氨基硼烷(NH3BH3, AB)作为一种高容量、低放氢温度的化学氢化物储氢材料,近年来被科研工作者进行了广泛的研究。本文以氨基硼烷为中心,通过模板法和电纺丝方法将氨基硼烷纳米化,来研究纳米作用对氨基硼烷放氢速率以及放氢纯度的影响。同时我们又通过化学改性的方法合成出了一系列的氨基硼烷衍生物,来研究有机官能团的引入对氨基硼烷分子间双氢键的影响,以及此类影响对其放氢性质及放氢机理的改善。主要结果如下：(1)通过用“氨液化”方法将氨基硼烷注入Pt/CNTs以后,我们发现纳米效应可以消除氨基硼烷分解放氢过程中的诱导期,同时可以降低放氢过程的活化能而大大提高放氢速率。并且Pt纳米颗粒对氨基硼烷分解过程也有一定的催化作用。用Pt/CNTs做模板对氨基硼烷进行改性,把纳米效应和催化效应结合了起来,这不仅克服了放氢速率低的问题,同时也制止了杂质气体的释放。(2)采用电纺丝的方法成功制备了聚乙烯基吡咯烷酮为载体的氨基硼烷纳米线,实现了氨基硼烷的纳米化,从而提高了氨基硼烷的分解速率并降低起始放氢温度。但是所制备的聚合物载体氨基硼烷纳米线虽然抑制了含硼杂质气体的释放,但是氨气的释放却相对加强了。最后我们通过添加MgCl2抑制了NH3的释放,使得氨基硼烷纳米线成为纯氢释放体系。(3)为了能够深入理解聚合物与氨基硼烷之间相互作用的现象并解释造成这种现象的原因,我们选择了一种新的聚合物聚丙烯酰胺(PAM),然后用PAM与AB共混。共混后的样品通过XRD、红外和固体11B核磁共振的方法进行了研究,我们发现由于这一系列的聚合物中都含有C=O双键,其中的O原子可以和AB中的B原子发生相互作用,导致新的反应机理的产生,也就是在分解过程中随着温度的升高B-N键断裂释放NH3,同时形成新的-OB键。同时我们通过实验发现,在体系内部添加金属氯化物可以制止NH3释放的原因是金属离子加强了B-N键,同时金属氯化物可以和NH3配位。(4)通过化学改性的方法合成出了两种新的氨基硼烷衍生物(硼氢化对/间苯二胺),并研究了这些新物质的放氢情况。这两种物质相对于硼氢化铵在常温时更稳定,起始放氢温度在50℃左右。放氢过程中,氢气纯度较高,只释放少量B2H6杂质。此外,通过化学改性的方法合成了一系列含有多个AB单元的C-N-B化合物(DETAB、TETAB和TEPAB),此类化合物相对于纯AB有更低的起始放氢温度和更快的放氢速率。在此三个物质内部进行比较发现,随着烷基取代数目的增加,它们的放氢活化能逐渐降低,造成这种现象的原因可能是烷基取代数的增加进一步破坏了氨基硼烷中的双氢键作用。这些体系都是纯氢释放体系,在放氢过程中除了主要的正负氢结合放氢以外,还存在少量的负负氢结合放氢现象。
Recently, ammonia-borane (NH3BH3, AB) as a typical chemical hydride system has received great attention as a promising hydrogen storage candidate, because of its large hydrogen content of19.6wt.%and relatively low hydrogen desorption temperature. In this thesis, the influence of nanocofinement on the dehydrogenation properties of ammonia-borane was investigated through incorporation of it into nano-scale templates and electrospinning techniques. Furthermore, a series of derivatives of ammonia-borane were synthesized by modifying its structure. The main results are as below:(1) The ammonia-borane (AB, NH3BH3) modified with platinum nanoparticle functionalized carbon nanotubes (CNTs)(Pt@CNTs) was prepared through a new $$ammonia-deliquescence$$ method. It has been demonstrated that the synergetic catalysis of CNTs and platinum nanoparticles, and the nanoconfinement of AB are two crucial factors in enhancing the dehydrogenation of AB. Both CNTs and platinum nanoparticles showed favorable catalytic activities towards the thermolysis of AB, which not only depressed the emission of the poisonous by-product borazine, but also prevented severe material foaming and expansion during the decomposition. Furthermore, the nanoconfinement of AB through the $$ammonia-deliquescence$$ method also led to enhanced dehydrogenation kinetics.(2) According to the results of the nanoconfinement of AB above, we tried to prepare PVP/AB nanofibers through electrospinning techniques, because this kind of method could decrease the size of AB particles to nano-scale. The AB nanofibers prepared shows significant improvements in dehydrogenation kinetics and complete suppression of boracic byproducts. However, the evolution of ammonia can not be suppressed, and which is shifted to low temperature. To depress the evolution of ammonia, MgCl2was doped in the PVP/AB nanofibers system and pure hydrogen release was relized successfully.