphology were obtained. In dependence of the reaction parameters, the La(OH)3 nanoparticles undergo a shape transformation from short nanorods with an average aspect ratio of 2.1 to micron-sized nanofibers (average aspect ratio is more than 59.5). Although not directly involved, KMnO4 plays a crucial role in determining the particle morphology of La(OH)3. The reason lies in the fact that KMnO4 is able to oxidize the benzyl alcohol to benzoic acid, which presumably induces the anisotropic particle growth in [0 0 1] direction upon preferential coordination to the ±(1 0 0), ±(0 1 0) and ±(−110) crystal facets. By adjusting the molar La(OiPr)3-to-KMnO4 ratio as well as by using the appropriate solvent mixture it is possible to tailor the morphology, phase purity and microstructure of the La(OH)3 nanoparticles. Postsynthetic thermal treatment of the sample containing La(OH)3 nanofibers and β-MnOOH nanoparticles at the temperature of 800 °C for 8 h yielded polyhedral LaMnO3 and worm-like La2O3 nanoparticles as final products.
Keywords :
Nonaqueous synthesis , Solvothermal synthesis , Transmission electron microscopy , Lanthanum hydroxide nanofibers
Journal title :
JOURNAL OF SOLID STATE CHEMISTRY
Journal title :
JOURNAL OF SOLID STATE CHEMISTRY