采用乙炔等离子体蒸发Mg的方法成功制备了40nm左右的超细Mg纳米颗粒.通过透射电子显微镜(TEM)、X射线衍射(XRD)、比表面积测试(BET)和吸放氢测试等方法对其微观结构和吸放氢循环性质进行了研究.超细Mg纳米颗粒具有比普通Mg颗粒更大的比表面积,氢扩散至颗粒内部所需距离更短,因而大大提高了其吸放氢动力学性质.Mg纳米颗粒表面的C既减少了Mg的氧化。又阻碍了吸放氢过程中Mg颗粒的长大.这种超细结构的Mg纳米颗粒具有良好的循环性质,30次循环后容量仍没有衰减.
Ultrafine Mg nanoparticles of around 40 nm in size were prepared by an acetylene plasma metal reaction, which is a revised approach of the traditional hydrogen plasma metal reaction. The morphology and the cyclic hydrogenation properties were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), specific surface area (BET) tests, and the kinetics of hydrogenation and dehydrogenation. Because of the short diffusion distance and the large specific surface area, the kinetics of hydrogenation and dehydrogenation of the small Mg nanoparticles improved. The nanostructured carbon cover on the Mg nanoparticles decreased the amount of Mg nanoparticle oxidation and also prevented the growth of Mg nanoparticles during the hydrogenation and dehydrogenation process. Therefore, the Mg ultrafine nanoparticles exhibited excellent cycling stability. Cycling tests showed little loss in hydrogen storage capacity after 30 cycles.