金属硼氨储氢化合物及其与硝基高能化合物相互作用机理研究
发布时间：2018-08-18 09:35
【摘要】：世界各国当前都在面临极其严峻的环境问题,尤其是我国近几年突显的城市雾霾问题,更是需要新型的清洁能源来替换传统的化石燃料以实现节能减排。氢能作为一种清洁能源一直引起广泛的关注,然而其安全储存一直是人类面临的难题。近年来,基于金属硼氨储氢化合物的固态储氢材料具有广阔的潜在应用价值,已日益成为新能源领域的研究热点之一。本论文以金属氨硼烷为主要目标化合物,以理论计算为主要研究手段,结合已有的实验数据,系统研究了一元金属氨硼烷、二元金属氨硼烷、以及金属氨硼烷衍生物——金属硼氨络合物的电子结构、热分解机理、热力学和动力学性质,为寻求新型储氢材料提供基础数据和理论依据。同时,积极探索该类化合物在含能材料领域的应用。主要在以下方面开展了相关研究:1)金属氨硼烷的电子结构和释氢机理由于单金属氨硼烷(MNH2BH3,MAB)具有良好的储氢性质,因此有望成为未来理想储氢材料的重要候选物。首先,通过Monte-Carlo方法预测了未获得单晶结构的MAB化合物的周期性结构。其次,通过第一性原理详细探究了轻金属Li、Na、K、Mg、Al和Ca为取代金属的金属氨硼烷固态体系的电子结构,设计并计算了其分解过程中相关释氢和释氨过程以及反应热力学函数变化。最后,通过气相分子动力学和传统过渡态理论研究了其释氢键的形成机理(N-Hδ+···-δH-B)、反应势能面和释氢速率常数。由于二元金属氨硼烷化合物(MM'AB)中多金属离子间的相互作用,使得其比相应的一元金属化合物有更好的储氢性能和释氢表现。首先在试验合成SMAB的基础上,结合Monte-Carlo方法预测了SMAB的周期性结构并对其进行了优化。计算了4种MM'AB的相关结构与电子能态、声子谱及热力学性质。其次,详细的讨论了分子中两种H原子的解离过程,设计并研究了分解反应中涉及的释氢和释氨过程及其反应焓、反应Gibbs自由能。第三,通过使用NVT系综,结合BOMD动力学方法计算了300 K下4种化合物中两种不同氢原子的扩散均方根速率。最后,对Na2Mg(NH2BH3)4和Na[Li(NH2BH3)2]的单分子结构,设计了不同的释氢反应路径,研究得到了反应最小势能面以及温度-速率方程。2)金属硼氨络合物的电子结构和释氢机理金属硼氨络合物(缩写为AMB)相对于MAB具备更高的储氢含量,且通过NH3上的Hδ+与[BH4]δ+中的Hδ-之间形成释氢键释氢时,反应能垒更低。通过研究Li2Al(BH4)5(NH3)6(AALB)、LiMg(BH4)3(NH3)2(AMLB)和LiCa(BH4)3(NH3)2(ACLB)共3种含LiBH4结构的金属硼氨络合物的结构、初始释氢机理和反应热力学性质,并与[Li(BH4)(NH3)]2(ALLB)相关性质进行了对比。AMB由于中心金属离子的不同,会表现出完全相反的分解机理和释氢性能。通过采用Car-Parrinello分子动力学方法对两种结构类似、分解过程截然不同的两种金属硼氨络合物Mg(BH4)2(NH3)2和Li BH4NH3的分解机理的研究,发现了不同类型的金属硼氨络合物的分解过程以及其所分解所涉及的过渡态与中间体。3)硼氨化合物对含能材料的催化性能探索研究了典型的硼氨类储氢化合物对硝基高能化合物的热分解过程的影响。选取了AB和LAB两种储氢材料分别与CL20、RDX和PETN共3种不同类型的硝基高能化合物,通过不同比例混合,得到一系列LAB/AB和CL20/RDX/PETN来探讨硼氨类储氢化合物对传统硝胺或硝酸酯类猛炸药热分解过程中的催化性能。并通过对不同混合体系建立模型,使用传统分子动力学方法计算了不同组分之间的相互作用能以及相容性,通过静态力学方法分析其相应的力学性能,从理论上探讨了复杂体系的组分、结构和性能的关系。
[Abstract]:All countries in the world are now facing extremely serious environmental problems, especially the Urban Haze in recent years in China. It is necessary to replace traditional fossil fuels with new clean energy to achieve energy saving and emission reduction. In recent years, solid-state hydrogen storage materials based on metal boron-ammonia hydrogen storage compounds have broad potential application value and become one of the hot spots in the field of new energy. In this paper, metal ammonia-borane as the main target compound, theoretical calculation as the main research means, combined with existing experimental data, a systematic study of gold monomer was carried out. The electronic structure, thermal decomposition mechanism, thermodynamic and kinetic properties of metal boron ammonia complexes, which belong to ammonia borane, binary metal ammonia borane and derivatives of metal ammonia borane, provide basic data and theoretical basis for seeking new hydrogen storage materials. At the same time, actively explore the application of these compounds in energetic materials. Relevant studies have been carried out: 1) The electronic structure and hydrogen release mechanism of metal aminoborane (MNH2BH3, MAB) are expected to be an important candidate for future ideal hydrogen storage materials because of its good hydrogen storage properties. First, the periodic structure of MAB compounds without single crystal structure is predicted by Monte-Carlo method. The electronic structure of light metals Li, Na, K, Mg, Al and Ca as substituted metals in solid-state ammonia-borane system was investigated in detail by first-principles. The processes of hydrogen release and ammonia release and the changes of thermodynamic functions during the decomposition were designed and