高等学校化学学报 ›› 2012, Vol. 33 ›› Issue (03): 536.doi: 10.3969/j.issn.0251-0790.2012.03.020

• 物理化学 • 上一篇    下一篇

Mg2 FeH6 纳米晶的制备及储氢性能

马建丽, 王艳, 陶占良, 陈军   

  1. 南开大学先进能源材料化学教育部重点实验室, 天津 300071
  • 收稿日期:2011-09-05 出版日期:2012-03-10 发布日期:2012-03-10
  • 通讯作者: 陶占良, 男, 博士, 副教授, 主要从事储氢及能源化学研究. E-mail:taozhl@nankai.edu.cn
  • 基金资助:

    国家"九七三"计划项目(批准号: 2010CB631301)、 国家"八六三"计划项目(批准号: 2009AA03Z224)、 国家自然科学基金(批准号: 21076108)、 天津科技计划(批准号: 10JCYBJC08400, 10SYSYJC27600)和中央高校基本科研业务费专项资助.

Preparation and Hydrogen Storage Properties of Mg2FeH6 Nanocrystals

MA Jian-Li, WANG Yan, TAO Zhan-Liang, CHEN Jun   

  1. Key Laboratory of Advanced Energy Materials Chemistry, Ministry of Education, Nankai University, Tianjin 300071, China
  • Received:2011-09-05 Online:2012-03-10 Published:2012-03-10

摘要:

在室温和氩气气氛下, 以MgH2 和纳米Fe为原料, 采用机械合金化(球磨法)制备了Mg2FeH6纳米晶. 考察了球磨参数(时间、 转速)对产物的影响, 对所制备的Mg2FeH6 纳米晶的组成、 结构和形貌进行了表征, 并对其储氢性能进行了测试. 结果表明, 所制备的Mg2FeH6纳米晶为立方结构, 纯度较高(91.4%), 其晶粒尺寸较小, 约为10~30 nm, 但团聚现象较为严重. Mg2FeH6纳米晶具有较低的活化能和较好的吸放氢动力学性能, 其放氢的脱附焓和脱附熵分别为(-42.8±2) kJ/mol和(-72.0±3) J/(mol·K). 在503 K和6 kPa的氢气压力下, Mg2FeH6纳米晶在70 min内放氢量达到2.5%(质量分数); 在2 MPa的氢气压力下, 上述放氢产物具有较快的起始吸氢速率.

关键词: Mg2FeH6纳米晶, 机械合金化, 储氢性能

Abstract:

The preparation of Mg2FeH6 nanocrystals and their hydrogen storage properties were reported. Mg2FeH6 nanocrystals were prepared by mechanical ball-milling the mixture of MgH2 and Fe nanoparticles at room temperature under an argon atmosphere. The processing parameters(time, milling speed), crystal structure, morphologies, and hydrogen storage properties of the as-prepared Mg2FeH6 nanocrystals were investigated. The results show that the cubic Mg2FeH6 nanocrystals have a yield ratio around 91.4%, and a grain size between 10—30 nm in the powder. However, the agglomeration of particles are more serious. Mg2FeH6 nanocrystals show fast absorption/desorption kinetics. The desorption enthalpy and entropy for Mg2FeH6 are (-42.8±2) kJ/mol and (-72.0±3) J/(mol·K), respectively. At 503 K, the as-prepared Mg2FeH6 nanocrystals can release about 2.5%(mass fraction) hydrogen in 70 min under an initial hydrogen pressure of 6 kPa. Under 2 MPa hydrogen pressure, the rehydrogenation rate for the Mg2FeH6 decomposed product is fastZ)

Key words: Mg2FeH6 nanocrystal, Mechanical ball-milling, Hydrogen storage property

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