摘要
通过刻蚀Mo_(2)TiAlC_(2)合成二维Mo_(2)TiC_(2) MXene材料,并将其与MgH_(2)复合以调节MgH_(2)的储氢性能。Mo_(2)TiC_(2)的掺杂使MgH_(2)的初始放氢温度从330℃显著降低至187℃。等温放氢性能测试表明,MgH_(2)+9%Mo_(2)TiC_(2)(质量分数)复合材料在300℃时4min内可快速释放6.4%(质量分数)的氢气。对于吸氢反应,完全脱氢的MgH_(2)+9%Mo_(2)TiC_(2)在175℃时5 min内吸收了6.5%(质量分数)的氢气。经过计算,MgH_(2)+9%Mo_(2)TiC_(2)的放氢反应活化能为(135.6±1.9)kJ/mol,吸氢反应活化能为(46.1±0.2)kJ/mol。20次循环后,MgH_(2)+9%Mo_(2)TiC_(2)复合材料的储氢容量损失1.0%(质量分数)。显微组织分析表明,Mo_(2)TiC_(2)中的Mo使MXene的稳定性增强、循环过程中活性Ti的生成量减少,从而导致催化剂的催化效果不如Ti_(3)C_(2)。
Two-dimensional Mo_(2)TiC_(2) MXene material was synthesized by etching Mo_(2)TiAlC_(2) and then doped into MgH_(2) to tailor its hydrogen storage performance.The initial hydrogen desorption temperature of the Mo_(2)TiC_(2)-doped MgH_(2) was significantly reduced from 330℃(pristine MgH_(2))to 187℃.Isothermal dehydrogenation analysis indicated that the MgH_(2)+9 wt.%Mo_(2)TiC_(2) composite rapidly discharged 6.4 wt.%H_(2) at 300℃ within 4 min.For hydrogenation,the dehydrogenated MgH_(2)+9 wt.%Mo_(2)TiC_(2) uptook 6.5 wt.%H_(2) at 175℃ within 5 min.By calculation,the activation energy for MgH_(2)+9 wt.%Mo_(2)TiC_(2) was calculated to be(135.6±1.9)kJ/mol for the desorption reaction and(46.1±0.2)kJ/mol for the absorption reaction.After 20 cycles,1.0 wt.%H_(2) was lost for the MgH_(2)+9 wt.%Mo_(2)TiC_(2) composite.Microstructure analysis results showed that the presence of Mo in Mo_(2)TiC_(2) enhanced the thermal stability of MXene and reduced the amount of active Ti during cycling,leading to poorer catalytic effect of the catalyst compared to Ti_(3)C_(2).
作者
章浩宇
田贵宾
吴富英
姚振东
郑家广
张刘挺
Hao-yu ZHANG;Gui-bin TIAN;Fu-ying WU;Zhen-dong YAO;Jia-guang ZHENG;Liu-ting ZHANG(School of Energy and Power,Jiangsu University of Science and Technology,Zhenjiang 212003,China;School of Materials and Chemistry,China Jiliang University,Hangzhou 310018,China)
基金
support from the National Natural Science Foundation of China(No.51801078)
the Natural Science Foundation of Jiangsu Province,China(No.BK20210884).
作者简介
Corresponding author:Fu-ying WU,Tel:+86-18344819581,E-mail:wufuying@just.edu.cn;Corresponding author:Liu-ting ZHANG,Tel:+86-15262913186,E-mail:zhanglt89@just.edu.cn。
