添加叔丁醇钾对Mg(NH_(2))_(2)‑2LiH体系储氢性能的影响  

Effect of Potassium tert‑Butoxide on Hydrogen Storage Properties of Mg(NH_(2))_(2)‑2LiH System

作　　者：冯文钦 李超[1,2] 刘凯元[1] 蔡明源 范美强 FENG Wen‑Qin;LI Chao;LIU Kai‑Yuan;CAI Ming‑Yuan;FAN Mei‑Qiang(School of Materials and Chemistry,China Jiliang University,Hangzhou 310018,China;State Key Laboratory of Silicon Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]中国计量大学材料与化学学院,杭州310018 [2]硅材料国家重点实验室,浙江大学材料科学与工程学院,杭州310027

出　　处：《无机化学学报》2021年第6期1097-1105,共9页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.51501175);浙江省杰出青年基金(No.LQ16E010001)资助。

摘　　要：叔丁醇钾(C_(4)H_(9)OK)的添加显著改善了Mg(NH_(2))_(2)‑2LiH体系的储氢性能。添加0.08 mol C_(4)H_(9)OK的Mg(NH_(2))_(2)‑2LiH‑0.08C_(4)H_(9)OK样品表现出最佳储氢性能。该样品的起始放氢温度仅为70℃,较Mg(NH_(2))_(2)‑2LiH原始样品降低了60℃;130℃完全放氢后,该样品可在50℃开始吸氢,较原始样品降低了50℃。Mg(NH_(2))_(2)‑2LiH‑0.08C_(4)H_(9)OK样品可在150℃的等温条件下50 min内迅速放出质量分数3.82%的氢气,完全放氢后可在120℃的等温条件下50 min内快速吸收质量分数4.11%的氢气,表现出良好的吸放氢动力学性能。C_(4)H_(9)OK的添加降低了样品放氢反应的表观活化能和反应焓变,改善了放氢反应的动力学和热力学性能,从而降低了放氢反应温度。进一步的放氢反应机理研究发现,在180℃之前,C_(4)H_(9)OK对Mg(NH_(2))_(2)‑2LiH体系的放氢起催化改性作用;温度继续升高后,C_(4)H_(9)OK将会分解并参与放氢反应最终生成Li_(3)K(NH_(2))_(4)。The hydrogen storage properties of Mg(NH_(2))_(2)‑2LiH system were significantly enhanced by adding a small amount of potassium tert‑butoxide(C_(4)H_(9)OK).The 0.08 mol C_(4)H_(9)OK‑added sample(Mg(NH_(2))_(2)‑2LiH‑0.08C_(4)H_(9)OK)showed optimum hydrogen storage performances.The on‑set dehydrogenation temperature of Mg(NH_(2))_(2)‑2LiH‑0.08C_(4)H_(9)OK sample was only 70℃,which was 60℃lower than that of pristine Mg(NH_(2))_(2)‑2LiH sample.After fully dehydrogenated at 130℃,the Mg(NH_(2))_(2)‑2LiH‑0.08C_(4)H_(9)OK sample begined to absorb hydrogen at 50℃,which was 50℃lower than the pristine sample.At 150℃,mass ratio of 3.82%of hydrogen can be rapidly released from the Mg(NH_(2))_(2)‑2LiH‑0.08C_(4)H_(9)OK sample within 50 min.The fully dehydrogenated Mg(NH_(2))_(2)‑2LiH‑0.08C_(4)H_(9)OK sample could absorb mass ratio of 4.11%hydrogen at 120℃within 50 min.Adding C_(4)H_(9)OK decreases the dehydrogenation activation energy and reaction enthalpy of the Mg(NH_(2))_(2)‑2LiH system,and enhances the hydrogen desorption kinetic and thermodynamic properties.Mechanistic investigations indicate that C_(4)H_(9)OK acts catalytically to enhance the dehydrogenation properties before 180℃,then it participates in the reaction to generate Li_(3)K(NH_(2))_(4)by further increasing the operating temperature.

关 键 词：储氢材料 氨基物 叔丁醇钾 动力学 催化改性 反应机理 

分 类 号：TK91[动力工程及工程热物理]