高频热等离子体制备形状可控的一维结构纳米材料

Controlled synthesis of one-dimensional nanomaterials by RF plasma

介绍了采用高频热等离子体宏量制备ZnO、ZnS和A1N等一维结构纳米材料。研究了不同工艺条件对形貌的影响；采用锌粉为原料，成功制备了不同长径比的氧化锌纳米棒；同样，采用锌粉和硫粉混合物为原料，获得了均匀的棒状和四角状等不同形貌的一维结构纳米ZnS；采用铝粉与氨气在等离子体中的反应，获得了一维结构纳米A1N。通过控制不同的参数可以调控合成产物的大小、长径比和形貌等。在等离子体合成过程中，合成产物可以达到50g／min，而且，产物的大小和形貌均匀。XRD、SEM、HRTEM和拉曼光谱等表征了合成产物的结构和形貌。在高频常压热等离子体合成过程中，一维结构纳米材料的生长过程只有数秒，而合成的一维纳米材料的长度甚至可以达到几十微米。通过分析发现，在等离子体合成过程中，一维纳米材料的生长符合VS机制，而且，生长过程是双向进行的。

In this paper, different one-dimensional nanomaterials, including ZnO, ZnS and A1N was synthesized by radio frequency plasma system, and influences of process parameters on the morphology of final products were investigated. By oxidation the Zn in the plasma, well-controlled ZnO nanorods was prepared, and the ZnS nanocrystals with nanorods, tetrapods were obtained using Zn and S powders as starting materials. One-dimensional A1N nanocrystals were synthesized by reacting between Zn and ammonia gas. The morphology of synthesized products could be well controlled by adjusting the process parameters. The quantities of final products are more than 50g/min. The products were characteristic by XRD, SEM, HRTEM etc. The resident time of the particles in plasma system is no more than several seconds, and the length of obtained products could beyond several micrometers. The growth process was governed by a two-dimensional and wall-free VS growth mechanism.