calculated. Finally, the hydrogen release bonds were studied by gas-phase molecular dynamics and traditional transition state theory. The formation mechanism (N-Hdelta+... - Delta H-B), the reaction potential energy surface and the rate constant of hydrogen release are discussed. Due to the interaction between the polymetallic ions in the binary metal ammonia borane compound (MM'AB), it has better hydrogen storage and hydrogen release performance than the corresponding monometallic compound. The periodic structure of SMAB was measured and optimized. The electronic energy states, phonon spectra and thermodynamic properties of four MM'AB were calculated. Secondly, the dissociation process of two H atoms in the molecule was discussed in detail. The hydrogen and ammonia release processes involved in the decomposition reaction and their reaction enthalpies, Gibbs free energy were designed and studied. By using NVT ensemble and BOMD kinetic method, the diffusion RMS rates of two different hydrogen atoms in four compounds at 300 K were calculated. Finally, different hydrogen release pathways were designed for the single molecular structures of Na2Mg (NH2BH3) 4 and Na [Li (NH2BH3) 2). The minimum potential energy surface and the TEMPERATURE-RATE equation were obtained. The electronic structure and hydrogen release mechanism of ammonia complex metal boron ammonia complex (abbreviated as AMB) has higher hydrogen storage content than MAB, and the reaction barrier is lower when the hydrogen release bond is formed between Hdelta + on NH3 and Hdelta - in [BH4] delta + to release hydrogen. Through the study of Li2Al (BH4) 5 (NH3) 6 (AALB), LiMg (BH4) 3 (NH3) 2 (AMLB) and LiCa (BH4) 3 (NH3) 2 (ACLB) 3 co-3. The structure, initial hydrogen release mechanism and reaction thermodynamic properties of a metal boron-ammonia complex containing LiBH4 structure were compared with those of [Li(BH4)(NH3)]2(ALLB). AMB exhibited completely opposite decomposition mechanism and hydrogen release performance due to the difference of central metal ions. Car-Parrinello molecular dynamics method was used to study the two kinds of metal boron-ammonia complexes. The decomposition mechanism of two metal boron-ammonia complexes Mg(BH4)2(NH3)2 and Li BH4 NH3 with similar structure and different decomposition process was studied. The decomposition process of different metal boron-ammonia complexes and the transition state and intermediate involved in their decomposition were found. 3) The catalytic performance of boron-ammonia compounds on energetic materials was studied. The effects of boron-ammonia hydrogen storage compounds on the thermal decomposition process of nitro-high-energy compounds were studied. Three different types of nitro-high-energy compounds, namely, AB and LAB hydrogen storage materials and CL20, RDX and PETN, were selected and mixed in different proportions. A series of LAB/AB and CL20/RDX/PETN were obtained to investigate the effects of boron-ammonia hydrogen storage compounds on traditional nitramine or nitrate. Catalytic performance of ester explosives during thermal decomposition was studied. The interaction energy and compatibility of different components were calculated by traditional molecular dynamics method. The corresponding mechanical properties were analyzed by static mechanics method. Components, structures and properties of complex systems were discussed theoretically. Energy relations.
