Ni／MnO纳米复合粒子的生长机制

Characterization and growth mechanism of Ni/MnO nanocompsite particles

以Ni和MnO_2微米粉为原料,采用直流电弧等离子法在氢-氩混合气氛中合成了MnO包覆Ni纳米复合粒子,用XRD、TEM、TG-SDTA等方法分析了纳米粒子的相组成、形貌和热稳定性.结果表明:Ni/MnO复合纳米粒子具有一致的"核/壳"微结构,尺寸分布在100-120 nm范围.核和壳分别为Ni和MnO相.根据定量氧辅助V-L-S机制,Ni纳米核在复合粒子生长过程中的催化作用,是"核/壳"结构形成的重要因素.

Shell/core-type MnO-coated Ni nanoparticles were prepared by arc discharge method using micron-sized Ni and MnO2 powders as the raw materials, under the evaporating atmosphere of hydrogen and argon. The morphology, phase structure and chemical composition of the as-prepared nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and thermal gravity analysis （TGA）, respectively. It is showed that most of nanoparticles were in spherical shapes in the range of 100-120 nm, with a shell of MnO phase and a core of Ni. The formation of nanoparticles was effectively explained by an extended mechanism of the Vapor-Liquid-Solid （VLS） with the existence of stoichiometric oxygen. The Ni core plays an essential catalyst in the formation of the core/shell structure.