摘要
在氢气气氛下用反应球磨法制备了镁碳复合储氢材料70Mg30C,用透射电子显微镜（TEM）和选区电子衍射（SAED）观测了材料的微观形貌和晶态特征,用X射线衍射仪（XRD）分析了其物相组成,并通过材料放氢的p-c-T曲线得到的放氢平台压强以及Van’t Hoff方程计算了材料放氢的焓变和熵变。结果表明：材料的主相是MgH2,并混有少量的Fe和MgO;在一定范围内,延长球磨时间可使材料的粒径进一步减小,并可增加非晶纳米晶在材料中的含量,而且可降低材料的放氢平台压强和材料放氢时的焓变,从而降低材料的相结构稳定性,增强体系的解氢能力,最终改善材料的放氢性能;在300~380℃范围内,lnpH2与1/T基本呈线性关系,同时材料具有较长的放氢平台和较高的放氢量。
Mg/C composites 70Mg30 Cfor hydrogen storage were prepared by reactive ball milling method under hydrogen atmosphere.The microstructure and crystalline characteristics of materials were investigated by transmission electron microscopy（TEM）and selected area electron diffraction（SAED）,the phase composition of materials were analyzed by X ray diffracmeter（XRD）.The enthalpy change and entropy change during the dehydrogenation process were calculated by Van＇t Hoff equation and dehydrogenation equilibrium pressure acquired from dehydrogenation p-c-T curves.The experimental results show that MgH2 is the main phase,and small amount of Fe and MgO were also found in the materials.The particle size of materials was became smaller by more ball milling time in a certain range,and the content of amorphousnanocrystalline in the materials was increased.The dehydrogenation equilibrium pressure and enthalpy change of materials were also decreased,thus the phase structural stability of materials was reduced and the dehydrogenation ability of system was improved.As a result,dehydrogenation performance of materials was improved.The experimental results also showed that the relationship between lnpH2 and 1/T was approximate linear,and the materials had a longer dehydrogenation platform and a higher dehydrogenation amount between 300℃and 380℃.
出处
《化工新型材料》
CAS
CSCD
北大核心
2015年第11期151-153,共3页
New Chemical Materials
基金
贵州省科学技术基金项目(黔科合J字20122008号)
贵州工程应用技术学院科学研究基金项目(院科合字20112005号
G2012006号)
贵州省省级教学团队项目(物理化学系列课程)
关键词
储氢材料
热力学
放氢反应
P-C-T曲线
hydrogen storage material
thermodynamics
dehydrogenation
p-c-Tcurve