【学位授予单位】：北京理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：O641.3
本文编号：2189071
[Abstract]:All countries in the world are now facing extremely serious environmental problems, especially the Urban Haze in recent years in China. It is necessary to replace traditional fossil fuels with new clean energy to achieve energy saving and emission reduction. In recent years, solid-state hydrogen storage materials based on metal boron-ammonia hydrogen storage compounds have broad potential application value and become one of the hot spots in the field of new energy. In this paper, metal ammonia-borane as the main target compound, theoretical calculation as the main research means, combined with existing experimental data, a systematic study of gold monomer was carried out. The electronic structure, thermal decomposition mechanism, thermodynamic and kinetic properties of metal boron ammonia complexes, which belong to ammonia borane, binary metal ammonia borane and derivatives of metal ammonia borane, provide basic data and theoretical basis for seeking new hydrogen storage materials. At the same time, actively explore the application of these compounds in energetic materials. Relevant studies have been carried out: 1) The electronic structure and hydrogen release mechanism of metal aminoborane (MNH2BH3, MAB) are expected to be an important candidate for future ideal hydrogen storage materials because of its good hydrogen storage properties. First, the periodic structure of MAB compounds without single crystal structure is predicted by Monte-Carlo method. The electronic structure of light metals Li, Na, K, Mg, Al and Ca as substituted metals in solid-state ammonia-borane system was investigated in detail by first-principles. The processes of hydrogen release and ammonia release and the changes of thermodynamic functions during the decomposition were designed and calculated. Finally, the hydrogen release bonds were studied by gas-phase molecular dynamics and traditional transition state theory. The formation mechanism (N-Hdelta+... - Delta H-B), the reaction potential energy surface and the rate constant of hydrogen release are discussed. Due to the interaction between the polymetallic ions in the binary metal ammonia borane compound (MM'AB), it has better hydrogen storage and hydrogen release performance than the corresponding monometallic compound. The periodic structure of SMAB was measured and optimized. The electronic energy states, phonon spectra and thermodynamic properties of four MM'AB were calculated. Secondly, the dissociation process of two H atoms in the molecule was discussed in detail. The hydrogen and ammonia release processes involved in the decomposition reaction and their reaction enthalpies, Gibbs free energy were designed and studied. By using NVT ensemble and BOMD kinetic method, the diffusion RMS rates of two different hydrogen atoms in four compounds at 300 K were calculated. Finally, different hydrogen release pathways were designed for the single molecular structures of Na2Mg (NH2BH3) 4 and Na [Li (NH2BH3) 2). The minimum potential energy surface and the TEMPERATURE-RATE equation were obtained. The electronic structure and hydrogen release mechanism of ammonia complex metal boron ammonia complex (abbreviated as AMB) has higher hydrogen storage content than MAB, and the reaction barrier is lower when the hydrogen release bond is formed between Hdelta + on NH3 and Hdelta - in [BH4] delta + to release hydrogen. Through the study of Li2Al (BH4) 5 (NH3) 6 (AALB), LiMg (BH4) 3 (NH3) 2 (AMLB) and LiCa (BH4) 3 (NH3) 2 (ACLB) 3 co-3. The structure, initial hydrogen release mechanism and reaction thermodynamic properties of a metal boron-ammonia complex containing LiBH4 structure were compared with those of [Li(BH4)(NH3)]2(ALLB). AMB exhibited completely opposite decomposition mechanism and hydrogen release performance due to the difference of central metal ions. Car-Parrinello molecular dynamics method was used to study the two kinds of metal boron-ammonia complexes. The decomposition mechanism of two metal boron-ammonia complexes Mg(BH4)2(NH3)2 and Li BH4 NH3 with similar structure and different decomposition process was studied. The decomposition process of different metal boron-ammonia complexes and the transition state and intermediate involved in their decomposition were found. 3) The catalytic performance of boron-ammonia compounds on energetic materials was studied. The effects of boron-ammonia hydrogen storage compounds on the thermal decomposition process of nitro-high-energy compounds were studied. Three different types of nitro-high-energy compounds, namely, AB and LAB hydrogen storage materials and CL20, RDX and PETN, were selected and mixed in different proportions. A series of LAB/AB and CL20/RDX/PETN were obtained to investigate the effects of boron-ammonia hydrogen storage compounds on traditional nitramine or nitrate. Catalytic performance of ester explosives during thermal decomposition was studied. The interaction energy and compatibility of different components were calculated by traditional molecular dynamics method. The corresponding mechanical properties were analyzed by static mechanics method. Components, structures and properties of complex systems were discussed theoretically. Energy relations.
【学位授予单位】：北京理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：O641.3
【参考文献】
相关期刊论文 前1条
1 贡雪东,肖鹤鸣,高贫;季戊四醇四硝酸酯的分子结构和热解机理[J];有机化学;1997年06期
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