(3) In order to further understand the mechanism of AB upon thermal decomposition in the presence of polymers, we chose another polymer (polyacrylamide, PAM) to blend with AB. The prepared samples (AB@PAM) showed similar dehydrogenation properties as the PVP/AB nanofibers.It was demonstrated that the enhanced kinetics may owe to the refinement of crystal particles and disruption of the dihydrogen bonding network of AB after blending, while the entire suppress of boracic impurities and the evolution of ammonia may be due to the interaction between O in the carbonyl groups (C=O) of PAM and B in the AB molecules, which weakens the B-N bonds to release NH3and subsequently forms B-O bonds to inhibit the emission of boracic impurities. Finally, metal chlorides (CaCl2, MgCl2and ZnCl2were introduced to the AB@PAM, which leads to a significant depress of NH3evolution, thereby enabling the dehydrogenation of the polymeric composite to occur at low temperature with enhanced hydrogen purity.(4) Finally, we synthesized two novel N, N’-phenyl substituted derivatives of [NH4]+[BH4]-(m/p-BABB) and three linear C-N-B materials (DETAB, TETAB and TEPAB). The m/p-BABB exhibited high stability compared to pure [NH4]+[BH4]-, and they start to release H2at about50℃with the evolution of a small amount of B2H6during their decmposition. Furthermore, the three linear C-N-B materials also exhibited favorable dehydr with the onset H2-release temperature of about60℃, and release of pure H2without any impurities upon their decomposition. The introduction of organic groups is expected to disrupt the dihydrogen bonding network and lower their activation energy for hydrogen release compared to the NH3BH3.
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第一章物质的结构
1-20 氦首先发现于日冕。1868年后30年间，太阳是研究氦的物理，化学性质的唯一源泉。
（a）观察到太阳可见光谱中有波长为4338A，4540A，4858A，5410A，6558A
的吸收（1A 10-10m来分析，这些吸收是由哪一种类氢原子激发造成的？是 He，He +还是He2+
（b）以上跃迁都是由ni 4向较高能级（nf）的跃迁。试确定 nf 值，求里德堡常数RHei+。
（c）求上述跃迁所涉及的粒子的电离能I（Hej+），用电子伏特为单位。
（d）已知 I（He+）/
I（He） 2.180。这两个电离能的和是表观能A（He2+），即从He
得到He2+的能量。A（He2+）是最小的能量子。试计算能够引起He 电离成He2+ 所需要的最
低能量子。在太阳光中，在地球上，有没有这种能量子的有效源泉？
（c 2.8 ms-1;h 6.626×10-34Js;1eV 96.486KJ.mol-1 2.Hz） 38、第8周期的最后一个元素的原子序数为：148。 电子组态：8S26P6
39、二维化的周期表可叫宝塔式或滴水钟式周期表。这种周期表的优点是能够十分清楚地看到元素周期系是如何由于核外电子能级的增多而螺旋发展的，缺点是每个横列不是一个周期，纵列元素的相互关系不容易看清。
40、“类铝”熔点在1110K～1941K之间，沸点在K之间，密度在1.55g/m3 ～4.50 g/m3之间。
41、最高氧化态+3，最低氧化态-5。
1、解：O O
14（e-）； C O
10e- ；0 C O 16e- ；
Cl-N-Cl 26e- ；FCS - F
2、解：共13种，如：
28、解：邻羟基苯甲酸分子内形成氢键，间羟基苯甲酸和对羟基苯甲酸分子间形成氢键。
的分子量。为什么？乙醛会不会也有这种现象？
29、解：部分气态乙酸分子因氢键而缔合成（CH3COOH）2，乙醛分子没有形成氢键的条件。
30、手性：CHCl CHClpC6H6
极性：H2O2 （非平面结构）
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