镁-镍/石墨烯复合物的储氢性能  

Hydrogen Storage Properties of Mg-Ni/Graphene Composites

作　　者：宦清清[1] 朱云峰[1] 卫灵君[1] 李李泉[1] 

机构地区：[1]南京工业大学,江苏南京210009

出　　处：《稀有金属材料与工程》2014年第2期356-360,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51071085;51171079);江苏高校优势学科建设工程资助项目

摘　　要：分别通过物理法和化学法制备石墨烯载镍催化剂(Ni/Graphene),并采用球磨预处理或超声分散的方式与镁粉混匀,结合氢化燃烧合成和机械球磨复合技术制备镁-镍/石墨烯(Mg-Ni/Graphene)复合物储氢材料。采用X射线衍射仪、扫描电镜及气体反应控制器研究了材料的相组成、微观形貌和吸放氢性能。比较发现,添加化学法制备的Ni/Graphene并采用球磨预处理的Mg-Ni/Graphene复合物具有最佳的吸放氢性能,复合物的起始放氢温度降低,放氢速率加快。其在373 K温度下,100 s内就基本能达到饱和吸氢量6.21%(质量分数);553 K,1800 s内完全放氢,且放氢量达到6.05%。球磨预处理使得Ni/Graphene更均匀的与Mg接触,利于发挥Ni的催化作用和石墨烯优异的导电导热性。化学法制备的Ni/Graphene原位还原出纳米晶Ni,有利于形成纳米级Mg2NiH4晶粒,促进复合物储氢性能的改善。Graphene supported nickel catalysts （Ni/Graphene） were synthesized by physical method and chemical method, respectively. The as prepared Ni/Graphene was further mixed with Mg by ball milling pretreatment or ultrasonic dispersion. Then the well mixed powders were used to prepare Mg-Ni/Graphene composites by the combined process of hydriding combustion synthesis and mechanical milling （HCS＋MM）. The phase compositions, surface morphologies and hydriding/dehydriding properties of the samples were examined by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and gas reaction controller （GRC）. Results show that the Mg-Ni/Graphene composite which mixed Ni/Graphene synthesized by chemical method and Mg through ball milling pretreatment exhibits the best hydriding/dehydriding properties. It has the lowest onset hydrogen desorption temperature and faster dehydrogenation rate. About 6.21% hydrogen can be absorbed within 100 s at 373 K, and 6.05 % hydrogen can be desorbed within 1800 s at 553 K. Ball milling pretreatment makes Ni/Grapheme and Mg contact homogeneous, thus the excellent thermal and electrical conductivity of Grapheme and the catalytic effect of Ni are enhanced. In addition, nano-crystalline Ni with smaller grain size synthesized by chemical method is helpful to the formation of nanosized Mg2NiH4 grains, leading to the improvement in hydrogen storage properties of the composite.

关 键 词：石墨烯载镍 镁基合金 氢化燃烧合成 机械球磨 储氢性能 

分 类 号：TB34[一般工业技术—材料科学与工程]